The New Economies of the Redwood Region in the 21st Century

Science.gov (United States)

William Stewart

2007-01-01

The redwood region of California has experienced a number of major land use changes over the past one hundred and fifty years. A review of recent economic trends in the redwood region suggests the emergence of three new themes. First, it appears that the transition from an old growth to a young growth redwood industry is essentially complete. Lower revenues and...

Using wood quality measures to evaluate second-growth redwood

Science.gov (United States)

Stephen L. Quarles; Yana. Vlachovic

2012-01-01

Redwood (Sequoia sempervirens) a valued species for use in appearance grade applications, such as decking, exterior siding and interior paneling, because of its dimensional stability. It is also valued for certain exterior-use applications because of its natural decay resistance. Studies have found that young-growth redwood is less resistant to...

Response of old-growth conifers to reduction in stand density in western Oregon forests

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Latham, P.; Tappeiner, J. C.

2002-01-01

The positive growth response of healthy young trees to density reduction is well known. In contrast, large old trees are usually thought to be intrinsically limited in their ability to respond to increased growing space; therefore, density reduction is seldom used in stands of old-growth trees. We tested the null hypothesis that old-growth trees are incapable of responding with increased growth following density reduction. The diameter growth response of 271 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws) and sugar pine (Pinus lambertiana Dougl.) trees ranging in age from 158 to 650 years was examined 20 to 50 years after density reduction. Density reduction involved either light thinning with removal of less vigorous trees, or shelterwood treatments in which overstory trees were not removed. Ratios of basal area growth after treatment to basal area growth before treatment, and several other measures of growth, all indicated that the old trees sometimes benefited and were not harmed by density reduction. Growth increased by 10% or more for 68% of the trees in treated stands, and nearly 30% of trees increased growth by over 50%. This growth response persisted for at least 20 years. During this 20-year period, only three trees in treated stands (1.5%) exhibited a rapid decrease in growth, whereas growth decreased in 64% of trees in untreated stands. The length of time before a growth response to density reduction occurred varied from 5 to 25 years, with the greatest growth response often occurring 20 to 25 years after treatment. These results have important implications both for the basic biology of aging in woody plants as well as for silvicultural practices in forests with old-growth trees.

Ecological restoration of an old-growth longleaf pine stand utilizing prescribed fire

Science.gov (United States)

J. Morgan Varner; John S. Kush; Ralph S. Meldahl

2000-01-01

Ecological restoration using prescribed fire has been underway for 3 years in an uncut, old-growth longleaf pine (Pinus palustris) stand located in south Alabama. The longleaf pine ecosystem requires frequent (once every 1-10 years) surface fire to prevent succesion to later several stages. Before this study began, this stand had not burned in >...

Management practices eelated to the Restoration of old dorest characteristics in coast redwood forests

Science.gov (United States)

Gregory A. Guisti

2012-01-01

A standardized, interactive, interview process was used with practicing Registered Professional Foresters asking a suite of questions to ascertain their management approaches to coast redwood (Sequoia sempervirens [D. Don] Endl.) stands that could best be transferred to other projects and lands interested in recruiting older forest...

Rangewide Genetic Variation in Coast Redwood Populations at a Chloroplast Microsatellite Locus

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Chris Brinegar

2012-01-01

Old growth and second growth populations of coast redwood (Sequoia sempervirens) were sampled at 10 locations throughout its range and analyzed at a highly variable chloroplast microsatellite locus. Very low FST values indicated that there was no significant genetic differentiation between adjacent old growth and second growth populations at each location. Genetic...

Implementation of a thinning and burning study in tanoak-redwood stands in Santa Cruz and Mendocino counties

Science.gov (United States)

Kevin L. O?Hara; Kristen M. Waring

2008-01-01

Three silvicultural treatment study sites are being established to examine the effects of thinning and prescribed burning on infection and spread of Phytophthora ramorum. Study sites are located in Mendocino and Santa Cruz counties, California. Stands are even-aged redwood/tanoak mixtures.

Abundance of Armillaria within old-growth eastern hemlock stands in South-Central Pennsylvania

Science.gov (United States)

Matthew S. Fromm; Donald D. Davis

2007-01-01

Abstract—In early summer 2002, 329 soil-sampling pits were dug within an old-growth, eastern hemlock (Tsuga canadensis [L.] Carrière) stand in south-central Pennsylvania recently infested with the hemlock woolly adelgid (Adelges tsugae Annand). For comparison, 199 similar pits were dug in an adjacent hardwood stand. Rhizomorphs of...

Structural attributes of two old-growth Cross Timbers stands in western Arkansas

Science.gov (United States)

Don C. Bragg; David W. Stahle; K. Chris Cerny

2012-01-01

Comprised of largely non-commercial, xeric, oak-dominated forests, the Cross Timbers in Arkansas have been heavily altered over the last two centuries, and thus only scattered parcels of old-growth timber remain. We inventoried and mapped two such stands on Fort Chaffee Military Training Center in Sebastian County, Arkansas. The west-facing Christmas Knob site is...

CARBON ISOTOPE DISCRIMINATION AND GROWTH RESPONSE OF OLD PINUS PONDEROSA TREES TO STAND DENSITY REDUCTIONS

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Stand density reductions have been proposed as a method by which old-growth ponderosa pine (Pinus ponderosa) forests of North America can be converted back to pre-1900 conditions, thereby reducing the danger of catastrophic forest fires and insect attacks while increasing product...

Abiotic and Biotic Soil Characteristics in Old Growth Forests and Thinned or Unthinned Mature Stands in Three Regions of Oregon

Directory of Open Access Journals (Sweden)

David A. Perry

2012-09-01

Full Text Available We compared forest floor depth, soil organic matter, soil moisture, anaerobic mineralizable nitrogen (a measure of microbial biomass, denitrification potential, and soil/litter arthropod communities among old growth, unthinned mature stands, and thinned mature stands at nine sites (each with all three stand types distributed among three regions of Oregon. Mineral soil measurements were restricted to the top 10 cm. Data were analyzed with both multivariate and univariate analyses of variance. Multivariate analyses were conducted with and without soil mesofauna or forest floor mesofauna, as data for those taxa were not collected on some sites. In multivariate analysis with soil mesofauna, the model giving the strongest separation among stand types (P = 0.019 included abundance and richness of soil mesofauna and anaerobic mineralizable nitrogen. The best model with forest floor mesofauna (P = 0.010 included anaerobic mineralizable nitrogen, soil moisture content, and richness of forest floor mesofauna. Old growth had the highest mean values for all variables, and in both models differed significantly from mature stands, while the latter did not differ. Old growth also averaged higher percent soil organic matter, and analysis including that variable was significant but not as strong as without it. Results of the multivariate analyses were mostly supported by univariate analyses, but there were some differences. In univariate analysis, the difference in percent soil organic matter between old growth and thinned mature was due to a single site in which the old growth had exceptionally high soil organic matter; without that site, percent soil organic matter did not differ between old growth and thinned mature, and a multivariate model containing soil organic matter was not statistically significant. In univariate analyses soil mesofauna had to be compared nonparametrically (because of heavy left-tails and differed only in the Siskiyou Mountains, where

Physiology and growth of redwood and Douglas-fir planted after variable density retention outside redwood’s range

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Lucy Kerhoulas; Nicholas Kerhoulas; Wade Polda; John-Pascal Berrill

2017-01-01

Reforestation following timber harvests is an important topic throughout the coast redwood (Sequoia sempervirens (D. Don) Endl.) range. Furthermore, as drought-induced mortality spreads across many of California’s forests, it is important to understand how physiology and stand structure influence reforestation success. Finally, as climate...

Living and Dead Aboveground Biomass in Mediterranean Forests: Evidence of Old-Growth Traits in a Quercus pubescens Willd. s.l. Stand

Directory of Open Access Journals (Sweden)

Emilio Badalamenti

2017-05-01

Full Text Available For a long time, human impact has deeply simplified most of the forest ecosystems of the Mediterranean Basin. Here, forests have seldom had the chance to naturally develop a complex and multilayered structure, to host large and old trees and rich biological communities, approaching old-growth conditions. Also for this reason, limited information is currently available about Mediterranean old-growth forests, particularly with regard to deadwood. The main aim of this work is to help fill this critical knowledge gap. In Sicily (Italy, we identified a Quercus pubescens forest that seemed to show some typical old-growth features. Total living volume (360 m3 ha−1 and basal area (34 m2 ha−1 were, respectively, about 6 and 3 times higher than the averages recorded in the regional forest inventory for this forest type. Deadwood was particularly abundant, exceeding the threshold of 30 m3 ha−1, mainly represented by lying dead elements. Dead to live wood ratio reached 9%, a value close to the threshold of 10% considered for Mediterranean old-growth forests. As the investigated forest showed some typical old-growth traits, it deserves to be fully protected and could be a permanent monitoring area for studying deadwood and stand dynamics in mature Mediterranean stands.

An Old-Growth Definition for Dry and Dry-Mesic Oak-Pine Forests.

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David L. White; F. Thomas. Lloyd

1998-01-01

Dry and dry-mesic oak-pine forests are widely distributed from New Jersey to Texas, but representative old-growth stands are rare. Historical accounts of composition, along with information from existing old-growth stands, were used to characterize this type. Shortleaf pine and white oak were the most widely distributed trees across all old-growth stands. Shortleaf was...

An Old-Growth Definition for Southern Mixed Hardwood Forests

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William B. Batista; William J. Platt

1997-01-01

This report provides an old-growth definition for the southern mixed hardwood forests based on five exemplary stands that show no evidence of having undergone any natural catastrophe or clearcutting for at least 200 years. This forest type occurs in the U.S. southeastern Coastal Plain from the Carolinas to eastern Texas. The exemplary old-growth stands were restricted...

Soil carbon storage following road removal and timber harvesting in redwood forests

Science.gov (United States)

Seney, Joseph; Madej, Mary Ann

2015-01-01

Soil carbon storage plays a key role in the global carbon cycle and is important for sustaining forest productivity. Removal of unpaved forest roads has the potential for increasing carbon storage in soils on forested terrain as treated sites revegetate and soil properties improve on the previously compacted road surfaces. We compared soil organic carbon (SOC) content at several depths on treated roads to SOC in adjacent second-growth forests and old-growth redwood forests in California, determined whether SOC in the upper 50 cm of soil varies with the type of road treatment, and assessed the relative importance of site-scale and landscape-scale variables in predicting SOC accumulation in treated road prisms and second-growth redwood forests. Soils were sampled at 5, 20, and 50 cm depths on roads treated by two methods (decommissioning and full recontouring), and in adjacent second-growth and old-growth forests in north coastal California. Road treatments spanned a period of 32 years, and covered a range of geomorphic and vegetative conditions. SOC decreased with depth at all sites. Treated roads on convex sites exhibited higher SOC than on concave sites, and north aspect sites had higher SOC than south aspect sites. SOC at 5, 20, and 50 cm depths did not differ significantly between decommissioned roads (treated 18–32 years previous) and fully recontoured roads (treated 2–12 years previous). Nevertheless, stepwise multiple regression models project higher SOC developing on fully recontoured roads in the next few decades. The best predictors for SOC on treated roads and in second-growth forest incorporated aspect, vegetation type, soil depth, lithology, distance from the ocean, years since road treatment (for the road model) and years since harvest (for the forest model). The road model explained 48% of the variation in SOC in the upper 50 cm of mineral soils and the forest model, 54%

Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

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Silver, Emily J.; D'Amato, Anthony W.; Fraver, Shawn; Palik, Brian J.; Bradford, John B.

2013-01-01

The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several long-term datasets from old growth, extended rotation, and unmanaged second growth Pinus resinosa (red pine) forests in northern Minnesota, USA, to quantify the range of variation in structural conditions for this forest type and to evaluate the effectiveness of extended rotation forestry at promoting the development of late-successional structural conditions. Long-term tree population data from permanent plots for one of the old-growth stands and the extended rotation stands (87 and 61 years, respectively) also allowed for an examination of the long-term structural dynamics of these systems. Old-growth forests were more structurally complex than unmanaged second-growth and extended rotation red pine stands, due in large part to the significantly higher volumes of coarse woody debris (70.7 vs. 11.5 and 4.7 m3/ha, respectively) and higher snag basal area (6.9 vs. 2.9 and 0.5 m2/ha, respectively). In addition, old-growth forests, although red pine-dominated, contained a greater abundance of other species, including Pinus strobus, Abies balsamea, and Picea glauca relative to the other stand types examined. These differences between stand types largely reflect historic gap-scale disturbances within the old-growth systems and their corresponding structural and compositional legacies. Nonetheless, extended rotation thinning treatments, by accelerating advancement to larger tree diameter

Growth of 11 introduced tree species on selected forest sites in Hawaii

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Michael G Buck; Roger H. Imoto

1982-01-01

Growth and volume data for trees on 25 plots reprsenting 11 introduced species in Hawaii were recorded during a 21-year period. Tree were measured at about 5-year intervals to determine overall growth and stand development. The sites selected were considered better-than-average in terms of elevation, amount of precipitation, and soil quality. Except for redwood, stands...

Summary of watershed conditions in the vicinity of Redwood National Park, California

Science.gov (United States)

Janda, Richard J.

1977-01-01

The Redwood Creek Unit of Redwood National Park is located in the downstream end of an exceptionally rapidly eroding drainage basin. Spatial distribution and types of erosional landforms, observed in the field and on time-sequential aerial photographs, measured sediment loads, and the lithologic heterogeneity of streambed materials indicated (1) that sediment discharges reflect a complex suite of natural and man-induced mass movement and fluvial erosion processes operating on a geologically heterogeneous, naturally unstable terrain, and (2) that although infrequent exceptionally intense storms control the timing and general magnitude of major erosion events, the loci, types, and amounts of erosion occurring during those events are substantially influence by land use. Erosional impacts of past timber harvest in the Redwood Creek basin reflect primarily the cumulative impact of many small erosion problems caused not so much by removal. Recently modified riparian and aquatic environments reflect stream channel adjustments to recently increased water and sediment discharges, and are classified by the National Park Service as damaged resources because the modifications reflect, in part, unnatural causes. Newly strengthened State regulations and cooperative review procedures result in proposed timber harvest plans being tailored to specific site conditions, as well as smaller, more dispersed harvest units and more sophisticated attempts at minimizing ground-surface disruption than those used in most previous timber harvesting in this basin. However, application of improved timber harvest technology alone will not assure protection of park resources. Much remaining intact residual commercial old-growth timber is on hillslopes that are steeper, wetter, more susceptible to landsliding, and more nearly adjacent to major stream channels than most of the previously harvested hillslopes in the lower Redwood Creek basin. Moreover, natural debris barriers along streams flowing

Turbulence considerations for comparing ecosystem exchange over old-growth and clear-cut stands for limited fetch and complex canopy flow conditions

Science.gov (United States)

Sonia Wharton; Matt Schroeder; Kyaw Tha Paw U; Matthias Falk; Ken Bible

2009-01-01

Carbon dioxide (CO2), water vapor, and energy fluxes were measured using eddy covariance (EC) methodology over three adjacent evergreen forests in southern Washington State to identify stand-level age-effects on ecosystem exchange. The sites represent Douglas-fir forest ecosystems at two contrasting successional stages: old-growth (OG) and early...

Characterizing large strain crush response of redwood

International Nuclear Information System (INIS)

Cramer, S.M.; Hermanson, J.C.

1996-12-01

Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most rudimentary information exists on its crush properties. The objectives of the study were to fill the information gap by collecting triaxial load-deformation data for redwood; to use these data to characterize redwood crush, assess current wood failure theories, provide developments toward a complete stress-strain theory for redwood; and to review the literature on strain-rate effects on redwood crush performance. The load-deformation responses of redwood at temperature conditions corresponding to ambient (70 degrees F), 150 degrees F, and -20 degrees F conditions were measured in approximately 100 confined compression tests for crush levels leading to material densification. Data analysis provided a more complete description of redwood crush performance and a basis for assessing proposed general orthotropic stress-strain relationships for redwood. A review of existing literature indicated that strain-rate effects cause at most a 20 percent increase in crush stress parallel to grain

Annosus Root disease of Western Conifers (FIDL)

Science.gov (United States)

Craig L. Schmitt; John R. Parmeter; John T. Kliejunas

2000-01-01

Annosus root disease is found on all western conifer species but is of most concern on true firs, hemlocks, and pines. Incense cedar, coast redwood and sequoia are sometimes infected in California. Western juniper is infected throughout its range. Annosus is common and causes extensive decay in old-growth western and mountain hemlock stands. Many mixed conifer stands...

Climate indices strongly influence old-growth forest carbon exchange

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Sonia Wharton; Matthias Falk

2016-01-01

We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running...

Regeneration after cutting of old-growth northern hardwoods in New Hampshire

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William B. Leak; Robert W., Jr. Wilson

1958-01-01

Past experience with cuttings in old-growth northern hardwoods has demonstrated that the primary regeneration problem is to obtain a large proportion of desirable species of good quality. Regardless of method or intensity of cutting, the total amount of reproduction usually is adequate. Second-growth stands are a different story: this report pertains only to old-growth...

Economics of replacing young-growth ponderosa pine stands . . . a case study

Science.gov (United States)

Dennis E. Teeguarden

1968-01-01

Compares the expected capital value growth of five ponderosa pine stands (70 to 80 years old) on the Challenge Experimental Forest, Yuba County, Calif., with the cost of delaying harvest (defined as sum of stock-holding and land-holding costs). Suggests that replacement of all five stands would be financially desirable under constant stumpage prices. Recommends...

[Effects of crop tree release on stand growth and stand structure of Cunninghamia lanceolata plantation].

Science.gov (United States)

Wu, Jian-qiang; Wang, Yi-xiang; Yang, Yi; Zhu, Ting-ting; Zhu, Xu-dan

2015-02-01

Crop trees were selected in a 26-year-old even-aged Cunninghamia lanceolata plantation in Lin' an, and compared in plots that were released and unreleased to examine growth and structure responses for 3 years after thinning. Crop tree release significantly increased the mean increments of diameter and volume of individual tree by 1.30 and 1.25 times relative to trees in control stands, respectively. The increments of diameter and volume of crop trees were significantly higher than those of general trees in thinning plots, crop trees and general trees in control plots, which suggested that the responses from different tree types to crop tree release treatment were different. Crop tree release increased the average distances of crop trees to the nearest neighboring trees, reducing competition among crop trees by about 68.2%. 3-year stand volume increment for thinning stands had no significant difference with that of control stands although the number of trees was only 81.5% of the control. Crop trees in thinned plots with diameters over than 14 cm reached 18.0% over 3 years, compared with 12.0% for trees without thinning, suggesting that crop tree release benefited the larger individual trees. The pattern of tree locations in thinning plots tended to be random, complying with the rule that tree distribution pattern changes with growth. Crop tree release in C. lanceolata plantation not only promoted the stand growth, but also optimized the stand structure, benefiting crop trees sustained rapid growth and larger diameter trees production.

Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA

Science.gov (United States)

Sonia Wharton; Matt Schroeder; Ken Bible; Matthias Falk; Kyaw Tha Paw U

2009-01-01

This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral (ES) stands (0 to 15 years old) and an old-growth (OG) (~450 to 500 years old) forest in the Wind River Experimental Forest,...

Turbulence Considerations for Comparing Ecosystem Exchange over Old-Growth and Clear-Cut Stands For Limited Fetch and Complex Canopy Flow Conditions

Energy Technology Data Exchange (ETDEWEB)

Wharton, S; Schroeder, M; Paw U, K T; Falk, M; Bible, K

2009-01-08

Carbon dioxide, water vapor and energy fluxes were measured using eddy covariance (EC) methodology over three adjacent forests in southern Washington State to identify stand-level age-effects on ecosystem exchange. The sites represent Douglas-fir forest ecosystems at two contrasting successional stages: old-growth (OG) and early seral (ES). Here we present eddy flux and meteorological data from two early seral stands and the Wind River AmeriFlux old-growth forest during the growing season (March-October) in 2006 and 2007. We show an alternative approach to the usual friction velocity (u*) method for determining periods of adequate atmospheric boundary layer (ABL) mixing based on the ratio of mean horizontal ({bar u}) and vertical ({bar w}) wind flow to a modified turbulent kinetic energy scale (uTKE). This new parameter in addition to footprint modeling showed that daytime CO{sub 2} fluxes (F{sub NEE}) in small clear-cuts (< 10 hectares) can be measured accurately with EC if micrometeorological conditions are carefully evaluated. Peak midday CO{sub 2} fluxes (F{sub NEE} = -14.0 to -12.3 {micro}mol m{sup -2} s{sup -1}) at OG were measured in April in both 2006 and 2007 before bud break when air and soil temperatures and vapor pressure deficit were relatively low, and soil moisture and light levels were favorable for photosynthesis. At the early seral stands, peak midday CO{sub 2} fluxes (F{sub NEE} = -11.0 to -8.7 {micro}mol m{sup -2} s{sup -1}) were measured in June and July while spring-time CO{sub 2} fluxes were much smaller (F{sub NEE} = -3.8 to -3.6 {micro}mol m{sup -2} s{sup -1}). Overall, we measured lower evapotranspiration (OG = 230 mm; ES = 297 mm) higher midday F{sub NEE} (OG F{sub NEE} = -9.0 {micro}mol m{sup -2} s{sup -1}; ES F{sub NEE} = -7.3 {micro}mol m{sup -2} s{sup -1}) and higher Bowen ratios (OG {beta} = 2.0. ES {beta} = 1.2) at the old-growth forest than at the ES sites during the summer months (May-August). Eddy covariance studies such as ours

Understanding old-growth red and white pine dominated forests in Ontario. Forest fragmentation and biodiversity project technical report No. 2

Energy Technology Data Exchange (ETDEWEB)

Carleton, T.J.; Gordon, A.M.

1992-01-01

In summer 1991, a variety of forest stands dominated by old specimens of white pine and red pine were sampled across a representative portion of the species' range in northcentral Ontario. Plots were established in 40 stands of those surveyed to identify the salient structural components of old-growth, to survey the floristic composition (vascular plants and autotrophic non- vascular plants), to survey site characteristics, and to estimate the links in understorey alpha diversity with site conditions and stand structure. Long-term objectives include a definition of old- growth pine forest, recognition criteria, and prospective management options. Forest stand structure was enumerated through mapping, mensurational, and age estimation techniques. Forest vegetation, including over and understorey species, was non- destructively sampled and a range of data on stand and soil-site variables was also collected in conjunction with information on stand variables peculiar to old growth forests.

Tree growth and competition in an old-growth Picea abies forest of boreal Sweden: influence of tree spatial patterning

Science.gov (United States)

Fraver, Shawn; D'Amato, Anthony W.; Bradford, John B.; Jonsson, Bengt Gunnar; Jönsson, Mari; Esseen, Per-Anders

2013-01-01

Question: What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location: Old-growth Picea abies forest of boreal Sweden. Methods: Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results: Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions: Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree

Capturing Old-Growth Values for Use in Forest Decision-Making

Science.gov (United States)

Owen, Rochelle J.; Duinker, Peter N.; Beckley, Thomas M.

2009-02-01

Old-growth forests have declined significantly across the world. Decisions related to old growth are often mired in challenges of value diversity, conflict, data gaps, and resource pressures. This article describes old-growth values of citizens and groups in Nova Scotia, Canada, for integration in sustainable forest management (SFM) decision-making. The study is based on data from 76 research subjects who participated in nine field trips to forest stands. Research subjects were drawn from Aboriginal groups, environmental organizations, forestry professionals, and rural and urban publics. Diaries, group discussions, and rating sheets were used to elicit information during the field trips. Findings show that different elicitation techniques can influence the articulation of intensity with which some values are held. In addition, certain values are more often associated with old-growth than with other forest-age classes. Some values associated with old-growth are considered more important than others, and some silvicultural treatments are perceived to compromise old-growth values more than others. Demographic characteristics, such as constituency group, gender, and age, are shown to influence value priorities. Ideas on how to incorporate old-growth values into SFM decision-making are highlighted.

Influence of competition and age on tree growth in structurally complex old-growth forests in northern Minnesota, USA

Science.gov (United States)

Tuomas Aakala; Shawn Fraver; Anthony W. D' Amato; Brian J. Palik

2013-01-01

Factors influencing tree growth in structurally complex forests remain poorly understood. Here we assessed the influence of competition on Pinus resinosa (n = 224) and Pinus strobus (n = 90) growth in four old-growth stands in Minnesota, using mixed effects models. A subset of trees, with...

Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

Science.gov (United States)

McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

2015-02-01

Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

Redwoods, restoration, and implications for carbon budgets

Science.gov (United States)

Madej, Mary Ann

2010-01-01

The coast redwoods (Sequoia sempervirens) of California have several unique characteristics that influence interactions between vegetation and geomorphic processes. Case studies, using a combination of in-channel wood surveys and an air photo inventory of landslides, illustrate current conditions in a redwood-dominated watershed undergoing restoration work, and the influence of wood loading and landslides on the carbon budget. Redwood trees have extremely large biomass (trunk wood volumes of 700 to 1000 m3) and are very decay-resistant; consequently, they have a large and persistent influence on in-channel wood loading. Large wood surveys indicate high wood loading in streams in uncut forests (0.3-0.5 m3/m2 of channel), but also show that high wood loading can persist in logged basin with unlogged riparian buffers because of the slow decay of fallen redwoods. Through a watershed restoration program, Redwood National Park increases in-channel wood loading in low-order streams, but the effectiveness of this technique has not yet been tested by a large flood. Another unique characteristic of redwood is its ability to resprout from basal burls after cutting, so that root strength may not decline as sharply following logging as in other types of forests. An air photo inventory of landslides following a large storm in 1997 indicated: 1) that in the Redwood Creek watershed the volume of material displaced by landslides in harvested areas was not related to the time elapsed since logging, suggesting that the loss of root strength was not a decisive factor in landslide initiation, 2) landslide production on decommissioned logging roads was half that of untreated roads, and 3) landslides removed an estimated 28 Mg of organic carbon/km2 from hillslopes. The carbon budget of a redwood-dominated catchment is dominated by the vegetative component, but is also influenced by the extent of mass movement, erosion control work, and in-channel storage of wood.

Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska

Science.gov (United States)

Robert L. Deal; Troy Heithecker; Eric K. Zenner

2010-01-01

The effects of partial cutting on tree size structure and stand growth were evaluated in 52 plots in 13 stands in southeast Alaska that were partially harvested 53 to 96 years ago and compared with 50-year-old even-aged stands that developed after clearcutting. The net basal-area growth was greater in the partially cut plots than in the uncut plots, and basal-area...

Evaluating growth performance of young stands

Science.gov (United States)

A. L. Roe; R. E. Benson

1966-01-01

A simple procedure for evaluating the diameter growth of young stands in relation to potential growth is described. A comparison technique is developed which contrasts relative diameter of crop trees to the relative diameter growth of the last decade to show the condition and trend of growth in the stand. The method is objective, easy to use, and has several...

Ground beetles as indicators of past management of old-growth forests

Directory of Open Access Journals (Sweden)

Mazzei A

2017-06-01

Full Text Available Old-growth forests are terrestrial ecosystems with the highest level of biodiversity and the main environments for the study of conservation and dynamics of the forest system. In Mediterranean Europe, two millennia of human exploitation deeply altered the structural complexity of the native forests. Some animal groups, including insects, may be used as a proxy of such changes. In this paper we explored the possible effects of forest management on the functional diversity (species traits of carabid beetle communities. Three old-growth forests of the Sila National Park were sampled by pitfall traps set up in pure beech, beech-silver fir and Calabrian black pine forests. In each forest, five managed vs. five unmanaged stands were considered. Managed sites were exploited until the sixties of the past century and then left unmanaged. More than 6000 carabid specimens belonging to 23 species were collected. The functional diversity in carabid groups is influenced by forest management especially in beech and beech-silver fir stands. Body size, specialized predators, endemic species and forest species were negatively affected by stand management. On the contrary, omnivorous ground beetles populations (or species with a high dispersal power (macropterous and large geographic distribution were positively influenced by stand management. In pine forests the old-growth community seems less sensitive to past management and more affected by soil evolution. Soil erosion and disturbance may reduce species diversity of ground beetles. Anyway, the composition of the carabid community shows that 50-60 years of forest restoration are enough for the reconstruction of a fairly diverse assemblage reflecting a “subclimax” situation.

Comparison of red-cockaded woodpecker (Picoides borealis) nestling diet in old-growth and old-field longleaf pine (Pinus palustris) habitats

Science.gov (United States)

James L. Hanula; R. Todd Engstrom

2000-01-01

Automatic cameras were used to record adult red-cockaded woodpecker (Picoides borealis) nest visits with food for nestlings. Diet of nestlings on or near an old-growth longleaf pine (Pinus palustris) remnant in southern Georgia was compared to that in longleaf pine stands established on old farm fields in western South Carolina....

Seasonal Variation in Soil Greenhouse Gas Emissions at Three Age-Stages of Dawn Redwood (Metasequoia glyptostroboides Stands in an Alluvial Island, Eastern China

Directory of Open Access Journals (Sweden)

Shan Yin

2016-11-01

Full Text Available Greenhouse gas (GHG emissions are an important part of the carbon (C and nitrogen (N cycle in forest soil. However, soil greenhouse gas emissions in dawn redwood (Metasequoia glyptostroboides stands of different ages are poorly understood. To elucidate the effect of plantation age and environmental factors on soil GHG emissions, we used static chamber/gas chromatography (GC system to measure soil GHG emissions in an alluvial island in eastern China for two consecutive years. The soil was a source of CO2 and N2O and a sink of CH4 with annual emissions of 5.5–7.1 Mg C ha−1 year−1, 0.15–0.36 kg N ha−1 year−1, and 1.7–4.5 kg C ha−1 year−1, respectively. A clear exponential correlation was found between soil temperature and CO2 emission, but a negative linear correlation was found between soil water content and CO2 emission. Soil temperature had a significantly positive effect on CH4 uptake and N2O emission, whereas no significant correlation was found between CH4 uptake and soil water content, and N2O emission and soil water content. These results implied that older forest stands might cause more GHG emissions from the soil into the atmosphere because of higher litter/root biomass and soil carbon/nitrogen content compared with younger stands.

Participation of gibberellin in the control of apical dominance in soybean and redwood

Energy Technology Data Exchange (ETDEWEB)

Ruddat, M.; Pharis, R.P.

1966-01-01

Loss of apical dominance in soybeans and redwood was increased when the plants were treated with the growth retardant AMO-1618. Simultaneous application of gibberellin reduced the number of elongating buds and promoted growth of the first or second uppermost auxillary bud, thus restoring apical dominance. It is concluded that gibberellin participates in the expression of apical dominance. 30 references, 2 tables.

Characteristics and dynamics of an upland Missouri old-growth forest

Science.gov (United States)

R. Hoyt Richards; Stephen R. Shifley; Alan J. Rebertus; Stephen J. Chaplin

1995-01-01

We describe the structure, composition, and dynamics of Schnabel Woods, an 80-acre mixed mesophytic old-growth stand located in the loess-covered River Hills adjoining the Missouri River floodplain in central Missouri. In 1982 all trees on a 1.5-ac northwest-facing plot and a 1.5-ac southeast-facing plot were mapped and measured. In 1992 we remeasured those plots to...

Abundance and Size Distribution of Cavity Trees in Second-Growth and Old-Growth Central Hardwood Forests

Science.gov (United States)

Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson III; David R. Larsen

2005-01-01

In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

Abundance and size distribution of cavity trees in second-growth and old-growth central hardwood forests

Science.gov (United States)

Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson; David R. Larsen

2005-01-01

In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

Historical harvests reduce neighboring old-growth basal area across a forest landscape.

Science.gov (United States)

Bell, David M; Spies, Thomas A; Pabst, Robert

2017-07-01

While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old-growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30-m resolution live tree basal area maps in lower and middle elevation mature and old-growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (800 m). Surprisingly, we found no or weak effects of harvest age (13-60 yr) and harvest area (0.2-110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi-decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old-growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision-making in old-growth forest landscapes by broadening the traditional view of stand boundaries. Furthermore, the consequences

Canopy structure and tree condition of young, mature, and old-growth Douglas-fir/hardwood forests

Science.gov (United States)

B.B. Bingham; J.O. Sawyer

1992-01-01

Sixty-two Douglas-fir/hardwood stands ranging from 40 to 560 years old were used to characterize the density; diameter, and height class distributions of canopy hardwoods and conifers in young (40 -100 yr), mature (101 - 200 yr) and old-growth (>200 yr) forests. The crown, bole, disease, disturbance, and cavity conditions of canopy conifers and hardwoods were...

Biomass and water storage dynamics of epiphytes in old-growth and secondary montane cloud forest stands in Costa Rica

NARCIS (Netherlands)

Koehler, L.; Tobon, C.; Frumau, K.F.A.; Bruijnzeel, L.A.

2007-01-01

Epiphytic biomass, canopy humus and associated canopy water storage capacity are known to vary greatly between old-growth tropical montane cloud forests but for regenerating forests such data are virtually absent. The present study was conducted in an old-growth cloud forest and in a 30-year-old

A comparison of litter production in young and old baldcypress (Taxodium distichum L.) stands at Caddo Lake, Texas

Science.gov (United States)

McCoy, John W.; Draugelis-Dale, Rassa O.; Keeland, Bobby D.; Darville, Roy

2010-01-01

Aboveground primary productivity for cypress forests was assessed from measurements of litter production in two age groups and in two hydrological regimes (standing water and free-flowing). Caddo Lake, located in northeast Texas on the Texas-Louisiana border, offered a unique study site since it is dominated by extensive stands composed entirely of Taxodium distichum (L.) Rich, (baldcypress) in different age groups. Young stands (approximately 100 years old) are found along the shoreline and on shallow flooded islands. Old stands (-150 to 300 years old) are found in deeper water where they were continuously flooded. Litter production over three years from October 1998 to September 2001 was measured. Litter consisting of leaves, twigs, bark, reproductive parts, and Tillandsia usneoides (L.) L. (Spanish moss) was collected monthly using 0.5 m2 floating traps. Tree diameters were measured within 200 m2 circular plots in each stand. The young stands supported densities greater than 2,000 stems/ha and a mean stand basal area of 72.3 m2/ha, whereas old stands supported lower densities of about 500 stems/ha but with a similar mean stand basal area of 73.3 m2/ha. There was a significant difference between old and young stands for overall yearly litter production, averaging about 670 g/m2/yr in the young stands and 460 g/m2/yr in the old stands. Leaves and twigs were significantly greater in the young stands, while reproductive parts were higher in old stands. Litter collections between years or hydrological regimes were not significantly different.

Compatible growth models and stand density diagrams

International Nuclear Information System (INIS)

Smith, N.J.; Brand, D.G.

1988-01-01

This paper discusses a stand average growth model based on the self-thinning rule developed and used to generate stand density diagrams. Procedures involved in testing are described and results are included

Roles of Fog and Topography in Redwood Forest Hydrology

Science.gov (United States)

Francis, E. J.; Asner, G. P.

2017-12-01

Spatial variability of water in forests is a function of both climatic gradients that control water inputs and topo-edaphic variation that determines the flows of water belowground, as well as interactions of climate with topography. Coastal redwood forests are hydrologically unique because they are influenced by coastal low clouds, or fog, that is advected onto land by a strong coastal-to-inland temperature difference. Where fog intersects the land surface, annual water inputs from summer fog drip can be greater than that of winter rainfall. In this study, we take advantage of mapped spatial gradients in forest canopy water storage, topography, and fog cover in California to better understand the roles and interactions of fog and topography in the hydrology of redwood forests. We test a conceptual model of redwood forest hydrology with measurements of canopy water content derived from high-resolution airborne imaging spectroscopy, topographic variables derived from high-resolution LiDAR data, and fog cover maps derived from NASA MODIS data. Landscape-level results provide insight into hydrological processes within redwood forests, and cross-site analyses shed light on their generality.

Stand characteristics of 65-year-old planted and naturally regenerated stands near Sequim, Washington.

Science.gov (United States)

Richard E. Miller; Harry W. Anderson

1995-01-01

Tree numbers, height, and volume were determined in six 63- to 66-year-old plantations of coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) in northwest Washington. These stands resulted from the first extensive plantings of this species in the Pacific Northwest. Data from 0.25-acre plots in these...

Rare Plants of the Redwood Forest and Forest Management Effects

Science.gov (United States)

Teresa Sholars; Clare Golec

2007-01-01

Coast redwood forests are predominantly a timber managed habitat type, subjected to repeated disturbances and short rotation periods. What does this repeated disturbance mean for rare plants associated with the redwood forests? Rare plant persistence through forest management activities is influenced by many factors. Persistence of rare plants in a managed landscape is...

Forest evaporation models: Relationships between stand growth and evaporation

CSIR Research Space (South Africa)

Le Maitre, David C

1997-06-01

Full Text Available The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation...

Tree dynamics in canopy gaps in old-growth forests of Nothofagus pumilio in Southern Chile

NARCIS (Netherlands)

Fajardo, Alex; Graaf, de N.R.

2004-01-01

The gap dynamics of two Nothofagus pumilio (lenga) stands have been investigated. We evaluated and compared tree diameter distributions, spatial patterns, tree fall and gap characteristics and regeneration responses in gaps in two old-growth forests of Nothofagus pumilio in Southern Chile

Growth after precommercial thinning in two stands of Douglas-fir.

Science.gov (United States)

Robert W. Steele

1955-01-01

Twenty years ago, portions of two young Douglas-fir stands on the Wind River Experimental Forest in Skamania County, Washington, were thinned by removing some of the trees in the suppressed and intermediate crown classes. At time of thinning, one stand, (A), was 23 years old and the second, (B), was 30 years old. In both cases site quality is IV. The trees taken out...

Does water chemistry limit the distribution of New Zealand mud snails in Redwood National Park?

Science.gov (United States)

Vazquez, Ryan; Ward, Darren M.; Sepulveda, Adam

2016-01-01

New Zealand mud snails (NZMS) are exotic mollusks present in many waterways of the western United States. In 2009, NZMS were detected in Redwood Creek in Redwood National Park, CA. Although NZMS are noted for their ability to rapidly increase in abundance and colonize new areas, after more than 5 years in Redwood Creek, their distribution remains limited to a ca. 300 m reach. Recent literature suggests that low specific conductivity and environmental calcium can limit NZMS distribution. We conducted laboratory experiments, exposing NZMS collected from Redwood Creek to both natural waters and artificial treatment solutions, to determine if low conductivity and calcium concentration limit the distribution of NZMS in Redwood National Park. For natural water exposures, we held NZMS in water from their source location (conductivity 135 μS/cm, calcium 13 mg/L) or water from four other locations in the Redwood Creek watershed encompassing a range of conductivity (77–158 μS/cm) and calcium concentration (4 months) in the lowest conductivity waters from Redwood Creek and all but the lowest-conductivity treatment solutions, regardless of calcium concentration. However, reproductive output was very low in all natural waters and all low-calcium treatment solutions. Our results suggest that water chemistry may inhibit the spread of NZMS in Redwood National Park by reducing their reproductive output.

Past, Present, and Future Old Growth in Frequent-fire Conifer Forests of the Western United States

Directory of Open Access Journals (Sweden)

Scott R. Abella

2007-12-01

Full Text Available Old growth in the frequent-fire conifer forests of the western United States, such as those containing ponderosa pine (Pinus ponderosa, Jeffrey pine (P. jeffreyi, giant sequoia (Sequioa giganteum and other species, has undergone major changes since Euro-American settlement. Understanding past changes and anticipating future changes under different potential management scenarios are fundamental to developing ecologically based fuel reduction or ecological restoration treatments. Some of the many changes that have occurred in these forests include shifts from historically frequent surface fire to no fire or to stand-replacing fire regimes, increases in tree density, increased abundance of fire-intolerant trees, decreases in understory productivity, hydrological alterations, and accelerated mortality of old trees. Although these changes are widespread, the magnitude and causes of changes may vary within and among landscapes. Agents of change, such as fire exclusion or livestock grazing, likely interacted and had multiple effects. For example, historical ranching operations may have altered both fire regimes and understory vegetation, and facilitated institutional fire exclusion through fragmentation and settlement. Evidence exists for large variation in presettlement characteristics and current condition of old growth across this broad forest region, although there are many examples of striking similarities on widely distant landscapes. Exotic species, climate change, unnatural stand-replacing wildfires, and other factors will likely continue to degrade or eradicate old growth in many areas. As a policy of fire exclusion is proving to be unsustainable, mechanical tree thinning, prescribed fire, or wildland fire use will likely be key options for forestalling continued eradication of old growth by severe crown fires. For many practical and societal reasons, the wildland-urban interface may afford some of the most immediate opportunities for re

Coast redwood science symposium—2016: Past successes and future direction

Science.gov (United States)

Richard B. Standiford; Yana Valachovic

2017-01-01

There is no more iconic tree or more closely watched forest ecosystem than coast redwood. With its limited range and high value, the coast redwood forest is a microcosm of many of the emerging science and management issues facing today’s forested landscapes. As new information is collected and new management approaches and treatments tried, it is critical that policies...

Stand conditions immediately following a restoration harvest in an old-growth pine-hardwood remnant

Science.gov (United States)

D. C. Bragg

2010-01-01

Portions of the Levi Wilcoxon Demonstration Forest (LWDF), a privately owned parcel of old-growth pine and hardwoods in Ashley County, Arkansas, were recently treated to restore conditions similar to some historic accounts of the virgin forest. Following a hardwood-only cut, a post-harvest inventory showed that the number of tree species in the sample area declined...

Bark water uptake promotes localized hydraulic recovery in coastal redwood crown

Science.gov (United States)

J. Mason Earles; Or Sperling; Lucas C. R. Silva; Andrew J. McElrone; Craig R. Brodersen; Malcolm P. North; Maciej A. Zwieniecki

2015-01-01

Coastal redwood (Sequoia sempervirens), the world’s tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, exploring potential flow mechanisms and biological significance. Using isotopic labelling and microCT imaging, we observed that water...

Ectomycorrhizal Community Structure and Soil Characteristics of Mature Lodgepole Pine (Pinus Contorta) and Adjacent Stands of Old Growth Mixed Conifer in Yellowstone National Park, Wyoming USA

Science.gov (United States)

Douglas, Robert B.; Parker, V. Thomas; Cullings, Kenneth W.; Sun, Sidney (Technical Monitor)

2003-01-01

Forest development patterns following disturbance are known to influence the physical and chemical attributes of soils at different points in time. Changes in soil resources are thought to have a corresponding effect on ectomycorrhizal (ECM) community structure. We used molecular methods to compare below-ground ECM species richness, composition, and abundance between adjacent stands of homogenous lodgepole pine and old growth mixed conifer in Yellowstone National Park (YNP). In each stand-type we collected soil cores to both identify mycorrhizae and assess soil chemistry. Although no statistical difference was observed in the mean number of ECM root tips per core between stand types, the total number of species identified (85 versus 35) and the mean number of species per core (8.8 +/- 0.6 versus 2.5 +/- 0.3) were significantly higher in lodgepole pine. Differences between the actual and estimated species richness levels indicated that these forest types support a high number of ECM species and that undersampling was severe. Species compositions were widely disparate between stands where only four species were shared out of a total of 116. Soil analysis also revealed that mixed conifer was significantly lower in pH, but higher in organic matter, potassium, phosphorus, and ammonium when compared to lodgepole pine stands. Species richness per core was correlated with these chemical data, however, analysis of covariance indicated that stand type was the only statistically significant factor in the observed difference in species richness. Our data suggest that ECM fungal richness increases as homogenous lodgepole pine stands grow and mature, but declines after Engelmann spruce and subalpine fir colonize. Despite difficulties linking species composition with soil chemistry, there are a variety of physical and chemical factors that could be influencing ECM community structure. Future field experiments are necessary to test some of the mechanisms potentially operating

Two commercial thinnings in century-old Douglas-fir.

Science.gov (United States)

Robert W. Steele

1954-01-01

As young-growth forests replace old-growth forests as the primary source of Douglas-fir raw material, the technique of managing young stands becomes increasingly important. Managers of young-growth timber need to know whether it is economical and silviculturally feasible to make thinnings in stands that are close to rotation age. Final harvest of some stands of this...

The limited contribution of large trees to annual biomass production in an old-growth tropical forest.

Science.gov (United States)

Ligot, Gauthier; Gourlet-Fleury, Sylvie; Ouédraogo, Dakis-Yaoba; Morin, Xavier; Bauwens, Sébastien; Baya, Fidele; Brostaux, Yves; Doucet, Jean-Louis; Fayolle, Adeline

2018-04-16

Although the importance of large trees regarding biodiversity and carbon stock in old-growth forests is undeniable, their annual contribution to biomass production and carbon uptake remains poorly studied at the stand level. To clarify the role of large trees in biomass production, we used data of tree growth, mortality, and recruitment monitored during 20 yr in 10 4-ha plots in a species-rich tropical forest (Central African Republic). Using a random block design, three different silvicultural treatments, control, logged, and logged + thinned, were applied in the 10 plots. Annual biomass gains and losses were analyzed in relation to the relative biomass abundance of large trees and by tree size classes using a spatial bootstrap procedure. Although large trees had high individual growth rates and constituted a substantial amount of biomass, stand-level biomass production decreased with the abundance of large trees in all treatments and plots. The contribution of large trees to annual stand-level biomass production appeared limited in comparison to that of small trees. This pattern did not only originate from differences in abundance of small vs. large trees or differences in initial biomass stocks among tree size classes, but also from a reduced relative growth rate of large trees and a relatively constant mortality rate among tree size classes. In a context in which large trees are increasingly gaining attention as being a valuable and a key structural characteristic of natural forests, the present study brought key insights to better gauge the relatively limited role of large trees in annual stand-level biomass production. In terms of carbon uptake, these results suggest, as already demonstrated, a low net carbon uptake of old-growth forests in comparison to that of logged forests. Tropical forests that reach a successional stage with relatively high density of large trees progressively cease to be carbon sinks as large trees contribute sparsely or even

Northern California redwood forests provide important seasonal habitat for migrant bats

Science.gov (United States)

Theodore J. Weller; Craig A. Stricker

2012-01-01

Bats are known to roost in redwood forests year-round, but their activities outside the summer season are poorly understood. To improve understanding of the use of redwoods by resident and migrant bats, we conducted 74 mist net surveys between February 2008 and October 2010. Captures were dominated by Yuma myotis (M. yumanensis) in the summer and...

Decomposition and N cycling changes in redwood forests caused by sudden oak death

Science.gov (United States)

Richard C. Cobb; David M. Rizzo

2012-01-01

Phytophthora ramorum is an emergent pathogen in redwood forests which causes the disease sudden oak death. Although the disease does not kill coast redwood (Sequoia sempervirens), extensive and rapid mortality of tanoak (Notholithocarpus densiflorus) has removed this...

Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

Science.gov (United States)

Ruete, Alejandro; Snäll, Tord; Jönsson, Mari

2016-07-01

Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100 m) to the forest interior (beyond 100 m), and we analyzed stand-level changes after 10 yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50 yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for

Thinning cherry-maple stands in West Virginia: 5-year results

Science.gov (United States)

Neil I. Lamson; H. Clay. Smith; H. Clay. Smith

1988-01-01

In northern West Virginia, 60-year-old cherry-maple stands were thinned to 75,60, and 45 percent relative stand density. Analysis of 5-year growth data showed that basal-area growth was not reduced by thinning. Cubic-foot and board-foot volume growth decreased slightly. Individual-tree growth of all trees, dominant/codominant trees, and the 50 largest diameter trees...

Destroyed virgin longleaf pine stand lives-on digitally

Science.gov (United States)

John C. Gilbert; S. Kush; Rebecca J. Barlow

2015-01-01

The Flomaton Natural Area (FNA) once stood as one of the few remnant fragments of virgin, old-growth longleaf pine stands (Pinus palustris Mill.) in the Southeast. This 80-acre stand contained trees over 200 years old. A restoration effort began in 1994 to remove off-site trees and to reintroduce fire to the site after over 40 years of fire suppression. A geographic...

Crop-tree release increases growth of 12-year-old yellow-poplar and black cherry

Science.gov (United States)

Neil I. Lamson; H. Clay. Smith; H. Clay. Smith

1989-01-01

Precommercial thinning was done in a 12-year-old Appalachian hardwood sapling stand in West Virginia. Two crop-tree release techniques were used--crown touching and crown touching plus 5 feet. Results indicated that both treatments significantly increased 5-year d.b.h. growth for released yellow-poplar and black cherry crop trees. Although there was a major increase in...

Old-growth Policy

Directory of Open Access Journals (Sweden)

Diane Vosick

2007-12-01

Full Text Available Most federal legislation and policies (e.g., the Wilderness Act, Endangered Species Act, National Forest Management Act fail to speak directly to the need for old-growth protection, recruitment, and restoration on federal lands. Various policy and attitudinal barriers must be changed to move beyond the current situation. For example, in order to achieve the goal of healthy old growth in frequent-fire forests, the public must be educated regarding the evolutionary nature of these ecosystems and persuaded that collaborative action rather than preservation and litigation is the best course for the future of these forests. Land managers and policy makers must be encouraged to look beyond the single-species management paradigm toward managing natural processes, such as fire, so that ecosystems fall within the natural range of variability. They must also see that, given their recent evidence of catastrophic fires, management must take place outside the wildland-urban interface in order to protect old-growth forest attributes and human infrastructure. This means that, in some wilderness areas, management may be required. Land managers, researchers, and policy makers will also have to agree on a definition of old growth in frequent-fire landscapes; simply adopting a definition from the mesic Pacific Northwest will not work. Moreover, the culture within the federal agencies needs revamping to allow for more innovation, especially in terms of tree thinning and wildland fire use. Funding for comprehensive restoration treatments needs to be increased, and monitoring of the Healthy Forest Initiative and Healthy Forest Restoration Act must be undertaken.

Restoring hydrology and old-growth structures in a former production forest

DEFF Research Database (Denmark)

Mazziotta, Adriano; Heilmann-Clausen, Jacob; Bruun, Hans Henrik

2016-01-01

to restore hydrology and old-growth structure. We collected presence/absence data for four organism groups (vascular plants, epiphytic bryophytes and lichens, wood-inhabiting fungi) and measured environmental variables associated with species occurrence and influenced by restoration (dead or living tree...... characteristics, stand age, water level). We investigated biodiversity consequences of restoration towards pristine environmental characteristics by using a space-for-time substitution model. We evaluated how and through what mechanisms species richness is likely to react when pre-forestry hydrological conditions......-restoration conditions. Furthermore, the increase in soil moisture shifted the forest plots towards an alder carr, while the stand ageing process sustained the shade-tolerant beech despite its low tolerance for high soil humidity. Our prediction shows an increase in species richness for plants directly driven...

Plant Uptake of Atmospheric Carbonyl Sulfide in Coast Redwood Forests

Science.gov (United States)

Campbell, J. E.; Whelan, M. E.; Berry, J. A.; Hilton, T. W.; Zumkehr, A.; Stinecipher, J.; Lu, Y.; Kornfeld, A.; Seibt, U.; Dawson, T. E.; Montzka, S. A.; Baker, I. T.; Kulkarni, S.; Wang, Y.; Herndon, S. C.; Zahniser, M. S.; Commane, R.; Loik, M. E.

2017-12-01

The future resilience of coast redwoods (Sequoia sempervirens) is now of critical concern due to the detection of a 33% decline in California coastal fog over the 20th century. However, ecosystem-scale measurements of photosynthesis and stomatal conductance are challenging in coast redwood forests, making it difficult to anticipate the impacts of future changes in fog. To address this methodological problem, we explore coastal variations in atmospheric carbonyl sulfide (COS or OCS), which could potentially be used as a tracer of these ecosystem processes. We conducted atmospheric flask campaigns in coast redwood sites, sampling at surface heights and in the canopy ( 70 m), at the University of California Landels-Hill Big Creek Reserve and Big Basin State Park. We simulated COS atmosphere-biosphere exchange with a high-resolution 3-D model to interpret these data. Flask measurements indicated a persistent daytime drawdown between the coast and the downwind forest (45 ± 6 ppt COS) that is consistent with the expected relationship between COS plant uptake, stomatal conductance, and gross primary production. Other sources and sinks of COS that could introduce noise to the COS tracer technique (soils, anthropogenic activity, nocturnal plant uptake, and surface hydrolysis on leaves) are likely to be small relative to daytime COS plant uptake. These results suggest that COS measurements may be useful for making ecosystem-scale estimates of carbon, water, and energy exchange in coast redwood forests.

Maximum growth potential in loblolly pine: results from a 47-year-old spacing study in Hawaii

Science.gov (United States)

Lisa J. Samuelson; Thomas L. Eberhardt; John R. Butnor; Tom A. Stokes; Kurt H. Johnsen

2010-01-01

Growth, allocation to woody root biomass, wood properties, leaf physiology, and shoot morphology were examined in a 47-year-old loblolly pine (Pinus taeda L.) density trial located in Maui, Hawaii, to determine if stands continued to carry the high density, basal area, and volume reported at younger ages and to identify potential factors controlling...

Fog and soil weathering as sources of nutrients in a California redwood forest

Science.gov (United States)

Holly A. Ewing; Kathleen C. Weathers; Amanda M. Lindsey; Pamela H. Templer; Todd E. Dawson; Damon C. Bradbury; Mary K. Firestone; Vanessa K.S. Boukili

2012-01-01

Fog water deposition is thought to influence the ecological function of many coastal ecosystems, including coast redwood forests. We examined cation and anion inputs from fog and rain, as well as the fate of these inputs, within a Sonoma County, California, coast redwood forest to elucidate the availability of these ions and some of the biotic and abiotic processes...

Inbreeding depression in selfs of redwood

Science.gov (United States)

W. J. Libby; B. G. McCutchan; C. I. Millar

1981-01-01

Given the polyploid chromosome constitution of Sequoia sempervirens, there was reason to question whether it would exhibit inbreeding depression. Preliminary results from studies of self and related outcross families are reported as a guide to the selection of trees for redwood seed orchards and breeding-orchards. The data indicate that, compared to...

Kinematic Analysis of the Standing Long Jump in Children 6- to 12-Years-Old

Science.gov (United States)

Fernandez-Santos, Jorge R.; Gonzalez-Montesinos, Jose Luis; Ruiz, Jonatan R.; Jiménez-Pavón, David; Castro-Piñero, Jose

2018-01-01

The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and…

Exploring Old Growth Forests: A Teacher's Manual.

Science.gov (United States)

Lemieux, Chris; Powers, Jennene; Quinby, Peter; Schultz, Caroline; Stabb, Mark

"Exploring Old Growth Forests" is an Ontario (Canada) program that provides secondary students with hands-on experiences in old growth forests. Activity-based and student-centered, the program aims to develop student awareness of the importance of old growth forests and the need to conserve them. This manual provides teachers with…

Carbon storage in young growth coast redwood stands

Science.gov (United States)

Dryw A. Jones; Kevin A. O' Hara

2012-01-01

Carbon sequestration is an emerging forest management objective within California and around the world. With the passage of the California's Global Warming Solutions Act (AB32) our need to understand the dynamics of carbon sequestration and to accurately measure carbon storage is essential to insure successful implementation of carbon credit projects throughout...

Simulation of growth and competition in mixed stands of Douglas-fir and beech

NARCIS (Netherlands)

Bartelink, H.H.

1998-01-01

For a long time, the emphasis in silviculture in Western Europe was solely on even-aged, monospecific stands; many empirical stand-level growth models were developed and successfully used for managing such stands. In contrast, no generally accepted growth and yield approach has emerged so

Cradle-to-gate life cycle impacts of redwood forest resource harvesting in northern California

Science.gov (United States)

Han-Sup Han; Elaine Oneil; Richard D. Bergman; Ivan L. Eastin; Leonard R. Johnson

2015-01-01

The first life cycle impact assessment for redwood (Sequoia sempervirens) forest management activities (i.e. a cradle-to-sawmill gate input) including the growing, harvesting, and hauling of redwood sawlogs to a sawmill was completed. In the stump-to-truck timber harvesting analysis, primary transport activities such as skidding and yarding consumed...

Marbled Murrelets Select Distinctive Nest Trees within Old-Growth Forest Patches

Directory of Open Access Journals (Sweden)

Michael P. Silvergieter

2011-12-01

Full Text Available The coastal old-growth forests of North America's Pacific Coast are renowned both for their commercial and ecological value. This study adds to growing evidence that selective harvesting of the largest trees may have a disproportionate ecological impact. Marbled Murrelets (Brachyramphus marmoratus, a threatened species, nest almost exclusively in these old-growth forests. Detailed knowledge of nesting habitat selection provides guidance for habitat management and conservation. Habitat selection for this species has been studied at a variety of scales using ground and remote methods. However, because Marbled Murrelet nesting activity is limited to a single mossy platform on a single tree, we investigated nest tree selection within old-growth forest patches, using a set of 59 forest patches containing active nests. Nest trees were usually distinctive compared with neighboring trees in the surrounding 25 m radius patch. They averaged 15 to 20% taller than neighboring trees depending on region, had significantly larger stem diameters, more potential nesting platforms, and more moss. They had the most extreme values of height and width about three times as often as expected by chance. An analysis of moss platform use as a function of number of platforms per platform tree suggests that murrelets select individual platforms, rather than platform trees per se. Nonetheless, highly selective logging practices that remove high-value trees from stands may also remove trees most likely to be selected by nesting murrelets.

Post-fire response of coast redwood one year after the Mendocino lightning complex fires

Science.gov (United States)

Robert B. Douglas; Tom. Bendurel

2012-01-01

Coast redwood (Sequoia sempervirens) forests have undergone significant changes over the past century and are now in state more conducive for wildfires. Because fires have been uncommon in redwood forests over the past 80 years, managers have limited data to make decisions about the post-fire environment. In June 2008, a series of lightning storms...

Response of forest soil Acari to prescribed fire following stand structure manipulation in the southern Cascade Range.Can

Science.gov (United States)

Michael A. Camann; Nancy E. Gillette; Karen L. Lamoncha; Sylvia R. Mori

2008-01-01

We studied responses of Acari, especially oribatid mites, to prescribed low-intensity fire in an east side pine site in the southern Cascade Range in California. We compared oribatid population and assemblage responses to prescribed fire in stands that had been selectively logged to enhance old growth characteristics, in logged stands to minimize old growth...

Thirty-two years of change in an old-growth Ohio beech-maple forest.

Science.gov (United States)

Runkle, James R

2013-05-01

Old-growth forests dominated by understory-tolerant tree species are among forest types most likely to be in equilibrium. However, documentation of the degree to which they are in equilibrium over decades-long time periods is lacking. Changes in climate, pathogens, and land use all are likely to impact stand characteristics and species composition, even in these forests. Here, 32 years of vegetation changes in an old-growth beech (Fagus grandifolia)-sugar maple (Acer saccharum) forest in Hueston Woods, southwest Ohio, USA, are summarized. These changes involve canopy composition and structure, turnover in snags, and development of vegetation in treefall gaps. Stand basal area and canopy density have changed little in 32 years. However, beech has decreased in canopy importance (49% to 32%) while sugar maple has increased (32% to 47%). Annual mortality was about 1.3% throughout the study period. Mortality rates increased with stem size, but the fraction of larger stems increased due to ingrowth from smaller size classes. Beech was represented by more very large stems than small canopy stems: over time, death of those larger stems with inadequate replacement has caused the decrease in beech importance. Sugar maple was represented by more small canopy stems whose growth has increased its importance. The changes in beech and sugar maple relative importance are hypothesized to be due to forest fragmentation mostly from the early 1800s with some possible additional effects associated with the formation of the state park. Snag densities (12-16 snags/ha) and formation rates (1-3 snags.ha(-1).yr(-1)) remained consistent. The treefall gaps previously studied are closing, with a few, large stems remaining. Death of gap border trees occurs consistently enough to favor species able to combine growth in gaps and survival in the understory.

Impact of fire in two old-growth montane longleaf pine stands

Science.gov (United States)

John S. Kush; John C. Gilbert; Crystal Lupo; Na Zhou; Becky Barlow

2013-01-01

The structure of longleaf pine (Pinus palustris Mill.) forests of the Southeastern United States Coastal Plains has been the focus of numerous studies. By comparison, the forests in the mountains of Alabama and Georgia are not well understood. Less than 1 percent of longleaf pine stands found in the montane portion of longleaf’s range are considered...

Quantifying climate-growth relationships at the stand level in a mature mixed-species conifer forest.

Science.gov (United States)

Teets, Aaron; Fraver, Shawn; Weiskittel, Aaron R; Hollinger, David Y

2018-03-11

A range of environmental factors regulate tree growth; however, climate is generally thought to most strongly influence year-to-year variability in growth. Numerous dendrochronological (tree-ring) studies have identified climate factors that influence year-to-year variability in growth for given tree species and location. However, traditional dendrochronology methods have limitations that prevent them from adequately assessing stand-level (as opposed to species-level) growth. We argue that stand-level growth analyses provide a more meaningful assessment of forest response to climate fluctuations, as well as the management options that may be employed to sustain forest productivity. Working in a mature, mixed-species stand at the Howland Research Forest of central Maine, USA, we used two alternatives to traditional dendrochronological analyses by (1) selecting trees for coring using a stratified (by size and species), random sampling method that ensures a representative sample of the stand, and (2) converting ring widths to biomass increments, which once summed, produced a representation of stand-level growth, while maintaining species identities or canopy position if needed. We then tested the relative influence of seasonal climate variables on year-to-year variability in the biomass increment using generalized least squares regression, while accounting for temporal autocorrelation. Our results indicate that stand-level growth responded most strongly to previous summer and current spring climate variables, resulting from a combination of individualistic climate responses occurring at the species- and canopy-position level. Our climate models were better fit to stand-level biomass increment than to species-level or canopy-position summaries. The relative growth responses (i.e., percent change) predicted from the most influential climate variables indicate stand-level growth varies less from to year-to-year than species-level or canopy-position growth responses. By

Uneven-aged silviculture can enhance within stand heterogeneity and beetle diversity.

Science.gov (United States)

Joelsson, Klara; Hjältén, Joakim; Work, Timothy

2018-01-01

Uneven-aged silviculture may better maintain species assemblages associated with old-growth forests than clear felling in part due to habitat heterogeneity created by maintaining standing retention strips adjacent to harvest trails. Retention strips and harvest trails created at the time of tree removal will likely have different microclimate and may harbor different assemblages. In some cases, the resultant stand heterogeneity associated with uneven-aged silviculture may be similar to natural small-scale disturbances. For beetles, increased light and temperature as well as potential access to young vegetation and deadwood substrates present in harvset trails may harbor beetle assemblages similar to those found in natural gaps. We sampled saproxylic beetles using flight intercept traps placed in harvest corridors and retention strips in 9 replicated uneven-aged spruce stands in central Sweden. We compared abundance, species richness and composition between harvest corridors and retention strips using generalized linear models, rarefaction, permutational multivariate analysis of variance and indicator species analysis. Canopy openness doubled, mean temperature and variability in daily temperature increased and humidity decreased on harvest trails. Beetle richness and abundance were greater in harvests trails than in retention strips and the beetle species composition differed significantly between habitats. Twenty-five species were associated with harvest trails, including three old-growth specialists such as Agathidium discoideum (Erichson), currently red-listed. We observed only one species, Xylechinus pilosus (Ratzeburg) that strongly favored retention strips. Harvest trails foster both open habitat species and old-growth species while retention strips harbored forest interior specialists. The combination of closed canopy, stratified forest in the retention strips and gap-like conditions on the harvest trails thus increases overall species richness and maintains

A new method for evaluating forest thinning: growth dominance in managed Pinus resinosa stands

Science.gov (United States)

John B. Bradford; Anthony W. D' Amato; Brian J. Palik; Shawn. Fraver

2010-01-01

Growth dominance is a relatively new, simple, quantitative metric of within-stand individual tree growth patterns, and is defined as positive when larger trees in the stand display proportionally greater growth than smaller trees, and negative when smaller trees display proportionally greater growth than larger trees. We examined long-term silvicultural experiments in...

FINE ROOT TURNOVER IN PONDEROSA PINE STANDS OF DIFFERENT AGES: FIRST-YEAR RESULTS

Science.gov (United States)

Root minirhizotron tubs were installed in two ponderosa pine (Pinus ponderosa Laws.) Stands of different ages to examine patterns of root growth and death. The old-growth site (OS) consists of a mixture of old (>250 years) and young trees (ca.45 yrs)< and is located near clamp S...

Growth reductions in naturally regenerated southern pine stands in Alabama and Georgia

Science.gov (United States)

G.A. Ruark; C.E. Thomas; W.A. Bechtold; D.M. May

1991-01-01

Data from Forest Inventory and analysis (FIA) units of the USDA Forest Service were used to compare average annual stand-level basal area accretion onto survivor pines in naturally regenerated pine stands throughout Alabama and Georgia. Growth rates measured between 1972-82 were compared to growth rates during the previous 10-year survey cycle in each state. Separate...

Foliar uptake of fog in the coast redwood ecosystem: a novel drought-alleviation strategy shared by most redwood forest plants

Science.gov (United States)

Emily Limm; Kevin Simonin; Tod. Dawson

2012-01-01

Fog inundates the coast redwood forests of northern California frequently during the summer months (May to September) when rainfall is largely absent (Azevedo and Morgan 1974, Byers 1953, Oberlander 1956). This maritime fog modifies otherwise warm and dry summer climate by increasing humidity, decreasing the air temperature, reducing solar radiation, and...

Old-growth forests as global carbon sinks

NARCIS (Netherlands)

Luyssaert, S; Schulze, E.D.; Börner, A.

2008-01-01

Old- growth forests remove carbon dioxide from the atmosphere(1,2) at rates that vary with climate and nitrogen deposition(3). The sequestered carbon dioxide is stored in live woody tissues and slowly decomposing organic matter in litter and soil(4). Old- growth forests therefore serve as a global

Stand-Level Gas-Exchange Responses to Seasonal Drought in Very Young Versus Old Douglas-fir Forests of the Pacific Northwest, USA

Energy Technology Data Exchange (ETDEWEB)

Wharton, S; Schroeder, M; Bible, K; Falk, M; Paw U, K T

2009-02-23

This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral stands (ES) (0-15 years old) and an old-growth (OG) ({approx} 450-500) forest in the Wind River Experiment Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide (F{sub NEE}), latent energy ({lambda}E) and sensible heat (H) to derive evapotranspiration rate (E{sub T}), bowen ratio ({beta}), water use efficiency (WUE), canopy conductance (G{sub c}), the Priestley-Taylor coefficient ({alpha}) and a canopy decoupling factor ({Omega}). The canopy and bulk parameters are examined to see how ecophysiological responses to water stress, including changes in available soil water ({theta}{sub r}) and vapor pressure deficit ({delta}e) differ among the two forest successional-stages. Despite very different rainfall patterns in 2006 and 2007, we observed distinct successional-stage relationships between E{sub T}, {alpha}, and G{sub c} to {delta}e and {theta}{sub r} during both years. The largest stand differences were (1) higher morning G{sub c} (> 10 mm s{sup -1}) at the OG forest coinciding with higher CO{sub 2} uptake (F{sub NEE} = -9 to -6 {micro}mol m{sup -2} s{sup -1}) but a strong negative response in G{sub c} to moderate {delta}e later in the day and a subsequent reduction in E{sub T}, and (2) higher E{sub T} at the ES stands because midday canopy conductance did not decrease until very low water availability levels (<30%) were reached at the end of the summer. Our results suggest that early seral stands are more likely than mature forests to experience declines in production if the summer drought becomes longer or intensifies because water conserving ecophysiological responses were only observed at the very end of the seasonal drought period in the youngest stands.

Life-Cycle Inventory Analysis of Manufacturing Redwood Decking

Science.gov (United States)

Richard D. Bergman; Han-Sup Han; Elaine Oneil; Ivan L. Eastin

2012-01-01

Green building has become increasingly important. Therefore, consumers and builders often take into account the environmental attributes of a building material. This study determined the environmental attributes associated with manufacturing 38-mm × 138-mm (nominal 2 × 6) redwood decking in northern California using the life-cycle inventory method. Primary data...

Stocking and structure for maximum growth in sugar maple selection stands.

Science.gov (United States)

Thomas R. Crow; Carl H. Tubbs; Rodney D. Jacobs; Robert R. Oberg

1981-01-01

The impacts of stocking, structure, and cutting cycle on basal area, cubic foot volume, board foot volume, and diameter growth are considered. Recommendations are provided for maximum growth in uneven-aged sugar maple stands.

Light thinning in century-old Douglas-fir.

Science.gov (United States)

Robert W. Steele

1948-01-01

A stand-improvement study in century-old Douglas-fir at the Wind River Experimental Forest provides an example of a commercial thinning that gave a substantial intermediate harvest, salvaged considerable material that would have been lost through mortality, greatly increased the net growth rate, and improved the general vigor of the stand, leaving the forest in a more...

An analytical model of stand dynamics as a function of tree growth, mortality and recruitment: the shade tolerance-stand structure hypothesis revisited.

Science.gov (United States)

Zavala, Miguel A; Angulo, Oscar; Bravo de la Parra, Rafael; López-Marcos, Juan C

2007-02-07

Light competition and interspecific differences in shade tolerance are considered key determinants of forest stand structure and dynamics. Specifically two main stand diameter distribution types as a function of shade tolerance have been proposed based on empirical observations. All-aged stands of shade tolerant species tend to have steeply descending, monotonic diameter distributions (inverse J-shaped curves). Shade intolerant species in contrast typically exhibit normal (unimodal) tree diameter distributions due to high mortality rates of smaller suppressed trees. In this study we explore the generality of this hypothesis which implies a causal relationship between light competition or shade tolerance and stand structure. For this purpose we formulate a partial differential equation system of stand dynamics as a function of individual tree growth, recruitment and mortality which allows us to explore possible individual-based mechanisms--e.g. light competition-underlying observed patterns of stand structure--e.g. unimodal or inverse J-shaped equilibrium diameter curves. We find that contrary to expectations interspecific differences in growth patterns can result alone in any of the two diameter distributions types observed in the field. In particular, slow growing species can present unimodal equilibrium curves even in the absence of light competition. Moreover, light competition and shade intolerance evaluated both at the tree growth and mortality stages did not have a significant impact on stand structure that tended to converge systematically towards an inverse J-shaped curves for most tree growth scenarios. Realistic transient stand dynamics for even aged stands of shade intolerant species (unimodal curves) were only obtained when recruitment was completely suppressed, providing further evidence on the critical role played by juvenile stages of tree development (e.g. the sampling stage) on final forest structure and composition. The results also point out the

Not all is lost: old adults retain flexibility in motor behaviour during sit-to-stand.

Directory of Open Access Journals (Sweden)

Christian Greve

Full Text Available Sit-to-stand is a fundamental activity of daily living, which becomes increasingly difficult with advancing age. Due to severe loss of leg strength old adults are required to change the way they rise from a chair and maintain stability. Here we examine whether old compared to young adults differently prioritize task-important performance variables and whether there are age-related differences in the use of available motor flexibility. We applied the uncontrolled manifold analysis to decompose trial-to-trial variability in joint kinematics into variability that stabilizes and destabilizes task-important performance variables. Comparing the amount of variability stabilizing and destabilizing task-important variables enabled us to identify the variable of primary importance for the task. We measured maximal isometric voluntary force of three muscle groups in the right leg. Independent of age and muscle strength, old and young adults similarly prioritized stability of the ground reaction force vector during sit-to-stand. Old compared to young adults employed greater motor flexibility, stabilizing ground reaction forces during sit-to-sand. We concluded that freeing those degrees of freedom that stabilize task-important variables is a strategy used by the aging neuromuscular system to compensate for strength deficits.

Multi-decade biomass dynamics in an old-growth hemlock-northern hardwood forest, Michigan, USA

Directory of Open Access Journals (Sweden)

Kerry D. Woods

2014-09-01

Full Text Available Trends in living aboveground biomass and inputs to the pool of coarse woody debris (CWD in an undisturbed, old-growth hemlock-northern hardwood forest in northern MI were estimated from multi-decade observations of permanent plots. Growth and demographic data from seven plot censuses over 47 years (1962–2009, combined with one-time measurement of CWD pools, help assess biomass/carbon status of this landscape. Are trends consistent with traditional notions of late-successional forests as equilibrial ecosystems? Specifically, do biomass pools and CWD inputs show consistent long-term trends and relationships, and can living and dead biomass pools and trends be related to forest composition and history? Aboveground living biomass densities, estimated using standard allometric relationships, range from 360–450 Mg/ha among sampled stands and types; these values are among the highest recorded for northeastern North American forests. Biomass densities showed significant decade-scale variation, but no consistent trends over the full study period (one stand, originating following an 1830 fire, showed an aggrading trend during the first 25 years of the study. Even though total above-ground biomass pools are neither increasing nor decreasing, they have been increasingly dominated, over the full study period, by very large (>70 cm dbh stems and by the most shade-tolerant species (Acer saccharum and Tsuga canadensis.CWD pools measured in 2007 averaged 151 m3/ha, with highest values in Acer-dominated stands. Snag densities averaged 27/ha, but varied nearly ten-fold with canopy composition (highest in Tsuga-dominated stands, lowest in Acer-dominated; snags constituted 10–50% of CWD biomass. Annualized CWD inputs from tree mortality over the full study period averaged 1.9–3.2 Mg/ha/yr, depending on stand and species composition. CWD input rates tended to increase over the course of the study. Input rates may be expected to increase over longer

Dynamic growth and yield model for Black pine stands in Spain

Energy Technology Data Exchange (ETDEWEB)

Mora, J. V.; Rio, M. del; Bravo-Oviedo, A.

2012-07-01

In a forestry context, modelling stand development over time relies on estimates of different stand characteristics obtained from equations which usually constitute a multivariate system. In this study we have developed a stand growth model for even-aged stands of Black pine (Pinus nigra Arn.) in Spain. The 53 plots used to fit the equations came from the permanent sample plot network established by the Forest Research Centre (INIA) in 1963 and 1964 in the main distribution regions of Black pine. The model is made up of a system of equations to predict growth and yield in volume and basal area. In the fitting phase we took into account the correlation between the measurements within the same plot and the cross-equation residual correlations. The model incorporates a control function to estimate the thinning effect and a function for predicting the reduction in tree number due to regular mortality. In addition, we use the three parameter Weibull distribution function to estimate the number of trees in each diameter class by recovering the parameters using the moment method. The developed model is useful for simulating the evolution of even-aged stands with and without thinnings and allows the estimation of number of trees by diameter classes. (Author) 44 refs.

Life-cycle assessment of redwood decking in the United States with a comparison to three other decking materials

Science.gov (United States)

R. Bergman; H. Sup-Han; E. Oneil; I. Eastin

2013-01-01

The goal of the study was to conduct a life-cycle inventory (LCI) of California redwood (Sequoia sempervirens) decking that would quantify the critical environmental impacts of decking from cradle to grave. Using that LCI data, a life-cycle assessment (LCA) was produced for redwood decking. The results were used to compare the environmental footprint...

Status and conservation of old-growth forests and endemic birds in the pine-oak zone of the Sierra Madre occidental Mexico

OpenAIRE

Lammertink, J.M.; Rojas-Tome, J.A.; Casillas-Orona, F.M.; Otto, R.L.

1996-01-01

The pine-oak forests of the Sierra Madre Occidental, a mountain range in NW Mexico, have recently been recognized as an area of high endemism and biodiversity. Selective logging threatens three bird species endemic to this habitat, who depend on standing dead trees (snags). This report is based on an 11 month field survey that aimed to locate oldgrowth remnants and to assess the status of the endemic birds. Old-growth is defined here as a forest that has never been logged mechanically. Old-gr...

The Role of Old-growth Forests in Frequent-fire Landscapes

Directory of Open Access Journals (Sweden)

Daniel Binkley

2007-12-01

Full Text Available Classic ecological concepts and forestry language regarding old growth are not well suited to frequent-fire landscapes. In frequent-fire, old-growth landscapes, there is a symbiotic relationship between the trees, the understory graminoids, and fire that results in a healthy ecosystem. Patches of old growth interspersed with younger growth and open, grassy areas provide a wide variety of habitats for animals, and have a higher level of biodiversity. Fire suppression is detrimental to these forests, and eventually destroys all old growth. The reintroduction of fire into degraded frequent-fire, old-growth forests, accompanied by appropriate thinning, can restore a balance to these ecosystems. Several areas require further research and study: 1 the ability of the understory to respond to restoration treatments, 2 the rate of ecosystem recovery following wildfires whose level of severity is beyond the historic or natural range of variation, 3 the effects of climate change, and 4 the role of the microbial community. In addition, it is important to recognize that much of our knowledge about these old-growth systems comes from a few frequent-fire forest types.

Modelling growth and water use in four Pinus patula stands with the ...

African Journals Online (AJOL)

Existing prediction models do not take sufficient stand and site detail into account to usefully predict water use patterns on a scale that is practical to forest managers. Several relatively simple simulation models based on the major physiological processes behind growth and water use of forest stands have emerged recently, ...

Old-growth forests can accumulate carbon in soils

Science.gov (United States)

Zhou, G.; Liu, S.; Li, Z.; Zhang, Dongxiao; Tang, X.; Zhou, C.; Yan, J.; Mo, J.

2006-01-01

Old-growth forests have traditionally been considered negligible as carbon sinks because carbon uptake has been thought to be balanced by respiration. We show that the top 20-centimeter soil layer in preserved old-growth forests in southern China accumulated atmospheric carbon at an unexpectedly high average rate of 0.61 megagrams of carbon hectare-1 year-1 from 1979 to 2003. This study suggests that the carbon cycle processes in the belowground system of these forests are changing in response to the changing environment. The result directly challenges the prevailing belief in ecosystem ecology regarding carbon budget in old-growth forests and supports the establishment of a new, nonequilibrium conceptual framework to study soil carbon dynamics.

Fire-mediated pathways of stand development in Douglas-fir/western hemlock forests of the Pacific Northwest, USA

Science.gov (United States)

A.J. Tepley; F.J. Swanson; T.A. Spies

2013-01-01

Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR...

A Stand-Class Growth and Yield Model for Mexico’s Northern Temperate, Mixed and Multiaged Forests

Directory of Open Access Journals (Sweden)

José Návar

2014-12-01

Full Text Available The aim of this research was to develop a stand-class growth and yield model based on the diameter growth dynamics of Pinus spp. and Quercus spp. of Mexico’s mixed temperate forests. Using a total of 2663 temporary, circular-sampling plots of 1000 m2 each, nine Weibull distribution techniques of parameter estimation were fitted to the diameter structures of pines and oaks. Statistical equations using stand attributes and the first three moments of the diameter distribution predicted and recovered the Weibull parameters. Using nearly 1200 and 100 harvested trees for pines and oaks, respectively, I developed the total height versus diameter at breast height relationship by fitting three non-linear functions. The Newnham model predicted stem taper and numerical integration was done to estimate merchantable timber volume for all trees in the stand for each diameter class. The independence of the diameter structures of pines and oaks was tested by regressing the Weibull parameters and projecting diameter structures. The model predicts diameter distributions transition from exponential (J inverse, logarithmic to well-balanced distributions with increasing mean stand diameter at breast height. Pine diameter distributions transition faster and the model predicts independent growth rates between pines and oaks. The stand-class growth and yield model must be completed with the diameter-age relationship for oaks in order to carry a full optimization procedure to find stand density and genera composition to maximize forest growth.

Simulating historical disturbance regimes and stand structures in old-forest ponderosa pine/Douglas-fir forests

Science.gov (United States)

Mike Hillis; Vick Applegate; Steve Slaughter; Michael G. Harrington; Helen Smith

2001-01-01

Forest Service land managers, with the collaborative assistance from research, applied a disturbance based restoration strategy to rehabilitate a greatly-altered, high risk Northern Rocky Mountain old-forest ponderosa pine-Douglas-fir stand. Age-class structure and fire history for the site have been documented in two research papers (Arno and others 1995, 1997)....

Radial Growth Response of Black Spruce Stands Ten Years after Experimental Shelterwoods and Seed-Tree Cuttings in Boreal Forest

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Miguel Montoro Girona

2016-10-01

Full Text Available Partial cutting is thought to be an alternative to achieve sustainable management in boreal forests. However, the effects of intermediate harvest intensity (45%–80% on growth remain unknown in black spruce (Picea mariana (Mill. B.S.P. stands, one of the most widely distributed boreal species with great commercial interest. In this study, we analysed the effect of three experimental shelterwood and one seed-tree treatments on tree radial growth in even-aged black spruce stands, 10 years after intervention. Our results show that radial growth response 8–10 years after cutting was 41% to 62% higher than in untreated plots, with stand structure, treatment, tree position relative to skidding trails, growth before cutting and time having significant interactions. The stand structure conditioned tree growth after cutting, being doubled in younger and denser stands. Tree spatial position had a pronounced effect on radial growth; trees at the edge of the skidding trails showed twice the increase in growth compared to interior trees. Dominant trees before cutting located close to the skidding trails manifested the highest growth response after cutting. This research suggests that the studied treatments are effective to enhance radial wood production of black spruce especially in younger stands, and that the edge effect must be considered in silvicultural management planning.

A Linked Model for Simulating Stand Development and Growth Processes of Loblolly Pine

Science.gov (United States)

V. Clark Baldwin; Phillip M. Dougherty; Harold E. Burkhart

1998-01-01

Linking models of different scales (e.g., process, tree-stand-ecosystem) is essential for furthering our understanding of stand, climatic, and edaphic effects on tree growth and forest productivity. Moreover, linking existing models that differ in scale and levels of resolution quickly identifies knowledge gaps in information required to scale from one level to another...

Comparison of Red-Cockaded Woodpecker (Piciodes borealis) Nestling Diet in Old-Growth and Old-Field Longleaf Pine (Pinus palustris)

Energy Technology Data Exchange (ETDEWEB)

Hanula, J.L.; Engstrom, R.T.

1999-10-01

Automatic cameras were used to record adult woodpecker diets in old-growth and old-field longleaf pine in the South. Roaches were the number one prey for the woodpeckers based on either biomass or numbers. The latter ranged from 37% to 57% of the prey numbers and 55%-73% of the biomass. Morisita's index of similarity between old-field and old growth varied from 0.89 to 0.95. The authors conclude that the prey base is similar in both conditions and that old-growth provides similar foraging habitat.

Recent climatic drying leads to age-independent growth reductions of white spruce stands in western Canada.

Science.gov (United States)

Hogg, Edward H; Michaelian, Michael; Hook, Trisha I; Undershultz, Michael E

2017-12-01

Since 2001, climatic conditions have been notably drier than normal across large areas of the western Canadian interior, leading to widespread impacts on the forests of this region. This poses a major concern for the future, given climate change projections for continued warming and drying. We conducted tree-ring analysis in 75 pure stands of white spruce (Picea glauca) across Alberta and west-central Saskatchewan to examine the effects of recent climatic drying on the growth of this important boreal tree species. Allometric equations were used to calculate annual growth in aboveground tree biomass (G BM ) from ring width measurements. Results showed an increasing trend in G BM from the 1960s to the 1990s, followed by a sharp decline during the severe drought of 2001-2002. Of the 75 stands, only 18 recovered sufficiently to cause an increase in mean G BM from the predrought decade of 1991-2000 to the subsequent decade of 2001-2010. The remaining 57 stands exhibited a decline in mean G BM between these decades. Climatic drying was a major cause of the growth decline, as shown by the significant stand-level relationship between percentage change in decadal mean G BM and the change in decadal mean values of a climate moisture index from 1991-2000 to 2001-2010. Subsequent analyses of boreal stands sampled across Alberta during 2015 revealed that white spruce growth had declined even further as drought conditions intensified during 2014-2015. Overall, there was a 38% decrease in mean G BM between 1997 and 2015, but surprisingly, the percentage decrease was not significantly different for young, productive stands compared with older, less productive stands. Thus, stand ageing cannot explain the observed decline in white spruce growth during the past quarter century, suggesting that these forests are at risk if the trend towards more frequent, severe drought continues in the region. © 2017 Her Majesty the Queen in Right of Canada Global Change Biology ©2017 John Wiley

Hydrothermal growth of upright-standing ZnO sheet microcrystals

International Nuclear Information System (INIS)

Shi, Ruixia; Yang, Ping; Dong, Xiaobin; Jia, Changchao; Li, Jia

2014-01-01

Highlights: • Upright-standing ZnO sheet microcrystals were hydrothermally fabricated. • The ZnO sheets were prepared with sodium oxalate at 70 °C without any surfactant. • The preferable adsorption of oxalate anions causes the formation of ZnO sheet. • The continuous growth in six directions leads to the formation of hexagonal sheets. - Abstract: Large-scale upright-standing ZnO sheet microcrystals were fabricated on Zn substrate using sodium oxalate as structure-directing agent by a hydrothermal method at low temperature (70 °C) without any surfactant. The sheets are about 3–5 μm in dimension and 100–300 nm in thickness. The strong and narrow diffraction peaks of ZnO indicate that the sample has a good crystallinity and size. The morphology of sheet-like ZnO varied with the concentrations of sodium oxalate and reaction time. The sheet-like ZnO would transform into rod-like ones when sodium oxalate was substituted by equivalent sodium acetate. The formation of sheet-like ZnO is attributed to the preferable adsorption of oxalate anions on (0 0 0 1) face of ZnO, which inhibits the intrinsic growth of ZnO. Additionally, the continuous growth in six (0 1 −1 0) directions that have the lowest surface energy leads to the formation of hexagonal sheets

Old growth revisited: integrating social, economic, and ecological perspectives

Science.gov (United States)

Marie Oliver; Thomas Spies; Sally.   Duncan

2009-01-01

How should old-growth forests be managed? Should they be managed? Stakeholders with differing values and agendas have debated these questions for years. Over time, the debate has evolved: now there is greater awareness about the complexity of old-growth ecosystems and different ways humans value them. A scientist at the Pacific Northwest Research Station has co-edited...

Growth, yield, and structure of extended rotation Pinus resinosa stands in Minnesota, USA

Science.gov (United States)

Anthony W. D' Amato; Brian J. Palik; Christel C. Kern

2010-01-01

Extended rotations are increasingly used to meet ecological objectives on forestland; however, information about long-term growth and yield of these systems is lacking for most forests in North America. Additionally, long-term growth responses to repeated thinnings in older stands have received little attention. We addressed these needs by examining the growth and...

The influence of weather variation on regional growth of Douglas-fir stands in the U.S. Pacific Northwest.

Science.gov (United States)

Charles E. Peterson; Linda S. Heath

1991-01-01

In this paper we examine the influence of precipitation and temperature deviations on regional volume growth rates in even aged, onnen.,ed second growth Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) stands. Between 1969 and 1986, average volume growth rates in natural stands of coast Douglas fix in western Washington and Oregon were negatively...

Managing redwood ecosystems using Sudden Oak Death as a silvicultural tool

Science.gov (United States)

Frederick D. Euphrat

2015-01-01

In response to the wave of sudden oak death (SOD), caused by Phytophthora ramorum, sweeping the redwood forest ecosystems of California's North Coast, the role of foresters and other ecosystem managers is being tested. On Bear Flat Tree Farm, near Healdsburg, California, Forest, Soil & Water, Inc. (FSW) has conducted a multi-year,...

Comparative Structural Dynamics of the Janj Mixed Old-Growth Mountain Forest in Bosnia and Herzegovina: Are Conifers in a Long-Term Decline?

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Srdjan Keren

2014-06-01

Full Text Available Regression of conifers in European mixed old-growth mountain forests has been observed for a long period and studied from different aspects. Old-growth (OG forests in Bosnia and Herzegovina (BiH have not experienced heavy air pollution and chronic overbrowsing that have affected many other European OG forests, while climatic and anthropogenic disturbances have been well documented. We analysed stand structure in the Janj OG forest, compared it with inventories of Lom and Perucica OG forests (BiH and with earlier inventories of the same reserves. At present, OG forest Janj is characterized by a high growing stock (1215 m3∙ha−1. This is due to good site quality, prevalence of conifers (84% and dominant endogenous processes in recent decades. In all three OG forests, indicators of structural change exhibited progression of European beech over time. Historical evidence revealed the occurrence of warm summers and droughts followed by bark beetle outbreaks in the 1920s, 1940s and early 1950s, which in turn influenced a marked conifer decline. It seems likely that repeated canopy opening released waves of European beech regeneration. These stand structural changes have delayed the rejuvenation of conifers and can help explain the early observations of conifer decline.

Sapwood area - leaf area relationships for coast redwood

OpenAIRE

Stancioiu, P T; O'Hara, K L

2005-01-01

Coast redwood (Sequoia sempervirens (D. Don) Endl.) trees in different canopy strata and crown positions were sampled to develop relationships between sapwood cross-sectional area and projected leaf area. Sampling occurred during the summers of 2000 and 2001 and covered tree heights ranging from 7.7 to 45.2 m and diameters at breast height ranging from 9.4 to 92.7 cm. Foliage morphology varied greatly and was stratified into five types based on needle type (sun or shade) and twig color. A str...

Using Scientific Information to Develop Management Strategies for Commercial Redwood Timberlands

Science.gov (United States)

Jeffrey C. Barrett

2007-01-01

In 1999, PALCO (Pacific Lumber Company), a private landowner, and the state and federal governments agreed to implement a unique Habitat Conservation Plan (HCP) on 89,000 hectares of commercial redwood and Douglas-fir timberlands in Humboldt County, California. The aquatics portion of the PALCO HCP contains a set of "interim" conservation strategies developed...

Five years of monitoring infection and mortality in redwood tanoak forests

Science.gov (United States)

Richard C. Cobb; Shannon C. Lynch; Ross K. Meentemeyer; David M. Rizzo

2008-01-01

Rates of disease incidence and tree mortality in redwood-tanoak forests were determined by repeated sampling across a system of 120 plots at five long-term research sites from 2001 through 2006. Plots were located within the known geographic area of Phytophthora ramorum in California, ranging from Monterey to Sonoma counties. All overstory species...

Growth and yield predictions for upland oak stands. 10 years after initial thinning

Science.gov (United States)

Martin E. Dale; Martin E. Dale

1972-01-01

The purpose of this paper is to furnish part of the needed information, that is, quantitative estimates of growth and yield 10 years after initial thinning of upland oak stands. All estimates are computed from a system of equations. These predictions are presented here in tabular form for convenient visual inspection of growth and yield trends. The tables show growth...

Spatial elements of mortality risk in old-growth forests

Science.gov (United States)

Das, Adrian; Battles, John; van Mantgem, Phillip J.; Stephenson, Nathan L.

2008-01-01

For many species of long-lived organisms, such as trees, survival appears to be the most critical vital rate affecting population persistence. However, methods commonly used to quantify tree death, such as relating tree mortality risk solely to diameter growth, almost certainly do not account for important spatial processes. Our goal in this study was to detect and, if present, to quantify the relevance of such processes. For this purpose, we examined purely spatial aspects of mortality for four species, Abies concolor, Abies magnifica, Calocedrus decurrens, and Pinus lambertiana, in an old-growth conifer forest in the Sierra Nevada of California, USA. The analysis was performed using data from nine fully mapped long-term monitoring plots.In three cases, the results unequivocally supported the inclusion of spatial information in models used to predict mortality. For Abies concolor, our results suggested that growth rate may not always adequately capture increased mortality risk due to competition. We also found evidence of a facilitative effect for this species, with mortality risk decreasing with proximity to conspecific neighbors. For Pinus lambertiana, mortality risk increased with density of conspecific neighbors, in keeping with a mechanism of increased pathogen or insect pressure (i.e., a Janzen-Connell type effect). Finally, we found that models estimating risk of being crushed were strongly improved by the inclusion of a simple index of spatial proximity.Not only did spatial indices improve models, those improvements were relevant for mortality prediction. For P. lambertiana, spatial factors were important for estimation of mortality risk regardless of growth rate. For A. concolor, although most of the population fell within spatial conditions in which mortality risk was well described by growth, trees that died occurred outside those conditions in a disproportionate fashion. Furthermore, as stands of A. concolor become increasingly dense, such spatial

Study on Growth Rhythm of Juveniles Cistolemmys Flavomarginata for One and Two Years Old

Science.gov (United States)

Huang, Bin

Growth of one and two year old Cistolemmys flavomarginata is studied. In natural temperature and under artificial feeding condition, juvenile turtles grow for 180 days in Xinyang, one year old turtle average body weight increased from 18.1 g to 54.5 g, the relative growth rate is 204.1%, the absolute growth rate is 0.21. two year old turtle average body weight increased from 46.8 g to 101.1 g, the relative growth rate is 115.98%, the absolute growth rate is 0.30. But two year old turtle growth rate is slower than that of one year old turtle. The body weight, carapace length, carapace width, plastron length, plastron width and carapace high are correlated positively to daily age. The body weight growth equations of one and two year old turtles are deduced. Compared with other reptiles, whole growth cycle is grasped systemically by the growth patterns.

Longevity of Wood-Forced Pools in an Old-Growth Forest

Science.gov (United States)

Buffington, J. M.; Woodsmith, R. D.; Johnson, A. C.

2009-12-01

Wood debris plays an important role in scouring pools in forest channels and providing resultant habitat for aquatic organisms. We investigated the longevity of such pools in a gravel-bed river flowing through old-growth forest in southeastern Alaska by aging trees and “bear’s bread” fungi (Ganoderma applanatum, Fomitopsis pinicola) growing on pool-forming wood debris. Ages were determined by counting annual growth rings from cores and cross sections of trees and fungi growing on the wood debris. These ages are minimum values because they do not account for lag time between debris recruitment and seedling/spore establishment on the debris, nor do they account for flood scour that may periodically reset tree and fungi growth on the debris. The study stream has a gradient of about 1%, bankfull width and depth of 13.3 and 0.78 m, respectively, median grain size of 18 mm, a high wood loading (0.8 pieces/m), and a correspondingly low pool spacing (0.3 bankfull widths/pool), with 81% of the pools forced by wood debris. The size of wood debris in the study stream is large relative to the channel (average log length of 7.6 m and diameter of 0.35 m), rendering most debris immobile. Eighty-one pool-forming pieces of wood were dated over 1.2 km of stream length, with 28% of these pieces causing scour of more than one pool. In all, 122 wood-forced pools were dated, accounting for 38% of all pools at the site and 47% of the wood-forced pools. Fifty-three percent of the wood-forced pools lacked datable wood because these pieces either: were newly recruited; had been scoured by floods; or were contained below the active channel elevation, prohibiting vegetation establishment on the wood debris (the most common cause). The debris age distribution declined exponentially from 2 to 113 yrs., with a median value of 18 yrs. Similar exponential residence time distributions have been reported in other studies, but our analysis focused specifically on the ages of pool-forming wood

Subdivide or silviculture: choices facing family forest owners in the redwood region

Science.gov (United States)

William Stewart; Shasta Ferranto; Gary Nakamura; Christy Getz; Lynn Huntsinger; Maggi. Kelly

2012-01-01

Families or family businesses own nearly all of the private redwood forestland in California. Family forest owners have practiced both subdivision and silviculture for decades but the dominant theme for most family owners is environmental stewardship. Parcel size is more important than expressed values as a predictor of resource management activities. All landowners...

Diagnostic reliability of the cervical vertebral maturation method and standing height in the identification of the mandibular growth spurt.

Science.gov (United States)

Perinetti, Giuseppe; Contardo, Luca; Castaldo, Attilio; McNamara, James A; Franchi, Lorenzo

2016-07-01

To evaluate the capability of both cervical vertebral maturation (CVM) stages 3 and 4 (CS3-4 interval) and the peak in standing height to identify the mandibular growth spurt throughout diagnostic reliability analysis. A previous longitudinal data set derived from 24 untreated growing subjects (15 females and nine males,) detailed elsewhere were reanalyzed. Mandibular growth was defined as annual increments in Condylion (Co)-Gnathion (Gn) (total mandibular length) and Co-Gonion Intersection (Goi) (ramus height) and their arithmetic mean (mean mandibular growth [mMG]). Subsequently, individual annual increments in standing height, Co-Gn, Co-Goi, and mMG were arranged according to annual age intervals, with the first and last intervals defined as 7-8 years and 15-16 years, respectively. An analysis was performed to establish the diagnostic reliability of the CS3-4 interval or the peak in standing height in the identification of the maximum individual increments of each Co-Gn, Co-Goi, and mMG measurement at each annual age interval. CS3-4 and standing height peak show similar but variable accuracy across annual age intervals, registering values between 0.61 (standing height peak, Co-Gn) and 0.95 (standing height peak and CS3-4, mMG). Generally, satisfactory diagnostic reliability was seen when the mandibular growth spurt was identified on the basis of the Co-Goi and mMG increments. Both CVM interval CS3-4 and peak in standing height may be used in routine clinical practice to enhance efficiency of treatments requiring identification of the mandibular growth spurt.

Crush performance of redwood for developing design procedures for impact limiters

International Nuclear Information System (INIS)

Cramer, S.M.; Hermanson, J.C.; McMurtry, W.M.

1995-01-01

Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most simplistic information exists on its crush properties. Tbe stress-strain interrelationship for any wood species subject to three-dimensional stresses is largely unknown for any all stress condition and wood behavior at both high strains and high strain-rates is known only in general terms. Both stress-strain and crush failure theories have been developed based only on uniaxial load tests. The anisotropy of wood adds an additional complexity to measuring wood response and developing suitable theories to describe it. A long history of wood utilization in the building industry has led to design procedures and property information related to simple uniaxial loadings that do not inflict damage to the wood. This lack of knowledge may be surprising for a material that has a long history of engineered use, but the result is difficulty in utilizing wood in more sophisticated designs such as impact limiters. This study provides a step toward filling the information gap on wood material response for high performance applications such as impact limiters

Stand response of 16-year-old upland hardwood regeneration to crop-tree release on a medium quality site in the Southern Appalachians after 24 years

Science.gov (United States)

W. Henry. McNab

2010-01-01

A crop tree release was made in a 16-year-old upland hardwood stand on a medium-quality site using one of two treatments: mechanical or chemical. After 24 years there was no significant difference in stand response between the two treatments as measured by mean increase in stand diameter, basal area, total height, height to base of live...

Forty-two years of change in an old-growth and second-growth beech-maple forest of north central Ohio

Science.gov (United States)

Natalie R. Pinheiro; P. Charles Goebel; David M. Hix

2008-01-01

Using data collected in 1964 and 2006, we examined changes in the composition and structure of a second-growth and old-growth beech-maple forest of Crall Woods, located in Ashland County of north central Ohio. Over the 42 years, the old-growth forest (estimated to be at least 250 years old) experienced a significant shift in species composition as American beech,...

A whole stand growth and yield system for young longleaf pine plantations in Southwest Georgia

Science.gov (United States)

John R. Brooks; Steven B. Jack

2006-01-01

A whole stand growth and yield system for planted longleaf pine (Pinus palustris Mill.) was developed from permanent plot data collected annually over an 8 year period. The dataset consists of 12 intensively-managed longleaf pine plantations that are located in Lee, Worth, Mitchell, and Baker counties in southwest Georgia. Stand survival, dominant...

Growth Response of Northern White-Cedar (Thuja occidentalis to Natural Disturbances and Partial Cuts in Mixedwood Stands of Quebec, Canada

Directory of Open Access Journals (Sweden)

Jean-Claude Ruel

2014-05-01

Full Text Available Northern white-cedar (Thuja occidentalis is a species of high commercial and ecological value, the abundance of which has been declining since the middle of the 19th century. Very little information regarding its silviculture in mixedwood stands is currently available, even though a significant portion of wood resources comes from these stands. The present study is a retrospective analysis of white-cedar growth in partially harvested mixedwood stands of western Quebec, Canada. Eight stands distributed across two regions were analyzed. Dendrochronological approaches examined long-term diameter growth for sample white-cedar trees and stems of associated species. These approaches were used to reconstruct stand characteristics at the time of harvesting, together with local harvesting intensity. The study demonstrated white-cedar’s capacity to maintain good growth for long periods of time and at large tree sizes. Accession to the upper canopy positions occurs through repeated episodes of suppression/release, most of which seem to be associated with spruce budworm (Choristoneura fumiferana outbreaks. White-cedar response to partial harvesting varies with tree size, residual basal area and species composition. Growth response was generally stronger for small trees, even though large trees still maintained the best diameter growth. Growth of white-cedar was negatively affected by an increase in softwood proportion in basal area. Growth responses to harvesting could be sustained for a period of 20 years.

Nanopattern formation using localized plasma for growth of single-standing carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Javadi, Mohammad; Abdi, Yaser, E-mail: y.abdi@ut.ac.ir [University of Tehran, Nanophysics Research Laboratory, Department of Physics (Iran, Islamic Republic of)

2017-01-15

We report a novel method for formation of self-organized single-standing carbon nanotubes by customizing a plasma-based process. The growth of carbon nanotubes by plasma-enhanced chemical vapor deposition provides suitable grounds to utilize plasma–solid interactions for nanopatterning. The bulk plasma is utilized to fabricate carbon nanotubes on the prepatterned Ni catalyst which in turn can confine the plasma to the growth region. The plasma localization leads to a dielectrophoretic force exerted on Ni atoms and can be engineered in order to grow a specific pattern of self-organized single-standing carbon nanotubes. Numerical simulations based on the plasma localization and dielectrophoretic force confirmed the experimental results. This method provides a simple and cost-effective approach to obtain nanopatterned arrays of carbon nanotubes which can be used for fabrication of photonic and phononic crystals, self-gated field emission-based transistors and displays.

Temperate and boreal old-growth forests: how do their growth dynamics and biodiversity differ from young stands and managed forests?

NARCIS (Netherlands)

Schulze, E.D.; Hessenmoeller, D; Knohl, A.; Luyssaert, S; Boerner, A; Grace, J.

2009-01-01

This chapter investigates biomass, net primary productivity (NPP), and net ecosystem productivity (NEP) of boreal and temperate forest ecosystems in relation to stand density and age. Forests may accumulate woody biomass at constant rate for centuries and there is little evidence of an age-related

Arthropod Diversity and Functional Importance in Old-Growth Forests of North America

Directory of Open Access Journals (Sweden)

Timothy Schowalter

2017-03-01

Full Text Available Old-growth forests have become rare in North America but provide habitat for unique assemblages of species that often are rare in younger forests. Insects and related arthropods reach their highest diversity in old-growth forests because of their stable moderate temperature and relative humidity and the rich variety of resources represented by high plant species richness and structural complexity. Old-growth arthropod assemblages typically are distinct from those in younger, managed forests. Major subcommunities include the arboreal community that is composed of a rich assemblage of herbivores, fungivores, and their associated predators and parasitoids that function to regulate primary production and nutrient fluxes, the stem zone community that includes bark- and wood-boring species and their associated predators and parasitoids that initiate the decomposition of coarse woody debris, and the forest floor community composed of a variety of detritivores, fungivores, burrowers, and their associated predators and parasitoids that are instrumental in litter decomposition. Insect outbreaks are relatively rare in old-growth forests, where the diversity of resources and predators limit population growth. In turn, insects contribute to plant diversity and limit primary production of host plant species, thereby promoting development of old-growth forest characteristics. Arthropods also provide important functions in decomposition and nutrient cycling that may be lost in younger, managed forests with limited provision of coarse woody debris and accumulated litter. Protection of remnant old-growth forests within the forest matrix may be particularly valuable for maintaining the diversity of plant and arthropod predators that can minimize outbreaks, thereby contributing to resilience to changing environmental conditions.

Spatially random mortality in old-growth red pine forests of northern Minnesota

Science.gov (United States)

Tuomas ​Aakala; Shawn Fraver; Brian J. Palik; Anthony W. D' Amato

2012-01-01

Characterizing the spatial distribution of tree mortality is critical to understanding forest dynamics, but empirical studies on these patterns under old-growth conditions are rare. This rarity is due in part to low mortality rates in old-growth forests, the study of which necessitates long observation periods, and the confounding influence of tree in-growth during...

Effects of mountain beaver management and thinning on 15-year-old Douglas fir growth and survival.

Science.gov (United States)

Campbell, Dan L; Engeman, Richard M; Farley, James P

2015-07-01

We examined 4-year growth of 15-year-old damaged and undamaged Douglas fir (Pseudotsuga menzesii) after integrating temporary population reductions of mountain beaver (Aplodontia rufa) with thinning in a pre-commercial hand-planted plantation in western Washington. Five treatment combinations were considered: (1) trapping mountain beavers in an unthinned area, (2) trapping before thinning to 65 trees/ha (160 trees/ac), (3) no trapping and thinning to 65 trees/ha, (4) no trapping and thinning to 146 trees/ha (360 trees/ac), and (5) no trapping and no thinning. Removal of ≥ 90 % of mountain beavers temporarily reduced mountain beaver activity whether the stand was unthinned or thinned. Diameter growth at breast height (dbh) was greater for undamaged trees than for damaged trees in thinned areas. Tree height growth was greatest in trapped areas whether thinned or not. No differences were detected in 4-year survival between trees damaged aboveground and those without aboveground damage, which may be related to undetected root damage to trees without aboveground damage. Basal diameter growth and dbh growth were greatest for areas thinned to 65 trees/ha. Seventy-eight percent of stomachs from mountain beaver trapped in winter contained Douglas fir root or stem materials. Overall, short-term removal of mountain beavers integrated with pre-commercial thinning promoted growth of crop trees.

Differences in Townsend's chipmunk populations between second- and old-growth forests in western Oregon

Science.gov (United States)

D.K. Rosenberg; R.G. Anthony

1993-01-01

Because Townsend's chipmunks (Tomias townsendii) may be important in maintaining natural ecosystem processes in forests in the central Oregon Cascade Range, we compared their population characteristics in young second-growth and old-growth forests. We live-trapped Townsend's chipmunks in 5 young (30-60 yr old) second-growth and 5 old-...

Sudden Oak Death in redwood forests: vegetation dynamics in the wake of tanoak decline

Science.gov (United States)

Benjamin Ramage; Kevin O’Hara

2010-01-01

Numerous lines of inquiry have concluded that tanoak (Lithocarpus densiflorus) will continue to experience drastic population declines and may even disappear entirely from redwood (Sequoia sempervirens) forests as a result of the exotic disease sudden oak death (SOD) (Maloney and others 2005, McPherson and others 2005,...

Climate, canopy disturbance, and radial growth averaging in a second-growth mixed-oak forest in West Virginia, USA

Science.gov (United States)

James S. Rentch; B. Desta Fekedulegn; Gary W. Miller

2002-01-01

This study evaluated the use of radial growth averaging as a technique of identifying canopy disturbances in a thinned 55-year-old mixed-oak stand in West Virginia. We used analysis of variance to determine the time interval (averaging period) and lag period (time between thinning and growth increase) that best captured the growth increase associated with different...

Early lessons from commercial thinning in a 30-year-old Sitka Spruce-Western Hemlock forest.

Science.gov (United States)

Sarah E. Greene; William H. Emmingham

1986-01-01

A commercial thinning study was undertaken in a 30-year-old stand, pre-commercially thinned at 15 years of age, at Cascade Head Experimental Forest on the Oregon coast. Measurements obtained after three different thinning treatments are presented and include stand volume, basal area, current growth rate, scar damage, crown ratio, and sapwood radius. Method of...

The History of Redwood Records: Cultural and Economic Perspectives on a Feminist Subculture.

Science.gov (United States)

Lont, Cynthia M.

Using interviews and subcultural artifacts, such as inner sleeves of albums, this paper reports on the career of Holly Near and the history of Redwood Records, a label providing music to the lesbian-feminist subculture. First, the paper discusses the political and artistic avenues that were available to Near, the reasons she chose political music,…

Nitrogen Fertilization Increases Cottonwood Growth on Old-Field Soil

Science.gov (United States)

B. G. Blackmon; E. H. White

1972-01-01

Nitrogen (150 lb ./acre as NH4N03 ) applied to a 6-year-old eastern cottonwood plantation in an old field on Commerce silt loam soil increased diameter, basal area, and volume growth by 200 percent over untreated controls. The plantation did not respond to 100 pounds P per acre from concentrated superphosphate.

Effect of thinning, fertilization with biosolids, and weather on interannual ring specific gravity and carbon accumulation of a 55-year-old Douglas-fir stand in western Washington

Energy Technology Data Exchange (ETDEWEB)

Kantavichai, R.; Briggs, D.G.; Turnblom, E.C. [Washington Univ., Seattle, WA (United States). School of Forest Resources

2010-01-15

Soil moisture deficits (SMD) cause trees to conserve water by closing stomata, which in turn limits the uptake of atmospheric carbon dioxide (CO{sub 2}) and curtails photosynthesis and wood formation. This study investigated the combined effect of temperature, precipitation, SMD, and various silviculture treatments on interannual ring specific gravity (SG). A model was developed to predict post-treatment interannual ring SG from the treatment and environmental variables. The study assumed that thinning the stand would increase SG, while fertilization with biosolids would decrease SG. The SGs associated with each treatment were then used to calculate the dry mass and carbon content associated with stem growth. Results were then compared with estimates taken from standard publications. The experiment was conducted on a 55-year old Douglas fir stand. Twelve rings were used to assess the effect of the treatments. The study showed that use of the published average to consider only carbon sequestered by tree growth distorts the comparison of management regimes. The thinning process produced logs from which long-term structures were built, and continue to sequester carbon. When product pools of stored carbon are combined with forest carbon pools, thinning and biosolids treatment regimes are preferable to other carbon storage regimes. 40 refs., 6 tabs., 2 figs.

Climatic and physiological effects on leaf and tree-ring stable isotopes in California redwoods

Science.gov (United States)

Ambrose, A. R.; Baxter, W.; Wong, C.; Dawson, T. E.; Carroll, A.; Voelker, S.

2016-12-01

Variation in the stable isotope composition of organic matter can provide important information about environmental change and biological responses to it. We analyzed the stable carbon (d13C) and oxygen (d18O) isotope ratios of leaves and of the cellulose from individual tree-rings of California's two redwood species to examine how these trees have responded to environmental variation and change in both time and space. Analyses of leaf d13C for both coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum) from throughout their geographical ranges show a marked gradient with tree height for trees of all sizes and ages but no clear difference among species or populations. The gradient is best explained by tree response to changes in both microenvironment and physiology that are known to change with height. In contrast, leaf d18O for both species showed no clear relationship with height but very clear differences between species and populations with giant sequoia displaying a much stronger inferred leaf-level response to the higher evaporative conditions present in the Sierra Nevada mountains as compared to the coast. Both species showed population-level differences with the driest and warmest sites most distinct from all of the others. Intra-annual analyses of d13C and d18O in tree-rings over a 21-year period (1974-1994) were also used to explore how climate and tree response to climate was recorded for both species. These analyses revealed unique (local) climatic effects and response to the climate for each species and population of both redwood species. Most pronounced was a significant increase in intrinsic Water Use Efficiency (iWUE) derived from d13C data over the study period in both species, and a distinct d18O response in relation to drought (e.g. 1976/1977) and to warmer days and nights and above-average precipitation (e.g., 1982-1985). Patterns of co-variation in d13C and d18O in both species suggest that during dry and also warm

The Growth of Agarwood Plants on the Different Canopy Covers Level and Fertilizer in Oil Palm Plantation

Science.gov (United States)

Rahayu Prastyaningsih, Sri; Azwin

2017-12-01

The development of agar wood plants in oil palm plantation requires the forestry techniques in order to obtain maximum production. In an oil palm stands, the age of plant will affect the height, diameter, population and stands density. The older age of an oil palm stands will affect the canopy cover on the forest floor. Agar wood plants are semi-tolerant growth and oil palm can be used as shade. Unilak has an oil palm plantation area of 10 hectares around the campus with 10 years old and 20 years old. The soil condition at the study is Podsolik Merah Kuning (PMK) which poor nutrient and needs fertilization to increase soil fertility. This study aims to find out the effect of age of oil palm stands and fertilization for optimal growth. The split plot design with 2 main plots of the age of palm tree ( 10 years old and 20 years old) and five kinds of fertilizing sub plot (without fertilizer, 40 gram/plant of NPK, 80 gram/plat of NPK, 120 gram/plant of NPK and 180 gram/plant of NPK were used. The results of this research showed that the age of palm tree (canopy cover) treatment gave non-significant influence on the growing of agar wood until it reaches 4 months of growth. The canopyy cover by 10 years old of oil palm tree produce the best response on height (15 cm) and diameter (0,4 cm) growth of agar woods..Fertilizing treatment di not give any significant influence on the heigh and diameter growth of agarwood plants until reach 3 months. The interaction by 10 years old of palm with fertilizing gave non significant results.

Polarity driven simultaneous growth of free-standing and lateral GaAsP epitaxial nanowires on GaAs (001) substrate

International Nuclear Information System (INIS)

Sun, Wen; Xu, Hongyi; Guo, Yanan; Gao, Qiang; Hoe Tan, Hark; Jagadish, Chennupati; Zou, Jin

2013-01-01

Simultaneous growth of 〈111〉 B free-standing and ±[110] lateral GaAsP epitaxial nanowires on GaAs (001) substrates were observed and investigated by electron microscopy and crystallographic analysis. It was found that the growth of both free-standing and lateral ternary nanowires via Au catalysts was driven by the fact that Au catalysts prefer to maintain low-energy (111) B interfaces with surrounding GaAs(P) materials: in the case of free-standing nanowires, Au catalysts maintain (111) B interfaces with their underlying GaAsP nanowires; while in the case of lateral nanowires, each Au catalyst remain their side (111) B interfaces with the surrounding GaAs(P) material during the lateral nanowire growth

Nutrient uptake and community metabolism in streams draining harvested and old-growth watersheds: A preliminary assessment

Science.gov (United States)

Brian H. Hill; Frank H. McCormick

2004-01-01

The effect of timber harvesting on streams is assessed using two measures of ecosystem function: nutrient spiraling and community metabolism. This research is being conducted in streams of the southern Appalachian Mountains of North Carolina, the Ouachita Mountains of Arkansas, the Cascade Mountains of Oregon, and the redwood forests of northern California, in order to...

Influence of thinning intensity and canopy type on Scots pine stand and growth dynamics in a mixed managed forest

Energy Technology Data Exchange (ETDEWEB)

Primicia, I.; Artázcoz, R.; Imbert, J.B.; Puertas, F.; Traver, M.C.; Castillo, F.J.

2016-07-01

Aim of the study: We analysed the effects of thinning intensity and canopy type on Scots pine growth and stand dynamics in a mixed Scots pine-beech forest. Area of the study: Western Pyrenees. Material and methods: Three thinning intensities were applied in 1999 (0, 20 and 30% basal area removed) and 2009 (0, 20 and 40%) on 9 plots. Within each plot, pure pine and mixed pine-beech patches are distinguished. All pine trees were inventoried in 1999, 2009 and 2014. The effects of treatments on the tree and stand structure variables (density, basal area, stand and tree volume), on the periodic annual increment in basal area and stand and tree volume, and on mortality rates, were analysed using linear mixed effects models. Main Results: The enhancement of tree growth was mainly noticeable after the second thinning. Growth rates following thinning were similar or higher in the moderate than in the severe thinning. Periodic stand volume annual increments were higher in the thinned than in the unthinned plots, but no differences were observed between the thinned treatments. We observed an increase in the differences of the Tree volume annual increment between canopy types (mixed < pure) over time in the unthinned plots, as beech crowns developed. Research highlights: Moderate thinning is suggested as an appropriate forest practice at early pine age in these mixed forests, since it produced higher tree growth rates than the severe thinning and it counteracted the negative effect of beech on pine growth observed in the unthinned plots. (Author)

Gap Dynamics and Structure of Two Old-Growth Beech Forest Remnants in Slovenia

Science.gov (United States)

Rugani, Tihomir; Diaci, Jurij; Hladnik, David

2013-01-01

Context Due to a long history of intensive forest exploitation, few European beech (Fagus sylvatica L.) old-growth forests have been preserved in Europe. Material and Methods We studied two beech forest reserves in southern Slovenia. We examined the structural characteristics of the two forest reserves based on data from sample plots and complete inventory obtained from four previous forest management plans. To gain a better understanding of disturbance dynamics, we used aerial imagery to study the characteristics of canopy gaps over an 11-year period in the Kopa forest reserve and a 20-year period in the Gorjanci forest reserve. Results The results suggest that these forests are structurally heterogeneous over small spatial scales. Gap size analysis showed that gaps smaller than 500 m2 are the dominant driving force of stand development. The percentage of forest area in canopy gaps ranged from 3.2 to 4.5% in the Kopa forest reserve and from 9.1 to 10.6% in the Gorjanci forest reserve. These forests exhibit relatively high annual rates of coverage by newly established (0.15 and 0.25%) and closed (0.08 and 0.16%) canopy gaps. New gap formation is dependant on senescent trees located throughout the reserve. Conclusion We conclude that these stands are not even-sized, but rather unevenly structured. This is due to the fact that the disturbance regime is characterized by low intensity, small-scale disturbances. PMID:23308115

Intracortical inhibition in the soleus muscle is reduced during the control of upright standing in both young and old adults

NARCIS (Netherlands)

Papegaaij, Selma; Baudry, Stéphane; Négyesi, János; Taube, Wolfgang; Hortobagyi, Tibor

Purpose In a previous study, we reported that a short-interval intracortical inhibition (SICI) decreases in old but not in young adults when standing on foam vs. a rigid surface. Here, we examined if such an age by task difficulty interaction in motor cortical excitability also occurs in easier

A review of thinning effects on Scots pine stands: From growth and yield to new challenges under global change

Directory of Open Access Journals (Sweden)

Miren del Río

2017-10-01

Full Text Available Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L. stands have been carried out since long in different regions of its distribution. The aim of this paper is to gather the knowledge about the thinning effects on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the framework of climate change. Area of study: The review covered studies from different regions of the distribution area of Scots pine Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L. stands have been carried out for many years in different regions of its distribution. The aim of this paper is to gather knowledge regarding the effects of thinning on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the context of climate change. Area of study: The review covers studies from different regions of the distribution area of Scots pine Material and methods: We reviewed the effect of thinning on four aspects: growth and yield, stability against snow and wind, response to drought, and ecosystem services. Main results: Heavy thinning involves a loss in volume yield, although the magnitude depends on the region, site and stand age. Thinning generally does not affect dominant height while the positive effect on tree diameter depends on the thinning regime. The stability of the stand against snow and wind is lower after the first thinning and increases in the long term. The impact of extreme droughts on tree growth is lower in thinned stands, which is linked to a better capacity to recover after the drought. Thinning generally reduces the wood quality, litter mass, and stand structural diversity, while having neutral or positive effects on other ecosystem services, although these effects can vary depending on the thinning regime. However, scarce information is available for most of the ecosystem services. Research highlight: Existing thinning experiments in

A review of thinning effects on Scots pine stands: From growth and yield to new challenges under global change

International Nuclear Information System (INIS)

Miren del Río, M.P.; Bravo-Oviedo, Andrés; Pretzsch, Hans; Löf, Magnus; Ruiz-Peinado, Ricardo

2017-01-01

Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out since long in different regions of its distribution. The aim of this paper is to gather the knowledge about the thinning effects on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the framework of climate change. Area of study: The review covered studies from different regions of the distribution area of Scots pine Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out for many years in different regions of its distribution. The aim of this paper is to gather knowledge regarding the effects of thinning on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the context of climate change. Area of study: The review covers studies from different regions of the distribution area of Scots pine Material and methods: We reviewed the effect of thinning on four aspects: growth and yield, stability against snow and wind, response to drought, and ecosystem services. Main results: Heavy thinning involves a loss in volume yield, although the magnitude depends on the region, site and stand age. Thinning generally does not affect dominant height while the positive effect on tree diameter depends on the thinning regime. The stability of the stand against snow and wind is lower after the first thinning and increases in the long term. The impact of extreme droughts on tree growth is lower in thinned stands, which is linked to a better capacity to recover after the drought. Thinning generally reduces the wood quality, litter mass, and stand structural diversity, while having neutral or positive effects on other ecosystem services, although these effects can vary depending on the thinning regime. However, scarce information is available for most of the ecosystem services. Research highlight: Existing thinning experiments in Scots pine stands

A review of thinning effects on Scots pine stands: From growth and yield to new challenges under global change

Energy Technology Data Exchange (ETDEWEB)

Miren del Río, M.P.; Bravo-Oviedo, Andrés; Pretzsch, Hans; Löf, Magnus; Ruiz-Peinado, Ricardo

2017-11-01

Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out since long in different regions of its distribution. The aim of this paper is to gather the knowledge about the thinning effects on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the framework of climate change. Area of study: The review covered studies from different regions of the distribution area of Scots pine Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out for many years in different regions of its distribution. The aim of this paper is to gather knowledge regarding the effects of thinning on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the context of climate change. Area of study: The review covers studies from different regions of the distribution area of Scots pine Material and methods: We reviewed the effect of thinning on four aspects: growth and yield, stability against snow and wind, response to drought, and ecosystem services. Main results: Heavy thinning involves a loss in volume yield, although the magnitude depends on the region, site and stand age. Thinning generally does not affect dominant height while the positive effect on tree diameter depends on the thinning regime. The stability of the stand against snow and wind is lower after the first thinning and increases in the long term. The impact of extreme droughts on tree growth is lower in thinned stands, which is linked to a better capacity to recover after the drought. Thinning generally reduces the wood quality, litter mass, and stand structural diversity, while having neutral or positive effects on other ecosystem services, although these effects can vary depending on the thinning regime. However, scarce information is available for most of the ecosystem services. Research highlight: Existing thinning experiments in Scots pine stands

Ecological setting of the Wind River old-growth forest.

Science.gov (United States)

David C. Shaw; Jerry F. Franklin; Ken Bible; Jeffrey Klopatek; Elizabeth Freeman; Sarah Greene; Geoffrey G. Parker

2004-01-01

The Wind River old-growth forest, in the southern Cascade Range of Washington State, is a cool (average annual temperature, 8.7°C), moist (average annual precipitation, 2223 mm), 500-year-old Douglas-fir-western hemlock forest of moderate to low productivity at 371-m elevation on a less than 10% slope. There is a seasonal snowpack (November-March), and rain-on-snow and...

Production potential and stability of a broadleaved mixed oak/hornbeam forest stand situated on a eutrophic site, Ždánický les

Directory of Open Access Journals (Sweden)

Václav Hurt

2012-01-01

Full Text Available The paper focuses on assessing the growth and production of a mixed oak/hornbeam forest stand established by combined regeneration in 1940 to 1942. The stand is situated at an altitude of 460 m. Since 1961, it is left to its natural development. The 25–year–old stand was characterized as an individually mixed, both diameter- and height-differentiated pole-stage stand. The proportion of tree species was as follows: sessile oak 77 %, hornbeam 19 %, birch 1 %, lime 1 %, black poplar 1 %, wild cherry tree, wild service tree, and field maple. During 41 years of measurements, the proportion of oak slightly decreased to 76 %, on the other hand, the proportion of hornbeam increased to 22%. The initial growing stock of the 25–year–old stand, 75 m3.ha−1, increased to 323 m3.ha−1 at an age of 66 years in 2008. At present, current volume increment ranged between 6.3 m3.ha−1.year−1 and 11.6 m3.ha−1.year−1 during years 1967 and 1998. Since the age of 61, the growth of the stand has decreased and then even ceased due to increased mortality of oak.

FlorNExT®, a cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait.) stands in Northeastern Portugal

Energy Technology Data Exchange (ETDEWEB)

Barreiro, S.; Rua, J.; Tomé, M.

2016-07-01

Aim of the study. To introduce and describe FlorNExT®, a free cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait.) even-aged stands in the Northeast of Portugal (NE Portugal). Area of study: NE Portugal. Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves) and basal area, as well as output functions for tree and stand volume, biomass, and carbon content. Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/. Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal. (Author)

New and interesting lichen records from old-growth forest stands in the German National Park Bayerischer Wald

Czech Academy of Sciences Publication Activity Database

Printzen, C.; Halda, J.; Palice, Zdeněk; Toensberg, T.

2002-01-01

Roč. 74, 1-2 (2002), s. 25-49 ISSN 0029-5035 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : lichens * forest stands * Bayerischer Wald National Park Subject RIV: EF - Botanics Impact factor: 0.588, year: 2002

Spatial aspects of tree mortality strongly differ between young and old-growth forests.

Science.gov (United States)

Larson, Andrew J; Lutz, James A; Donato, Daniel C; Freund, James A; Swanson, Mark E; HilleRisLambers, Janneke; Sprugel, Douglas G; Franklin, Jerry F

2015-11-01

Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, mortality should be primarily density dependent due to competition for light, leading to an increasingly spatially uniform pattern of surviving trees. In contrast, mortality in old-growth forests should be primarily caused by contagious and spatially autocorrelated agents (e.g., insects, wind), causing spatial aggregation of surviving trees to increase through time. We tested these predictions by contrasting a three-decade record of tree mortality from replicated mapped permanent plots located in young (old) and old-growth (> 300-year-old) Abies amabilis forests. Trees in young forests died at a rate of 4.42% per year, whereas trees in old-growth forests died at 0.60% per year. Tree mortality in young forests was significantly aggregated, strongly density dependent, and caused live tree patterns to become more uniform through time. Mortality in old-growth forests was spatially aggregated, but was density independent and did not change the spatial pattern of surviving trees. These results extend current theory by demonstrating that density-dependent competitive mortality leading to increasingly uniform tree spacing in young forests ultimately transitions late in succession to a more diverse tree mortality regime that maintains spatial heterogeneity through time.

Tree- and Stand-Level Thinning Effects on Growth of European Beech (Fagus sylvatica L. on a Northeast- and a Southwest-Facing Slope in Southwest Germany

Directory of Open Access Journals (Sweden)

Daniela Diaconu

2015-09-01

Full Text Available Anticipated changes in climate and research findings on the drought sensitivity of beech have triggered controversial discussions about the future of European beech. We investigated the growth response of beech on the tree- and stand-level in mature stands to three different thinning intensities (no thinning, strong thinning, very strong thinning on a northeast- and southwest-facing slope in Southwest Germany. Linear mixed-effects models were formulated to describe effects on growth parameters on the tree- and stand-level (diameter, height, basal area, volume. At the stand-level, the stand basal area increment and stand volume increment were lower on the thinned plots. At the tree-level, the basal area increment significantly increased with increasing thinning intensity. The growth of individual trees was also influenced by initial tree size, the size-related rank of the tree within a stand, and by the aspect of the site. Our data indicate that growth of European beech is impaired on the southwest-facing slope with a warmer and drier climate and that a very strong thinning regime applied at advanced age can accelerate growth of European beech trees even on the warmer and drier site. Our findings, therefore, imply that in a warmer climate intensive thinning may also represent an important adaptive forest management measure in European beech stands.

Treefall gap disturbance in an old-growth beech forest in southwestern Japan by a catastrophic typhoon

International Nuclear Information System (INIS)

Ida, Hideyuki

2000-01-01

In 1991, the catastrophic Typhoon 9119 created many treefall gaps in an old-growth beech (Fagus crenata) forest on Mt. Garyu, southwestern Japan. In a 3.3-ha plot, the density and basal area of fatally damaged trunks (DBH ≥ 20 cm) were 29.1 trunks/ha (16.9% of all pre-typhoon trunks) and 9.1 m 2 /ha. (24.4% of total pre-typhoon basal area), respectively. Many of the dominant beech were lost and larger trunks were damaged. The pre- and post-typhoon DBH distribution both had an inverse J-shape. Spatial distribution of living trunks was not random but clustered irrespective of typhoon damage or DBH size, suggesting that the stand structure of the study plot would be an unusual one as compared with the previous study stands in Japanese beech forests. The death of pre-typhoon trunks, seemed to die standing or to be killed by snap-off, occurred singly; however, the typhoon fatally damaged many clustered trunks at the same time. Uprooting was the most frequent cause of gaps created by the typhoon. The intermediate DBH size class (40 - 70 cm) would be more likely to be uprooted than snapped-off. The DBH distribution of snap-off may reflect the total pre-typhoon trunk distribution. Branch-fall had a flat DBH distribution. Uprooting might have a clustered distribution, while snap-off and branch-fall both had random distributions. The smaller trunks of snap-off and branch-fall seemed to result from injuries caused by the fall of larger trunks

Wafer bowing control of free-standing heteroepitaxial diamond (100) films grown on Ir(100) substrates via patterned nucleation growth

International Nuclear Information System (INIS)

Yoshikawa, Taro; Kodama, Hideyuki; Kono, Shozo; Suzuki, Kazuhiro; Sawabe, Atsuhito

2015-01-01

The potential of patterned nucleation growth (PNG) technique to control the wafer bowing of free-standing heteroepitaxial diamond films was investigated. The heteroepitaxial diamond (100) films were grown on an Ir(100) substrate via PNG technique with different patterns of nucleation regions (NRs), which were dot-arrays with 8 or 13 μm pitch aligned to < 100 > or < 110 > direction of the Ir(100) substrate. The wafer bows and the local stress distributions of the free-standing films were measured using a confocal micro-Raman spectrometer. For each NR pattern, the stress evolutions within the early stage of diamond growth were also studied together with a scanning electron microscopic observation of the coalescing diamond particles. These investigations revealed that the NR pattern, in terms of pitch and direction of dot-array, strongly affects the compressive stress on the nucleation side of the diamond film and dominantly contributes to the elastic deformation of the free-standing film. This indicates that the PNG technique with an appropriate NR pattern is a promising solution to fabricate free-standing heteroepitaxial diamond films with extremely small bows. - Highlights: • Wafer bowing control of free-standing heteroepitaxial diamond (100) films • Effect of patterned nucleation and growth (PNG) technique on wafer bowing reduction • Influence of nucleation region patterns of PNG on wafer bowing • Internal stress analysis of PNG films via confocal micro-Raman spectroscopy

FlorNExT®, a cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait. stands in Northeastern Portugal

Directory of Open Access Journals (Sweden)

Fernando Pérez-Rodríguez

2016-07-01

Full Text Available Aim of the study: To introduce and describe FlorNExT®, a free cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait. even-aged stands in the Northeast of Portugal (NE Portugal. Area of study: NE Portugal. Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves and basal area, as well as output functions for tree and stand volume, biomass, and carbon content. Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/. Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal. Keywords: forest management; maritime pine; forest modelling; knowledge transfer tool.

The old age security hypothesis and optimal population growth.

Science.gov (United States)

Bental, B

1989-03-01

The application of the Samuelson-Diamond overlapping generations framework to the old age security hypothesis indicates that government intervention schemes can influence the relationship between population growth and capital accumulation. The most direct means of optimizing population growth is through taxes or subsidies that relate to the intergenerational transfer of wealth. A pay-as-you-go social security scheme, in which payment is predicated on the number of children the receiver has and is financed by taxes levied on the working population, emerges as the most likely intervention to produce the optimal steady state equilibrium. This system is able to correct any distortions the private sector may build into it. In contrast, a child support system, in which the government subsidizes or taxes workers according to their family size, can guarantee the optimal capital:labor ratio but not the optimal population growth rate. Thus, if the government seeks to decrease the population growth rate, the appropriate intervention is to levy a lump-sum social-security tax on workers and transfer the revenues to the old; the direction should be reversed if the goal is to increase population growth. Another alternative, a lump sum social security system, can guarantee optimal population growth but not a desirable capital:labor ratio. Finally, the introduction of money as a valued commodity into an economy with a high capital:labor ratio will also serve to decrease the population growth rate and solve the intergenerational transfer problem through the private sector without any need for government intervention.

An analysis of phenotypic selection in natural stands of northern red oak (Quercus rubra L.)

Science.gov (United States)

Jeffery W. Stringer; David B. Wagner; Scott E. Schlarbaum; Daniel B. Houston

1995-01-01

Comparison of growth and stem quality parameters of 19-year-old progeny from superior and comparison trees indicates that rigorous phenotypic selection of trees in natural stands may not be an efficient method of parent tree selection for Quercus rubra L. Total tree height, dbh, number of branches in the butt log, fork height, and number of mainstem...

[Growth effect of eucalyptus-acacia mixed plantation in South China].

Science.gov (United States)

Yang, Zeng-Jiang; Xu, Da-Ping; Chen, Wen-Ping; Huang, Lie-Jian; Li, Shang-Jun; Chen, Yuan

2009-10-01

Eucalyptus U6 and Acacia crassicarpa were mixed planted with different ratios and modes to investigate the growth parameters of the two tree species. In the 2-3 years old mixed plantation, the wind-throw of A. crassicarpa decreased markedly with increasing ratio of Eucalyptus U6, the decrement being 26.14% when the Eucalyptus U6/A. crassicarpa ratio was 3 : 1, but the survival rates of Eucalyptus U6 and A. crassicarpa had no significant difference under different planting modes. Mixed planting retarded the A. crassicarpa growth to some extent, with the DBH being 90% of that in pure A. crassicarpa stand. The mixed planting had little effects on the height growth of Eucalyptus U6, but promoted its DBH growth markedly, and the beneficial effect increased with increasing ratio of A. crassicarpa. In the 6 years old 1 : 1 Eucalyptus U6/A. crassicarpa plantation, the Eucalyptus U6 individuals with DBH > 15 cm occupied 32.1%; while in pure Eucalyptus U6 stand, they only accounted for 5.83%. Mixed planting with 2 : 1 Eucalyptus U6/A. crassicarpa could obtain a maximum total biomass of 198.8 m3 x hm(-2), which was 118.8% of the total biomass in pure Eucalyptus U6 stand, or 169.9% of that in pure A. crassicarpa stand. Mixture of Eucalyptus with Acacia would be a good choice to produce Eucalyptus trees with larger DBH.

Family forest owners in the redwood region: management priorities and opportunities in a carbon market

Science.gov (United States)

Erin Clover Kelly; Joanna Di Tommaso; Arielle Weisgrau

2017-01-01

California’s cap-and-trade carbon market has included forest offset projects, available to all private landowners across the United States. The redwood region has been at the forefront of the market, creating the earliest forest carbon projects. From carbon registries, we compiled a database of all forest carbon projects in the market, in order to determine...

SPECIES-SPECIFIC PARTITIONING OF SOIL WATER RESOURCES IN AN OLD-GROWTH DOUGLAS-FIR/WESTERN HEMLOCK FOREST

Science.gov (United States)

Although tree- and stand-level estimates of forest water use are increasingly common, relatively little is known about partitioning of soil water resources among co-occurring tree species. We studied seasonal courses of soil water utilization in a 450-year-old Pseudotsuga menzies...

Structural and compositional controls on transpiration in 40- and 450-year-old riparian forests in western Oregon, USA.

Science.gov (United States)

Moore, Georgianne W; Bond, Barbara J; Jones, Julia A; Phillips, Nathan; Meinzer, Federick C

2004-05-01

Large areas of forests in the Pacific Northwest are being transformed to younger forests, yet little is known about the impact this may have on hydrological cycles. Previous work suggests that old trees use less water per unit leaf area or sapwood area than young mature trees of the same species in similar environments. Do old forests, therefore, use less water than young mature forests in similar environments, or are there other structural or compositional components in the forests that compensate for tree-level differences? We investigated the impacts of tree age, species composition and sapwood basal area on stand-level transpiration in adjacent watersheds at the H.J. Andrews Forest in the western Cascades of Oregon, one containing a young, mature (about 40 years since disturbance) conifer forest and the other an old growth (about 450 years since disturbance) forest. Sap flow measurements were used to evaluate the degree to which differences in age and species composition affect water use. Stand sapwood basal area was evaluated based on a vegetation survey for species, basal area and sapwood basal area in the riparian area of two watersheds. A simple scaling exercise derived from estimated differences in water use as a result of differences in age, species composition and stand sapwood area was used to estimate transpiration from late June through October within the entire riparian area of these watersheds. Transpiration was higher in the young stand because of greater sap flux density (sap flow per unit sapwood area) by age class and species, and greater total stand sapwood area. During the measurement period, mean daily sap flux density was 2.30 times higher in young compared with old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Sap flux density was 1.41 times higher in young red alder (Alnus rubra Bong.) compared with young P. menziesii trees, and was 1.45 times higher in old P. menziesii compared with old western hemlock (Tsuga heterophylla (Raf

Watershed restoration, jobs-in-the woods, and community assistance: Redwood National Park and the Northwest Forest Plan.

Science.gov (United States)

Christopher E. DeForest

1999-01-01

There are many parallels between the 1978 legislation to expand Redwood National Park and the Northwest Forest Plan, which together with the Northwest Economic Adjustment Initiative formed the 1993 Pacific Northwest Initiative. In both situations, the Federal Government sought to promote retraining for displaced workers, to undertake watershed assessment and...

Stand model for upland forests of Southern Arkansas

Energy Technology Data Exchange (ETDEWEB)

Mielke, D.L.; Shugart, H.H.; West, D.C.

1978-06-01

A forest stand growth and composition simulator (FORAR) was developed by modifying a stand growth model by Shugart and West (1977). FORAR is a functional stand model which used ecological parameters to relate individual tree growth to environment rather than using Markov probability matrices or differential equations to determine single tree or species replacement rates. FORAR simulated tree growth and species composition of upland forests of Union County, Ark., by considering 33 tree species on a /sup 1///sub 12/ ha circular plot.

Metal stress and decreased tree growth in response to biosolids application in greenhouse seedlings and in situ Douglas-fir stands

International Nuclear Information System (INIS)

Cline, Erica T.; Nguyen, Quyen T.N.; Rollins, Lucy; Gawel, James E.

2012-01-01

To assess physiological impacts of biosolids on trees, metal contaminants and phytochelatins were measured in Douglas-fir stands amended with biosolids in 1982. A subsequent greenhouse study compared these same soils to soils amended with fresh wastewater treatment plant biosolids. Biosolids-amended field soils had significantly higher organic matter, lower pH, and elevated metals even after 25 years. In the field study, no beneficial growth effects were detected in biosolids-amended stands and in the greenhouse study both fresh and historic biosolids amendments resulted in lower seedling growth rates. Phytochelatins – bioindicators of intracellular metal stress – were elevated in foliage of biosolids-amended stands, and significantly higher in roots of seedlings grown with fresh biosolids. These results demonstrate that biosolids amendments have short- and long-term negative effects that may counteract the expected tree growth benefits. - Highlights: ► Biosolids amendment increases soil metals over 25 years later. ► Douglas-fir growth benefits fail to materialize from biosolids amendments. ► Phytochelatins are elevated in foliage of trees and roots of greenhouse seedlings after new biosolids are added to soil. ► Biosolids connected to metal stress in Douglas-fir. - Biosolids applications increase bioindicators of intracellular metal stress and may counteract tree growth benefits.

Fertilization increases diameter growth of birch-beech-maple trees in New Hampshire

Science.gov (United States)

L. O. Safford

1973-01-01

In a 60-year-old northern hardwood stand treated with lime plus NPK fertilizer, the following increases in average basal area growth rate over untreated trees were observed: sugar maple 128 percent, paper birch 69 percent, yellow birch 51 percent, and beech 20 percent. Magnitude of response was inversely related to relative growth rate of the species. Growth rate...

Sediment transport and storage in North Fork Caspar Creek, Mendocino County, California: water years 1980-1988

Science.gov (United States)

Michael Brent Napolitano

1996-01-01

Abstract - The old-growth redwood forest of North Fork Caspar Creek was clear-cut between 1864 and 1904. Previous research on logging-related changes in suspended sediment and streamflow would suggest that North Fork Caspar Creek has recovered from historical logging (Rice et al., 1979; Ziemer, 1981); research on the influence of large woody debris (LWD) on channel...

Conserving and Restoring Old Growth in Frequent-fire Forests: Cycles of Disruption and Recovery

Directory of Open Access Journals (Sweden)

Dave Egan

2007-12-01

Full Text Available I provide a synthesis of the papers in the Special Issue, The Conservation and Restoration of Old Growth in Frequent-fire Forests of the American West. These papers - the product of an Old Growth Writing Workshop, held at Northern Arizona University in Flagstaff, Arizona on 18-19 April 2006 - represent the ideas of 25 workshop participants who argue for a new attitude toward managing old growth in the frequent-fire forests of the American West. Unlike the lush, old-growth rainforests of the Pacific Northwest, the dry, frequent-fire forests of the western United States evolved with surface fires that disturbed the system with such regularity that young trees were almost always killed. When saplings did survive, they grew beyond the harm of frequent surface fires and, ultimately, attained the characteristics that define old growth in these systems. This system worked well, producing old-growth trees in abundance, until the onset of Euro-American settlement in the mid- to late-19th century. The arrival of these settlers put in motion an interplay of unprecedented social, political, economic, and ecological forces (e.g., removal of Native Americans and their fire-based land management systems, overgrazing of the understory, aggressive logging, establishment of federal land management agencies, implementation of a federal fire suppression policy. These activities have culminated in 1 overly dense forested ecosystems that are now on the verge of collapse because of catastrophic fires (i.e., crown fire at the landscape level; the Rodeo-Chediski Fire and insect outbreaks, 2 the emergence of conservation-minded environmental legislation and policy, and 3 greater levels of interaction between citizens, federal agencies, and fire-prone landscapes. Recognizing the tenuous ecological situation of these forests, restoration ecologists, foresters, and others have developed ways to return historic ecological processes and lower tree densities to these forests

Stand-level growth and yield component models for red oak-sweetgum forests on Mid-South minor stream bottoms

Science.gov (United States)

Emily B. Schultz; J. Clint Iles; Thomas G. Matney; Andrew W. Ezell; James S. Meadows; Theodor D. Leininger; al. et.

2010-01-01

Greater emphasis is being placed on Southern bottomland hardwood management, but relatively few growth and yield prediction systems exist that are based on sufficient measurements. We present the aggregate stand-level expected yield and structural component equations for a red oak (Quercus section Lobatae)-sweetgum (Liquidambar styraciflua L.) growth and yield model....

Using a stand-level model to predict light absorption in stands with vertically and horizontally heterogeneous canopies

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David I Forrester

2014-09-01

Full Text Available Background Forest ecosystem functioning is strongly influenced by the absorption of photosynthetically active radiation (APAR, and therefore, accurate predictions of APAR are critical for many process-based forest growth models. The Lambert-Beer law can be applied to estimate APAR for simple homogeneous canopies composed of one layer, one species, and no canopy gaps. However, the vertical and horizontal structure of forest canopies is rarely homogeneous. Detailed tree-level models can account for this heterogeneity but these often have high input and computational demands and work on finer temporal and spatial resolutions than required by stand-level growth models. The aim of this study was to test a stand-level light absorption model that can estimate APAR by individual species in mixed-species and multi-layered stands with any degree of canopy openness including open-grown trees to closed canopies. Methods The stand-level model was compared with a detailed tree-level model that has already been tested in mixed-species stands using empirical data. Both models were parameterised for five different forests, including a wide range of species compositions, species proportions, stand densities, crown architectures and canopy structures. Results The stand-level model performed well in all stands except in the stand where extinction coefficients were unusually variable and it appears unlikely that APAR could be predicted in such stands using (tree- or stand-level models that do not allow individuals of a given species to have different extinction coefficients, leaf-area density or analogous parameters. Conclusion This model is parameterised with species-specific information about extinction coefficients and mean crown length, diameter, height and leaf area. It could be used to examine light dynamics in complex canopies and in stand-level growth models.

Effects of crown release on growth and quality of even-aged red maple stands

Science.gov (United States)

Terry F. Strong; Audra E. Hubbell; Adam H. Weise; Gayne G. Erdmann

2006-01-01

The effects of six crown-release treatments on growth and bole quality of 54 dominant, codominant, and intermediate red maples (Acer rubrum L.) were examined in an even-aged stand in upper Michigan. Treatments included an unreleased control, a single-tree and a two-tree crown release, and a full crown-to-crown release of 5, 10, and 15ft. Twenty-two...

Spatial models reveal the microclimatic buffering capacity of old-growth forests.

Science.gov (United States)

Frey, Sarah J K; Hadley, Adam S; Johnson, Sherri L; Schulze, Mark; Jones, Julia A; Betts, Matthew G

2016-04-01

Climate change is predicted to cause widespread declines in biodiversity, but these predictions are derived from coarse-resolution climate models applied at global scales. Such models lack the capacity to incorporate microclimate variability, which is critical to biodiversity microrefugia. In forested montane regions, microclimate is thought to be influenced by combined effects of elevation, microtopography, and vegetation, but their relative effects at fine spatial scales are poorly known. We used boosted regression trees to model the spatial distribution of fine-scale, under-canopy air temperatures in mountainous terrain. Spatial models predicted observed independent test data well (r = 0.87). As expected, elevation strongly predicted temperatures, but vegetation and microtopography also exerted critical effects. Old-growth vegetation characteristics, measured using LiDAR (light detection and ranging), appeared to have an insulating effect; maximum spring monthly temperatures decreased by 2.5°C across the observed gradient in old-growth structure. These cooling effects across a gradient in forest structure are of similar magnitude to 50-year forecasts of the Intergovernmental Panel on Climate Change and therefore have the potential to mitigate climate warming at local scales. Management strategies to conserve old-growth characteristics and to curb current rates of primary forest loss could maintain microrefugia, enhancing biodiversity persistence in mountainous systems under climate warming.

Growth and yield of mixed polyclonal stands of Populus in short-rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Benbrahim, Mohammed; Gavaland, Andre [INRA centre de Toulouse (France). Unite Agroforesterie et foret Paysanne; Gauvin, Jean [INRA centre d' Orleans (France). Unite d' Amelioration des arbres forestiers

2000-07-01

Eight clones of poplar were used to compare the growth and productivity of monoclonal and polyclonal mixed plantations in short-rotation coppice. At the end of the eight growing season, the diameter at breast height (DBH) and height of trees were measured and dry weight and yield were estimated. Polyclonal mixtures did not affect mortality. Few differences in growth were observed between clones in monoclonal plots. Polyclonal mixture slightly affected the growth and tree size of the clones compared with monoclonal plots. No increase in stand heterogeneity in relation to clone deployment was observed. A neighbourhood index was calculated for each tree and was significantly affected by polyclonal mixture. However, the relationship between the neighbourhood index and the DBH indicated that this effect did not cause a great change in DBH. Consequently, dry weight and yield productivity were not affected by clone deployment.

Size-dependence of tree growth response to drought for Norway spruce and European beech individuals in monospecific and mixed-species stands.

Science.gov (United States)

Ding, H; Pretzsch, H; Schütze, G; Rötzer, T

2017-09-01

Climate anomalies have resulted in changing forest productivity, increasing tree mortality in Central and Southern Europe. This has resulted in more severe and frequent ecological disturbances to forest stands. This study analysed the size-dependence of growth response to drought years based on 384 tree individuals of Norway spruce [Picea abies (L.) Karst.] and European beech [Fagus sylvatica ([L.)] in Bavaria, Germany. Samples were collected in both monospecific and mixed-species stands. To quantify the growth response to drought stress, indices for basal area increment, resistance, recovery and resilience were calculated from tree ring measurements of increment cores. Linear mixed models were developed to estimate the influence of drought periods. The results show that ageing-related growth decline is significant in drought years. Drought resilience and resistance decrease significantly with growth size among Norway spruce individuals. Evidence is also provided for robustness in the resilience capacity of European beech during drought stress. Spruce benefits from species mixing with deciduous beech, with over-yielding spruce in pure stands. The importance of the influence of size-dependence within tree growth studies during disturbances is highlighted and should be considered in future studies of disturbances, including drought. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor

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Daniel Leightley

2018-03-01

Full Text Available The aim of this study was to compare the performance between young adults (n = 15, healthy old people (n = 10, and masters athletes (n = 15 using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions, which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups.

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor.

Science.gov (United States)

Leightley, Daniel; Yap, Moi Hoon

2018-03-02

The aim of this study was to compare the performance between young adults ( n = 15), healthy old people ( n = 10), and masters athletes ( n = 15) using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions), which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups.

StandsSIM-MD: a Management Driven forest SIMulator

Energy Technology Data Exchange (ETDEWEB)

Barreiro, S.; Rua, J.; Tomé, M.

2016-07-01

Aim of the study. The existing stand level forest simulators available in Portugal were not developed with the aim of including up-to-date model versions and were limited in terms of accounting for forest management. The simulators’ platform, sIMfLOR was recently created to implement different growth models with a common philosophy. The objective was developing one easily-updatable, user-friendly, forest management and climate change sensitive simulator capable of projecting growth for the main tree species in Portugal. Area of the study: Portugal. Material and methods: The new simulator was programmed in a modular form consisting of several modules. The growth module integrates different forest growth and yield models (empirical and process-based) for the main wood production tree species in Portugal (eucalypt, umbrella and maritime pines); whereas the management module drives the growth projections along the planning horizon according to a range of forest management approaches and climate (at present only available for eucalypt). Main results: The main result is the StandsSIM-MD Management Driven simulator that overcomes the limitations of the existing stand level simulators. It is a step forward when compared to the models currently available in the sIMfLOR platform covering more tree species, stand structures and stand compositions. It is focused on end-users and it is based on similar concepts regarding the generation of required inputs and generated outputs. Research highlights: Forest Management Driven simulations approach. Multiple Prescriptions-Per-Stand functionality. StandsSIM-MD can be used to support landowners decisions on stand forest management. StandsSIM-MD simulations at regional level can be combined with optimization routines. (Author)

Age class, longevity and growth rate relationships: protracted growth increases in old trees in the eastern United States.

Science.gov (United States)

Johnson, Sarah E; Abrams, Marc D

2009-11-01

This study uses data from the International Tree-Ring Data Bank website and tree cores collected in the field to explore growth rate (basal area increment, BAI) relationships across age classes (from young to old) for eight tree species in the eastern US. These species represent a variety of ecological traits and include those in the genera Populus, Quercus, Pinus, Tsuga and Nyssa. We found that most trees in all age classes and species exhibit an increasing BAI throughout their lives. This is particularly unusual for trees in the older age classes that we expected to have declining growth in the later years, as predicted by physiological growth models. There exists an inverse relationship between growth rate and increasing age class. The oldest trees within each species have consistently slow growth throughout their lives, implying an inverse relationship between growth rate and longevity. Younger trees (trees when they are of the same age resulting from a higher proportion of fast-growing trees in these young age classes. Slow, but increasing, BAI in the oldest trees in recent decades is a continuation of their growth pattern established in previous centuries. The fact that they have not shown a decreasing growth rate in their old age contradicts physiological growth models and may be related to the stimulatory effects of global change phenomenon (climate and land-use history).

Effects of herbicide release on the growth of 8- to 12-year-old hardwood trees

Science.gov (United States)

G.W. Wendel; Neil I. Lamson; Neil I. Lamson

1987-01-01

In 8- to 12-year-old Appalachian hardwood stands, crop trees were released by stem injecting competing trees with a 20 percent aqueous solution of glyphosate. Species released were black cherry, red oak, and sugar maple. Release treatments were (a) injection of all trees within a 5-foot radius of the crop tree bole and (b) injections of all trees whose crown touched...

Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

Directory of Open Access Journals (Sweden)

Mark W Schwartz

Full Text Available Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1 whether the forest appears in transition toward increased hardwood composition; 2 if conifers appear stressed by recent climate change relative to hardwoods; and 3 how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

To live fast or not: growth, vigor and longevity of old-growth ponderosa pine and lodgepole pine trees

Energy Technology Data Exchange (ETDEWEB)

Kaufmann, M. R. [Forest Service, Fort Collins, CO (United States). Rocky Mountain Forest and Range Experiment Station

1996-01-01

Old ponderosa pine and lodgepole pine trees were studied to determine volume growth patterns in relation to leaf area. Ponderosa pine trees varied in age from 166 to 432 years and were about 77 inches in diameter; lodgepole pine trees ranged in age from 250 to 296 years and were 31 inches in diameter. Trees of both species had flat tops, heavy branches and foliage distribution characteristic of older trees. Annual volume increments were determined from crossdated radial increments measured on discs at four meter height intervals; leaf areas were determined based on leaf area/branch sapwood area ratios. Ponderosa pine volume growth was found to have been gradual at first, reaching a plateau that persisted for a century or more, followed by a rapid increase, and a sudden decrease in growth to less than one half of the earlier rate and persisting at these levels for several decades. In lodgepole pine growth decline was less frequent and less spectacular; growth in general was more even, with slight annual variations. Volume growth in the most recent years prior to felling weakly correlated with leaf area. Growth efficiencies were generally higher for trees having the lowest leaf areas. The fact that these persisted for many decades with low growth efficiencies suggests that defence mechanisms are more effective in old trees than in younger ones. 16 refs., 8 figs.

Two decades of stability and change in old-growth forest at Mount Rainier National Park.

Science.gov (United States)

Steven A. Acker; Jerry F. Franklin; Sarah E. Greene; Ted B. Thomas; Robert Van Pelt; Kenneth J. Bible

2006-01-01

We examined how composition and structure of old-growth and mature forests at Mount Rainier National Park changed between the mid-1970s and mid-1990s. We assessed whether the patterns of forest dynamics observed in lower elevation old-growth forests in the Pacific Northwest held true for the higher-elevation forests of the Park. We used measurements of tree recruitment...

Breakage or uprooting: How tree death type affects hillslope processes in old-growth temperate forests

Science.gov (United States)

Šamonil, Pavel; Daněk, Pavel; Adam, Dušan; Phillips, Jonathan D.

2017-12-01

Tree breakage and uprooting are two possible scenarios of tree death that have differing effects on hillslope processes. In this study we aimed to (i) reveal the long-term structure of the biomechanical effects of trees (BETs) in relation to their radial growth and tree death types in four old-growth temperate forests in four different elevation settings with an altitudinal gradient of 152-1105 m a.s.l., (ii) quantify affected areas and soil volumes associated with the studied BETs in reserves, and (iii) derive a general model of the role of BETs in hillslope processes in central European temperate forests. We analyzed the individual dynamics of circa 55,000 trees in an area of 161 ha within four old-growth forests over 3-4 decades. Basal tree censuses established in all sites in the 1970s and repeated tree censuses in the 1990s and 2000s provided detailed information about the radial growth of each tree of DBH ≥ 10 cm as well as about types of tree death. We focused on the quantification of: (i) surviving still-living trees, (ii) new recruits, (iii) standing dead trees, (iv) uprooted trees, and (v) broken trees. Frequencies of phenomena were related to affected areas and volumes of soil using individual statistical models. The elevation contrasts were a significant factor in the structure of BETs. Differences between sites increased from frequencies of events through affected areas to volumes of soil associated with BETs. An average 2.7 m3 ha-1 year-1 was associated with all BETs of the living and dying trees in lowlands, while there was an average of 7.8 m3 ha-1 year-1 in the highest mountain site. Differences were caused mainly by the effects of dying trees. BETs associated with dead trees were 7-8 times larger in the mountains. Effects of dying trees and particularly treethrows represented about 70% of all BETs at both mountain sites, while it was 58% at the highland site and only 32% at the lowland site. Our results show a more significant role of BETs in

On the Effect of Thinning on Tree Growth and Stand Structure of White Birch (Betula platyphylla Sukaczev and Siberian Larch (Larix sibirica Ledeb. in Mongolia

Directory of Open Access Journals (Sweden)

Alexander Gradel

2017-03-01

Full Text Available The forests of North Mongolia are largely dominated either by larch (Larix sibirica Ledeb. or birch (Betula platyphylla Sukaczev. The increasing demand for timber and firewood is currently met by removal of wood from these forest stands. Therefore, silvicultural approaches that account for both utilization and protection are needed. Thinning trials were established in the research area Altansumber, in the mountain forest steppe west of the town of Darkhan. We analyzed the response of non-spatial and spatial structure and growth of birch and larch stands on thinning. Before thinning, spatial tree distribution was largely clumped. Thinning promoted regular tree distribution. Ingrowth of new stems after thinning tended to redirect stand structure towards clumping. Both relative and absolute tree growth and competition were evaluated before, directly after, and three years after the thinning. Competition played a significant role in tree growth before thinning. A reduction in competition after thinning triggered significantly increased growth of both birch and larch. The observed positive growth response was valid in absolute and relative terms. A methodically based forest management strategy, including thinning operations and selective cuttings, could be established, even under the harsh Mongolian conditions. Our findings could initiate the development of broader forest management guidelines for the light-taiga dominated stands.

StandsSIM-MD: a Management Driven forest SIMulator

Directory of Open Access Journals (Sweden)

Susana Barreiro

2016-07-01

Full Text Available Aim of the study: The existing stand level forest simulators available in Portugal were not developed with the aim of including up-to-date model versions and were limited in terms of accounting for forest management. The simulators’ platform, sIMfLOR was recently created to implement different growth models with a common philosophy. The objective was developing one easily-updatable, user-friendly, forest management and climate change sensitive simulator capable of projecting growth for the main tree species in Portugal. Area of the study: Portugal. Material and methods: The new simulator was programmed in a modular form consisting of several modules. The growth module integrates different forest growth and yield models (empirical and process-based for the main wood production tree species in Portugal (eucalypt, umbrella and maritime pines; whereas the management module drives the growth projections along the planning horizon according to a range of forest management approaches and climate (at present only available for eucalypt. Main results: The main result is the StandsSIM-MD Management Driven simulator that overcomes the limitations of the existing stand level simulators. It is a step forward when compared to the models currently available in the sIMfLOR platform covering more tree species, stand structures and stand compositions. It is focused on end-users and it is based on similar concepts regarding the generation of required inputs and generated outputs. Research highlights: -          Forest Management Driven simulations approach -          Multiple Prescriptions-Per-Stand functionality -          StandsSIM-MD can be used to support landowners decisions on stand forest management -          StandsSIM-MD simulations at regional level can be combined with optimization routines Keywords: Forest simulator, Forest Management Approaches; StandsSIM-MD; forest management.

Clinical research of serum transforming growth factor-α in old patients with silicotuberculosis

International Nuclear Information System (INIS)

Ye Yixiu; Wang Wei; Liu Weimin; Li Hongmin; Yao Hao; Zhang Tao; Ouyang Xiaohui; Jiang Ping; Chen Dongjin; Feng Bai

2002-01-01

To study the change of transforming growth factor-α (TGF-α) in old patients with silicotuberculosis, the serum TGF-α in 69 patients with silicotuberculosis were measured by RIA, and compared with that in the group of old patients with pulmonary tuberculosis and the old normal control. The level of serum TGF-α in old patients with silicotuberculosis was significantly higher than that in the others (P 0.05). The level of TGF-α does not correlate with numbers of bacterium in sputum. The level of serum TGF-α in old patients with silicotuberculosis was higher than that of pulmonary tuberculosis and old normal control. The change regularity of TGF-α should been studied further

Mixing Effects in Norway Spruce—European Beech Stands Are Modulated by Site Quality, Stand Age and Moisture Availability

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Léa Houpert

2018-02-01

Full Text Available Although mixing tree species is considered an efficient risk-reduction strategy in the face of climate change, the conditions where mixtures are more productive than monocultures are under ongoing debate. Generalizations have been difficult because of the variety of methods used and due to contradictory findings regarding the effects of the species investigated, mixing proportions, and many site and stand conditions. Using data from 960 plots of the Swiss National Forest Inventory data, we assessed whether Picea abies (L. Karst–Fagus sylvatica L. mixed stands are more productive than pure stands, and whether the mixing effect depends on site- or stand-characteristics. The species proportions were estimated using species proportion by area, which depends on the maximum stand basal area of an unmanaged stand (BAmax. Four different alternatives were used to estimate BAmax and to investigate the effect of these differing alternatives on the estimated mixture effect. On average, the mixture had a negative effect on the growth of Picea abies. However, this effect decreased as moisture availability increased. Fagus sylvatica grew better in mixtures and this effect increased with site quality. A significant interaction between species proportions and quadratic mean diameter, a proxy for stand age, was found for both species: the older the stand, the better the growth of Fagus sylvatica and the lower the growth of Picea abies. Overyielding was predicted for 80% of the investigated sites. The alternative to estimate BAmax weakly modulated the estimated mixture effect, but it did not affect the way mixing effects changed with site characteristics.

Communicating old-growth forest management on the Allegheny National Forest

Science.gov (United States)

Brad Nelson; Chris Nowak; Dave deCalesta; Steve Wingate

1997-01-01

Successful communication of old-growth management, including the role of silviculture, is achieved by integrating as a working whole the topics addressed in this workshop. We have used research, technology transfer and adaptive management to achieve this integration on the Allegheny National Forest. Program success depends on scientists and practitioners working...

Pituitary mammosomatotroph adenomas develop in old mice transgenic for growth hormone-releasing hormone

DEFF Research Database (Denmark)

Asa, S L; Kovacs, K; Stefaneanu, L

1990-01-01

It has been shown that mice transgenic for human growth hormone-releasing hormone (GRH) develop hyperplasia of pituitary somatotrophs and mammosomatotrophs, cells capable of producing both growth hormone and prolactin, by 8 months of age. We now report for the first time that old GRH-transgenic...

Effect of Preservative Treatment on Fungal Colonization of Teak, Redwood, and Western Red Cedar

DEFF Research Database (Denmark)

Cabrera Orozco, Yohanna; Freitag, F.; Morrell, Jeffrey J.

Fungal flora present in preservative treated samples or non-treated samples from sapwood and heartwood of teak, western red cedar, redwood, and southern yellow pine was assessed after 6 to 18 months of exposure near Hilo, Hawaii. The objectives were to compare fungal composition and diversity...... between treated and non-treated samples, and to examine the use of molecular techniques for assessing fungal community structure in a ground-proximity-test located in Hilo, Hawaii. Fungi were recovered in culture after 6, 12, or 18 months, yielding 178 unique DNA sequences that represented 85 taxa...

The role of old forests and big trees in forest carbon sequestration in the Pacific Northwest

Science.gov (United States)

Andrew N. Gray

2015-01-01

Forest ecosystems are an important component of the global carbon (C) cycle. Recent research has indicated that large trees in general, and old-growth forests in particular, sequester substantial amounts of C annually. C sequestration rates are thought to peak and decline with stand age but the timing and controls are not well-understood. The objectives of this study...

Production economics of harvesting young hardwood stands in central Appalachia

Science.gov (United States)

Yaoxiang Li; Jingxin Wang; Gary W. Miller; Joe McNeel

2004-01-01

Three harvesting systems of chainsaw/cable skidder, fell-buncher/grapple skidder, and harvester/forwarder were simulated in harvesting three hardwood stands of 30 to 50 years old in central Appalachia. Stands were generated by using a stand generator and harvesting prescriptions included clearcut, shelterwood cut, selective cut, diameter limit cut, and crop tree...

The Effect of Different Competition Indices on Diameter Growth of Individual Tree Growth in Mixed Stands of Caucasion fir and Oriental spruce

Directory of Open Access Journals (Sweden)

Aydın Kahriman

2012-11-01

Full Text Available The aim of this study is to investigate statistical relations between each of 12 competition indices (both distance-dependent and distance-independent and diameter growth of trees. Also we investigated the relations between each of 12 competition indices together with diameter at breast height and diameter growth. For that reason, six sampling plots (ranging from 1000 to 2000 m2 in size were taken from in mixed stands of Caucasion fir and Oriental spruce located within the Forest Management Districts of Torul and Artvin. Our results from those sampling plots were in agreement with general growth models. Regression analysis between each of competition indexes and diameter growth resulted in coefficients of determination (R2 values ranging from 30 to 64%. The distance-dependent competition indices gave stronger correlations with diameter growth than the distance-independent competition indexes. Coefficients of determination were even higher when competition indexes and dbh were used together as independent variables (R2 = 0.31 - 0.82.

Stand development and yields of Appalachian hardwood stands managed with single-tree selection for at least 30 years

Science.gov (United States)

Neil I Lamson; H. Clay Smith; H. Clay Smith

1991-01-01

Appalachian hardwood stands in West Virginia were managed for 30 or more years using single-tree selection regeneration practices. Stand yield data suggest that current stand growth will provide economical harvest cuts for several future cutting cycles. This case study indicates that the single-tree selection practice has potential for landowners who want to maintain...

The effect of size and competition on tree growth rate in old-growth coniferous forests

Science.gov (United States)

Das, Adrian

2012-01-01

Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.

User's manual for FORAR: a stand model for composition and growth of upland forests of southern Arkansas

Energy Technology Data Exchange (ETDEWEB)

Mielke, D. L.; Shugart, H. H.; West, D. C.

1977-04-01

This report is a user's manual for FORAR, a computer model simulating stand growth and composition of upland forests of south central Arkansas. The model computes: the number and biomass of each tree species, and the dbh, age, and species of each individual tree on a 1/12-ha circular plot.

Management alternatives of energy wood thinning stands

International Nuclear Information System (INIS)

Heikkilae, Jani; Siren, Matti; Aeijaelae, Olli

2007-01-01

Energy wood thinning has become a feasible treatment alternative of young stands in Finland. Energy wood thinnings have been carried out mainly in stands where precommercial thinning has been neglected and the harvesting conditions for industrial wood thinning are difficult. Despite of its positive effects on harvesting costs and on renewable energy potential, whole-tree harvesting has been constantly criticized for causing growth loss. In this paper, the profitability of energy wood thinning was studied in 20 Scots pine-dominated stands where energy wood thinning was carried out. The growth of the stands after thinning was predicted with the help of Motti-stand simulator. Entire rotation time of the stands was simulated with different management alternatives. The intensity of first thinning and recovery level of logging residues varied between alternatives. In order to attain acceptable harvesting conditions, industrial wood thinning had to be delayed. The effect of energy wood thinning on subsequent stem wood growth was almost the same as in conventional thinning. Whole-tree harvesting for energy proved to be profitable alternative if the stumpage price is around 3EUR m -3 , the interest rate is 3% or 5% and the removal of pulpwood is less than 20 m 3 ha -1 . If the harvestable pulpwood yield is over 20 m 3 ha -1 , integrated harvesting of industrial and energy wood or delayed industrial wood harvesting becomes more profitable. (author)

The role of stand history in assessing forest impacts

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Dale, V.H.; Doyle, T.W.

1987-01-01

Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The model was run under the climatic conditions of east Tennessee, USA, and the results compared to stand structure and tree growth data from a yellow poplar-white oak forest. Basal area growth and forest biomass were more accurately projected when rough approximations of the thinning and fire history typical of the measured plots were included in the simulation model. Stand history can influence tree growth rates and forest structure and should be included in any attempt to assess forest impacts.

The effect of wood ash fertilization on soil respiration and tree stand growth in boreal peatland forests

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Liimatainen, Maarit; Maljanen, Marja; Hytönen, Jyrki

2017-04-01

Out of Finland's original 10 million hectares of peatlands over half has been drained for forestry. Natural peatlands act as a sink for carbon but when peatland is drained, increased oxygen concentration in the peat accelerates the aerobic decomposition of the old organic matter of the peat leading to carbon dioxide (CO2) emissions to atmosphere. Increasing use of bioenergy increases also the amount of ash produced as a byproduct in power plants. Wood ash contains all essential nutrients for trees to grow except nitrogen. Therefore, wood ash is ideal fertilizer for nitrogen rich peatland forests where lack of phosphorus or potassium may restrict tree growth. At the moment, wood ash is the only available PK-fertilizer for peatland forests in Finland and areas of peatland forests fertilized with ash are increasing annually. The effects of wood ash on vegetation, soil properties and tree growth are rather well known although most of the studies have been made using fine ash whereas nowadays mostly stabilized ash (e.g. granulated) is used. Transporting and spreading of stabilized ash is easier than that of dusty fine ash. Also, slower leaching rate of nutrients is environmentally beneficial and prolongs the fertilizer effect. The knowledge on the impact of granulated wood ash on greenhouse gas emissions is still very limited. The aim of this study was to examine the effects of granulated wood ash on CO2 emissions from peat and tree stand growth. Field measurements were done in two boreal peatland forests in 2011 and 2012. One of the sites is more nutrient rich with soil carbon to nitrogen ratio (C/N) of 18 whereas the other site is nutrient poor with C/N ratio of 82. Both sites were fertilized with granulated wood ash in 2003 (5000 kg ha-1). The effect of fertilization was followed with tree stand measurements conducted 0, 5 and 10 years after the fertilization. The CO2 emissions of the decomposing peat (heterotrophic respiration) were measured from study plots where

Crown dynamics and wood production of Douglas-fir trees in an old-growth forest

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H. Roaki Ishii; Stephen C. Sillett; Allyson L. Carroll

2017-01-01

Large trees are the most prominent structural features of old-growth forests, which are considered to be globally important carbon sinks. Because of their large size, estimates of biomass and growth of large trees are often based on ground-level measurements (e.g., diameter at breast height, DBH) and little is known about growth dynamics within the crown. As trees...

Comparative shoulder kinematics during free standing, standing depression lifts and daily functional activities in persons with paraplegia: considerations for shoulder health.

Science.gov (United States)

Riek, L M; Ludewig, P M; Nawoczenski, D A

2008-05-01

Case series; nonparametric repeated-measures analysis of variance. To compare and contrast three-dimensional shoulder kinematics during frequently utilized upper extremity weight-bearing activities (standing depression lifts used in brace walking, weight-relief raises, transfers) and postures (sitting rest, standing in a frame) in spinal cord injury (SCI). Movement Analysis Laboratory, Department of Physical Therapy, Ithaca College, Rochester, NY, USA. Three female and two male subjects (39.2+/-6.1 years old) at least 12 months post-SCI (14.6+/-6.7 years old), SCI distal to T2 and with an ASIA score of A. The Flock of Birds magnetic tracking device was used to measure three-dimensional positions of the scapula, humerus and thorax during various activities. Standing in a frame resulted in significantly less scapular anterior tilt (AT) and greater glenohumeral external rotation (GHER) than standing depression lifts and weight-relief raises. Standing frame posture offers the most favorable shoulder joint positions (less scapular AT and greater GHER) when compared to sitting rest posture, weight-relief raises, transfers and standing depression lifts. Knowledge of kinematic patterns associated with each activity is an essential first step to understanding the potential impact on shoulder health. Choosing specific activities or modifying techniques within functional activities that promote favorable shoulder positions may preserve long-term shoulder health.

Growth and relaxation processes in Ge nanocrystals on free-standing Si(001) nanopillars.

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Kozlowski, G; Zaumseil, P; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

2012-03-23

We study the growth and relaxation processes of Ge crystals selectively grown by chemical vapour deposition on free-standing 90 nm wide Si(001) nanopillars. Epi-Ge with thickness ranging from 4 to 80 nm was characterized by synchrotron based x-ray diffraction and transmission electron microscopy. We found that the strain in Ge nanostructures is plastically released by nucleation of misfit dislocations, leading to degrees of relaxation ranging from 50 to 100%. The growth of Ge nanocrystals follows the equilibrium crystal shape terminated by low surface energy (001) and {113} facets. Although the volumes of Ge nanocrystals are homogeneous, their shape is not uniform and the crystal quality is limited by volume defects on {111} planes. This is not the case for the Ge/Si nanostructures subjected to thermal treatment. Here, improved structure quality together with high levels of uniformity of the size and shape is observed.

Canopy transpiration of pure and mixed forest stands with variable abundance of European beech

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Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

2012-06-01

SummaryThe importance of tree species identity and diversity for biogeochemical cycles in forests is not well understood. In the past, forestry has widely converted mixed forests to pure stands while contemporary forest policy often prefers mixed stands again. However, the hydrological consequences of these changes remain unclear. We tested the hypotheses (i) that significant differences in water use per ground area exist among the tree species of temperate mixed forests and that these differences are more relevant for the amount of stand-level canopy transpiration (Ec) than putative complementarity effects of tree water use, and (ii) that the seasonal patterns of Ec in mixed stands are significantly influenced by the identity of the present tree species. We measured xylem sap flux during 2005 (average precipitation) and 2006 (relatively dry) synchronously in three nearby old-growth forest stands on similar soil differing in the abundance of European beech (pure beech stand, 3-species stand with 70% beech, 5-species stand with sapwood area basis, reflecting a considerable variation in hydraulic architecture and leaf conductance regulation among the co-existing species. Moreover, transpiration per crown projection area (ECA) also differed up to 5-fold among the different species in the mixed stands, probably reflecting contrasting sapwood/crown area ratios. We conclude that Ec is not principally higher in mixed forests than in pure beech stands. However, tree species-specific traits have an important influence on the height of Ec and affect its seasonal variation. Species with a relatively high ECA (notably Tilia) may exhaust soil water reserves early in summer, thereby increasing drought stress in dry years and possibly reducing ecosystem stability in mixed forests.

Managing for Old Growth in Frequent-fire Landscapes

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Carl E. Fiedler

2007-12-01

Full Text Available There is no one-size-fits-all approach to managing frequent-fire, old-growth forests. However, there are general guidelines to follow: 1 set objectives for both structure (tree density, diameter distribution, tree species composition, spatial arrangement, amount of coarse woody debris and function (nutrient cycling, desired tree species regeneration; 2 prioritize treatments according to ecological, economic, and social needs and risks; 3 identify the potential treatments (natural fire, prescribed fire, silvicultural cutting that best meet the objectives and scale of the project; and 4 implement the treatment(s. We discuss each of these guidelines in this article.

Early wide spacing in red alder (Alnus rubra Bong.): effects on stem form and stem growth.

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Bernard T. Bormann

1985-01-01

A thinning trial was established in 1962 in a 7-year-old red alder stand in northwestern Washington. Spacings were 8 x 8 ft (dense), 12 x 12 it (intermediate), and 16 x 16 ft (open). The effect of early thinning on growth and stem form was measured in 1982, 20 years after spacing treatment. There was negligible tree lean and sweep in open and intermediate stands except...

Production economics of harvesting small-diameter hardwood stands in central Appalachia

Science.gov (United States)

Yaoxiang Li; Jingxin Wang; Gary Miller; Joe McNeel

2006-01-01

Three harvesting systems of chainsaw/cable skidder, feller-buncher/grapple skidder, and harvester/forwarder were simulated in harvesting three hardwood stands 30 to 50 years old in central Appalachia. Stands were generated by using a 3D stand generator. Harvesting prescriptions included clearcut, shelterwood cut, selective cut, diameter limit cut, and crop tree release...

Test of four stand growth simulators for the northeastern United States

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Thomas M. Schuler; David A. Marquis; Richard L. Ernst; Brian T. Simpson; Brian T. Simpson

1993-01-01

Evaluates SILVAH, FIBER, NE-TWIGS, and OAKSIM, simulators commonly used in the northeastern United States, by comparing predicted stand development with actual stand development records for periods ranging from 15 to 50 years. Results varied with stand parameter, forest type, projection length, and geographic area. Except in the spruce-fir forest type where FIBER...

A Pine Is a Pine and a Spruce Is a Spruce--The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities.

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Bäcklund, Sofia; Jönsson, Mari; Strengbom, Joachim; Frisch, Andreas; Thor, Göran

2016-01-01

With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.

A Pine Is a Pine and a Spruce Is a Spruce--The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities.

Directory of Open Access Journals (Sweden)

Sofia Bäcklund

Full Text Available With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.

An approach to study the effect of harvest and wildfire on watershed hydrology and sediment yield in a coast redwood forest

Science.gov (United States)

Christopher G. Surfleet; Arne Skaugset; Brian Dietterick

2012-01-01

The Little Creek watershed, within California State Polytechnic University’s Swanton Pacific Ranch, is the location of a paired and nested watershed study to investigate the watershed effects of coast redwood forest management. Streamflow, suspended sediment, and stream turbidity have been collected during storms at two locations on the North Fork Little Creek and at...

Foliar and ecosystem respiration in an old-growth tropical rain forest

Science.gov (United States)

Molly A. Cavaleri; Steven F. Oberbauer; Michael G. Ryan

2008-01-01

Foliar respiration is a major component of ecosystem respiration, yet extrapolations are often uncertain in tropical forests because of indirect estimates of leaf area index (LAI).A portable tower was used to directly measure LAI and night-time foliar respiration from 52 vertical transects throughout an old-growth tropical rain forest in Costa Rica. In this study, we (...

A Pine Is a Pine and a Spruce Is a Spruce – The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities

Science.gov (United States)

Bäcklund, Sofia; Jönsson, Mari; Strengbom, Joachim; Frisch, Andreas; Thor, Göran

2016-01-01

With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden. PMID:26799558

Growth, development and productivity of Jerusalem artichoke depending on plant stand in the conditions of the Republic of Karakalpakstan

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Zhangabaeva A.S.

2017-08-01

Full Text Available the article presents the results of studying the influence of various schemes of planting seed tubers of Jerusalem artichoke on the rate of plant growth and development in the soil and climatic conditions of the Republic of Karakalpakstan. Differences in the rate of growth and development of plants are revealed, depending on the varietal features of Jerusalem artichoke and the density of their standing. The most optimal scheme for planting tubers of Jerusalem artichoke is 70x40 cm.

Ash recycling to spruce and beech stands effects on nutrients, growth, nitrogen dynamics and carbon balance; Askaaterfoering till gran- och bokbestaand - effekter paa naering, tillvaext, kvaevedynamik och kolbalans

Energy Technology Data Exchange (ETDEWEB)

Thelin, Gunnar

2006-03-15

Ash recycling is an important part in a modern, sustainable forestry, especially in whole-tree harvest systems. Nutrients lost at harvest are returned to the forest with the wood-ash. In the project the effects of ash treatment on needle and leaf chemistry, tree growth, soil chemistry, soil water chemistry, and carbon and nitrogen dynamics were studied on 23 Norway spruce sites in south-western Sweden and in ten European beech sites in Scania, southern Sweden. On some of the sites there were previously established ash recycling experiments, but on a majority of the sites ash recycling was performed without experimental lay-out and ash and control plots were established afterwards. The most common dose was two tons of self hardened crushed wood-ash and two tons of Mg-lime. On average seven to eight years after ash recycling the results were 1. increased exchangeable stores of base cations in the soil in the beech and the spruce stands 2. increased base saturation in the beech and the spruce stands and increased BC/Al in the spruce stands 3. increased concentrations and ratios to N of P, Ca, Zn, and S in the needles, the increased P-values are especially important since P is close to or below deficiency levels in a majority of the spruce stands 4. decreased K-concentration in the beech leaves 5. increased tree growth with on average 14 % in the ash treated spruce stands compared to the control plots 6. increased carbon and nitrogen amounts in the biomass in the spruce stands 7. tendencies towards increased amounts of carbon and nitrogen in the soil in the beech stands and no effect in the soil in the spruce stands 8. increased concentrations of Ca, Mg, and SO{sub 4} and no effect on ANC in the soil water 9. no effect on potential net mineralization but increased potential nitrification rates 10. decreased concentration of nitrate in the soil water in the beech stands and no effect in the spruce stands 11. lower system N losses in the beech stands and possibly in the

Ground cover in old-growth forests of the central hardwood region

Science.gov (United States)

Martin A. Spetich; Stephen R. Shifley; George R. Parker; Felix, Jr. Ponder

1997-01-01

Differences in ground cover (percent cover of litter, percent cover of vegetation and litter weight) in old-growth forests across this region are not well understood. We initiated a long-term study in a three-state region to enhance knowledge in this area. We present baseline results for ground cover and compare these data across productivity regions. Thirty 0.25-ac (0...

Notes on Some Old-Growth Forests in Ohio, Indiana, and Illinois

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John T. Auten

1941-01-01

The disturbing increase in acreage of abandoned land in the Central States has heightened interest in the region's few remnants of old-growth hardwood forest. Studies are being made to determine what kinds of trees originally grew on different kinds of soil, what was the original character of the soil, how many trees grew on an acre, and how large the trees were...

Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

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Emily J. Silver; Anthony W. D' Amato; Shawn Fraver; Brian J. Palik; John B. Bradford

2013-01-01

The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types....

Long-Term Trends In Loblolly Pine Productivity And Stand Characteristics In Response To Stand Density And Fertilization In The Western Gulf Region

Science.gov (United States)

M.A. Sword; J. L. Chambers; Z. Tang; T. J. Dean; J. C. Goelz

2002-01-01

Two levels each of fertilization and stand density were established to create four environments in a 7-year-old loblolly pine plantation on a N and P deficient western Gulf Coastal Plain site in Louisiana. Levels of fertilization were no fertilization and application of 120 lb N and 134 lb P/ac. Levels of stand density were the original stocking (1,210 trees/ac), and...

Structural inspection and wind analysis of redwood cooling towers at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Chung, T.; Solack, T.; Hortel, J.

1991-01-01

As part of the plant upgrade program, structural analyses and field inspections were performed on four redwood cooling towers at the DOE Portsmouth gaseous diffusion plant located in Piketon, Ohio. The cooling towers are categorized as important hazard facilities. The loadings are derived from UCRL-15910 according to the pertinent hazard category. In addition to the seismic and wind loadings, the wood cooling towers are constantly subject to adverse environmental effects such as elevated temperature, chemical attack, icing and snow load, and motor vibrations. A thorough structural evaluation for all load combinations was performed for each of the cooling towers based on the structural code requirements of the Cooling Tower Institute and National Forest Products Association. Most stress criteria are unique for the redwood material. This evaluation was performed using finite element techniques on the global structural integrity and supplemented by hand calculations on the individual connection joints. Overloaded wood structural members and joints are identified by the analysis. The rectangular tower structure sits on a concrete basin that span across 60 ft by 200 ft. A major part of the cooling towers upgrading program involved field inspections of the individual cells of each tower. The primary purpose of these inspections was to identify any existing structural damage or deficiencies such as failed members, degraded wood, and deficiencies resulting from poor construction practice. Inspection of 40 cells identified some generic deficiencies that mostly are consistent with the analytical finding. Based on the analysis, some effective but inexpensive upgrading techniques were developed and recommended to bring the cooling towers into compliance with current DOE requirements

Thinning in artificially regenerated young beech stands

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Novák Jiří

2015-12-01

Full Text Available Although beech stands are usually regenerated naturally, an area of up to 5,000 ha year−1 is artificially regenerated by beech in the Czech Republic annually. Unfortunately, these stands often showed insufficient stand density and, consequently, lower quality of stems. Therefore, thinning methods developed for naturally regenerated beech stands are applicable with difficulties. The paper evaluates the data from two thinning experiments established in young artificially regenerated beech stands located in different growing conditions. In both experiments, thinning resulted in the lower amount of salvage cut in following years. Positive effect of thinning on periodic stand basal area increment and on periodic diameter increment of dominant trees was found in the beech stand located at middle elevations. On the other hand, thinning effects in mountain conditions were negligible. Thinning focusing on future stand quality cannot be commonly applied in artificially regenerated beech stands because of their worse initial quality and lower density. However, these stands show good growth and response to thinning, hence their management can be focused on maximising beech wood production.

Heavy thinning of ponderosa pine stands: An Arizona case study

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Peter F. Ffolliott; Jr. Baker; Gerald J. Gottfried

2000-01-01

Growth and structural changes in a mosaic of even-aged ponderosa pine (Pinus ponderosa) stands were studied for 25 years to determine the long-term impacts of a heavy thinning treatment to a basal-area level of 25 ft2/acre. Basal area and volume growth of these stands has increased since thinning and likely will continue to...

Seed Dispersal, Microsites or Competition—What Drives Gap Regeneration in an Old-Growth Forest? An Application of Spatial Point Process Modelling

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Georg Gratzer

2018-04-01

Full Text Available The spatial structure of trees is a template for forest dynamics and the outcome of a variety of processes in ecosystems. Identifying the contribution and magnitude of the different drivers is an age-old task in plant ecology. Recently, the modelling of a spatial point process was used to identify factors driving the spatial distribution of trees at stand scales. Processes driving the coexistence of trees, however, frequently unfold within gaps and questions on the role of resource heterogeneity within-gaps have become central issues in community ecology. We tested the applicability of a spatial point process modelling approach for quantifying the effects of seed dispersal, within gap light environment, microsite heterogeneity, and competition on the generation of within gap spatial structure of small tree seedlings in a temperate, old growth, mixed-species forest. By fitting a non-homogeneous Neyman–Scott point process model, we could disentangle the role of seed dispersal from niche partitioning for within gap tree establishment and did not detect seed densities as a factor explaining the clustering of small trees. We found only a very weak indication for partitioning of within gap light among the three species and detected a clear niche segregation of Picea abies (L. Karst. on nurse logs. The other two dominating species, Abies alba Mill. and Fagus sylvatica L., did not show signs of within gap segregation.

Defining old growth for fire-adapted forests of the Western United States

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Merrill R. Kaufmann; Daniel Binkley; Peter Z. Fule; Johnson Marlin; Scott L. Stephens; Thomas W. Swetnam

2007-01-01

There are varying definitions of old-growth forests because of differences in environment and differing fire influence across the Intermountain West. Two general types of forests reflect the role of fire: 1) forests shaped by natural changes in structure and species makeup-plant succession-that are driven by competitive differences among species and individual trees...

The effect of water availability on stand-level productivity, transpiration, water use efficiency and radiation use efficiency of field-grown willow clones

International Nuclear Information System (INIS)

Linderson, Maj-Lena; Iritz, Zinaida; Lindroth, Anders

2007-01-01

The effect of water availability on stand-level productivity, transpiration, water use efficiency (WUE) and radiation use efficiency (RUE) is evaluated for different willow clones at stand level. The measurements were made during the growing season 2000 in a 3-year-old plantation in Scania, southernmost Sweden. Six willow clones were included in the study: L78183, SW Rapp, SW Jorunn, SW Jorr, SW Tora and SW Loden. All clones were exposed to two water treatments: rain-fed, non-irrigated treatment and reduced water availability by reduced soil water recharge. Field measurements of stem sap-flow and biometry are up-scaled to stand transpiration and stand dry substance production and used to assess WUE. RUE is estimated from the ratio between the stand dry substance production and the accumulated absorbed photosynthetic active radiation over the growing season. The total stand transpiration rate for the 5 months lies between 100 and 325 mm, which is fairly low compared to the Penman-Monteith transpiration for willow, reaching 400-450 mm for the same period. Mean WUE of all clones and treatments is 5.3 g/kg, which is high compared to earlier studies, while average RUE is 0.31 g/mol, which is slightly low compared to other results. Generally, all clones, except for Jorunn, seem to be better off concerning biomass production, WUE and RUE than the reference clone. Jorr, Jorunn and Loden also seem to be able to cope with the reduced water availability with increase in the water use efficiency. Tora performs significantly better than the other clones concerning both growth and efficiency in light and water use, but the effect of the dry treatment on stem growth shows sensitivity to water availability. The reduced stem growth could be due to a change in allocation patterns

Flooding effects on stand development in cypress-tupelo

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Richard F. Keim; Thomas J. Dean; Jim L. Chambers

2013-01-01

The effects of inundation on growth of cypress (Taxodium spp.) and tupelo (Nyssa spp.) trees have been extensively researched, but conclusions are often complicated by attendant effects on stand development. Flooding affects development of cypress-tupelo stands by limiting seedling germination and survival, truncating species...

Age-related effects on leaf area/sapwood area relationships, canopy transpiration and carbon gain of Norway spruce stands (Picea abies) in the Fichtelgebirge, Germany.

Science.gov (United States)

Köstner, B; Falge, E; Tenhunen, J D

2002-06-01

Stand age is an important structural determinant of canopy transpiration (E(c)) and carbon gain. Another more functional parameter of forest structure is the leaf area/sapwood area relationship, A(L)/A(S), which changes with site conditions and has been used to estimate leaf area index of forest canopies. The interpretation of age-related changes in A(L)/A(S) and the question of how A(L)/A(S) is related to forest functions are of current interest because they may help to explain forest canopy fluxes and growth. We conducted studies in mature stands of Picea abies (L.) Karst. varying in age from 40 to 140 years, in tree density from 1680 to 320 trees ha(-1), and in tree height from 15 to 30 m. Structural parameters were measured by biomass harvests of individual trees and stand biometry. We estimated E(c) from scaled-up xylem sap flux of trees, and canopy-level fluxes were predicted by a three-dimensional microclimate and gas exchange model (STANDFLUX). In contrast to pine species, A(L)/A(S) of P. abies increased with stand age from 0.26 to 0.48 m(2) cm(-2). Agreement between E(c) derived from scaled-up sap flux and modeled canopy transpiration was obtained with the same parameterization of needle physiology independent of stand age. Reduced light interception per leaf area and, as a consequence, reductions in net canopy photosynthesis (A(c)), canopy conductance (g(c)) and E(c) were predicted by the model in the older stands. Seasonal water-use efficiency (WUE = A(c)/E(c)), derived from scaled-up sap flux and stem growth as well as from model simulation, declined with increasing A(L)/A(S) and stand age. Based on the different behavior of age-related A(L)/A(S) in Norway spruce stands compared with other tree species, we conclude that WUE rather than A(L)/A(S) could represent a common age-related property of all species. We also conclude that, in addition to hydraulic limitations reducing carbon gain in old stands, a functional change in A(L)/A(S) that is related to

Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly.

Science.gov (United States)

Fichtner, Andreas; Forrester, David I; Härdtle, Werner; Sturm, Knut; von Oheimb, Goddert

2015-01-01

The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica) forest by quantifying variation in the intensity of above- (shading) and belowground competition (crowding) among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.

Facilitative-Competitive Interactions in an Old-Growth Forest: The Importance of Large-Diameter Trees as Benefactors and Stimulators for Forest Community Assembly

Science.gov (United States)

Fichtner, Andreas; Forrester, David I.; Härdtle, Werner; Sturm, Knut; von Oheimb, Goddert

2015-01-01

The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica) forest by quantifying variation in the intensity of above- (shading) and belowground competition (crowding) among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services. PMID:25803035

Benchmark carbon stocks from old-growth forests in northern New England, USA

Science.gov (United States)

Coeli M. Hoover; William B. Leak; Brian G. Keel

2012-01-01

Forests world-wide are recognized as important components of the global carbon cycle. Carbon sequestration has become a recognized forest management objective, but the full carbon storage potential of forests is not well understood. The premise of this study is that old-growth forests can be expected to provide a reasonable estimate of the upper limits of carbon...

Factors affecting cone production in Pinus pinaster Ait.: lack of growth-reproduction trade-offs but significant effects of climate and tree and stand characteristics

Energy Technology Data Exchange (ETDEWEB)

Bravo, F.; Maguire, D.A.; González-Martínez, S.G.

2017-11-01

Aim of study: Our main goal is to determine the relationship between cone production and radial growth in Pinus pinaster Ait. under different climatic conditions across the Iberian Peninsula. Area of study: Coca Intensive Sampling Plateau, Northern Plateau (Spain). Material and methods: Cone counts were conducted on an intensive monitoring plot in Coca (North-Central Spain) during the years 2000, 2006 and 2007. A ZIP (zero-inflated Poisson) model was adjusted for simultaneously estimating the probability of obtaining crop cones and its amount. The Northern Atlantic Oscillation (NAO) index was used as explanatory variable, together with a wide variety of tree and local stand variables. Climate (as evaluated by NAO), local stand density (here estimated from the six nearest trees), tree size and vigor, competition and growth efficiency significantly influenced both occurrence and intensity of cone production. Main results: ZIP models for predicting reproductive effort seems an adequate tool to predict reproductive responses to climatic fluctuations and the resulting future species distribution in the face of climate change, as well as to identify silviculture actions that would promote reproductive success in naturally-regenerated stands, list and discuss relevant results (including numeric values of experimental results). Research highlights: Climate, stand density and tree conditions (size and vigor, competition and growth efficiency) influence significantly both cone occurrence and intensity of fruiting as shown by a ZIP model. As the climate variables included in the model (based on Northern Atlantic Oscillation, NAO) are general and easily obtained, the proposed model has practical applicability to predicting Pinus pinaster cone production in the Iberian Peninsula.

Factors affecting cone production in Pinus pinaster Ait.: lack of growth-reproduction trade-offs but significant effects of climate and tree and stand characteristics

Directory of Open Access Journals (Sweden)

Felipe Bravo

2017-10-01

Full Text Available Aim of study: Our main goal is to determine the relationship between cone production and radial growth in Pinus pinaster Ait. under different climatic conditions across the Iberian Peninsula. Area of study: Coca Intensive Sampling Plateau, Northern Plateau (Spain. Material and methods: Cone counts were conducted on an intensive monitoring plot in Coca (North-Central Spain during the years 2000, 2006 and 2007. A ZIP (zero-inflated Poisson model was adjusted for simultaneously estimating the probability of obtaining crop cones and its amount. The Northern Atlantic Oscillation (NAO index was used as explanatory variable, together with a wide variety of tree and local stand variables. Climate (as evaluated by NAO, local stand density (here estimated from the six nearest trees, tree size and vigor, competition and growth efficiency significantly influenced both occurrence and intensity of cone production. Main results: ZIP models for predicting reproductive effort seems an adequate tool to predict reproductive responses to climatic fluctuations and the resulting future species distribution in the face of climate change, as well as to identify silviculture actions that would promote reproductive success in naturally-regenerated stands, list and discuss relevant results (including numeric values of experimental results. Research highlights: Climate, stand density and tree conditions (size and vigor, competition and growth efficiency influence significantly both cone occurrence and intensity of fruiting as shown by a ZIP model. As the climate variables included in the model (based on Northern Atlantic Oscillation, NAO are general and easily obtained, the proposed model has practical applicability to predicting Pinus pinaster cone production in the Iberian Peninsula.

Factors affecting cone production in Pinus pinaster Ait.: lack of growth-reproduction trade-offs but significant effects of climate and tree and stand characteristics

International Nuclear Information System (INIS)

Bravo, F.; Maguire, D.A.; González-Martínez, S.G.

2017-01-01

Aim of study: Our main goal is to determine the relationship between cone production and radial growth in Pinus pinaster Ait. under different climatic conditions across the Iberian Peninsula. Area of study: Coca Intensive Sampling Plateau, Northern Plateau (Spain). Material and methods: Cone counts were conducted on an intensive monitoring plot in Coca (North-Central Spain) during the years 2000, 2006 and 2007. A ZIP (zero-inflated Poisson) model was adjusted for simultaneously estimating the probability of obtaining crop cones and its amount. The Northern Atlantic Oscillation (NAO) index was used as explanatory variable, together with a wide variety of tree and local stand variables. Climate (as evaluated by NAO), local stand density (here estimated from the six nearest trees), tree size and vigor, competition and growth efficiency significantly influenced both occurrence and intensity of cone production. Main results: ZIP models for predicting reproductive effort seems an adequate tool to predict reproductive responses to climatic fluctuations and the resulting future species distribution in the face of climate change, as well as to identify silviculture actions that would promote reproductive success in naturally-regenerated stands, list and discuss relevant results (including numeric values of experimental results). Research highlights: Climate, stand density and tree conditions (size and vigor, competition and growth efficiency) influence significantly both cone occurrence and intensity of fruiting as shown by a ZIP model. As the climate variables included in the model (based on Northern Atlantic Oscillation, NAO) are general and easily obtained, the proposed model has practical applicability to predicting Pinus pinaster cone production in the Iberian Peninsula.

Transformation of solar radiation in Norway spruce stands into produced biomass - the effect of stand density

International Nuclear Information System (INIS)

Marková, I.; Marek, M.V.; Pokorný, R.

2011-01-01

The present paper is focused on the assessment of the effects of stand density and leaf area development on radiation use efficiency in the mountain cultivated Norway spruce stand. The young even-aged (17-years-old in 1998) plantation of Norway spruce was divided into two experimental plots differing in their stand density in 1995. During the late spring of 2001 next cultivating high-type of thinning of 15% intensity in a reduction of stocking density was performed. The PAR regime of investigated stands was continually measured since 1992. Total aboveground biomass (TBa) and TBa increment were obtained on the basis of stand inventory. The dynamic of LAI development showed a tendency to be saturated, i.e. the LAI value close to 11 seems to be maximal for the local conditions of the investigated mountain cultivated Norway spruce stand in the Beskids Mts. Remarkable stimuli (up to 17%) of LAI formation were started in 2002, i.e. as an immediate response to thinning. Thus, the positive effect of thinning on LAI increase was confirmed. The data set of absorbed PAR and produced TBa in the period 1998-2003 was processed by the linear regression of Monteith's model, which provided the values of the coefficient of solar energy conversion efficiency into biomass formation. The differences in biomass formation values between the dense and sparse plot after thinning amounted to 18%

From a tree to a stand in Finnish boreal forests - biomass estimation and comparison of methods

Energy Technology Data Exchange (ETDEWEB)

Liu, Chunjiang

2009-07-01

There is an increasing need to compare the results obtained with different methods of estimation of tree biomass in order to reduce the uncertainty in the assessment of forest biomass carbon. In this study, tree biomass was investigated in a 30-year-old Scots pine (Pinus sylvestris) (Young-Stand) and a 130-year-old mixed Norway spruce (Picea abies)-Scots pine stand (Mature-Stand) located in southern Finland (61deg50' N, 24deg22' E). In particular, a comparison of the results of different estimation methods was conducted to assess the reliability and suitability of their applications. For the trees in Mature-Stand, annual stem biomass increment fluctuated following a sigmoid equation, and the fitting curves reached a maximum level (from about 1 kg yr-1 for understorey spruce to 7 kg yr-1 for dominant pine) when the trees were 100 years old). Tree biomass was estimated to be about 70 Mg ha-1 in Young-Stand and about 220 Mg ha-1 in Mature-Stand. In the region (58.00-62.13 degN, 14-34 degE, <= 300 m a.s.l.) surrounding the study stands, the tree biomass accumulation in Norway spruce and Scots pine stands followed a sigmoid equation with stand age, with a maximum of 230 Mg ha-1 at the age of 140 years. In Mature-Stand, lichen biomass on the trees was 1.63 Mg ha-1 with more than half of the biomass occurring on dead branches, and the standing crop of litter lichen on the ground was about 0.09 Mg ha-1. There were substantial differences among the results estimated by different methods in the stands. These results imply that a possible estimation error should be taken into account when calculating tree biomass in a stand with an indirect approach. (orig.)

From a tree to a stand in Finnish boreal forests: biomass estimation and comparison of methods

OpenAIRE

Liu, Chunjiang

2009-01-01

There is an increasing need to compare the results obtained with different methods of estimation of tree biomass in order to reduce the uncertainty in the assessment of forest biomass carbon. In this study, tree biomass was investigated in a 30-year-old Scots pine (Pinus sylvestris) (Young-Stand) and a 130-year-old mixed Norway spruce (Picea abies)-Scots pine stand (Mature-Stand) located in southern Finland (61º50' N, 24º22' E). In particular, a comparison of the results of different estimati...

Tolerance of GaAs as an original substrate for HVPE growth of free standing GaN

Science.gov (United States)

Suzuki, Mio; Sato, T.; Suemasu, T.; Hasegawa, F.

2004-09-01

In order to investigate possibility of thick GaN growth on a GaAs substrate by halide vapar phase epitaxy (HVPE), GaN was grown on GaAs(111)/Ti wafer with Ti deposited by E-gun. It was found that surface treatment of the GaAs substrate by HF solution deteriorated greatly the tolerence of GaAs and that Ti can protected GaAs from erosion by NH3. By depositing Ti on GaAs(111)A surface, a millor-like GaN layer could be grown at 1000 °C for 1 hour without serious deterioration of the original GaAs substrate. By increasing the growth rate, a thick free standing GaN will be obtained with GaAs as an original substrate in near future.

Robust, flexible, and bioadhesive free-standing films for the co-delivery of antibiotics and growth factors.

Science.gov (United States)

Chen, Dongdong; Wu, Mingda; Chen, Jie; Zhang, Chunqiu; Pan, Tiezheng; Zhang, Bing; Tian, Huayu; Chen, Xuesi; Sun, Junqi

2014-11-25

Free-standing polymer films that adhere strongly to tissue and can codeliver multiple therapeutic agents in a controlled manner are useful as medical plasters. In this study, a bilayer polymer film comprising a drug reservoir layer and a supporting layer is fabricated by spin-coating poly(lactic-co-glycolic acid) (PLGA) on top of a layer-by-layer assembled film of poly(β-amino esters) (PAE), alginate sodium (ALG), and recombinant human basic fibroblast growth factor (bFGF). Apart from bFGF, the bilayer film can also load antibiotic drug ceftriaxone sodium (CTX) by a postdiffusion process. The PLGA supporting layer facilitates the direct peeling of the bilayer film from substrate to produce a robust and flexible free-standing film with excellent adhesion onto the human skin and porcine liver. The excellent adhesion of the bilayer film originates from the ALG component in the drug reservoir layer. CTX is quickly released by easily breaking its electrostatic interaction with the drug reservoir layer, whereas the sustained release of bFGF is due to the slow degradation of PAE component in the drug reservoir layer. Wounds can be synergetically treated by fast release of CTX to effectively eradicate invasive bacteria and by sustained release of bFGF to accelerate wound healing. Our results serve as a basis for designing multifunctional free-standing films with combination therapy for biomedical applications.

Diameter Growth of Loblolly Pine Trees as Affected by Soil-Moisture Availibility

Science.gov (United States)

John R. Bassett

1964-01-01

In a 30-year-old even-aged stand of loblolly pine on a site 90 loessial soil in southeast Arkansas during foul growing seasons, most trees on plots thinned to 125 square feet of basal area per acre increased in basal area continuously when, under the crown canopy, available water in the surface foot remained above 65 percent. Measurable diameter growth ceased when...

Restoring old-growth southern pine ecosystems: strategic lessons from long-term silvicultural research

Science.gov (United States)

Don C. Bragg; Michael G. Shelton; James M. Guldin

2008-01-01

The successful restoration of old-growth-like loblolly (Pinus taeda) and shortleaf (Pinus echinata) pine-dominated forests requires the integration of ecological information with long-term silvicultural research from places such as the Crossett Experimental Forest (CEF). Conventional management practices such as timber harvesting or competition control have supplied...

Thinning to improve growth, bole quality, and forest health in an Inonotus hispidus-infected, red oak-sweetgum stand in the Mississippi Delta: 10-year results

Science.gov (United States)

James S. Meadows; Theodor D. Leininger; David Montwé; T. Evan Nebeker

2013-01-01

A 55-year-old red oak-sweetgum (Quercus spp.- Liquidambar styraciflua) stand on the Delta National Forest in western Mississippi was subjected to a combination of low thinning and improvement cutting in 1997. Special emphasis was placed on removing all red oaks infected with Inonotus hispidus, a canker decay...

Stand Dynamics and Biomass Increment in a Lucidophyllous Forest over a 28-Year Period in Central Japan

Directory of Open Access Journals (Sweden)

Siyu Chen

2017-10-01

Full Text Available Secondary lucidophyllous forest is one of the dominant forests in human-dominated subtropical/warm-temperate regions in East Asia. There were few direct monitoring techniques to elucidate the following hypotheses: (a self-thinning may govern the stand development process and (b wood production decline can be observed during secondary succession in a lucidophyllous forest. We conducted a long-term study at a permanent plot in central Japan, since 1989. The forest consists mainly of Castanopsis cuspidata in a canopy layer, Cleyera japonica, and Eurya japonica in a subtree layer. During the 28-year period, the basal area of the stand significantly increased due to the growth of C. cuspidata, from 29.18 ± 1.84 (87.8% of total to 38.71 ± 2.22 m2 ha−1 (91.9%, while the stem density of C. cuspidata significantly decreased from 666 ± 13 to 404 ± 10 stems ha−1 in proportion to accumulating biomass (117.8 to 166.6 ton ha−1. The annual woody net primary production ranged from 2.40 ± 0.13 to 3.93 ± 0.33 ton ha−1 year−1 as a nearly 70-year-old forest. There was no age-related decline of woody net primary production (NPP was found during secondary succession, and the growth of individual tree still increased when the self-thinning process governed the stand.

Secondary forest regeneration benefits old-growth specialist bats in a fragmented tropical landscape.

Science.gov (United States)

Rocha, Ricardo; Ovaskainen, Otso; López-Baucells, Adrià; Farneda, Fábio Z; Sampaio, Erica M; Bobrowiec, Paulo E D; Cabeza, Mar; Palmeirim, Jorge M; Meyer, Christoph F J

2018-02-28

Tropical forest loss and fragmentation are due to increase in coming decades. Understanding how matrix dynamics, especially secondary forest regrowth, can lessen fragmentation impacts is key to understanding species persistence in modified landscapes. Here, we use a whole-ecosystem fragmentation experiment to investigate how bat assemblages are influenced by the regeneration of the secondary forest matrix. We surveyed bats in continuous forest, forest fragments and secondary forest matrix habitats, ~15 and ~30 years after forest clearance, to investigate temporal changes in the occupancy and abundance of old-growth specialist and habitat generalist species. The regeneration of the second growth matrix had overall positive effects on the occupancy and abundance of specialists across all sampled habitats. Conversely, effects on generalist species were negligible for forest fragments and negative for secondary forest. Our results show that the conservation potential of secondary forests for reverting faunal declines in fragmented tropical landscapes increases with secondary forest age and that old-growth specialists, which are often of most conservation concern, are the greatest beneficiaries of secondary forest maturation. Our findings emphasize that the transposition of patterns of biodiversity persistence in island ecosystems to fragmented terrestrial settings can be hampered by the dynamic nature of human-dominated landscapes.

Understory plant diversity in riparian alder-conifer stands after logging in southeast Alaska.

Science.gov (United States)

Robert L. Deal

1997-01-01

Stand structure, tree height growth, and understory plant diversity were assessed in five mixed alder-conifer stands after logging in southeast Alaska. Tree species composition ranged from 7- to 91-percent alder, and basal area ranged from 30 to 55 m2/ha. The alder exhibited rapid early height growth, but recent growth has slowed considerably. Some conifers have...

Modeling Coast Redwood Variable Retention Management Regimes

Science.gov (United States)

John-Pascal Berrill; Kevin O' Hara

2007-01-01

Variable retention is a flexible silvicultural system that provides forest managers with an alternative to clearcutting. While much of the standing volume is removed in one harvesting operation, residual stems are retained to provide structural complexity and wildlife habitat functions, or to accrue volume before removal during subsequent stand entries. The residual...

The effects of stand characteristics on reindeer lichens and range use by semi-domesticated reindeer

Directory of Open Access Journals (Sweden)

T. Helle

1990-09-01

Full Text Available The study was carried out in Kuusamo (66°15'N, 29°05'E and Inari (68°30'N, 28°15'E, northern Finland, where 24 and 22 Scots pine stands were studied respectively. Clear-cutting (logging residue caused a decline in lichen biomass for some few years, but otherwise the age of the stand had no effect upon lichen biomass. Instead, a positive correlation was found between litter/logging residue and the mean height of lichens; in Kuusamo, logging residue decreased significantly with the age of the stand. Grazing pressure in terms of fecal group density increased with the age of the stand. The preference of old forests came visible also as a lower mean height of lichens, which eliminates the possibility that the preference of old forests is associated only to the use of arboreal lichens. In Inari, grazing pressure sharply increased after the stand had reached the age of 100 years despite scarce litter/logging residue and fair lichen ranges in younger forests; there prevailed a negative correlation between stand density and grazing pressure. It has been suggested that there might be three main reasons for reindeers preferring old forests: 1 hardening of the snow (because of winds on clear-cut areas, 2 logging residue preventing digging for the food beneath the snow, and 3 poor visibility in young pine stands (Inari which might increase predation risk.

The Tribal Perspective of Old Growth in Frequent-fire Forests - Its History

Directory of Open Access Journals (Sweden)

Victoria Yazzie

2007-12-01

Full Text Available Anyone who has not lived in "Indian country" cannot understand just how extensively the United States government and its laws affect Native Americans and their natural resource management. These effects are sobering, and touch upon sensitive issues that all Native Americans hold within us. In this article, I outline the historic cycle of tribal entities, and characterize today's tribal self-determination in forest management. I provide an historical account from the "colonial" period and its use of the Doctrine of Discovery to the relations between the United States government and Native Americans from the 18th through the 20th centuries, during which time Native Americans struggled to establish their legal status as tribes, and solidify their land base to sustain and conserve culturally important lands, including areas of old-growth forests, to the current self-determination and self-governance potential of Indian tribes. More importantly, I discuss the cultural connectivity that Native Americans have to the land, and address the unique inherent right of tribes to integrate this cultural view into current forest management, including the protection of old-growth forests, on their reservations.

Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

Science.gov (United States)

Cross, Alison; Perakis, Steven S.

2011-01-01

Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

Site quality influence over understory plant diversity in old-growth and harvested Nothofagus pumilio forests

Directory of Open Access Journals (Sweden)

E. A. Gallo

2013-04-01

Full Text Available Aim of study: The effects and interactions of shelterwood forest harvesting and site qualities over understory plant species diversity and composition were compared among primary and harvested Nothofagus pumilio forests.Area of study: Tierra del Fuego (Argentina, on three pure conditions (one and six year-old harvested, and primary without previous harvesting forests and three site qualities (high, medium and low.Material and Methods: Understory richness and cover (% were registered in five replicates of 1 hectare each per treatment. Taxonomic species were classified in categories (groups, origin and life forms. Two-way ANOVAs and multivariate analyses were conducted.Main results: Shelterwood harvesting and site quality significantly influenced understory cover and richness, which allow the introduction of native and exotic species and increasing of dicot and monocot covers. In dicots, monocots, exotics and total groups, higher richness and covers were related to time. Meanwhile, cover reached similar high values in all site qualities on dicot, native and total groups. On the other hand, monocot and exotic richness and cover remain similar in primary and recently harvested forests, and greatly increased in old harvested forests. Mosses and ferns were among the most sensitive groups.Research highlights: Impacts of shelterwood cut depend on site quality of the stands and time since harvesting occurs. For this, different site quality stands should received differential attention in the development of conservation strategies, as well as variations in the shelterwood implementation (as irregularity and patchiness should be considered to better promote understory plant species conservation inside managed areas.Key words: plant species conservation; years after harvesting; forest management; Tierra del Fuego.

Tolerance of GaAs as an original substrate for HVPE growth of free standing GaN

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Mio; Sato, T.; Suemasu, T.; Hasegawa, F. [University of Tsukuba, Institute of Applied Physics, Tsukuba, Ibaraki 305-8573 (Japan)

2004-09-01

In order to investigate possibility of thick GaN growth on a GaAs substrate by halide vapar phase epitaxy (HVPE), GaN was grown on GaAs(111)/Ti wafer with Ti deposited by E-gun. It was found that surface treatment of the GaAs substrate by HF solution deteriorated greatly the tolerance of GaAs and that Ti can protected GaAs from erosion by NH{sub 3}. By depositing Ti on GaAs(111)A surface, a mirror-like GaN layer could be grown at 1000 C for 1 hour without serious deterioration of the original GaAs substrate. By increasing the growth rate, a thick free standing GaN will be obtained with GaAs as an original substrate in near future. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Complementary models of tree species-soil relationships in old-growth temperate forests

Science.gov (United States)

Cross, Alison; Perakis, Steven S.

2011-01-01

Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and species specific studies of tree species soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common tree species across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess tree species soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative species based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. Tree species soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by tree species across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among species in both forest floor and mineral soil, and most of ten followed adivergence model,where by species differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent species differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent species differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and

Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly.

Directory of Open Access Journals (Sweden)

Andreas Fichtner

Full Text Available The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica forest by quantifying variation in the intensity of above- (shading and belowground competition (crowding among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.

Similar net ecosystem exchange of beech stands located in France and Denmark

DEFF Research Database (Denmark)

Granier, A.; Pilegaard, K.; Jensen, N.O.

2002-01-01

Net ecosystem exchange (NEE), as measured with eddy covariance was compared for two European beech stands for the years 1996-1999: a young beech forest (32 year-old) growing in east France, and a mature beech stand (80 year-old) located in Denmark. Those sites are included in the Carboeuroflux....../Carbodata European networks. Except for some short-term differences (1-5 days), the temporal variation of NEE followed similar patterns in both sites. This similarity followed from similar values of. (i) dates of bud break and of leaf fall; (ii) ecosystem respiration rates during winter; (iii) diurnal NEE during...

Ponderosa pine growth response to soil strength in the volcanic ash soils of central Oregon.

Science.gov (United States)

R.T. Parker; D.A. Maguire; D.D. Marshall; P. Cochran

2007-01-01

Mechanical harvesting and associated logging activities have the capacity to compact soil across large portions of harvest units. Two thinning treatments (felled only versus felled and skidded) in 70- to 80-year-old ponderosa pine stands were replicated at three sites with volcanic soils in central Oregon. Growth in diameter, height, and volume of residual trees were...

Thinning results from a mixed upland hardwood stand after 35 years

Science.gov (United States)

Ronald J., Jr. Myers; Kenneth R. Roeder; W. Henry McNab

2008-01-01

A long-term study of precommercial thinning was installed in a 6-year-old oak-dominated stand regenerated by clearcutting in the southern Appalachian Mountains of North Carolina. Three levels of residual stand density were tested: control (no thinning), and 200, and 400 residual trees per acre (TPA). Objectives of the study were to determine the response of an upland...

Dynamics models and modeling of tree stand development

Directory of Open Access Journals (Sweden)

M. V. Rogozin

2015-04-01

Full Text Available Brief analysis of scientific works in Russia and in the CIS over the past 100 years. Logical and mathematical models consider the conceptual and show some of the results of their verification. It was found that the models include different laws and the parameters, the sum of which allows you to divide them into four categories: models of static states, development models, models of care for the natural forest and models of cultivation. Each category has fulfilled and fulfills its tasks in economic management. Thus, the model states in statics (table traverse growth played a prominent role in figuring out what may be the most productive (full stands in different regions of the country. However, they do not answer the question of what the initial states lead to the production of complete stands. In a study of the growth of stands used system analysis, and it is observed dominance of works studying static state, snatched from the biological time. Therefore, the real drama of the growth of stands remained almost unexplored. It is no accident there were «chrono-forestry» «plantation forestry» and even «non-traditional forestry», where there is a strong case of a number of new concepts of development stands. That is quite in keeping with Kuhn (Kuhn, 2009 in the forestry crisis began – there were alternative theories and coexist conflicting scientific schools. To develop models of stand development, it is proposed to use a well-known method of repeated observations within 10–20 years, in conjunction with the explanation of the history of the initial density. It mounted on the basis of studying the dynamics of its indicators: the trunk, crown overlap coefficient, the sum of volumes of all crowns and the relative length of the crown. According to these indicators, the researcher selects natural series of development stands with the same initial density. As a theoretical basis for the models it is possible to postulate the general properties of

Spatial and Temporal Relationships of Old-Growth and Secondary Forests in Indiana, USA

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Martin A. Spetich; George R. Parker; Eric J. Gustafson

1997-01-01

We examined the spatial pattern of forests in Indiana to: (1) determine the extent, connectivity and percent edge of all forests, (2) examine the change in connectivity among these forests if all riparian zones were replanted to forest or other native vegetation, (3) determine the location, spatial dispersion and percent edge of current old-growth forest remnants, (4)...

History of Tree Growth Declines Recorded in Old Trees at Two Sacred Sites in Northern China.

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Li, Yan; Zhang, Qi-Bin

2017-01-01

Old forests are an important component in sacred sites, yet they are at risk of growth decline from ongoing global warming and increased human activities. Growth decline, characterized by chronic loss of tree vigor, is not a recent phenomenon. Knowledge of past occurrence of declines is useful for preparing conservation plans because it helps understand if present day forests are outside the natural range of variation in tree health. We report a dendroecological study of growth decline events in the past two centuries at two sacred sites, Hengshan and Wutaishan, in Shanxi province of northern China. Tree rings collected at both sites show distinct periods of declining growth evident as narrow rings. These occurred in the 1830s in both sites, in the 1920s in Wutaishan and in the 2000s in Hengshan. By comparing the pattern of grow declines at the two sites, we hypothesize that resistance of tree growth to external disturbances is forest size dependent, and increased human activity might be a factor additional to climatic droughts in causing the recent strong growth decline at Hengshan Park. Despite these past declines, the forests at both sites have high resilience to disturbances as evidenced by the ability of trees to recover their growth rates to levels comparable to the pre-decline period. Managers should consider reducing fragmentation and restoring natural habitat of old forests, especially in areas on dry sites.

History of Tree Growth Declines Recorded in Old Trees at Two Sacred Sites in Northern China

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Yan Li

2017-11-01

Full Text Available Old forests are an important component in sacred sites, yet they are at risk of growth decline from ongoing global warming and increased human activities. Growth decline, characterized by chronic loss of tree vigor, is not a recent phenomenon. Knowledge of past occurrence of declines is useful for preparing conservation plans because it helps understand if present day forests are outside the natural range of variation in tree health. We report a dendroecological study of growth decline events in the past two centuries at two sacred sites, Hengshan and Wutaishan, in Shanxi province of northern China. Tree rings collected at both sites show distinct periods of declining growth evident as narrow rings. These occurred in the 1830s in both sites, in the 1920s in Wutaishan and in the 2000s in Hengshan. By comparing the pattern of grow declines at the two sites, we hypothesize that resistance of tree growth to external disturbances is forest size dependent, and increased human activity might be a factor additional to climatic droughts in causing the recent strong growth decline at Hengshan Park. Despite these past declines, the forests at both sites have high resilience to disturbances as evidenced by the ability of trees to recover their growth rates to levels comparable to the pre-decline period. Managers should consider reducing fragmentation and restoring natural habitat of old forests, especially in areas on dry sites.

"Growing trees backwards": Description of a stand reconstruction model

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Jonathan D. Bakker; Andrew J. Sanchez Meador; Peter Z. Fule; David W. Huffman; Margaret M. Moore

2008-01-01

We describe an individual-tree model that uses contemporary measurements to "grow trees backward" and reconstruct past tree diameters and stand structure in ponderosa pine dominated stands of the Southwest. Model inputs are contemporary structural measurements of all snags, logs, stumps, and living trees, and radial growth measurements, if available. Key...

Epicormic branching of California black oak: effect of stand and tree characteristics

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Philip M. McDonald; Martin W. Ritchie

1994-01-01

Young California black oak (Quercus kelloggii Newb.) stands usually require thinning to increase production of acorns and wood products, but epicormic branches, which yield no acorns and constitute a serious lumber degrade. often result. A crown thinning in 60-year-old hardwood stands on a south exposure at the Challenge Experimental Forest in thenorthern Sierra Nevada...

Ecosystem Responses to Partial Harvesting in Eastern Boreal Mixedwood Stands

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Brian D. Harvey

2013-05-01

Full Text Available Partial harvesting has been proposed as a key aspect to implementing ecosystem management in the Canadian boreal forest. We report on a replicated experiment located in boreal mixedwoods of Northwestern Quebec. In the winter of 2000–2001, two partial harvesting treatments, one using a dispersed pattern, and a second, which created a (400 m2 gap pattern, were applied to a 90-year-old aspen-dominated mixed stand. The design also included a clear cut and a control. Over the course of the following eight years, live tree, coarse woody debris, regeneration and ground beetles were inventoried at variable intervals. Our results indicate that all harvesting treatments created conditions favorable to balsam fir (Abies balsamea sapling growth and trembling aspen (Populus tremuloides sapling recruitment. However, balsam fir and trembling aspen regeneration and ground beetles response to gap cuts were closer to patterns observed in clear cuts than in dispersed harvesting. The underlying reasons for these differing patterns can be linked to factors associated with the contrasting light regimes created by the two partial harvesting treatments. The study confirms that partially harvesting is an ecologically sound approach in boreal mixedwoods and could contribute to maintaining the distribution of stand ages at the landscape level.

Occurrence of shrubs and herbaceous vegetation after clear cutting old-growth Douglas-fir in the Oregon Cascades.

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Vern P. Yerkes

1960-01-01

Land managers often express a need for more complete information about the vegetative cover that develops on cutover areas between harvest of old-growth Douglas-fir (Pseudotsuga menziesii) and establishment of a young-growth forest. The composition and density of this cover frequently determines the management techniques that must be used to...

Plot size recommendations for biomass estimation in a midwestern old-growth forest

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Martin A. Spetich; George R Parker

1998-01-01

The authors examine the relationship between disturbance regime and plot size for woody biomass estimation in a midwestern old-growth deciduous forest from 1926 to 1992. Analysis was done on the core 19.6 ac of a 50.1 ac forest in which every tree 4 in. d.b.h. and greater has been tagged and mapped since 1926. Five windows of time are compared—1926, 1976, 1981, 1986...

Examining the influences of tree-to-tree competition and climate on size-growth relationships in hydric, multi-aged Fraxinus nigra stands

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Christopher E. Looney; Anthony W. D' Amato; Shawn Fraver; Brian J. Palik; Michael R. Reinikainen

2016-01-01

Most research on tree-tree competition and size-growth relationship (SGR – a stand-level metric that infers the relative efficiency with which different sized trees utilize available resources) has focused on upland systems. It is unclear if inferences from these studies extend to wetland forests. Moreover, no study to date has thoroughly investigated the relationship...

Contrasting spatial patterns in active-fire and fire-suppressed Mediterranean climate old-growth mixed conifer forests.

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Fry, Danny L; Stephens, Scott L; Collins, Brandon M; North, Malcolm P; Franco-Vizcaíno, Ernesto; Gill, Samantha J

2014-01-01

In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha(-1), and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥ 56%) in large patches (≥ 10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

Space sequestration below ground in old-growth spruce-beech forests-signs for facilitation?

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Bolte, Andreas; Kampf, Friederike; Hilbrig, Lutz

2013-01-01

Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

Regeneration Responses to Management for Old-Growth Characteristics in Northern Hardwood-Conifer Forests

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Aviva J. Gottesman

2017-02-01

Full Text Available Successful tree regeneration is essential for sustainable forest management, yet it can be limited by the interaction of harvesting effects and multiple ecological drivers. In northern hardwood forests, for example, there is uncertainty whether low-intensity selection harvesting techniques will result in adequate and desirable regeneration. Our research is part of a long-term study that tests the hypothesis that a silvicultural approach called “structural complexity enhancement” (SCE can accelerate the development of late-successional forest structure and functions. Our objective is to understand the regeneration dynamics following three uneven-aged forestry treatments with high levels of retention: single-tree selection, group selection, and SCE. Regeneration density and diversity can be limited by differing treatment effects on or interactions among light availability, competitive environment, substrate, and herbivory. To explore these relationships, manipulations and controls were replicated across 2 ha treatment units at two Vermont sites. Forest inventory data were collected pre-harvest and periodically over 13 years post-harvest. We used mixed effects models with repeated measures to evaluate the effect of treatment on seedling and sapling density and diversity (Shannon–Weiner H’. The treatments were all successful in recruiting a sapling class with significantly greater sapling densities compared to the controls. However, undesirable and prolific beech (Fagus americana sprouting dominates some patches in the understory of all the treatments, creating a high degree of spatial variability in the competitive environment for regeneration. Multivariate analyses suggest that while treatment had a dominant effect, other factors were influential in driving regeneration responses. These results indicate variants of uneven-aged systems that retain or enhance elements of stand structural complexity—including old-growth characteristics�

Growth modeling of Cryptomeria japonica by partial trunk analysis

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Vinícius Morais Coutinho

2017-06-01

Full Text Available This study aimed to evaluate the growth pattern of Cryptomeria japonica increment (L. F. D. Don. and to describe the probability distribution in stands stablished at the municipality of Rio Negro, Paraná State. Twenty trees were sampled in a 34 years-old stand, with 3 m x 2 m spacing. Wood disks were taken from each tree at 1.3 m above the ground (DBH to perform partial stem analysis. Diameter growth series without bark were used to generate the average cumulative growth curves for DBH (cm, mean annual increment (MAI and current annual increment (CAI. From the increment data, the frequency distribution was evaluated by means of probability density functions (pdfs. The mean annual increment for DBH was 0.78 cm year-1 and the age of intersection of CAI and MAI curves was between the 7th and 8th years. It was found that near 43% of the species increments are concentrated bellow 0.5 cm. The results are useful to define appropriate management strategies for the species for sites similar to the studying regions, defining for example ages of silvicultural intervention, such as thinning.

User's Guide To CHEAP0 II-Economic Analysis of Stand Prognosis Model Outputs

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Joseph E. Horn; E. Lee Medema; Ervin G. Schuster

1986-01-01

CHEAP0 II provides supplemental economic analysis capability for users of version 5.1 of the Stand Prognosis Model, including recent regeneration and insect outbreak extensions. Although patterned after the old CHEAP0 model, CHEAP0 II has more features and analytic capabilities, especially for analysis of existing and uneven-aged stands....

Bilateral Posterior Native Hip Dislocations after Fall from Standing

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Jane Xiao

2017-10-01

Full Text Available We present a case of bilateral posterior native hip dislocations after a fall from standing. This exceedingly rare diagnosis is classically associated with younger patients whose bones are strong enough to dislocate rather than fracture in the setting of a high-momentum collision. We present an unusual case of an 88-year-old male with native hips who sustained a low-energy collision after falling from standing and was found to have bilateral posterior hip dislocations without associated pelvis or femur fractures.

EFFECT OF POST-LOGGING SILVICULTURAL TREATMENT ON GROWTH RATES OF RESIDUAL STAND IN A TROPICAL FOREST

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Haruni Krisnawati

2010-12-01

Full Text Available Post-logging silvicultural treatments are generally performed to improve yields of the remaining tree species by increasing their growth rate. In this study the effects of silvicultural treatment on the growth rates of commercial (dipterocarps and non-dipterocarps as well as non- commercial tree species in a tropical forest in West Kalimantan were examined and were compared to a control treatment. Silvicultural treatment applied was liberation of future crop trees from lianas and neighbouring competing trees. Treatments were applied to six plots of 80 m x 80 m each. The plots comprised 64 quadrats of 10 m x 10 m to allow better control of measurements. The treatment and control plots were established 6 years after logging. Effects were measured 2,4 and 7 years after treatment application. In all obser vation periods, the growth rates increased with silvicultural treatment. Overall, commercial dipterocarps, commercial non-dipterocarps and non-commercial tree species groups differed in response to silvicultural treatment. The growth rates of commercial tree species in plots that received silvicultural treatment were 62–97% higher than in the control plots. For non-commercial tree species, the increase of growth rates was 20–58%, compared to the control plots. These results indicate that the application of silvicultural treatments after logging could help improve the growth of the residual stands. These provide quantitative information that silvicultural treatments in logged-over forest should be considered as a viable management option and may guide the choice of cutting cycle.

Process-based modelling of tree and stand growth: towards a hierarchical treatment of multiscale processes

International Nuclear Information System (INIS)

Makela, A.

2003-01-01

A generally accepted method has not emerged for managing the different temporal and spatial scales in a forest ecosystem. This paper reviews a hierarchical-modular modelling tradition, with the main focus on individual tree growth throughout the rotation. At this scale, model performance requires (i) realistic long-term dynamic properties, (ii) realistic responses of growth and mortality of competing individuals, and (iii) realistic responses to ecophysio-logical inputs. Model development and validation are illustrated through allocation patterns, height growth, and size-related feedbacks. Empirical work to test the approach is reviewed. In this approach, finer scale effects are embedded in parameters calculated using more detailed, interacting modules. This is exemplified by (i) the within-year effect of weather on annual photosynthesis, (ii) the effects of fast soil processes on carbon allocation and photosynthesis, and (iii) the utilization of detailed stem structure to predict wood quality. Prevailing management paradigms are reflected in growth modelling. A shift of emphasis has occurred from productivity in homogeneous canopies towards, e.g., wood quality versus total yield, spatially more explicit models, and growth decline in old-growth forests. The new problems emphasize the hierarchy of the system and interscale interactions, suggesting that the hierarchical-modular approach could prove constructive. (author)

A Multiple Logistic Regression Model for Predicting the Development of Phytophthora ramorum symptoms in Tanoak (Lithocarpus densiflorus)

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Mark Spencer; Kevin O' Hara

2007-01-01

Phytophthora ramorum attacks tanoak (Lithocarpus densiflorus) in California and Oregon. We present a stand-level study examining the presence of disease symptoms in individual stems. Working with data from four plots in redwood (Sequoia sempervirens)/tanoak forests in Marin County, and three plots in Mendocino...

Multi-muscle electrical stimulation and stand training: Effects on standing.

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Momeni, Kamyar; Ramanujam, Arvind; Garbarini, Erica L; Forrest, Gail F

2018-02-15

To examine the biomechanical and neuromuscular effects of a longitudinal multi-muscle electrical stimulation (submaximal intensities) training of the lower limbs combined with/without activity-based stand training, on the recovery of stability and function for one individual with spinal cord injury (SCI). Single-subject, longitudinal study. Neuroplasticity laboratory. A 34-year-old male, with sensory- and motor-complete SCI (C5/C6). Two consecutive interventions: 61 hours of supine, lower-limb ES (ES-alone) and 51 hours of ES combined with stand training using an overhead body-weight support system (ST + ES). Clinical measures, trunk stability, and muscle activity were assessed and compared across time points. Trunk Stability Limit (TSL) determined improvements in trunk independence. Functional clinical values increased after both interventions, with further increases post ST + ES. Post ES-alone, trunk stability was maintained at 81% body-weight (BW) loading before failure; post ST + ES, BW loading increased to 95%. TSL values decreased post ST + ES (TSL A/P =54.0 kg.cm, TSL M/L =14.5 kg.cm), compared to ES-alone (TSL A/P =8.5 kg.cm, TSL M/L =3.9 kg.cm). Trunk muscle activity decreased post ST + ES training, compared to ES-alone. Neuromuscular and postural trunk control dramatically improved following the multi-muscle ES of the lower limbs with stand training. Multi-muscle ES training paradigm of the lower limb, using traditional parameters, may contribute to the functional recovery of the trunk.

Non-spray spruce budworm management alternatives: Will thinning second-growth balsam fir in northwestern Ontario alter the stands` vulnerability to spruce budworm damage. NWOFTDU technical report No. 53

Energy Technology Data Exchange (ETDEWEB)

Van Schip, W.M.; Towill, W.D.; Zago, T.

1990-12-31

The objective of this study was to determine whether balsam fir stands, thinned to different levels of basal area, differ in their susceptibility and vulnerability to damage created by infestations of spruce budworm. In 1976-77, the investigators thinned two relatively pure, juvenile, second-growth balsam fir stands in northwestern Ontario to four levels of basal area by girdling or felling. The stands were assessed in 1988. Annual aerial and ground monitoring of the study sites indicated that one area experienced a moderate to severe defoliation by spruce budworm during 1984-86, while the other area experienced moderate to severe defoliation by budworm during 1980-86. This report presents results of the study and discusses the relation between thinning, budworm damage, and stand productivity.

Spatially nonrandom tree mortality and ingrowth maintain equilibrium pattern in an old-growth Pseudotsuga-Tsuga forest.

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Lutz, James A; Larson, Andrew J; Furniss, Tucker J; Donato, Daniel C; Freund, James A; Swanson, Mark E; Bible, Kenneth J; Chen, Jiquan; Franklin, Jerry F

2014-08-01

Mortality processes in old-growth forests are generally assumed to be driven by gap-scale disturbance, with only a limited role ascribed to density-dependent mortality, but these assumptions are rarely tested with data sets incorporating repeated measurements. Using a 12-ha spatially explicit plot censused 13 years apart in an approximately 500-year-old Pseudotsuga-Tsuga forest, we demonstrate significant density-dependent mortality and spatially aggregated tree recruitment. However, the combined effect of these strongly nonrandom demographic processes was to maintain tree patterns in a state of dynamic equilibrium. Density-dependent mortality was most pronounced for the dominant late-successional species, Tsuga heterophylla. The long-lived, early-seral Pseudotsuga menziesii experienced an annual stem mortality rate of 0.84% and no new recruitment. Late-seral species Tsuga and Abies amabilis had nearly balanced demographic rates of ingrowth and mortality. The 2.34% mortality rate for Taxus brevifolia was higher than expected, notably less than ingrowth, and strongly affected by proximity to Tsuga. Large-diameter Tsuga structured both the regenerating conspecific and heterospecific cohorts with recruitment of Tsuga and Abies unlikely in neighborhoods crowded with large-diameter competitors (P old-growth forests.

Water and Energy Balances of Loblolly Pine Plantation Forests during a Full Stand Rotation

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Sun, G.; Mitra, B.; Domec, J. C.; Gavazi, M.; Yang, Y.; Tian, S.; Zietlow, D.; McNulty, S.; King, J.; Noormets, A.

2017-12-01

Loblolly pine (Pinus taeda) plantations in the southern U.S. are well recognized for their ecosystem services in supplying clean and stable water and mitigating climate change through carbon sequestration and solar energy partitioning. Since 2004, we have monitored energy, water, and carbon fluxes in a chronosequence of three drained loblolly pine plantations using integrated methods that include eddy covariance, sap flux, watershed hydrometeorology, remote sensing, and process-based simulation modeling. Study sites were located on the eastern North Carolina coastal plain, representing highly productive ecosystems with high groundwater table, and designated in the Ameriflux network as NC1 (0-10 year old), NC2 (12-25 year old) and NC3 (0-3 years old). The 13-year study spanned a wide range of annual precipitation (900-1600 mm/yr) including two exceptionally dry years during 2007-2008. We found that the mature stand (NC2) had higher net radiation (Rn) flux due to its lower albedo (α =0.11-12), compared with the young stands (NC1, NC3) (α=0.15-0.18). Annually about 75%-80% of net radiation was converted to latent heat in the pine plantations. In general, the mature stand had higher latent heat flux (LE) (i.e. evapotranspiration (ET)) rates than the young stands, but ET rates were similar during wet years when the groundwater table was at or near the soil surface. During a historic drought period (i.e., 2007-2008), total stand annual ET exceeded precipitation, but decreased about 30% at NC2 when compared to a normal year (e.g., 2006). Field measurements and remote sensing-based modeling suggested that annual ET rates increased linearly from planting age (about 800 mm) to age 15 (about 1050 mm) and then stabilized as stand leaf area index leveled-off. Over a full stand rotation, approximately 70% (young stand) to 90% (mature stand) of precipitation was returned to the atmosphere through ET. We conclude that both climatic variability and canopy structure controlled the

Stand quality management of a water oak plantation in Louisiana: preliminary results following thinning

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James S. Meadows; Daniel A., Jr. Skojac

2010-01-01

Stand quality management is a new guiding principle in which thinning prescriptions are based on tree quality rather than on residual stand density. We recently initiated a series of hardwood thinning studies to determine the effects of four stand quality management thinning prescriptions on both stand-level and individual-tree-level growth, quality, and value: (1) no...

The studies on ash dying (Fraxinus excelsior L. in the Włoszczowa Forest Unit stands

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Tadeusz Kowalski

2012-12-01

Full Text Available The studies were carried out in the Włoszczowa Forest Unit, in 9 ash stands differing in respect of age, origin (natural, artificial, site and in the nursery on 3 quarters differing due to a silvicultural method (transplanted and not transplanted and seedlings age. In each stand an analysis of disease symptoms was carried out on 100 trees (2 - 20 years old stands or 50 trees (21 - 80 years old stands growing side by side in central part of the stand, while in the nursery in each block 200 seedlings were analyzed (4 sectors with 50 seedlings each. From the infected seedlings and trees 120 fragments of dead branches, living branches with cankers, and dead roots were taken. Identification of fungi was made on the basis of fructification and over 300 isolations of fungi on malt agar medium. The most frequent disease symptoms in ash stands were: the dead top (34.7% trees, the dying of whole branches (83.5%, the dying of the top of branches (20.1%, the occurrence of healed (36.0% and unhealed cankers (18.9% and the slime flux (23.7% on the trunk, also the chlorosis of leaves (7.5% and their atrophy (11.2%. Most of the types of disease symptoms appeared irrespectively of the tree age, origin and site, sometimes showing only a difference in the frequency of occurrence. On the seedlings in the nursery the shoot discolouration, healed and unhealed cankers on shoots and necrosis of a part of leaves were recorded most frequently. Disease symptoms occurred more frequently on 4-year-old seedlings in comparison with 3-year-old. In respect of transplanted seedlings the leaves dying was more frequent. Within cankers and on dead tops of shoots the most frequent were: Alternaria alternata, Chalara sp., Cytospora ambiens, Diplodia mutila, Fusarium lateritium, Gloeosporidiella turgida, Phomopsis controversa and Phomopsis scobina. In sparsely found dead roots of living trees appeared mostly: Cryptosporiopsis radicicola, Cylindrocarpon destructans and Phialocephala

Impacts of more frequent droughts on a relict low-altitude Pinus uncinata stand in the French Alps

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Christophe eCorona

2015-01-01

Full Text Available Cold microclimatic conditions provide exceptional microhabitats to Pinus uncinata stands occurring at abnormally low altitudes in seven paleorefugia of the northern French Alps. Here, P. uncinata is located at the lower bounds of its ecological limits and therefore expected to provide a sensitive indicator of climate change processes. We used dendrochronological analysis to study the growth patterns of closely spaced chronologies across an elevational transect and compare a relict low-altitude to a P. uncinata stand located at the alpine treeline. Two detrending procedures are used to reveal high and low-frequency wavelengths embedded in annually resolved ring-width series. Growth response of P. uncinata to instrumental temperature and precipitation data is investigated by means of moving response function analyses. Results show an increase in the sensitivity of tree-ring widths to drought during previous summer in both stands. At the treeline stand, an increasing correlation with fall temperature is observed whereby low-frequency variability of fall temperature and radial tree growth increased in two synchronous steps around ~1930 and from ~1980–present. At the low-altitude stand, P. uncinata appears more drought sensitive and exhibits a sharp growth decline since the mid-1980s, coinciding with increasing summer temperatures. Growth divergence between the two stands can be observed since the mid-1980s. We argue that the positive growth trend at the high-altitude stand is due to increasing fall temperatures which would favor the formation of metabolic reserves in conjunction with atmospheric CO2 enrichment that in turn would facilitate improved water use efficiency. At the relict low-altitude stand, in contrast, it seems that improved water use efficiency cannot compensate for the increase in summer temperatures.

Contrasting spatial patterns in active-fire and fire-suppressed Mediterranean climate old-growth mixed conifer forests.

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Danny L Fry

Full Text Available In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha(-1, and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥ 56% in large patches (≥ 10 trees, and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

Space sequestration below ground in old-growth spruce-beech forests – signs for facilitation?

Directory of Open Access Journals (Sweden)

Andreas eBolte

2013-08-01

Full Text Available Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤ 2 mm by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1 spruce as a central tree, (2 spruce as competitor, (3 beech as a central tree, and (4 beech as competitor. Mean values of life fine root attributes like biomass (FRB, length (FRL, and root area index (RAI were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA, asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

Infant feeding practice on growth velocity in 4-6 month-olds

Directory of Open Access Journals (Sweden)

Joko Kurniawan

2018-03-01

Full Text Available Background In developing countries, 5-10% of infants suffer from failure to thrive. Adequate feeding is the most crucial factor for optimal growth in early life. Objective To assess the differences in growth velocity at 4 to 6 months of age, based on the infant feeding practices. Methods This cross-sectional study involving 4 to 6 month-old babies from 6 public health centres in Yogyakarta was performed from August to November 2016. Data on body weight, and growth velocity as they related to weight at birth were collected. Subjects were divided into groups according to their feeding practices. Results Of 173 subjects, 130 (75% infants were exclusively breastfed, 19 infants (11% were given breast milk and formula, 14 (8% infants were given breast milk and complementary food (8%, and 10 (6% infants were given formula and complementary food. The mean growth velocity z-scores by group were as follows: exclusively breastfed 0.04 (SD 1.15 (95%CI -0.16 to 0.24, breast milk and formula -0.61 (SD 0.84 (95%CI -1.01 to -0.21, breast milk and complementary food -0.69 (SD 1.14 (95%CI -1.35 to -0.04, formula and complementary food 0.23 (SD 1.50 (95%CI: -0.84 to 1.31. The mean difference in growth velocity between the exclusively breastfed vs. breast milk and formula groups was 0.65 (SD 0.28 (95%CI: 0.10 to 1.20; P=0.02; vs. breast milk and complementary food was 0.73 (SD 0.32 (95%CI: 0.10 to 1.37; P=0.02; and vs. formula and complementary food was -0.19 (SD 0.37 (95%CI: -0.93 to 0.55; P=0.61. Conclusion Exclusively breastfed have the most optimal growth velocity compared to infants who experience other feeding practices.

Do thinning and prescribed burning affect the growth of shortleaf pine?

Science.gov (United States)

H. A. Somes; G. R. Moorhead

1954-01-01

In January 1946 a small study of thinning and prescribed burning was started in an old-field stand mostly of shortleaf pines about 38 years old. The stand is located on private land in Salem County, N. J.

Predicted stand volume for Eucalyptus plantations by spatial analysis

Science.gov (United States)

Latifah, Siti; Teodoro, RV; Myrna, GC; Nathaniel, CB; Leonardo, M. F.

2018-03-01

The main objective of the present study was to assess nonlinear models generated by integrating the stand volume growth rate to estimate the growth and yield of Eucalyptus. The primary data was done for point of interest (POI) of permanent sample plots (PSPs) and inventory sample plots, in Aek Nauli sector, Simalungun regency,North Sumatera Province,Indonesia. from December 2008- March 2009. Today,the demand for forestry information has continued to grow over recent years. Because many forest managers and decision makers face complex decisions, reliable information has become the necessity. In the assessment of natural resources including plantation forests have been widely used geospatial technology.The yield of Eucalyptus plantations represented by merchantable volume as dependent variable while factors affecting yield namely stands variables and the geographic variables as independent variables. The majority of the areas in the study site has stand volume class 0 - 50 m3/ha with 16.59 ha or 65.85 % of the total study site.

The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape.

Science.gov (United States)

Chambers, Jeffrey Q; Negron-Juarez, Robinson I; Marra, Daniel Magnabosco; Di Vittorio, Alan; Tews, Joerg; Roberts, Dar; Ribeiro, Gabriel H P M; Trumbore, Susan E; Higuchi, Niro

2013-03-05

Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. The size distribution and return frequency of disturbance events, and subsequent recovery processes, determine to a large extent the spatial scale over which this old-growth steady state develops. Here, we characterize this mosaic for a Central Amazon forest by integrating field plot data, remote sensing disturbance probability distribution functions, and individual-based simulation modeling. Results demonstrate that a steady state of patches of varying successional age occurs over a relatively large spatial scale, with important implications for detecting temporal trends on plots that sample a small fraction of the landscape. Long highly significant stochastic runs averaging 1.0 Mg biomass⋅ha(-1)⋅y(-1) were often punctuated by episodic disturbance events, resulting in a sawtooth time series of hectare-scale tree biomass. To maximize the detection of temporal trends for this Central Amazon site (e.g., driven by CO2 fertilization), plots larger than 10 ha would provide the greatest sensitivity. A model-based analysis of fractional mortality across all gap sizes demonstrated that 9.1-16.9% of tree mortality was missing from plot-based approaches, underscoring the need to combine plot and remote-sensing methods for estimating net landscape carbon balance. Old-growth tropical forests can exhibit complex large-scale structure driven by disturbance and recovery cycles, with ecosystem and community attributes of hectare-scale plots exhibiting continuous dynamic departures from a steady-state condition.

Growth

Science.gov (United States)

John R. Jones; George A. Schier

1985-01-01

This chapter considers aspen growth as a process, and discusses some characteristics of the growth and development of trees and stands. For the most part, factors affecting growth are discussed elsewhere, particularly in the GENETICS AND VARIATION chapter and in chapters in PART 11. ECOLOGY. Aspen growth as it relates to wood production is examined in the WOOD RESOURCE...

An 8-Year-Old Boy With Treatment-Resistant Encopresis

NARCIS (Netherlands)

Stein, Martin T.; Benninga, Marc A.; Felt, Barbara T.

2010-01-01

CASE: Paul is an 8-year-old boy with a long-standing history of encopresis and enuresis. Potty training was initiated when he was 21/2 years old. At this time, his mother was absent from the home for 6 weeks when she cared for her ill father in a different city. The process of teaching Paul to use

An 8-Year-Old Boy With Treatment-Resistant Encopresis

NARCIS (Netherlands)

Stein, Martin T.; Benninga, Marc A.; Felt, Barbara T.

2017-01-01

Paul is an 8-year-old boy with a long-standing history of encopresis and enuresis. Potty training was initiated when he was 2 years old. At this time, his mother was absent from the home for 6 weeks when she cared for her ill father in a different city. The process of teaching Paul to use the

Stand structure modulates the long-term vulnerability of Pinus halepensis to climatic drought in a semiarid Mediterranean ecosystem.

Science.gov (United States)

Moreno-Gutiérrez, Cristina; Battipaglia, Giovanna; Cherubini, Paolo; Saurer, Matthias; Nicolás, Emilio; Contreras, Sergio; Querejeta, José Ignacio

2012-06-01

We investigated whether stand structure modulates the long-term physiological performance and growth of Pinus halepensis Mill. in a semiarid Mediterranean ecosystem. Tree radial growth and carbon and oxygen stable isotope composition of latewood (δ(13)C(LW) and δ(18)O(LW), respectively) from 1967 to 2007 were measured in P. halepensis trees from two sharply contrasting stand types: open woodlands with widely scattered trees versus dense afforested stands. In both stand types, tree radial growth, δ(13)C(LW) and δ(18)O(LW) were strongly correlated with annual rainfall, thus indicating that tree performance in this semiarid environment is largely determined by inter-annual changes in water availability. However, trees in dense afforested stands showed consistently higher δ(18)O(LW) and similar δ(13)C(LW) values compared with those in neighbouring open woodlands, indicating lower stomatal conductance and photosynthesis rates in the former, but little difference in water use efficiency between stand types. Trees in dense afforested stands were more water stressed and showed lower radial growth, overall suggesting greater vulnerability to drought and climate aridification compared with trees in open woodlands. In this semiarid ecosystem, the negative impacts of intense inter-tree competition for water on P. halepensis performance clearly outweigh potential benefits derived from enhanced infiltration and reduced run-off losses in dense afforested stands. © 2011 Blackwell Publishing Ltd.

Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China.

Science.gov (United States)

Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

2013-01-01

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and forests respectively, and thus play a minor role in total forest C storage in NE China.

Flexible integration of free-standing nanowires into silicon photonics.

Science.gov (United States)

Chen, Bigeng; Wu, Hao; Xin, Chenguang; Dai, Daoxin; Tong, Limin

2017-06-14

Silicon photonics has been developed successfully with a top-down fabrication technique to enable large-scale photonic integrated circuits with high reproducibility, but is limited intrinsically by the material capability for active or nonlinear applications. On the other hand, free-standing nanowires synthesized via a bottom-up growth present great material diversity and structural uniformity, but precisely assembling free-standing nanowires for on-demand photonic functionality remains a great challenge. Here we report hybrid integration of free-standing nanowires into silicon photonics with high flexibility by coupling free-standing nanowires onto target silicon waveguides that are simultaneously used for precise positioning. Coupling efficiency between a free-standing nanowire and a silicon waveguide is up to ~97% in the telecommunication band. A hybrid nonlinear-free-standing nanowires-silicon waveguides Mach-Zehnder interferometer and a racetrack resonator for significantly enhanced optical modulation are experimentally demonstrated, as well as hybrid active-free-standing nanowires-silicon waveguides circuits for light generation. These results suggest an alternative approach to flexible multifunctional on-chip nanophotonic devices.Precisely assembling free-standing nanowires for on-demand photonic functionality remains a challenge. Here, Chen et al. integrate free-standing nanowires into silicon waveguides and show all-optical modulation and light generation on silicon photonic chips.

"Growing trees backwards": Description of a stand reconstruction model (P-53)

Science.gov (United States)

Jonathan D. Bakker; Andrew J. Sanchez Meador; Peter Z. Fule; David W. Huffman; Margaret M. Moore

2008-01-01

We describe an individual-tree model that uses contemporary measurements to "grow trees backward" and reconstruct past tree diameters and stand structure in ponderosa pine dominated stands of the Southwest. Model inputs are contemporary structural measurements of all snags, logs, stumps, and living trees, and radial growth measurements, if available. Key...

The growth of Scots pine and the availability of nutrients in old Finnish liming experiments on drained peatlands

International Nuclear Information System (INIS)

Nieminen, M.; Paetilae, A.

1994-01-01

Liming (with applications of 1000 to 8000 kg/ha) had no long- term (1929-1985) effect on the growth of Scots pine on drained oligotrophic peatlands. Liming plus NPK fertilization had a variable effect on the growth of stands. The same treatment could result in a very different response in different experimental areas. Both liming alone and liming plus NPK fertilization increased the calcium, magnesium and nitrogen contents of peat and decreased the C/Nratio and acidity. Liming plus fertilization decreased needle boron and manganese and increased calcium and nitrogen concentrations. The results of peat and needle analysis indicated that the changes in nitrogen availability to trees caused by liming have not been sufficient enough to affect tree growth. It was also concluded that boron deficiency was the main reason for the lowered yield. (26 refs., 6 tabs., 8 figs.) (author)

Developing silvicultural systems based on partial cutting in western hemlock–Sitka spruce stands of southeast Alaska.

Science.gov (United States)

Robert L. Deal; J.C. Tappeiner; Paul E. Hennon

2002-01-01

The effects of partial cutting on species composition, stand structure and growth, tree size distribution, and tree disease and mortality were evaluated on 73 plots in 18 stands that were harvested 12–96 years ago in southeast Alaska. Partially-cut stands had diverse and highly complex stand structures similar to uncut stands. Sitka spruce was maintained in mixed...

Position stand on androgen and human growth hormone use.

Science.gov (United States)

Hoffman, Jay R; Kraemer, William J; Bhasin, Shalender; Storer, Thomas; Ratamess, Nicholas A; Haff, G Gregory; Willoughby, Darryn S; Rogol, Alan D

2009-08-01

Hoffman, JR, Kraemer, WJ, Bhasin, S, Storer, T, Ratamess, NA, Haff, GG, Willoughby, DS, and Rogol, AD. Position stand on Androgen and human growth hormone use. J Strength Cond Res 23(5): S1-S59, 2009-Perceived yet often misunderstood demands of a sport, overt benefits of anabolic drugs, and the inability to be offered any effective alternatives has fueled anabolic drug abuse despite any consequences. Motivational interactions with many situational demands including the desire for improved body image, sport performance, physical function, and body size influence and fuel such negative decisions. Positive countermeasures to deter the abuse of anabolic drugs are complex and yet unclear. Furthermore, anabolic drugs work and the optimized training and nutritional programs needed to cut into the magnitude of improvement mediated by drug abuse require more work, dedication, and preparation on the part of both athletes and coaches alike. Few shortcuts are available to the athlete who desires to train naturally. Historically, the NSCA has placed an emphasis on education to help athletes, coaches, and strength and conditioning professionals become more knowledgeable, highly skilled, and technically trained in their approach to exercise program design and implementation. Optimizing nutritional strategies are a vital interface to help cope with exercise and sport demands (). In addition, research-based supplements will also have to be acknowledged as a strategic set of tools (e.g., protein supplements before and after resistance exercise workout) that can be used in conjunction with optimized nutrition to allow more effective adaptation and recovery from exercise. Resistance exercise is the most effective anabolic form of exercise, and over the past 20 years, the research base for resistance exercise has just started to develop to a significant volume of work to help in the decision-making process in program design (). The interface with nutritional strategies has been less

Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica †

OpenAIRE

Grossmann, Sönnke; Dieckmann, Gerhard S.

1994-01-01

Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 × 108 to 3 × 108 liter-1, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low conce...

Growth and nutrition of coniferous forests on acidic mineral soils - status and effects of liming and fertilization

International Nuclear Information System (INIS)

Sikstroem, Ulf

2001-01-01

Deposited air-borne S- and N- containing pollutants acidify forest soils in southern Sweden. It has been suggested that this may severely affect forest yield. Liming and/or application of specific nutrients, e.g. phosphorus (P) and potassium (K), have been proposed as countermeasures. The influence of such measures, and of nitrogen (N) addition, was investigated in two experimental series over 5-10 years. Stem growth and needle element concentrations were assessed, predominantly in high-yielding Norway spruce [Picea abies (L.) Karst.] and Scots pine (Pinus sylvestris L.) stands, 30-60 years old, growing on acidic mineral soils in southern Sweden. The effect on crown transparency was also evaluated in some of the Norway spruce stands. The treatments included liming (500-6,000 kg ha -1 ), and N addition at low annual doses (2x10 kg N ha -1 ) and in single shots (150 kg N ha -1 ). Combinations of lime+N, lime+PK and lime+PKN were also tested. The effects were generally weak or negligible, except that growth was significantly increased by N fertilization in the Scots pine stands, and by lime+PKN in some of the Norway spruce stands. In another study, the survival and growth of Norway spruce seedlings were found to be more or less unaffected when planted in pre-harvest acidified, limed or N fertilized soil, although the Ca and Zn concentrations in their needles rose after liming, while those of Mn and Al declined. In closed-canopy stands of Norway spruce and Scots pine with N concentrations of more than 15-16 mg (g DM) -1 in current-year needles, N fertilization was indicated to not necessarily stimulate increased growth. Other indicators of highly N-rich forests (e.g. elevated arginine levels) also start to appear above this level. The closed-canopy stands growing on the most acidic soils showed no signs of severe damage or nutrient deficiencies. These findings, together with the small or negligible effects of the tested countermeasures against soil acidification

Managing Appalachian hardwood stands using four regeneration practices--34 year results

Science.gov (United States)

H. Clay Smith; Gary W. Miller

1987-01-01

Adjacent Appalachian hardwood stands in West Virginia established on excellent growing sites were managed for a 34-year period using four regeneration practices. These practices included a commercial clearcut, 15.5-in diameter-limit, and two single-tree selection practices. An uncut area was maintained as a control. Stand development, growth response, and some stumpage...

Accelerating the development of old-growth characteristics in second-growth northern hardwoods

Science.gov (United States)

Karin S. Fassnacht; Dustin R. Bronson; Brian J. Palik; Anthony W. D' Amato; Craig Lorimer; Karl J. Martin

2015-01-01

Active management techniques that emulate natural forest disturbance and stand development processes have the potential to enhance species diversity, structural complexity, and spatial heterogeneity in managed forests, helping to meet goals related to biodiversity, ecosystem health, and forest resilience in the face of uncertain future conditions. There are a number of...

Crown plasticity and neighborhood interactions of European beech (Fagus sylvatica L.) in an old-growth forest

NARCIS (Netherlands)

Schröter, M.; Härdtle, W.; Oheimb, von G.

2012-01-01

Competition for canopy space is a process of major importance in forest dynamics. Although virgin and old-growth European beech (Fagus sylvatica L.) forests in Europe have been studied for many years, there are to date no studies of individual-tree crown plasticity and the way this is influenced by

Isolated oestrogen deficiency in male 30-year-old: persistent growth plates with severe osteopenia

International Nuclear Information System (INIS)

Smith, T.; Roberts, J.; Howman-Giles, R.; Cowell, C.; Jeremy, R.

2000-01-01

Full text: A 31-year-old male presented with right rib pain and generalised skeletal symptoms. He has a past history of multiple fractures following trauma. No history of childhood fractures. Asthma (No steroids). A product of a consanguineous marriage, he has one child aged 7. Examination showed 178.6cm male with normal sexual characteristics. No abnormality detected apart from tenderness over right ribs. Bone scan showed active growth plates and right and left rib fractures. X-rays demonstrated a bone age of 15 1/2 - 16 yrs and a compression fracture of L2. His bone mineral density is severely reduced. Metabolic investigations revealed Testosterone 27.4 nmol (N 11-35), oestradiol < 70 pmol/L, ultrasensitive assay 14 and 17 pmol/L (consistent with 8-year-old male), LH N, FSH N, 46 XY Karyotype. Alkaline phosphatase. 148 (N<120), Normal glucose tolerance test. This patient illustrates a very rare condition of oestrogen deficiency in a male, probably due to aromatase deficiency. This enzyme converts testosterone to oestradiol. It illustrates the role of oestrogen in fusing growth plates and maintaining bone mass in males with otherwise normal androgen levels. A similar clinical picture can result from an oestrogen receptor abnormality. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Effects of thinnings on growth and yield in natural Pinus arizonica and Pinus durangensis stands in the El Largo-Madera region in Chihuahua State

Science.gov (United States)

Oscar Estrada Murrieta; Luis A. Dominguez Pereda; Marcelo Zepeda Bautista

1995-01-01

This paper presents the result of the first dasometric analysis made with the data of some permanent thinning plots established at different times since 1964 in the Unit of Conservation and Forest Development #2 in Chihuahua State, Mexico. The results show the benefits of thinnings on the growth rates of residual stands, the increment's redistribution, and the...

Development of silvicultural systems for maintaining old-growth conditions in the temperate rainforest of southeast Alaska.

Science.gov (United States)

Michael H. McClellan

2004-01-01

In the old-growth temperate rainforests of southeast Alaska, concerns over clearcutting effects on habitat, visual quality, slope stability, and biodiversity have created a demand for the use of other silvicultural systems. The forest vegetation and animal taxa of southeast Alaska appear to be well adapted to frequent, widespread, small-scale disturbance, suggesting...

Rainfall partitioning and related hydrochemical fluxes in a diverse and in a mono specific (Phenakospermum guyannense) secondary vegetation stand in eastern Amazonia.

Science.gov (United States)

Hölscher, D; Sá, T D A; Möller, R F; Denich, M; Fölster, H

1998-04-01

Rainfall partitioning into throughfall and stemflow was studied in a diverse and in a mono specific stand of secondary vegetation in Eastern Amazonia. The nutrient concentrations in the water were analysed in order to quantify the related hydrochemical fluxes. Secondary vegetation forms the fallow in the local shifting cultivation system and is usually dominated by shrubs and trees. Phenakospermum guyannense (Strelitziaceae), a banana-like herb, is one of the predominant non-woody species. The study was conducted during an 18-month period in a 2.5-year-old relatively species-rich stand and a 10-year-old stand dominated by P. guyannense. In a year with 1956 mm of rainfall 65% (1281 mm) of this quantity reached the soil as throughfall in the diverse stand and 38% (743 mm) in the mono specific stand. Stemflow was estimated to be 23% and 41% respectively. P. guyannense and Banara guianensis (Flacourtiaceae), a tree species, were causing these high funnelling effects. In the young diverse stand B. guianensis had a stemflow of more than 200 l year -1 and P. guyannense had a median flux of 77 l year -1 per pseudostem. In the older stand the taller plants of P.␣guyannense collected 644 l year -1 per pseudostem on the median. The reason for these high values could be the banana-like growth form of P. guyannense and the crown morphology of B. guianensis, which has inclined branches. The low proportion of throughfall and the high stemflow values differ from all previous studies in Amazonian primary forests. The proximity to the Atlantic Ocean strongly influenced the nutrient fluxes via rainfall at our study site. This becomes obvious from the high Na and Cl fluxes with rainfall (19.7 kg Na ha -1 year -1 , 37.2 kg Cl ha -1 year -1 ) which were approximately equal to the Na and Cl fluxes with the sum of throughfall and stemflow for both stands. K fluxes in throughfall and stemflow in both stands were higher than in rainfall by a factor of 8. The high K

Spatial and population characteristics of dwarf mistletoe infected trees in an old-growth Douglas-fir - western hemlock forest.

Science.gov (United States)

David C. Shaw; Jiquan Chen; Elizabeth A. Freeman; David M. Braun

2005-01-01

We investigated the distribution and severity of trees infected with western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones subsp. tsugense) in an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) - western hemlock (Tsuga heterophylla (Raf.) Sarg.)...

Land use history and population dynamics of free-standing figs in a maturing forest.

Directory of Open Access Journals (Sweden)

Larissa Albrecht

Full Text Available Figs (Ficus sp. are often considered as keystone resources which strongly influence tropical forest ecosystems. We used long-term tree-census data to track the population dynamics of two abundant free-standing fig species, Ficus insipida and F. yoponensis, on Barro Colorado Island (BCI, a 15.6-km2 island in Lake Gatún, Panama. Vegetation cover on BCI consists of a mosaic of old growth (>400 years and maturing (about 90-150 year old secondary rainforest. Locations and conditions of fig trees have been mapped and monitored on BCI for more than 35 years (1973-2011, with a focus on the Lutz Catchment area (25 ha. The original distribution of the fig trees shortly after the construction of the Panama Canal was derived from an aerial photograph from 1927 and was compared with previous land use and forest status. The distribution of both fig species (~850 trees is restricted to secondary forest. Of the original 119 trees observed in Lutz Catchment in 1973, >70% of F. insipida and >90% of F. yoponensis had died by 2011. Observations in other areas on BCI support the trend of declining free-standing figs. We interpret the decline of these figs on BCI as a natural process within a maturing tropical lowland forest. Senescence of the fig trees appears to have been accelerated by severe droughts such as the strong El Niño event in the year 1982/83. Because figs form such an important food resource for frugivores, this shift in resource availability is likely to have cascading effects on frugivore populations.

A system for predicting the amount of Phellinus (Fomes) igniarius rot in trembling aspen stands

Science.gov (United States)

Robert L. Anderson; Arthur L. Jr. Schipper

1978-01-01

The occurrence of Phellinus (Fomes) igniarius white trunk rot in 45- to 50-year-old trembling aspen stands can be predicted by applying a constant to the stand basal area with P. igniarius conks to estimate the total basal area with P. igniarius rot. Future decay projections can be made by reapplying the basal area of hidden decay for each 6 years projected. This paper...

Effects of age and stand density of mother trees on early Pinus thunbergii seedling establishment in the coastal zone, China.

Science.gov (United States)

Mao, Peili; Han, Guangxuan; Wang, Guangmei; Yu, Junbao; Shao, Hongbo

2014-01-01

Effects of age and stand density of mother tree on seed germination, seedling biomass allocation, and seedling growth of Pinus thunbergii were studied. The results showed that age of mother tree did not have significant influences on seed germination, but it was significant on seedling biomass allocation and growth. Seedlings from the minimum and maximum age of mother tree had higher leaf mass ratio and lower root mass ratio than from the middle age of mother tree. Moreover, they also had higher relative height growth rate and slenderness, which were related to their biomass allocation. Stand density of mother tree mainly demonstrated significant effects on seed germination and seedling growth. Seed from higher stand density of mother tree did not decrease germination rate, but had higher mean germination time, indicating that it delayed germination process. Seedlings of higher stand density of mother tree showed higher relative height growth rate and slenderness. These traits of offspring from higher stand density of mother tree were similar to its mother, indicating significant environmental maternal effects. So, mother tree identity of maternal age and environments had important effects on natural regeneration of the coastal P. thunbergii forest.

Seasonal variations in growth and body composition of 8-11-year-old Danish children

DEFF Research Database (Denmark)

Dalskov, Stine-Mathilde; Ritz, Christian; Larnkjær, Anni

2016-01-01

BACKGROUND: Earlier studies on seasonality in growth reported the largest height gains during spring and largest body weight gains during autumn. We examined seasonality in height, body weight, BMI, fat mass index (FMI) and fat-free mass index (FFMI) among contemporary Danish 8-11-year......-olds. METHODS: 760 children from the OPUS School Meal Study provided >2200 measurements on height, body weight and composition between September-June. Average velocities were calculated using change-score analyses based on three-month intervals. As a complementary analysis, point velocities derived from...... suggest seasonality in growth and body composition of Danish children. We recovered the well-known height velocity peak during spring time, but unlike earlier studies we found coincident peaks in body weight, BMI, and FFMI velocities.Pediatric Research (2015); doi:10.1038/pr.2015.206....

Local population extinction and vitality of an epiphytic lichen in fragmented old-growth forest.

Science.gov (United States)

Ockinger, Erik; Nilsson, Sven G

2010-07-01

The population dynamics of organisms living in short-lived habitats will largely depend on the turnover of habitat patches. It has been suggested that epiphytes, whose host plants can be regarded as habitat patches, often form such patch-tracking populations. However, very little is known about the long-term fate of epiphyte individuals and populations. We estimated life span and assessed environmental factors influencing changes in vitality, fertility, abundance, and distribution of the epiphytic lichen species Lobaria pulmonaria on two spatial scales, individual trees and forest patches, over a period of approximately 10 years in 66 old-growth forest fragments. The lichen had gone extinct from 7 of the 66 sites (13.0%) where it was found 10 years earlier, even though the sites remained unchanged. The risk of local population extinction increased with decreasing population size. In contrast to the decrease in the number of occupied trees and sites, the mean area of the lichen per tree increased by 43.0%. The number of trees with fertile ramets of L. pulmonaria increased from 7 (approximately 1%) to 61 (approximately 10%) trees, and the number of forest fragments with fertile ramets increased from 4 to 23 fragments. The mean annual rate of L. pulmonaria extinction at the tree level was estimated to be 2.52%, translating into an expected lifetime of 39.7 years. This disappearance rate is higher than estimated mortality rates for potential host trees. The risk of extinction at the tree level was significantly positively related to tree circumference and differed between tree species. The probability of presence of fertile ramets increased significantly with local population size. Our results show a long expected lifetime of Lobaria pulmonaria ramets on individual trees and a recent increase in vitality, probably due to decreasing air pollution. The population is, however, declining slowly even though remaining stands are left uncut, which we interpret as an

Biophysical controls on soil respiration in the dominant patch types of an old-growth, mixed-conifer forest

Science.gov (United States)

Siyan Ma; Jiquan Chen; John R. Butnor; Malcolm North; Eugénie S. Euskirchen; Brian Oakley

2005-01-01

Little is known about biophysical controls on soil respiration in California's Sierra Nevada old-growth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly...

Analysis of tree stand horizontal structure using random point field methods

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O. P. Sekretenko

2015-06-01

Full Text Available This paper uses the model approach to analyze the horizontal structure of forest stands. The main types of models of random point fields and statistical procedures that can be used to analyze spatial patterns of trees of uneven and even-aged stands are described. We show how modern methods of spatial statistics can be used to address one of the objectives of forestry – to clarify the laws of natural thinning of forest stand and the corresponding changes in its spatial structure over time. Studying natural forest thinning, we describe the consecutive stages of modeling: selection of the appropriate parametric model, parameter estimation and generation of point patterns in accordance with the selected model, the selection of statistical functions to describe the horizontal structure of forest stands and testing of statistical hypotheses. We show the possibilities of a specialized software package, spatstat, which is designed to meet the challenges of spatial statistics and provides software support for modern methods of analysis of spatial data. We show that a model of stand thinning that does not consider inter-tree interaction can project the size distribution of the trees properly, but the spatial pattern of the modeled stand is not quite consistent with observed data. Using data of three even-aged pine forest stands of 25, 55, and 90-years old, we demonstrate that the spatial point process models are useful for combining measurements in the forest stands of different ages to study the forest stand natural thinning.

Habitat Preferences of Boros schneideri (Coleoptera: Boridae) in the Natural Tree Stands of the Białowieża Forest

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Gutowski, Jerzy M.; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

2014-01-01

Abstract We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31–40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. PMID:25527586

Stand dynamics following gap-scale exogenous disturbance in a single cohort mixed species stand in Morgan County, Tennessee

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Brian S. Hughett; Wayne K. Clatterbuck

2014-01-01

Differences in composition, structure, and growth under canopy gaps created by the mortality of a single stem were analyzed using analysis of variance under two scenarios, with stem removed or with stem left as a standing snag. There were no significant differences in composition and structure of large diameter residual stems within upper canopy strata. Some...

Impact of a Mountain Pine Beetle Outbreak on Young Lodgepole Pine Stands in Central British Columbia

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Amalesh Dhar

2015-09-01

Full Text Available The current mountain pine beetle (MPB (Dendroctonous ponderosae Hopkins epidemic has severely affected pine forests of Western Canada and killed millions of hectares of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm. forest. Generally, MPB attack larger and older (diameter > 20 cm or >60 years of age trees, but the current epidemic extends this limit with attacks on even younger and smaller trees. The study’s aim was to investigate the extent of MPB attack in young pine stands and its possible impact on stand dynamics. Although MPB attacks were observed in trees as small as 7.5 cm diameter at breast height (DBH and as young as 13 years old, the degree of MPB attack (percent stems ha−1 increased with increasing tree diameter and age class (13–20, 21–40, 41–60, and 61–80 years old (6.4%, 49.4%, 62.6%, and 69.5% attack, respectively, by age class which is greater than that reported from previous epidemics for stands of this age. The mean density of surviving residual structure varied widely among age classes and ecological subzones. Depending on age class, 65% to 77% of the attacked stands could contribute to mid-term timber supply. The surviving residual structure of young stands offers an opportunity to mitigate the effects of MPB-attack on future timber supply, increase age class diversity, and enhance ecological resilience in younger stands.

Increase of an introduced bird competitor in old-growth forest associated with restoration

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Leonard Freed

2012-05-01

Full Text Available Many successful invasions involve long initial periods in which the invader exists at low densities followed by sudden population increases. The reasons for such time-lags remain poorly understood. Here we document a sudden increase in density of the introduced Japanese white-eye (Zosterops japonicus in a restoration area contiguous with old-growth forest at Hakalau Forest National Wildlife Refuge on the Island of Hawaii. The refuge, with very high density of native birds, existed in a pocket of low white-eye density that persisted for at least 20 years since the late 1970s. The refuge began an extensive native trees restoration project in 1989 within a 1314 ha abandoned pasture above old-growth forest. This area was soon colonized by white-eyes and their population grew exponentially once the trees had grown tall enough to develop a canopy. This increase was in turn followed by significantly more white-eyes in the open and closed forests adjacent to the restoration area. Competition between white-eyes and native species was documented on study sites within these forests. Density data indicate that competition was more widespread, with loss of tens of thousands of native birds in the 5371 ha area surveyed. Our results are consistent with the view that ecological barriers may delay the population increase of invaders and that human-derived activities may help invaders cross these barriers by creating new ecological opportunities. Control of white-eye numbers may be essential for recovery of native species.

Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

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Enqing Hou

Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

Century-scale Variations in Plant and Soil Nitrogen Pools and Isotopic Composition in Northern Hardwood Forests

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Goodale, C. L.; Fuss, C. B.; Lang, A.; Ollinger, S. V.; Ouimette, A.; Vadeboncoeur, M. A.; Zhou, Z.; Lovett, G. M.

2017-12-01

The mineral soil may act as both a source and a sink of nitrogen to plants over decadal to centennial timescales. However, the enormous size and spatial heterogeneity of mineral soil N regularly impede study of its role over the course of forest succession. Here, we measured tree and soil stocks of C, N and 15N to 50 cm depth in and near Hubbard Brook, New Hampshire, across eight forest stands of varying time since harvest (two stands each of 20, 40, and 100 years post-harvest, and old-growth forest). Measurements show that tree biomass and N stocks increased with stand age to an average of 145 t C/ha and 556 kg N/ha in old-growth forests, as cumulative net growth and N increment rates decreased from young (20 and 40-year old) to mature (100-year) to old-growth stands. Plant %N varied more by site than species, while plant 15N varied more by tree species than by site. Of the most common species, Acer saccharum (sugar maple) had consistently lighter 15N in all tissues (bark, leaf, wood) than Betula alleghaniensis (yellow birch). Soil organic matter stocks are very large, averaging 154 t C/ha and 8.1 tN/ha to 50 cm depth. Neither C nor N stock varied regularly with stand age, but old-growth stands had lower C:N ratios and higher 15N values than the successional stands. Ongoing analysis will predict the effects of harvest, regrowth, and N inputs and losses on expected and observed 15N changes over succession. These observations support the great capacity of the mineral soil to store and potentially supply N to northern hardwood forests.

Growth responses of young Douglas-fir and tanoak 11 years after various levels of hardwood removal and understory suppression in southwestern Oregon, USA

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Harrington, T.B.; Tappeiner, John C.

1997-01-01

At two sites in southwestern Oregon, height, diameter, and crown width of young Douglas-fir (Pseudotsuga menziesii) and sprout-origin tanoak (Lithocarpus densiflorus) were measured 1–11 years after reducing the density of a 2-year-old tanoak stand to 0%, 25%, 50%, and 100% of its initial cover. Some plots also included suppression of understory vegetation. Tanoak cover developed linearly with time, with steepness of the growth trajectory increasing at a diminishing rate with increasing percentage of initial tanoak cover. Fifth-year cover of understory vegetation declined linearly with increasing percentage of initial tanoak cover (R2 = 0.29). Survival of Douglas-fir (96–100%) differed little among initial abundances of tanoak, while growth trajectories for its size became increasingly exponential with decreasing percentage of initial tanoak cover. Eleventh-year heights of Douglas-fir were similar for 0%, 25%, and 50% of initial tanoak cover; however, diameter increased linearly with decreasing percentage of initial tanoak cover (R2 = 0.73), and the slope of the relationship steepened with understory suppression. Our results indicate that young stands exhibiting a wide range of stand compositions and productivities can be established by early manipulations of tanoak and understory abundance. Complete removal of tanoak plus understory suppression are necessary to maximize Douglas-fir growth, while productive, mixed stands can be achieved by removing 50% or more of tanoak cover.

Liming with powdered oil-shale ash in a heavily damaged forest ecosystem. 2.The effect on forest condition in a pine stand

International Nuclear Information System (INIS)

Terasmaa, T.; Pikk, J.

1995-01-01

First years after the treatment (in 1987) of forest soil with mineral fertilizers and powdered oil-shale ash in a heavily damaged 50-year-old Scots pine ecosystem showed a comparatively small effect (B<0.95) of liming on the stand characters. However, in comparison with the effect of only NPK fertilization on the volume growth and the health state of trees, liming (NPK+oil-shale ash) tended to increase the positive influence of fertilizers. Under the influence of oil-shale ash the mortality of the trees was lower, the density of the stand rose more, and the mean radial increment of trees was by 26% greater than after the NPK treatment without a lime agent. On the whole, the effect of oil-shale ash liming on the growth and health condition of the pine stand was not high. However, the first results of its experimental use on mineral forest soil cannot serve as the basis for essential conclusions. Still, the results give us some assurance to continue our experimental work with powdered oil-shale ash in forests with the purpose of regulating the high acidity of forest soils in some sites to gain positive shifts in the forest life. Taking into account the low price of the powdered oil-shale ash and the plentiful resources of this liming material in Estonia, even a small trend towards an improvement of forest condition on poor sandy soils would be a satisfactory final result of the work. It is essential to note that oil-shale ash is not only a simple liming material, but also a lime fertilizer consisting of numerous chemical elements necessary for plant growth. 2 tabs., 3 figs., 18 refs

Large woody debris budgets in the Caspar Creek Experimental Watersheds

Science.gov (United States)

Sue Hilton

2012-01-01

Monitoring of large woody debris (LWD) in the two mainstem channels of the Caspar Creek Experimental Watersheds since 1998, combined with older data from other work in the watersheds, gives estimates of channel wood input rates, survival, and outputs in intermediate-sized channels in coastal redwood forests. Input rates from standing trees for the two reaches over a 15...

Observations from old forests underestimate climate change effects on tree mortality.

Science.gov (United States)

Luo, Yong; Chen, Han Y H

2013-01-01

Understanding climate change-associated tree mortality is central to linking climate change impacts and forest structure and function. However, whether temporal increases in tree mortality are attributed to climate change or stand developmental processes remains uncertain. Furthermore, interpreting the climate change-associated tree mortality estimated from old forests for regional forests rests on an un-tested assumption that the effects of climate change are the same for young and old forests. Here we disentangle the effects of climate change and stand developmental processes on tree mortality. We show that both climate change and forest development processes influence temporal mortality increases, climate change-associated increases are significantly higher in young than old forests, and higher increases in younger forests are a result of their higher sensitivity to regional warming and drought. We anticipate our analysis to be a starting point for more comprehensive examinations of how forest ecosystems might respond to climate change.

Water Erosion in a Two Year Old Stand of Eucalyptus benthamii under three Plantation Methods

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Padilha, J.; Bertol, I.; Marioti, J.; Ramos, J. C.; Flores, M. C.; Tanaka, M. S.; Paz González, A.

2012-04-01

The preparation of the soil is the main issue of soil management. Thus, it is also one of the main operations with regard to management of planted forest during the whole productive process. Soil preparation is thought to directly affect various processes of the hydrologic cycle, water erosion, crop productivity and, subsequently, play an important role both for the environment and for the invested capital. Therefore knowledge of the effect of each specific soil management system on forest production is viewed as an essential issue. Based on these considerations, the aim of this work was to quantify soil and water losses by water erosion during the seasons of the year with the highest rainfall intensity in the south hemisphere, i.e. spring and summer in a two year old stand planted with Eucalyptus benthamii. This tree species was planted following three different conditions: 1) soil mechanical preparation in furrows following the land slope, 2) soil mechanical preparation in furrows dug perpendicular to the slope and 3) semi-mechanical preparation by digging an individual hole for each plant. The field experiment was located in Otacílio Costa municipality, SC, Brazil, at the Gropp forest farm owned by the Kablin SA company, 841 m asl altitude. The soil was classified as a "Cambissolo Húmico Alumínico Léptico" according with the Brazilian Soil Classification System with a slope of about 0.12 m m-1. The experimental design consisted of randomly located erosion plots with 3 repetitions, thus a total of 9 plots. The surface area of the plots was 12 x 24 m and they were oriented so that the main side followed the land slope. Suspended sediments and water losses were channelled to collecting tank at the end of the plot. Runoff water and eroded sediments were weakly measured, so that they correspond to cumulative weakly rainfall. The highest soil and water losses were recorded in plots with furrows dug perpendicular to the slope and the lowest ones corresponded to the

Growth of a progesterone receptor-positive meningioma in a female patient with congenital adrenal hyperplasia.

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O'Shea, T; Crowley, R K; Farrell, M; MacNally, S; Govender, P; Feeney, J; Gibney, J; Sherlock, M

2016-01-01

Meningioma growth has been previously described in patients receiving oestrogen/progestogen therapy. We describe the clinical, radiological, biochemical and pathologic findings in a 45-year-old woman with congenital adrenal hyperplasia secondary to a defect in the 21-hydroxylase enzyme who had chronic poor adherence to glucocorticoid therapy with consequent virilisation. The patient presented with a frontal headache and marked right-sided proptosis. Laboratory findings demonstrated androgen excess with a testosterone of 18.1 nmol/L (0-1.5 nmol) and 17-Hydroxyprogesterone >180 nmol/L (transsexual patients undergoing therapy with high-dose oestrogen and progestogens. Progesterone receptor positivity has been described previously in meningiomas. 17-Hydroxyprogesterone is elevated in CAH and has affinity and biological activity at the progesterone receptor. Therefore, we hypothesise that patients who have long-standing increased adrenal androgen precursor concentrations may be at risk of meningioma growth. Patients with long-standing CAH (particularly if not optimally controlled) may present with other complications, which may be related to long-standing elevated androgen or decreased glucocorticoid levels.Chronic poor control of CAH is associated with adrenal myelolipoma and adrenal rest tissue tumours.Meningiomas are sensitive to endocrine stimuli including progesterone, oestrogen and androgens as they express the relevant receptors.

Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - Conifer forests in southeast Alaska

Science.gov (United States)

Gomi, T.; Johnson, A.C.; Deal, R.L.; Hennon, P.E.; Orlikowska, E.H.; Wipfli, M.S.

2006-01-01

Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width (0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels. ?? 2006 NRC.

Responses of forest carbon and water coupling to thinning treatments at both the leaf and individual tree levels in a 16-year-old natural Pinus Contorta stand

Science.gov (United States)

Wang, Y.; Wei, A.; del Campo, A.; Li, Q.; Giles-Hansen, K.

2017-12-01

Large-scale disturbances in Canadian forests, including mountain pine beetle infestation in western Canada, forest fires, timber harvesting and climate change impacts, have significantly affected both forest carbon and water cycles. Thinning, which selectively removes trees at a given forest stand, may be an effective tool to mitigate the effect of these disturbances. Various studies have been conducted to assess the thinning effect on growth, transpiration, and nutrient availability; however, relatively few studies have been conducted to examine its effect on the coupling of forest carbon and water. Thus, the objective of this research is to evaluate the effect of thinning on forest carbon and water coupling at both the leaf and tree levels in a 16-year-old natural Pinus Contorta forest in the interior of British Columbia in Canada. We used water-use efficiency (WUE), the ratio of basal area increment (BA) to tree transpiration (E), as the indicator of the carbon and water coupling at individual tree level, and use intrinsic water-use efficiency (iWUE), the ratio of photosynthesis (A) to stomatal conductance (G), to represent the coupling at the leaf level. Field experiments were conducted in the Upper Penticton Watershed where the mean annual precipitation is 750 mm with seasonal drought during summer. A randomized block design was used, with three blocks each containing two thinning intensities and one unthinned plot (T1: 4,500, T2: 1,100, C: 26,400 trees per ha.). From May to October 2016, basal diameter, sap flow, and environmental conditions were monitored continuously at every 20 minutes, while A and G were measured weekly. Preliminary results showed that thinning significantly increased solar radiation, wind speed, and soil moisture in the treatment plots, where the changes observed were proportional to the intensity of the thinning; but thinning did not change stand level temperature and relative humidity. Thinning also significantly enhanced tree E and BA

Functional Ecology Effect Aspect Geographic on the Cypress (Cupresuss sempervirens L.var horizontalis) Growth in the Abbas Abad Behshahr Planting Stand

International Nuclear Information System (INIS)

Kalantari, H.; Fallah, A.; Hojjati, M.

2016-01-01

Background and Objective: To evaluate the growth of cypress in different aspects (North West, West, Northeast and Southwest) is a pure planting stand in the area of Abbas Abad Behshar was considered. Method: Using the inventory network 75 × 100 m and a stratified random method, 50 samples plot 2 R (200 square meters) in different geographical aspects was carried out. In each sample plots, diameters and height of four trees were measured. Excel and SPSS statistical software and statistical analyses and necessary calculations were performed. Findings: The results showed that there are significant differences between amplitude with different aspects of growth. So that the highest diameter increment in the West aspect (0.53 cm) and the lowest in the North East aspect (0.479 cm) were observed. The maximum height growth in the West and South-West aspects (0.53 m) and the lowest was in the northwest aspect (0.49 m) and for average basal area growth, the highest growth in the West aspect was 0.87 m square per ha and lowest in the North west aspect was 0.76 square meters per hectare respectively. The average volume growth to age, respectively, in the aspect of West aspect (4 sylve per ha) and Northeast aspect (6.3 sylve per hectare) were the highest and lowest values.

Old Growth Conifer Watersheds in the Western Cascades, Oregon: Sentinels of Climate Change

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Miles, K. M.

2011-12-01

In the Pacific Northwest, where the majority of precipitation falls during the winter, mountain snowpacks provide an important source of streamflow during the dry summer months when water demands are frequently highest. Increasing temperatures associated with climate change are expected to result in a decline in winter snowpacks in western North America, earlier snowmelt, and subsequently a shift in the timing of streamflows, with an increasing fraction of streamflows occurring earlier in the water year and drier conditions during the summer. Long-term records from headwater watersheds in old growth conifer forest at the H. J. Andrews Experimental Forest (HJ Andrews), Oregon, provide the opportunity to examine changes in climate, vegetation, and streamflow. Continuous streamflow records have been collected since 1953, 1964, and 1969 from three small (8.5-60 ha) watersheds (WS2, WS8, and WS9). Over the 40- to 50-year period of study, late winter to early summer monthly average minimum temperatures have increased by 1-2°C, and spring snow water equivalent at a nearby Snotel site has declined, but monthly precipitation has remained unchanged. Spring runoff ratios have declined in by amounts equivalent to 0.59-2.45 mm day-1 at WS2, WS8, and WS9, which are comparable to estimated rates of stand-level transpiration from trees in these watersheds. However, winter runoff ratios have not changed significantly at either WS2 or WS9, and have actually decreased at WS8 by 2.43 mm day-1 over the period of record. Furthermore, summer runoff ratios have not changed significantly at either WS8 or WS9, and have increased at WS2 by 0.34 mm day-1 over the period of record. These findings suggest that warming temperatures have resulted in a reduction in spring snowpacks and an earlier onset of evapotranspiration in the spring when soil moisture is abundant, but physiological responses of these conifer forests to water stress and water surplus may mitigate or exceed the expression of a

Richness of lichen species, especially of threatened ones, is promoted by management methods furthering stand continuity.

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Steffen Boch

Full Text Available Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin, the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m(2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging, various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks. We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1 conserving unmanaged forests, (2 promoting silvicultural methods assuring stand continuity, (3 conserving old trees in managed forests, (4 promoting stands of native deciduous

Richness of Lichen Species, Especially of Threatened Ones, Is Promoted by Management Methods Furthering Stand Continuity

Science.gov (United States)

Boch, Steffen; Prati, Daniel; Hessenmöller, Dominik; Schulze, Ernst-Detlef; Fischer, Markus

2013-01-01

Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species

Long-term changes in tree composition in a mesic old-growth upland forest in southern Illinois

Science.gov (United States)

James J. Zaczek; John W. Groninger; J.W. Van Sambeek

1999-01-01

The Kaskaskia Woods (Lat. 37.5 N, Long. 88.3 W), an old-growth hardwood forest in southern Illinois, has one of the oldest and best documented set of permanent plots with individual tree measurements in the Central Hardwood Region. In 1935, eight 0.101-ha plots were installed in a 7.4 ha upland area consisting of xeric oak-hickory and mesic mixed hardwoods communities...

Calculation of the increment reduction in spruce stands by charcoal smoke

Energy Technology Data Exchange (ETDEWEB)

Guede, J

1954-01-01

Chronic damage to spruce trees by charcoal smoke, often hardly noticeable from outward appearance but causing marked reductions of wood increment can be determined by means of a calculation by increment cores. Sulfurous acid anhydride causes the closure of the stomates of needles by which the circulation of water is checked. The assimilation and the wood increment are reduced. The cores are taken from uninjured trees belonging to the dominant class. These trees are liable to irregular variations in the trend of growth only by atmospheric influences and disturbances in the circulation of water. The decrease of increment of a stand can be judged by the trend of growth of the basal area of sample trees. Two methods are applied: in the first method, the difference between the mean total increment before the damage has been caused and that after it is calculated by the yield table in deriving the site quality classes from the basal area growth of dominant stems. This is possible by using the mean diameter of each age class and the frequency curve of basal area for each site class. In the other method, the reduction of basal area increment of sample trees is measured directly. The total reduction of a stand can be judged by the share of the dominant class of stem in the total current growth of the basal area of a sound stand and by the percent of reduction of the sample trees.

Disturbance legacies and climate jointly drive tree growth and mortality in an intensively studied boreal forest

Energy Technology Data Exchange (ETDEWEB)

Bond-Lamberty, Benjamin; Rocha, Adrian; Calvin, Katherine V.; Holmes, Bruce; Wang, Chuankuan; Goulden, Michael L.

2014-01-01

How will regional growth and mortality change with even relatively small climate shifts, even independent of catastrophic disturbances? This question is particularly acute for the North American boreal forest, which is carbon-dense and subject The goals of this study were to combine dendrochronological sampling, inventory records, and machine-learning algorithms to understand how tree growth and death have changed at one highly studied site (Northern Old Black Spruce, NOBS) in the central Canadian boreal forest. Over the 1999-2012 inventory period, mean DBH increased even as stand density and basal area declined significantly from 41.3 to 37.5 m2 ha-1. Tree mortality averaged 1.4±0.6% yr-1, with most mortality occurring in medium-sized trees. A combined tree ring chronology constructed from 2001, 2004, and 2012 sampling showed several periods of extreme growth depression, with increased mortality lagging depressed growth by ~5 years. Minimum and maximum air temperatures exerted a negative influence on tree growth, while precipitation and climate moisture index had a positive effect; both current- and previous-year data exerted significant effects. Models based on these variables explained 23-44% of the ring-width variability. There have been at least one, and probably two, significant recruitment episodes since stand initiation, and we infer that past climate extremes led to significant NOBS mortality still visible in the current forest structure. These results imply that a combination of successional and demographic processes, along with mortality driven by abiotic factors, continue to affect the stand, with significant implications for our understanding of previous work at NOBS and the sustainable management of regional forests.

Race, socioeconomic status, and obesity in 9- to 10 year-old girls : The NHLBI Growth and Health Study

NARCIS (Netherlands)

Kimm, SYS; Obarzanek, E; Barton, BA; Aston, CE; Similo, SL; Morrison, JA; Sabry, ZI; Schreiber, GB; McMahon, RP

The purpose of this investigation was to determine whether measures of socioeconomic status (SES) are inversely associated with obesity in 9- to 10-year-old black and white girls and their parents. Subjects were participants in the Growth and Health Study (NGHS) of the National Heart, Lung, and

Growth and yield of all-aged Douglas-fir -- western hemlock forest stands: a matrix model with stand diversity effects.

Science.gov (United States)

Jingjing Liang; Joseph Buonglorno; Robert A. Monserud

2005-01-01

A density-dependent matrix model was developed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) -- western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest stands in the Pacific Northwest of the United States. The model predicted the number and volume of trees for 4 species groups and 19 diameter classes. The parameters...

Introducing sit-stand desks increases classroom standing time among university students

Directory of Open Access Journals (Sweden)

Matthew Jerome

2017-12-01

Full Text Available Excessive sedentary behavior has been associated with many negative health outcomes. While an understudied health topic, there is evidence that university students are excessively sedentary. Sit-stand desks have been shown to reduce sedentary time among pre-university students (ages 5–18years and sedentary workers but have not been tested in university classrooms. This study tested the effects of introducing sit-stand desks into a university classroom on student's classroom sitting and standing behaviors. Using a cross-over design, students received access to both traditional seated desks and sit-stand desks for six weeks. Data were collected between September and December, 2016. We recruited 304 healthy undergraduate university students enrolled in one of two small (25 seats classrooms at a large Midwestern university during the fall of 2016. Average minutes of standing/hour/student, average percent class time spent standing, and the number of sit-stand transitions/student/hour were directly observed with video camera surveillance. Participants stood significantly more (p<0.001 when provided access to sit-stand desks (7.2min/h/student; 9.3% of class time spent standing compared to when they had access to seated desks (0.7min/h/student; 1.6% of class time spent standing but no differences were observed for the number of sit-stand transitions (p=0.47. Students reported high favorability for the sit-stand desks and improvements in several student engagement and affective outcomes while using the sit-stand desks. These findings support introducing sit-stand desks in university classrooms as an approach to reduce sedentary behaviors of university students. Keywords: Sedentary, University students, Sit-stand desk

Effects of stand composition and thinning in mixed-species forests : a modeling approach applied to Douglas-fir and beech

NARCIS (Netherlands)

Bartelink, H.H.

2000-01-01

Models estimating growth and yield of forest stands provide important tools for forest management. Pure stands have been modeled extensively and successfully for decades; however, relatively few models for mixed-species stands have been developed. A spatially explicit, mechanistic model (COMMIX) is

Capacity of old trees to respond to environmental change.

Science.gov (United States)

Phillips, Nathan G; Buckley, Thomas N; Tissue, David T

2008-11-01

Atmospheric carbon dioxide [CO2] has increased dramatically within the current life spans of long-lived trees and old forests. Consider that a 500-year-old tree in the early twenty-first century has spent 70% of its life growing under pre-industrial levels of [CO2], which were 30% lower than current levels. Here we address the question of whether old trees have already responded to the rapid rise in [CO2] occurring over the past 150 years. In spite of limited data, aging trees have been shown to possess a substantial capacity for increased net growth after a period of post-maturity growth decline. Observations of renewed growth and physiological function in old trees have, in some instances, coincided with Industrial Age increases in key environmental resources, including [CO2], suggesting the potential for continued growth in old trees as a function of continued global climate change.

Characterization of structure and development of models to quantify wood potential of an unmanaged Araucaria angustifolia stand

Directory of Open Access Journals (Sweden)

Rafaella De Angeli Curto

2014-12-01

Full Text Available The objective of this study was to characterize of an unmanaged stand of Araucaria angustifolia and to development of models to quantify the wood potential, aiming to support the development of forest management plans in stands with similar conditions. The work was developed into a stand established in 1946, in National Forest of Açungui, in Campo Largo County, Paraná State, Brazil. There was only one thinning in the stand, between 1970 and 1980. From the frequency of individuals in each diametric class, it was observed the condition of stagnation and competition with cohort in the beginning of class distribution. With the application of the probability density function of Weibull-3P, Trorey model, and the 5th polynomial by diameter class, it was possible to confirm the stock estimative of timber volume of the stand. This analysis indicated that the stand presents average annual wood production smaller than the species potential. So it is recommended the thinning to promote growth of remnant trees. With the probability density function of Weibull-3p, that was selected, it is possible to project the diametric distribution of the stand, when analyzed complementarily with growth diameter information, if the stand remains unmanaged. Certainly, the optimum potential of timber production could have been manifested if the stand were managed during the cycle planed.

The future of large old trees in urban landscapes.

Science.gov (United States)

Le Roux, Darren S; Ikin, Karen; Lindenmayer, David B; Manning, Adrian D; Gibbons, Philip

2014-01-01

Large old trees are disproportionate providers of structural elements (e.g. hollows, coarse woody debris), which are crucial habitat resources for many species. The decline of large old trees in modified landscapes is of global conservation concern. Once large old trees are removed, they are difficult to replace in the short term due to typically prolonged time periods needed for trees to mature (i.e. centuries). Few studies have investigated the decline of large old trees in urban landscapes. Using a simulation model, we predicted the future availability of native hollow-bearing trees (a surrogate for large old trees) in an expanding city in southeastern Australia. In urban greenspace, we predicted that the number of hollow-bearing trees is likely to decline by 87% over 300 years under existing management practices. Under a worst case scenario, hollow-bearing trees may be completely lost within 115 years. Conversely, we predicted that the number of hollow-bearing trees will likely remain stable in semi-natural nature reserves. Sensitivity analysis revealed that the number of hollow-bearing trees perpetuated in urban greenspace over the long term is most sensitive to the: (1) maximum standing life of trees; (2) number of regenerating seedlings ha(-1); and (3) rate of hollow formation. We tested the efficacy of alternative urban management strategies and found that the only way to arrest the decline of large old trees requires a collective management strategy that ensures: (1) trees remain standing for at least 40% longer than currently tolerated lifespans; (2) the number of seedlings established is increased by at least 60%; and (3) the formation of habitat structures provided by large old trees is accelerated by at least 30% (e.g. artificial structures) to compensate for short term deficits in habitat resources. Immediate implementation of these recommendations is needed to avert long term risk to urban biodiversity.

Standing footprint diagnostic method

Science.gov (United States)

Fan, Y. F.; Fan, Y. B.; Li, Z. Y.; Newman, T.; Lv, C. S.; Fan, Y. Z.

2013-10-01

Center of pressure is commonly used to evaluate standing balance. Even though it is incomplete, no better evaluation method has been presented. We designed our experiment with three standing postures: standing with feet together, standing with feet shoulder width apart, and standing with feet slightly wider than shoulder width. Our platform-based pressure system collected the instantaneous plantar pressure (standing footprint). A physical quantity of instantaneous standing footprint principal axis was defined, and it was used to construct an index to evaluate standing balance. Comparison between results from our newly established index and those from the center of pressure index to evaluate the stability of different standing postures revealed that the standing footprint principal axis index could better respond to the standing posture change than the existing one. Analysis indicated that the insensitive response to the relative position between feet and to the standing posture change from the center of pressure could be better detected by the standing footprint principal axis index. This predicts a wide application of standing footprint principal axis index when evaluating standing balance.

Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

Science.gov (United States)

Warren D. Devine; Timothy B. Harrington

2009-01-01

We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

Height development of shade-tolerant conifer saplings in multiaged Acadian forest stands

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Andrew R. Moores; Robert S. Seymour; Laura S. Kenefic

2007-01-01

Understory growth dynamics of northern conifer species were studied in four stands managed under multiaged silvicultural systems in eastern Maine. Height growth of Picea rubens Sarg., Abies balsamea (L.) Mill., and Tsuga canadensis (L.) Carr. saplings between 0.5 and 6.0 m in height was related to the proportion...

Cultural intensity and planting density effects on individual tree stem growth, stand and crown attributes, and stand dynamics in thinned loblolly pine plantations during the age 12- to age 15- year period in the Upper Coastal Plain and Piedmont of the Southeastern United States

Science.gov (United States)

Evan Johnson; Michael Kane; Dehai Zhao; Robert Teskey

2015-01-01

Three existing loblolly pine (Pinus taeda L.) installations in the Plantation Management Research Cooperative's Upper Coastal Plain/Piedmont Culture Density Study were used to examine the effects of two cultural intensities, four initial planting densities, and their interactions on stem growth at the individual tree level from age 12 to 15 years and at the stand...

Annual variations in the solar energy conversion efficiency in a willow coppice stand

International Nuclear Information System (INIS)

Noronha-Sannervik, A.; Kowalik, P.

2003-01-01

Productivity of an experimental willow coppice forest located at Uppsala, Sweden, was monitored between 1985 and 1994. The 2.7 ha stand was planted in 1984 with a density of 20 000 cuttings per ha and was harvested three times. During the monitored period, the annual stem wood production and the cumulated values of total solar radiation during the growing season, were measured. The conversion of incoming solar radiation into stem biomass was evaluated and the results show that the solar energy conversion efficiency (ECE), for the first and fourth year of the cutting cycle, is, on average, 64% of the ECE for the second and third year of the cutting cycle. It is discussed that the low ECE of 1-year-old shoots is related to a delay in leaf canopy development at the beginning of the growing season and lack of weed control after harvest. For the 4-years-old shoots, the low ECE, is believed to be related to the increased shoot and stool mortality caused by the self-thinning process ongoing in the willow stand. It is recommended that the harvesting interval should be based on the specific development of the stand and more attention should be paid to weed control, especially in the first growing season after harvest

Association of unipedal standing time and bone mineral density in community-dwelling Japanese women.

Science.gov (United States)

Sakai, A; Toba, N; Takeda, M; Suzuki, M; Abe, Y; Aoyagi, K; Nakamura, T

2009-05-01

Bone mineral density (BMD) and physical performance of the lower extremities decrease with age. In community-dwelling Japanese women, unipedal standing time, timed up and go test, and age are associated with BMD while in women aged 70 years and over, unipedal standing time is associated with BMD. The aim of this study was to clarify whether unipedal standing time is significantly associated with BMD in community-dwelling women. The subjects were 90 community-dwelling Japanese women aged 54.7 years. BMD of the second metacarpal bone was measured by computed X-ray densitometry. We measured unipedal standing time as well as timed up and go test to assess physical performance of the lower extremities. Unipedal standing time decreased with increased age. Timed up and go test significantly correlated with age. Low BMD was significantly associated with old age, short unipedal standing time, and long timed up and go test. Stepwise regression analysis revealed that age, unipedal standing time, and timed up and go test were significant factors associated with BMD. In 21 participants aged 70 years and over, body weight and unipedal standing time, but not age, were significantly associated with BMD. BMD and physical performance of the lower extremities decrease with older age. Unipedal standing time, timed up and go test, and age are associated with BMD in community-dwelling Japanese women. In women aged 70 years and over, unipedal standing time is significantly associated with BMD.

Lidar-derived canopy architecture predicts Brown Creeper occupancy of two western coniferous forests

Science.gov (United States)

Jody C. Vogeler; Andrew T. Hudak; Lee A. Vierling; Kerri T. Vierling

2013-01-01

In western conifer-dominated forests where the abundance of old-growth stands is decreasing, species such as the Brown Creeper (Certhia americana) may be useful as indicator species for monitoring the health of old-growth systems because they are strongly associated with habitat characteristics associated with old growth and are especially sensitive to forest...

Irrigation and fertilization effects on foliar and soil carbon and nitrogen isotope ratios in a loblolly pine stand

Science.gov (United States)

Woo-Jung Choi; Scott X. Chang; H. Lee Allen; Daniel L. Kelting; Hee-Myong Ro

2005-01-01

We examined 813C and 815N in needle (current and 1-year-old) and soil samples collected on two occasions (July and September 1999) from a 15-year-old loblolly pine (Pinus taeda L.) stand in an irrigation and fertilization experiment to investigate whether these treatments leave specific isotope signals in...

Determining baseline element composition of lichens. II. Hypogymnia enteromorpha and Usnea spp. at Redwood National Park, California

Science.gov (United States)

Gough, L.P.; Jackson, L.L.; Sacklin, J.A.

1988-01-01

Hypogymnia enteromorpha and Usnea spp. were collected in the Little Bald Hills ultramafic region of Redwood National Park, California, to establish element-concentration norms. Baselines are presented for Ba, Ca, Cu, Mn, Ni, P, Sr, V, and Zn for both lichen species; for Li, Mg, and K for H. enteromorpha; and for Al, Ce, Cr, Co, Fe, Na, and Ti for Usnea. Element concentrations of future collections of this same material can be used to monitor possible air quality changes anticipated from mining activities planned nearby. The variability in the element concentrations was partitioned between geographical distance increments and sample preparation and analysis procedures. In general, most of this variability was found in samples less than a few hundreds of meters apart rather than those at about 1 km apart. Therefore, except for Ba and Co, no large geographical element-concentration trends were observed. Samples of both species contained elevated levels of Ni and Mg, which probably reflect the ultramafic terrain over which they occur.

Higher Alu methylation levels in catch-up growth in twenty-year-old offsprings.

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Kittipan Rerkasem

Full Text Available Alu elements and long interspersed element-1 (LINE-1 or L1 are two major human intersperse repetitive sequences. Lower Alu methylation, but not LINE-1, has been observed in blood cells of people in old age, and in menopausal women having lower bone mass and osteoporosis. Nevertheless, Alu methylation levels also vary among young individuals. Here, we explored phenotypes at birth that are associated with Alu methylation levels in young people. In 2010, 249 twenty-years-old volunteers whose mothers had participated in a study association between birth weight (BW and nutrition during pregnancy in 1990, were invited to take part in our present study. In this study, the LINE-1 and Alu methylation levels and patterns were measured in peripheral mononuclear cells and correlated with various nutritional parameters during intrauterine and postnatal period of offspring. This included the amount of maternal intake during pregnancy, the mother's weight gain during pregnancy, birth weight, birth length, and the rate of weight gain in the first year of life. Catch-up growth (CUG was defined when weight during the first year was >0.67 of the standard score, according to WHO data. No association with LINE-1 methylation was identified. The mean level of Alu methylation in the CUG group was significantly higher than those non-CUG (39.61% and 33.66 % respectively, P < 0.0001. The positive correlation between the history of CUG in the first year and higher Alu methylation indicates the role of Alu methylation, not only in aging cells, but also in the human growth process. Moreover, here is the first study that demonstrated the association between a phenotype during the newborn period and intersperse repetitive sequences methylation during young adulthood.

Patterns of tree species diversity and composition in old-field successional forests in central Illinois

Science.gov (United States)

Scott M. Bretthauer; George Z. Gertner; Gary L. Rolfe; Jeffery O. Dawson

2003-01-01

Tree species diversity increases and dominance decreases with proximity to forest border in two 60-year-old successional forest stands developed on abandoned agricultural land in Piatt County, Illinois. A regression equation allowed us to quantify an increase in diversity with closeness to forest border for one of the forest stands. Shingle oak is the most dominant...

Overstory tree status following thinning and burning treatments in mixed pine-hardwood stands on the William B. Bankhead National Forest, Alabama

Science.gov (United States)

Callie Jo Schweitzer; Yong Wang

2013-01-01

Prescribed burning and thinning are intermediate stand treatments whose consequences when applied in mixed pine-hardwood stands are unknown. The William B. Bankhead National Forest in northcentral Alabama has undertaken these two options to move unmanaged, 20- to 50-year-old loblolly pine (Pinus taeda L.) plantations towards upland hardwood-dominated...

Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica

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Carolina Seas-Carvajal

2013-06-01

Full Text Available Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m². We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia=0.21, p=0.071. We found a significant relationship between the presence of fungi and the distribution of soil types (X²=18.89, df=9, p=0.026. We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.. Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.

Revised Indian Academy of Pediatrics 2015 growth charts for height, weight and body mass index for 5-18-year-old Indian children

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Vaman V Khadilkar

2015-01-01

Full Text Available Growth chart committee of Indian Academy of Pediatrics (IAP has revised growth charts for 5-18-year-old Indian children in Jan 2015. The last IAP growth charts (2007 were based on data collected in 1989-92 which is now >2 decades old. India is in an economic and nutrition transition and hence growth pattern of Indian children has changed over last few years. Thus, it was necessary to produce contemporary, updated growth references for Indian children. The new IAP charts were prepared by collating data from nine groups who had published studies in indexed journals on growth from India in the last decade. Growth charts were constructed from a total of 87022 middle and upper socioeconomic class children (m 54086, f 32936 from all five zones of India. Data from middle and upper socioeconomic class children are likely to have higher prevalence of overweight and obesity and hence growth charts produced on such populations are likely to "normalize" obesity. To remove such unhealthy weights form the data, method suggested by World Health Organization was used to produce weight charts. Thus, the new IAP weight charts are much lower than the recently published studies on affluent Indian children. Since Indian′s are at a higher risk of obesity-related cardiometabolic complications at lower body mass index (BMI, BMI charts adjusted for 23, and 27 adult equivalent cut-offs as per International obesity task force guidelines were constructed. IAP now recommends use of these new charts to replace the 2007 IAP charts.

Effect of stand edge on the natural regeneration of spruce, beech and Douglas-fir

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Lumír Dobrovolný

2012-01-01

Full Text Available Our work aimed at studying the strategy of woody plants regeneration during the regeneration of a spruce stand with the admixture of beech and Douglas-fir by border cutting (NW-SE aspect on acidic sites of higher elevations in the Bohemian-Moravian Upland. Spruce is better adapted to bear shade than Douglas-fir. Nevertheless, in optimal light conditions up to a distance of ca. 35 m (about 16% DIFFSF from the stand edge, the Douglas-fir can put the spruce into danger as to height growth. By contrast to beech, the density of spruce is significantly higher within the distance of 45 m (about 15% DIFFSF from the stand edge but further on the situation would change to the benefit of beech. The density of Douglas-fir significantly dominates over beech within a distance of 35 m from the stand edge; from 55 m (less than 15% DIFFSF, the situation changes in favour of beech. Beech can survive in full shade deep in the stand core waiting for its opportunity to come. As compared to spruce and Douglas-fir, the height growth of beech was at all times significantly greater at a distance of 25 m from the stand edge. Converted to practical conditions, spruce and Douglas-fir with individually admixed beech seedlings showed good prosperity approximately up to a distance of one stand height from the edge. A mixture of spruce and beech did well at a greater distance but good prosperity at a distance of 2–3 stand heights was shown only by beech. Thus, border regeneration eliminates disadvantages of the climatic extremes of clear-cutting and specifics of shelterwood felling during which one – usually shade-tolerant tree species dominates in the natural regeneration (e.g. beech.

Estimating biomass of shrubs and forbs in central Washington Douglas-fir stands.

Science.gov (United States)

Craig M. Olson; Robert E. Martin

1981-01-01

Understory plants in closed 70-year-old even-aged Douglas-fir stands in north central Washington were destructively sampled to determine the relationship of ground cover and height to dry weight. Weight of plant material can be estimated from the product of plant height and percentage of ground cover on 50- x 100-centimeter (cm) quadrats. Correlation coefficients for...

The Effect of Herbivory by White-Tailed Deer and Additionally Swamp Rabbits in an Old-Growth Bottomland Hardwood Forest

Science.gov (United States)

Margaret S. Devall; Bernard R. Parresol; Winston P. Smith

2001-01-01

Forest openings create internal patchiness and offer different habitat qualities that attract wildlife, especially herbivores, that flourish along forest edges. But intense herbivory in these openings can reduce or eliminate herbaceous and woody species and thus influence local species composition and structure of the forest. This study in an old-growth bottomland...

Productivity of black locust (Robinia pseudoacacia L. stands on chernozem in Vojvodina

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Andrašev Siniša

2014-01-01

Full Text Available This paper presents the elements of growth of black locust trees and stands in 15 sample plots in Vojvodina, at the age of 21-68 years. In each sample plot, based on soil profile horizons the determined soil type was chernozem as well as its lower systematic units (subtype, variety and form, according to the Škorić et al. (1985 classification. On the basis of the mean stand heights (hL, the stands on the subtype of chernozem on loess and loesslike sediments belong to height classes I-IV, and stands on calcareous aeolian sand to classes II-V (according to R e d e i et al. 2014, which indicates their considerable variability with respect to productivity within the determined subtypes of chernozem. Significant differences at the level of chernozem subtypes were found between the mean heights (p = 0.032, but not between the mean diameters (p = 0.083. The mean diameters at breast height in the studied black locust stands were on average lower than the models of diameter growth for the appropriate height classes and determined by a larger number of trees per hectare than in the tables (R e d e i et al, 2014. The volume per hectare is higher than in the tables also being conditioned by the large number of trees per hectare. [Projekat Ministarstva nauke Republike Srbije, br. III43007: Istraživanje klimatskih promena na životnu sredinu: praćenje uticaja, adaptacija i ublažavanje

Climatic control of stand thinning in unmanaged spruce forests of the southern taiga in European Russia

International Nuclear Information System (INIS)

Vygodskaya, N.N.; Schulze, E.D.; Tchebakova, N.M.

2002-01-01

The demography of Picea abies trees was studied over a period of about 30 yr on permanent plots in six forest types of an unmanaged forest located in a forest reserve of the Southern Taiga, NW of Moscow. This study encompassed a broad range of conditions that are typical for old growth spruce forests in the boreal region, including sites with a high water table and well drained sites, podzolic soils, acidic soils and organic soils. At all sites stand density, tree height, breast height diameter and age has been periodically recorded since 1968. Tree density ranged between 178 and 1035 trees/ha for spruce and between 232 and 1168 trees/ha for the whole stand, including mainly Betula and Populus. Biomass ranged between 5.4 and 170 tdw/ha for spruce and between 33 to 198 tdw/ha for the whole stand. Averaged over a long period of time, biomass did not change with stand density according to the self-thinning rule. In fact, on most sites biomass remained almost constant in the long term, while stand density decreased. The study demonstrates that the loss of living trees was not regulated by competitive interactions between trees, but by disturbances caused by climatic events. Dry years caused losses of minor and younger trees without affecting biomass. In contrast, periodic storms resulted in a loss of biomass without affecting density, except for extreme events, where the whole stand may fall. Dry years followed by wet years enhance the effect on stand density. Since mainly younger trees were lost, the apparent average age of the stand increased more than real time (20% for Picea). Average mortality was 2.8 ± 0.5% yr 1 for spruce. Thus, the forest is turned over once every 160-180 yr by disturbances. The demography of dead trees shows that the rate of decay depends on the way the tree died. Storm causes uprooting and stem breakage, where living trees fall to the forest floor and decay with a mean residence time (t1/2) of about 16 yr (decomposition rate constant k d = 0

Drive Stands

Data.gov (United States)

Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

The application of LANDSAT remote sensing technology to natural resources management. Section 1: Introduction to VICAR - Image classification module. Section 2: Forest resource assessment of Humboldt County.

Science.gov (United States)

Fox, L., III (Principal Investigator); Mayer, K. E.

1980-01-01

A teaching module on image classification procedures using the VICAR computer software package was developed to optimize the training benefits for users of the VICAR programs. The field test of the module is discussed. An intensive forest land inventory strategy was developed for Humboldt County. The results indicate that LANDSAT data can be computer classified to yield site specific forest resource information with high accuracy (82%). The "Douglas-fir 80%" category was found to cover approximately 21% of the county and "Mixed Conifer 80%" covering about 13%. The "Redwood 80%" resource category, which represented dense old growth trees as well as large second growth, comprised 4.0% of the total vegetation mosaic. Furthermore, the "Brush" and "Brush-Regeneration" categories were found to be a significant part of the vegetative community, with area estimates of 9.4 and 10.0%.

Protecting rare, old-growth, forest-associated species under the Survey and Manage program guidelines of the northwest forest plan.

Science.gov (United States)

Randy Molina; Bruce G. Marcot; Robin. Lesher

2006-01-01

The Survey and Manage Program of the Northwest Forest Plan (MFP) represents an unparalleled attempt to protect rare, little-known species associated with late-successional and old-growth forests on more than 7.7 million ha of federal lands. Approximately 400 species of amphibians, bryophytes, fungi, lichens, mollusks, vascular plants, arthropod functional groups, and...

The role of SiGe buffer in growth and relaxation of Ge on free-standing Si(001) nano-pillars.

Science.gov (United States)

Zaumseil, P; Kozlowski, G; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

2012-09-07

We study the growth and relaxation processes of Ge nano-clusters selectively grown by chemical vapor deposition on free-standing 90 nm wide Si(001) nano-pillars with a thin Si(0.23)Ge(0.77) buffer layer. We found that the dome-shaped SiGe layer with a height of about 28 nm as well as the Ge dot deposited on top of it partially relaxes, mainly by elastic lattice bending. The Si nano-pillar shows a clear compliance behavior-an elastic response of the substrate on the growing film-with the tensile strained top part of the pillar. Additional annealing at 800 °C leads to the generation of misfit dislocation and reduces the compliance effect significantly. This example demonstrates that despite the compressive strain generated due to the surrounding SiO(2) growth mask it is possible to realize an overall tensile strain in the Si nano-pillar and following a compliant substrate effect by using a SiGe buffer layer. We further show that the SiGe buffer is able to improve the structural quality of the Ge nano-dot.

Toddler Growth and Development

Science.gov (United States)

... the AAP Schedule of Well-Child Care Visits . ​​ Toddler Growth & Development Physical Skills Walks alone Pulls toys behind when ... 18 to 23 Month Old Language Delays in Toddlers: Information for Parents ... Physical Appearance and Growth: Your 1 Year Old Physical Appearance and Growth: ...

The ambiguity of standing in standing devices: a qualitative interview study concerning children and parents experiences of the use of standing devices.

Science.gov (United States)

Nordström, Birgitta; Näslund, Annika; Ekenberg, Lilly; Zingmark, Karin

2014-10-01

The aim of this study was to describe children's and parents' experiences of the significance of standing in a standing device. Individual interviews were performed with six children/teenagers (aged 7-19 years) and 14 parents. The interviews were transcribed and analyzed using a qualitative content analysis. The analysis resulted in the major theme, the duality of uprightness and the related themes: (1) the instrumental dimension of standing; (2) the social dimension of standing; and (3) the ambivalent dimension of standing. Each of the themes comprised several subthemes. There is an inherent duality related to the use of a standing device. Standing in a standing device was seen as a treatment of body structures and functions, as well as a possible source of pain. Standing was considered to influence freedom in activities and participation both positively and negatively. The parents experienced that standing influenced other peoples' views of their child, while the children experienced standing as a way to extend the body and as something that gave them benefits in some activities. Physiotherapists working with children should take into account both the social and physical dimensions of using a standing device and consider both the child's and the parents' views.

Scaling Hydrologic Processes in Boreal Forest Stands: New Eco-hydrological Perspectives or Deja vu?

Science.gov (United States)

Silins, U.; Lieffers, V. J.; Landhausser, S. M.; Mendoza, C. A.; Devito, K. J.; Petrone, R. M.; Gan, T. Y.

2006-12-01

The leaf area of forest canopies is both main attribute of stands controlling water balance through transpiration and interception, and "engine" driving stand growth, stand dynamics, and forest succession. While transpiration and interception dynamics are classic themes in forest hydrology, we present results from our eco-hydrological research on boreal trees to highlight how more recent eco-physiological insights into species specific controls over water use and leaf area such as hydraulic architecture, cavitation, sapwood-leaf area relationships, and root system controls over water uptake are providing new insights into integrated atmospheric-autecological controls over these hydrologic processes. These results are discussed in the context of newer eco-hydrological frameworks which may serve to aid in exploring how forest disturbance and subsequent trajectories of hydrologic recovery are likely to affect both forest growth dynamics and hydrology of forested landscapes in response to forest management, severe forest pest epidemics such as the Mountain Pine Beetle epidemic in Western Canada, and climate change.

Introducing sit-stand desks increases classroom standing time among university students.

Science.gov (United States)

Jerome, Matthew; Janz, Kathleen F; Baquero, Barbara; Carr, Lucas J

2017-12-01

Excessive sedentary behavior has been associated with many negative health outcomes. While an understudied health topic, there is evidence that university students are excessively sedentary. Sit-stand desks have been shown to reduce sedentary time among pre-university students (ages 5-18 years) and sedentary workers but have not been tested in university classrooms. This study tested the effects of introducing sit-stand desks into a university classroom on student's classroom sitting and standing behaviors. Using a cross-over design, students received access to both traditional seated desks and sit-stand desks for six weeks. Data were collected between September and December, 2016. We recruited 304 healthy undergraduate university students enrolled in one of two small (25 seats) classrooms at a large Midwestern university during the fall of 2016. Average minutes of standing/hour/student, average percent class time spent standing, and the number of sit-stand transitions/student/hour were directly observed with video camera surveillance. Participants stood significantly more (p classrooms as an approach to reduce sedentary behaviors of university students.

Tree communities of lowland warm-temperate old-growth and neighboring shelterbelt forests in the Shikoku region of southwestern Japan

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Shigeo Kuramoto; Shigenori Oshioka; Takahisa Hirayama; Kaori Sato; Yasumasa Hirata

2007-01-01

We characterized the tree species composition of a 30 ha old-growth and neighboring shelterbelt (reserved buffer strips among conifer plantations) in warm-temperate forests in the Shikoku region of southwestern Japan. Using a two-way indicator species analysis of data from 28 plots, we identified four structural groups in terms of relative basal area. These structural...

SEASONAL PATTERNS OF FINE ROOT PRODUCTION AND TURNOVER IN PONDEROSA PINE STANDS OF DIFFERENT AGES

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Root minirhizotron tubes were installed in two ponderosa pine (Pinus ponderosa Laws.) stands around three different tree age classes (16, 45, and > 250 yr old) to examine root spatial distribution in relation to canopy size and tree distribution, and to determine if rates of fine...

Distance-independent individual tree diameter-increment model for Thuya [Tetraclinis articulata (VAHL. MAST.] stands in Tunisia

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T. Sghaier

2013-12-01

Full Text Available Aim of study: The aim of the work was to develop an individual tree diameter-increment model for Thuya (Tetraclinis articulata in Tunisia.Area of study: The natural Tetraclinis articulata stands at Jbel Lattrech in north-eastern of Tunisia.Material and methods:  Data came from 200 trees located in 50 sample plots. The diameter at age t and the diameter increment for the last five years obtained from cores taken at breast height were measured for each tree. Four difference equations derived from the base functions of Richards, Lundqvist, Hossfeld IV and Weibull were tested using the age-independent formulations of the growth functions. Both numerical and graphical analyses were used to evaluate the performance of the candidate models.Main results: Based on the analysis, the age-independent difference equation derived from the base function Richards model was selected. Two of the three parameters (growth rate and shape parameter of the retained model were related to site quality, represented by a Growth Index, stand density and the basal area in larger trees divided by diameter of the subject tree expressing the inter-tree competition.Research highlights: The proposed model can be useful for predicting the diameter growth of Tetraclinis articulata in Tunisia when age is not available or for trees growing in uneven-aged stands.Keywords: Age-independent growth model; difference equations; Tetraclinis articulata; Tunisia.

Stand and within-stand factors influencing Golden-winged Warbler use of regenerating stands in the central Appalachian Mountains

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Marja H. Bakermans

2015-06-01

Full Text Available The Golden-winged Warbler (Vermivora chrysoptera is currently being considered for protected status under the U.S. Endangered Species Act. The creation of breeding habitat in the Appalachian Mountains is considered a conservation priority for this songbird, which is dependent on extensively forested landscapes with adequate availability of young forest. We modeled abundance of Golden-winged Warbler males in regenerating harvested forest stands that were 0-17 years postharvest at both mid-Appalachian and northeast Pennsylvania regional scales using stand and within-stand characteristics of 222 regenerating stands, 2010-2011. Variables that were most influential at the mid-Appalachian scale were different than those in the northeast region. Across the mid-Appalachian ecoregion, the proportion of young forest cover, i.e., shrub/scrub cover, within 1 km of regenerating stands best explained abundance of Golden-winged Warblers. Golden-winged Warbler response was best explained by a concave quadratic relationship in which abundance was highest with 5-15% land in young forest cover. We also found evidence that the amount of herbaceous cover, i.e., the amount of grasses and forbs, within a regenerating stand positively influenced abundance of Golden-winged Warblers. In northeastern Pennsylvania, where young forest cover is found in high proportions, the distance to the nearest regenerating stand best explained variation in abundance of Golden-winged Warblers. Abundance of Golden-winged Warblers was 1500 m away. When modeling within-stand features in the northeast region, many of the models were closely ranked, indicating that multiple variables likely explained Golden-winged Warbler response to within-stand conditions. Based on our findings, we have proposed several management guidelines for land managers interested in creating breeding habitat for Golden-winged Warblers using commercial timber operations. For example, we recommend when managing for

Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica.

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Grossmann, S; Dieckmann, G S

1994-08-01

Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 x 10 to 3 x 10 liter, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low concentrations of phytoplankton in the water column during freezing, incorporation of bacteria into newly formed ice via attachment to algal cells or aggregates was not recorded in this study. As soon as the ice had formed, the general metabolic activity of bacterial populations was strongly suppressed. Furthermore, the ratio of [H]leucine incorporation into proteins to [H]thymidine incorporation into DNA changed during ice growth. In thick pack ice, bacterial activity recovered and growth rates up to 0.6 day indicated actively dividing populations. However, biomass-specific utilization of organic compounds remained lower than in open water. Bacterial concentrations of up to 2.8 x 10 cells liter along with considerably enlarged cell volumes accumulated within thick pack ice, suggesting reduced mortality rates of bacteria within the small brine pores. In the course of ice development, bacterial carbon production increased from about 0.01 to 0.4 mug of C liter h. In thick ice, bacterial secondary production exceeded primary production of microalgae.

Plant distribution and stand characteristics in brackish marshes: Unravelling the roles of abiotic factors and interspecific competition

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Carus, Jana; Heuner, Maike; Paul, Maike; Schröder, Boris

2017-09-01

Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection.

Duff mound consumption and cambium injury for centuries-old western larch from prescribed burning in western Montana

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Michael G. Harrington

2012-01-01

Western larch is one of the most fire-adapted conifers in western North America. Its historical perpetuation depended upon regular fire disturbances, which creates open stand conditions and mineral seedbeds. A stand of 200- to 500-year-old larch in western Montana with deep duff mounds resulting from an unusually long 150-year fire-free period was mechanically thinned...

Stand and individual tree growth response to treatments in young natural hardwoods

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Daniel J. Robison; Tracy San Filipo; Charlie Lawrence III; Jamie L. Schuler; Bryan J. Berenguer

2012-01-01

Young even-aged upland Piedmont mixed hardwood and pine stands were treated with a variety of fertilizer and release (competition control) treatments. The sites studied are on the NC State University Hill Demonstration Forest in central North Carolina, and are characterized by formerly highly eroded agricultural sites (Richter et al. 2000) now in their third rotation...

Management of black Locust (Robinia pseudoacacia L.) stands in Hungary

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

Black locust (Robinia pseudoacacia L.) was the first forest tree species to be imported from North America to Europe at the beginning of the 17th century. It is the most important fast-growing stand-forming tree species in Hungary . Black locust plantations can be successfully established in response to arange of economic and ecological opportunities. Plantation survival and productivity are maximized by matching the species' growth characteristics with silvicultura l options and land management needs. In the paper the sequence of forest tending operations in black locust stands is proposed, based on results of long-term st and structure and forest yield trials. Implementing good silvicultural plans and models will lead to profitable black locust stands and greater acceptance of the species by land managers. Black locust would also beavery useful species for energy productions as the related research results have been shown in the paper .

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

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Esther Merlo

2014-04-01

Full Text Available Aim of study: Modelling the structural quality of Pinus pinaster Ait. wood on the basis of measurements made on standing trees is essential because of the importance of the species in the Galician forestry and timber industries and the good mechanical properties of its wood. In this study, we investigated how timber stiffness is affected by tree and stand properties, climatic and edaphic characteristics and competition. Area of study: The study was performed in Galicia, north-western Spain.Material and methods: Ten pure and even-aged P. pinaster stands were selected and tree and stand variables and the stress wave velocity of 410 standing trees were measured. A sub-sample of 73 trees, representing the variability in acoustic velocity, were felled and sawed into structural timber pieces (224 which were subjected to a bending test to determine the modulus of elasticity (MOE. Main results: Linear models including wood properties explained more than 97%, 73% and 60% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity and wood density as the main regressors. Other linear models, which did not include wood density, explained more than 88%, 69% and 55% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity as the main regressor. Moreover, a classification tree for estimating the visual grade according to standard UNE 56544:2011 was developed. Research highlights: The results have demonstrated the usefulness of acoustic velocity for predicting MOE in standing trees. The use of the fitted equations together with existing dynamic growth models will enable preliminary assessment of timber stiffness in relation to different silvicultural alternatives used with this species.Keywords: stress wave velocity, modulus of elasticity, site index, competition index, stepwise regression, CART.

Stand tending and root rot in Norway spruce stands - economical effects caused by root rot at different thinning regimes

International Nuclear Information System (INIS)

Johansson, Mats

1997-01-01

This report is divided into three parts: 1) a literature study describing the most common fungi causing rot in wood and descriptions of various strategies to reduce economic loss from root rot, 2) a check of a model describing the development of butt rot in pure Norway spruce plantations in southern Sweden, and 3) simulated economic effects of root rot in stands with various stand tending. The rot model was used to estimate future rot frequencies in the economic calculations. In order to avoid overestimations of rot frequencies, the calculations were also executed when assuming slower growth of rot than shown in the model. When analysing the economical effects of rot, the following three thinning programmes were used: Program 1: thinning at the ages of 30- and 45 years. Final felling at the ages 50-, 55-, 60-, 65-, and 70 years. Program 2: thinning at the ages of 40- and 60- years. Final felling at the ages 65 and 75 years. Program 3: thinning at the ages of 30-, 40-, 55-, and 70 years. Final felling at the ages 80 and 90 years. With an interest rate of 3%, programme 2 (final felling at the age of 65 years) had the highest value at present. This result was valid when presuming butt rot in the stand as well as when presuming no butt rot in the stand. There was a small difference between the value at present in programme 1 (final felling at the age of 60 years) and in programme 3 (final felling at the age of 80 years). When presuming butt rot in the stand, the value at present in programme 3 decreased somewhat more in comparison to the value at present in programme 1. Compared to no butt rot in the stand, the optimal final felling time appeared five to ten years earlier when assuming butt rot in the stand. Stand tending programme 1 and an interest rate of 3% were used. Interest rates 2 and 4% did not indicate shorter rotation. The calculated optimal time of final felling appeared at the same stand age whether assuming rot preset or not. The results in this study

A meta-analysis of functional group responses to forest recovery outside of the tropics.

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Spake, Rebecca; Ezard, Thomas H G; Martin, Philip A; Newton, Adrian C; Doncaster, C Patrick

2015-12-01

Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old-growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta-analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old-growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional-group-specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old-growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old-growth values (between 140 years and never for recovery to old-growth values at 95% prediction limits). Non-saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. © 2015 The Authors Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Spatial and temporal variation in soil CO2 efflux in an old-growth neotropical rain forest, LA Selva, Costa Rica

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Luitgard Schwendenmann; Edzo Veldkamp; Tania Brenes; Joseph J. O' Brien; Jens Mackensen

2003-01-01

Our objectives were to quantify and compare soil CO2, efflux of two doininant soil types in an old-growth neotropical rain forest in the Atlantic zone of Costa Rica, and to evaluate the control of environmental Factors on CO2, release. We measured soil CO2 efflux from eight permanent soil chamhers on...

ROOT GROWTH AND TURNOVER IN DIFFERENT AGED PONDEROSA PINE STANDS IN OREGON, USA

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The impacts of pollution and climate change on soil carbon dynamics are poorly understood, in part due to a lack of information regarding root production and turnover in natural ecosystems. In order to examine how root dynamics change with stand age in ponderosa pine forests (...

Unravelling the importance of forest age stand and forest structure driving microbiological soil properties, enzymatic activities and soil nutrients content in Mediterranean Spanish black pine(Pinus nigra Ar. ssp. salzmannii) Forest.

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Lucas-Borja, M E; Hedo, J; Cerdá, A; Candel-Pérez, D; Viñegla, B

2016-08-15

This study aimed to investigate the effects that stand age and forest structure have on microbiological soil properties, enzymatic activities and nutrient content. Thirty forest compartments were randomly selected at the Palancares y Agregados managed forest area (Spain), supporting forest stands of five ages; from 100 to 80years old to compartments with trees that were 19-1years old. Forest area ranging from 80 to 120years old and without forest intervention was selected as the control. We measured different soil enzymatic activities, soil respiration and nutrient content (P, K, Na, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb and Ca) in the top cm of 10 mineral soils in each compartment. Results showed that the lowest forest stand age and the forest structure created by management presented lower values of organic matter, soil moisture, water holding capacity and litterfall and higher values of C/N ratio in comparison with the highest forest stand age and the related forest structure, which generated differences in soil respiration and soil enzyme activities. The forest structure created by no forest management (control plot) presented the highest enzymatic activities, soil respiration, NH4(+) and NO3(-). Results did not show a clear trend in nutrient content comparing all the experimental areas. Finally, the multivariate PCA analysis clearly clustered three differentiated groups: Control plot; from 100 to 40years old and from 39 to 1year old. Our results suggest that the control plot has better soil quality and that extreme forest stand ages (100-80 and 19-1years old) and the associated forest structure generates differences in soil parameters but not in soil nutrient content. Copyright © 2016 Elsevier B.V. All rights reserved.

Supporting data for hydrologic studies in San Francisco Bay, California : meteorological measurements at the Port of Redwood City during 1998-2001

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Schemel, Laurence E.

2002-01-01

Meteorological data were collected during 1998-2001 at the Port of Redwood City, California, to support hydrologic studies in South San Francisco Bay. The measured meteorological variables were air temperature, atmospheric pressure, quantum flux (insolation), and four parameters of wind speed and direction: scalar mean horizontal wind speed, (vector) resultant horizontal wind speed, resultant wind direction, and standard deviation of the wind direction. Hourly mean values based on measurements at five-minute intervals were logged at the site. Daily mean values were computed for temperature, infolation, pressure, and scalar wind speed. Daily mean values for 1998-2001 are described in this report, and a short record of hourly mean values is compared to data from another near-by station. Data (hourly and daily mean) from the entire period of record (starting in April 1992) and reports describing data prior to 1998 are provided.

Structure and Composition of Vegetation of Longleaf Pine Plantations Compared to Natural Stands Occurring Along an Environmental Gradient at the Savannah River Site

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Gregory P. Smith; Victor B. Shelburne; Joan L. Walker

2002-01-01

Fifty-four plots in 33-43 year old longleaf pine plantations were compared to 30 remnant plots in longleaf stands on the Savannah River Site in South Carolina. Within these stands, the structure and composition of primarily the herb layer relative to a presumed soil moisture or soil texture gradient was studied using the North Carolina Vegetation Survey methodology....

Effect of acorn mass and size, and early shoot growth on one-year old container-grown RPM™ oak seedlings

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Benjamin C. Grossman; Michael A. Gold; Daniel C. Dey

2003-01-01

The purpose of this study was to evaluate the influence of seed source, acorn mass and size, and early shoot growth on morphological traits of 1-year-old oak seedlings. Forested bottomlands in the Midwest have been greatly reduced in the past 150 years as a result of conversion to agriculture and recent catastrophic floods. Due to a lack of available hard mast, intense...

Logging damage associated with thinning central Appalachian hardwood stands with a wheeled skidder

Science.gov (United States)

Gary W. Miller; Neil I. Lamson; Samuel M. Brock

1984-01-01

In north central West Virginia, unmanaged 53-year-old, mixed oak-cove hardwood stands were thinned to 75, 60, and 45 percent residual stocking. Cut trees were skidded tree-length with a rubber-tired skidder. Logging destroyed or severely bent 26, 29, and 34 percent of the unmarked stems in the 75, 60, and 45 percent stocking plots, respectively. Because 94 percent of...

Stand-alone photovoltaic systems in the Netherlands. Evaluation of the market introduction

International Nuclear Information System (INIS)

Cloin, J.; Van Dijk, A.L.; Westra, C.A.

1999-08-01

The policy followed for stand-alone PV systems in the Netherlands is evaluated for the period 1997-1998. The world-wide powerful growth of the PV industry is not being followed by the increase in volume of implemented stand-alone PV systems in the Netherlands. This leads to the question whether the Dutch policy to stimulate stand-alone PV systems is effective. Recommendations on the use of communication as a strategic instrument are given, including the drawing up of a marketing plan. Other recommendations include increased transparency in the application for subsidies and a pro-active role of the Netherlands Agency for Energy and the Environment (Novem) in the contact with relevant market parties. The increased focus on product development aimed at the environmental benefits and general reliability of PV systems is recommended. 38 refs

PATTERNS OF ROOT GROWTH, TURNOVER, AND DISTRIBUTION IN DIFFERENT AGED PONDEROSA PINE STANDS

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The objectives of this study are to examine the spatial distribution of roots in relation to canopy size and tree distribution, and to determine if rates of fine root production and turnover are similar in the different aged stands. During the fall of 1998, 54 clear plexiglass t...

Contribution to growth and increment analysis on the Italian CONECOFOR Level II Network

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Emilio AMORINI

2002-09-01

Full Text Available The paper deals with the "Estimation of growth and yield" included in the National Programme on Intensive Monitoring of Forest Ecosystems CONECOFOR Aims of the paper are: i to outline the composition and design of Level II PMPs network, also examining the structural characteristics of forest stands; ii to describe the contents of mensurational surveys carried out in winter 1996/97 and 1999/00; iii to analyse the growth rates in progress at each PMP using selected descriptors. Stand origin (11 high forests and 13 stored coppices and transitory crops and the number of forest types tested are focused as the main discriminants of the PMPs network. This composition, together with irregular forestry practice, results in a number of consequences (prevailing age classes, tree densities and related stand structures, growth patterns which cause a high in-and-between variability of all growth parameters. For the purposes of this analysis, the network of the plots was divided into three main sets: broadleaved high forest (i.e. beech stands, 6 PMPs; coniferous forest (i.e. Norway spruce stands, 5 PMPs; coppice forest (i.e. deciduous and evergreen oaks, beech and hardbeam stands, 13 PMPs. The measurement of basic growth variables (dbh and tree height was used to describe the tree populations in each PMP; the calculation of basal area, mean and top dbh, mean and top height, provided the reference dataset at each inventory. The assessment of social class according to Kraft gave information on vertical stand structure and made it possible to analyse growth according to tree layers. Data comparison provided increments in the interval 1997-2000. The occurrence of natural mortality and ingrowth was also assessed to take into account their combined effect on tree population dynamics. No trend was found, due to limited data availability, but it was possible to have a detailed overview of the stand situation and growth rates in PMPs.

Sugar maple growth in relation to nutrition and stress in the northeastern United States.

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Long, Robert P; Horsley, Stephen B; Hallett, Richard A; Bailey, Scott W

2009-09-01

Sugar maple, Acer saccharum, decline disease is incited by multiple disturbance factors when imbalanced calcium (Ca), magnesium (Mg), and manganese (Mn) act as predisposing stressors. Our objective in this study was to determine whether factors affecting sugar maple health also affect growth as estimated by basal area increment (BAI). We used 76 northern hardwood stands in northern Pennsylvania, New York, Vermont, and New Hampshire, USA, and found that sugar maple growth was positively related to foliar concentrations of Ca and Mg and stand level estimates of sugar maple crown health during a high stress period from 1987 to 1996. Foliar nutrient threshold values for Ca, Mg, and Mn were used to analyze long-term BAI trends from 1937 to 1996. Significant (P maples sampled in the 1990s had decreased growth in the 1970s, 10-20 years in advance of the 1980s and 1990s decline episode in Pennsylvania. Even apparently healthy stands that had no defoliation, but had below-threshold amounts of Ca or Mg and above-threshold Mn (from foliage samples taken in the mid 1990s), had decreasing growth by the 1970s. Co-occurring black cherry, Prunus serotina, in a subset of the Pennsylvania and New York stands, showed opposite growth responses with greater growth in stands with below-threshold Ca and Mg compared with above-threshold stands. Sugar maple growing on sites with the highest concentrations of foliar Ca and Mg show a general increase in growth from 1937 to 1996 while other stands with lower Ca and Mg concentrations show a stable or decreasing growth trend. We conclude that acid deposition induced changes in soil nutrient status that crossed a threshold necessary to sustain sugar maple growth during the 1970s on some sites. While nutrition of these elements has not been considered in forest management decisions, our research shows species specific responses to Ca and Mg that may reduce health and growth of sugar maple or change species composition, if not addressed.

Recent Trends of Tree Growth in Relation to Climate Change in Hungary

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SOMOGYI, Zoltán

2008-01-01

Full Text Available The paper addresses two related issues. One is whether, and how, growth patterns of standmean height have changed in Hungary in the last few decades, and the other is whether recentlyobserved increases in mean annual temperature might have caused changes in growth trends. Changesin tree growth were investigated for beech (Fagus sylvatica, sessile oak (Quercus petraea andTurkey oak (Quercus cerris by comparing stand mean heights over age using data from the forestinventories of 1981 and 2001, and for sessile oak using stand mean height data from permanentsample plots since 1961. Tree growth was found to have accelerated for each species mentioned, withTurkey oak showing the largest acceleration. To study the second issue, stand mean height was relatedto elevation, wich in turn was related to mean annual temperature and precipitation. For theseanalyses, too, data of many thousands of stands in the forest inventory was used. Stand mean heightwas found to increase with decreasing elevation, i.e. with increasing mean annual temperature, foreach of the three species. As the annual precipitation and air humidity decreases with decreasingelevation, it was concluded that increases of mean annual temperature could positively have affectedtree growth in the last few decades. However, this effect is expected to be soon limited by wateravailability.

Overweight among Four-Year-Old Children in Relation to Early Growth Characteristics and Socioeconomic Factors

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Jörgen Thorn

2010-01-01

Full Text Available Objectives. To assess early growth characteristics and socioeconomic factors of children in relation to body mass index (BMI and presence of overweight among four-year-old children. Methods. Two Child Health Centres (CHC participated in the study. They were selected to obtain two populations of children featuring divergent socio-economic characteristics. Growth data registered at the CHCs from birth to the 4-year check-up were recovered. Overweight was defined by the BMI cut-offs established by IOTF. BMI values expressed as BMI standard deviation score (BMISDS were used for analysis. Results. At the 4-year check-up, the BMISDS and the proportion of children with overweight (including the obese were significantly higher in the district with lower socio-economic status. High BMI at birth and low socio-economic status of the population in the CHC-district were shown to be independent determinants for overweight and BMISDS at four years of age. Conclusions. More research is needed to understand the mechanisms and how intervention programs should be designed in order to prevent the development of overweight and obesity in children.

Impact of selected risk factors on expected lifetime without long-standing, limiting illness in Denmark

DEFF Research Database (Denmark)

Brønnum-Hansen, Henrik; Juel, Knud; Davidsen, Michael

2007-01-01

long-standing, limiting illness was 8-10 years shorter among sedentary than physically active people. Obesity shortened lifetime without illness by 5 years for men and ten years for women. CONCLUSION: The results of this study could be used in health policy-making, as the potential gains in public......OBJECTIVE: To estimate the impacts of tobacco smoking, high alcohol consumption, physical inactivity and overweight on expected lifetime with and without long-standing, limiting illness. METHODS: Life tables for each level of exposure to the risk factors were constructed, mainly on the basis......-olds was 9-10 years shorter for heavy smokers than for those who never smoke, and all the lifetime lost would have been without long-standing, limiting illness. Similarly, all 5 years of expected lifetime lost by men with high alcohol consumption would have been without illness. The expected lifetime without...

Management Strategies for Annosus Root Disease in Pacific Northwest Coastal Western Hemlock

Science.gov (United States)

Kenelm W. Russell

1989-01-01

Actual loss from annosus root disease infections in hemlock stands is difficult to determine. As political trends move toward protecting old-growth timber, greater market demand will be placed on second growth western hemlock. These stands must be kept healthy for maximum productivity. The paper compares the following 70-year rotation timber management scenarios: The...

Effects of stand age and soil properties on soil bacterial and fungal community composition in Chinese pine plantations on the Loess Plateau.

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Peng Dang

Full Text Available The effects of Chinese pine (Pinus tabuliformis on soil variables after afforestation have been established, but microbial community changes still need to be explored. Using high-throughput sequencing technology, we analyzed bacterial and fungal community composition and diversity in soils from three stands of different-aged, designated 12-year-old (PF1, 29-year-old (PF2, and 53-year-old (PF3, on a Chinese pine plantation and from a natural secondary forest (NSF stand that was almost 80 years old. Abandoned farmland (BL was also analyzed. Shannon index values of both bacterial and fungal community in PF1 were greater than those in PF2, PF3 and NSF. Proteobacteria had the lowest abundance in BL, and the abundance increased with stand age. The abundance of Actinobacteria was greater in BL and PF1 soils than those in other sites. Among fungal communities, the dominant taxa were Ascomycota in BL and PF1 and Basidiomycota in PF2, PF3 and NSF, which reflected the successional patterns of fungal communities during the development of Chinese pine plantations. Therefore, the diversity and dominant taxa of soil microbial community in stands 12 and 29 years of age appear to have undergone significant changes; afterward, the soil microbial community achieved a relatively stable state. Furthermore, the abundances of the most dominant bacterial and fungal communities correlated significantly with organic C, total N, C:N, available N, and available P, indicating the dependence of these microbes on soil nutrients. Overall, our findings suggest that the large changes in the soil microbial community structure of Chinese pine plantation forests may be attributed to the phyla present (e.g., Proteobacteria, Actinobacteria, Ascomycota and Basidiomycota which were affected by soil carbon and nutrients in the Loess Plateau.

Rapid structural and compositional change in an old-growth subtropical forest: using plant traits to identify probable drivers.

Science.gov (United States)

Malizia, Agustina; Easdale, Tomás A; Grau, H Ricardo

2013-01-01

Recent studies have shown directional changes in old-growth tropical forests, but changes are complex and diverse, and their drivers unclear. Here, we report rapid net structural and compositional changes in an old-growth subtropical forest and we assess the functional nature of these changes to test hypothetical drivers including recovery from past disturbances, reduction in ungulate browsing, CO2 fertilization, and increases in rainfall and temperature. The study relies on 15 years of demographic monitoring within 8 ha of subtropical montane forest in Argentina. Between 1992 and 2007, stem density markedly increased by 50% (12 stems ha(-1) y(-1)) and basal area by 6% (0.13 m(2) ha(-1) y(-1)). Increased stem density resulted from enhanced recruitment of understory treelets (Piper tucumanum, Eugenia uniflora, Allophylus edulis) into small size classes. Among 27 common tree species, net population growth was negatively correlated with maximum tree size and longevity, and positively correlated with leaf size and leaf nutrient content, especially so when initial population size was controlled for. Changes were inconsistent with predictions derived from past disturbances (no increase in shade-tolerant or long-lived late-succesional species), rainfall or temperature increase (no increase in evergreen or deciduous species, respectively). However, the increase in nutrient-rich soft-leaved species was consistent with exclusion of large herbivores two decades before monitoring started; and CO2 fertilization could help explain the disproportionate increase in small stems. Reductions in populations of large vertebrates have been observed in many otherwise undisturbed tropical forests, and our results suggest they can have important structural and functional repercussions in these forests.

Developing contemporary and historical live tree biomass estimates for old pine-hardwood stands of the Midsouth, USA

Science.gov (United States)

Don C. Bragg

2012-01-01

Calculating stand biomass potential is an increasingly important aspect of silviculture, particularly when attempting to restore forest ecosystems or determining additionality in sequestered carbon. However, the lumbering of the original forests of the Midsouth region of the United States of America, coupled with the accelerating conversion of unmanaged natural-origin...

Ethylene production throughout growth and development of plants

Science.gov (United States)

Wheeler, Raymond M.; Peterson, Barbara V.; Stutte, Gary W.

2004-01-01

Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.

How second-growth northern hardwoods develop after thinning

Science.gov (United States)

Robert W., Jr. Wilson

1953-01-01

In the northern hardwood region, second-growth stands occupy thousands of acres. These stands are of all ages, in all conditions. They were brought about by fire, charcoal and fuelwood cuttings, land abandonment, or a combination of these causes.

PROPOSAL FOR BUILD A TEST STAND TO THE STUDY WATER RAM BASED ON THE RECOMMENDATIONS CONSTRUCTION

Directory of Open Access Journals (Sweden)

Dariusz GRYGO

2016-05-01

Full Text Available The main aim of this article was developed of a test stand to a study physics phenomena accruing at work in a ram water based on the construction recommendations. The experience gained by a number of attempts allowed to the developed construction recommendations that allowed to adjust the test stand to perform various studies of physics phenomena occurring at the work of water ram and easy adaptions to the new requirements. The article includes: the review of the test stands on which performed the study in the history and in the present times, description of the construction recommendations of the universal test stand and the proposal of the test stand developed based on the construction recommendations. Motivation to take up this issue follows from the interest of devices that work in an unconventional way, devices used a renewable energy that can be used in household e.g. to improve their energy balance, delivery water to houses, drinking water for animals, fields irrigation, etc. Analysis of the literature of the water ram, test stands and their performance shown that it is small and typically old development in popular science form. In times of intensive search new sources of renewable energy reactivation of this type equipment may be highly probable.

Oribatid Mite Community Decline Two Years after Low-Intensity Burning in the Southern Cascade Range of California, USA

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Nancy E. Gillette

2012-10-01

Full Text Available To assess effects of low-intensity fire, we combined two silvicultural prescriptions with prescribed fire in the California Cascade Range. In the first treatment, two 100-ha stands were thinned to reduce density while retaining old-growth structural characteristics, yielding residual stands with high structural diversity (HSD. Two other 100-ha plots were thinned to minimize old growth structure, producing even-aged stands of low structural diversity (LSD, and one 50-ha split-plot from each treatment was burned. In addition, two 50 ha old-growth Research Natural Areas (RNA were selected as untreated reference plots, one of which was also burned. Fire treatments profoundly altered mite assemblages in the short term, and forest structure modification likely exacerbated that response. Sampling conducted two years following treatment confirmed a continuing decline in oribatid mite abundance. Oribatid species richness and assemblage heterogeneity also declined, and community dominance patterns were disrupted. Oribatid responses to fire were either more intense or began earlier in the LSD treatments, suggesting that removal of old-growth structure exacerbated mite responses to fire. Prostigmatids recovered quickly, but their populations nonetheless diminished significantly in burned split-plots. Mite assemblage responses to prescribed fire were continuing nearly two years later, with no clear evidence of recovery.

Stand competition determines how different tree species will cope with a warming climate.

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Laura Fernández-de-Uña

Full Text Available Plant-plant interactions influence how forests cope with climate and contribute to modulate species response to future climate scenarios. We analysed the functional relationships between growth, climate and competition for Pinus sylvestris, Quercus pyrenaica and Quercus faginea to investigate how stand competition modifies forest sensitivity to climate and simulated how annual growth rates of these species with different drought tolerance would change throughout the 21st century. Dendroecological data from stands subjected to thinning were modelled using a novel multiplicative nonlinear approach to overcome biases related to the general assumption of a linear relationship between covariates and to better mimic the biological relationships involved. Growth always decreased exponentially with increasing competition, which explained more growth variability than climate in Q. faginea and P. sylvestris. The effect of precipitation was asymptotic in all cases, while the relationship between growth and temperature reached an optimum after which growth declined with warmer temperatures. Our growth projections indicate that the less drought-tolerant P. sylvestris would be more negatively affected by climate change than the studied sub-Mediterranean oaks. Q. faginea and P. sylvestris mean growth would decrease under all the climate change scenarios assessed. However, P. sylvestris growth would decline regardless of the competition level, whereas this decrease would be offset by reduced competition in Q. faginea. Conversely, Q. pyrenaica growth would remain similar to current rates, except for the warmest scenario. Our models shed light on the nature of the species-specific interaction between climate and competition and yield important implications for management. Assuming that individual growth is directly related to tree performance, trees under low competition would better withstand the warmer conditions predicted under climate change scenarios but in

Site classification of ponderosa pine stands under stocking control in California

Science.gov (United States)

Robert F. Powers; William W. Oliver

1978-01-01

Existing systems for estimating site index of ponderosa pine (Pinus ponderosa Laws.) do not apply well to California stands where stocking is controlled. A more suitable system has been developed using trends in natural height growth, derived from stem analysis of dominant trees in California. This site index system produces polymorphic patterns of...

Malaysian growth centiles for children under six years old.

Science.gov (United States)

Bong, Yiibonn; Shariff, Asma Ahmad; Mohamed, Abdul Majid; Merican, Amir Feisal

2015-03-01

Growth references are useful for the screening, assessment and monitoring of individual children as well as for evaluating various growth promoting interventions that could possibly affect a child in early life. To determine the growth centiles of Malaysian children and to establish contemporary cross-sectional growth reference charts for height and weight from birth to 6 years of age based on a representative sample of children from Malaysia. Gender- and age-specific centile curves for height and weight were derived using the Cole's LMS method. Data for this study were retrieved from Malaysian government health clinics using a two-stage stratified random sampling technique. Assessment of nutritional status was done with the SD scores (Z-scores) of WHO 2006 standards. Boys were found to be taller and heavier than girls in this study. The median length of Malaysian children was higher than the WHO 2006 standards and CDC 2000 reference. The overall prevalence of stunting and underweight were 8.3% and 9.3%, respectively. This study presents the first large-scale initiative for local reference charts. The growth reference would enable the growth assessment of a Malaysian child compared to the average growth of children in the country. It is suggested that the use of WHO 2006 Child Growth Standards should be complemented with local reference charts for a more wholesome growth assessment.

Comparison of N and C dynamics in two Norway spruce stands using a process oriented simulation model

DEFF Research Database (Denmark)

Eckersten, H.; Beier, C.

1998-01-01

) was located in south-west Sweden (Skogaby) growing on a loamy sand soil. The old stand (70 years old) was growing on a sandy soil in western Denmark (Klosterhede). Differences in specific rates of processes between the two sites were estimated in terms of parameter values derived by calibration of the model...... uptake of organic N. At both sites the average pools and fluxes over the years were fairly well simulated indicating that N leaching predictions on average might be reliable....

Growth, aboveground biomass, and nutrient concentration of young Scots pine and lodgepole pine in oil shale post-mining landscapes in Estonia.

Science.gov (United States)

Kuznetsova, Tatjana; Tilk, Mari; Pärn, Henn; Lukjanova, Aljona; Mandre, Malle

2011-12-01

The investigation was carried out in 8-year-old Scots pine (Pinus sylvestris L.) and lodgepole pine (Pinus contorta var. latifolia Engelm.) plantations on post-mining area, Northeast Estonia. The aim of the study was to assess the suitability of lodgepole pine for restoration of degraded lands by comparing the growth, biomass, and nutrient concentration of studied species. The height growth of trees was greater in the Scots pine stand, but the tree aboveground biomass was slightly larger in the lodgepole pine stand. The aboveground biomass allocation to the compartments did not differ significantly between species. The vertical distribution of compartments showed that 43.2% of the Scots pine needles were located in the middle layer of the crown, while 58.5% of the lodgepole pine needles were in the lowest layer of the crown. The largest share of the shoots and stem of both species was allocated to the lowest layer of the crown. For both species, the highest NPK concentrations were found in the needles and the lowest in the stems. On the basis of the present study results, it can be concluded that the early growth of Scots pine and lodgepole pine on oil shale post-mining landscapes is similar.

Spider (Arachnida, Araneae) diversity in secondary and old-growth southern Atlantic forests of Paraná state, Brazil.

Science.gov (United States)

Raub, Florian; Höfer, Hubert; Scheuermann, Ludger

2017-07-01

The data presented here have been collected in the southern part of the Atlantic Forest (Mata Atlântica) in the state of Paraná, Brazil within a bilateral scientific project (SOLOBIOMA). The project aimed to assess the quality of secondary forests of different regeneration stages in comparison with old-growth forests with regard to diversity of soil animals and related functions. The Atlantic Forest is a hotspot of biological diversity with an exceptionally high degree of endemic species, extending over a range of 3,500 km along the coast of Brazil. The anthropogenic pressure in the region is very high with three of the biggest cities of Brazil (São Paulo, Rio de Janeiro, and Curitiba) lying in its extension. An evaluation of the value of secondary forests for biodiversity conservation is becoming more and more important due to the complete disappearance of primary forests. In 2005, we sampled spiders in 12 sites of three successional stages (5-8, 10-15, 35-50 yr old, three replicates of each forest stage) and old-growth forests (> 100 yr untouched, also three replicates). All sites were inside a private nature reserve (Rio Cachoeira Nature Reserve). We repeated the sampling design and procedure in 2007 in a second private reserve (Itaqui Nature Reserve). The two nature reserves are within about 25 km of each other within a well preserved region of the Mata Atlântica, where the matrix of the landscape mosaic is still forest. A widely accepted standard protocol was used in a replicated sampling design to apply statistical analyses to the resulting data set and allow for comparison with other studies in Brazil. Spiders were sorted to family level and counted; the adult spiders further identified to species if possible or classified as morphospecies with the help of several spider specialists. © 2017 by the Ecological Society of America.

Growth and Your 2- to 3-Year-Old

Science.gov (United States)

... concerns you have about your child's growth or development with your doctor. Reviewed by: Mary L. Gavin, MD Date reviewed: January 2015 More on this topic for: Parents Your Child's Growth Toddlers: Learning by Playing Preparing Your Child for Visits ...

Relationships between growth, quality, and stocking within managed old-growth northern hardwoods

Science.gov (United States)

Chris Gronewold; Anthony W. D' Amato; Brian J. Palik

2012-01-01

An understanding of long-term growth dynamics is central to the development of sustainable uneven-aged silvicultural systems for northern hardwood forests in eastern North America. Of particular importance are quantitative assessments of the relationships between stocking control and long-term growth and quality development. This study examined these relationships in a...

An experimental test of the causes of forest growth decline with stand age.

Science.gov (United States)

Michael G. Ryan; Dan Binkley; James H. Fownes; Christian Giardina; Randy S. Senock

2004-01-01

The decline in aboveground wood production after canopy closure in even-aged forest stands is a common pattern in forests, but clear evidence for the mechanism causing the decline is lacking. The problem is fundamental to forest biology, commercial forestry (the decline sets the rotation age), and to carbon storage in forests. We tested three hypotheses...

Mechanized systems for early stand tending in central and eastern Canada

Energy Technology Data Exchange (ETDEWEB)

Ryans, M.; St-Amour, M. [Forest Engineering Research Inst. of Canada, Pointe Claire, PQ (Canada)

1996-12-31

Machines are currently being used for early stand tending in central and eastern Canada, but account for only 1 to 2% of the annual total for mechanical treatments (including manual and motor-manual operations). Selective and non-selective systems are used, depending on the application and stand conditions. Plantation cleaning operations and precommercial thinning (spacing) of naturally regenerated and seeded stands have been mechanized. Selective methods, primarily for plantation cleaning, use equipment with specialized prime movers, booms and controls, and cutting heads. This paper describes the Canadian experience to date based on FERIC`s studies of successful and unsuccessful operations, and lists the key features of a machine suitable for use in selective treatments. Strip precommercial thinning is used in denser natural stands, but limited improvements in crop-tree growth occur unless a motor-manual follow-up releases crop trees in the leave strips. Most off-the-shelf brushcutting equipment is not optimal for this application, primarily because it is too wide to meet local spacing prescriptions. Some applications such as the spacing of older natural stands have proven difficult to mechanize. Technical, biological, operational , regulatory, economic and social constraints prevent wider use of mechanized systems. Nonetheless, some machines are in operational use, and mechanized plantation cleaning is tested in some regions as an alternative to herbicides. 11 refs, 2 figs, 1 tab

Growth and non-renewable resources

DEFF Research Database (Denmark)

Groth, Christian; Schou, Poul

2007-01-01

, interest income taxes and investment subsidies can no longer affect the long-run growth rate, whereas resource tax instruments are decisive for growth. The results stand out both against observations in the literature from the 1970's on non-renewable resources and taxation-observations which were not based...

How old are you? Genet age estimates in a clonal animal.

Science.gov (United States)

Devlin-Durante, M K; Miller, M W; Precht, W F; Baums, I B

2016-11-01

Foundation species such as redwoods, seagrasses and corals are often long-lived and clonal. Genets may consist of hundreds of members (ramets) and originated hundreds to thousands of years ago. As climate change and other stressors exert selection pressure on species, the demography of populations changes. Yet, because size does not indicate age in clonal organisms, demographic models are missing data necessary to predict the resilience of many foundation species. Here, we correlate somatic mutations with genet age of corals and provide the first, preliminary estimates of genet age in a colonial animal. We observed somatic mutations at five microsatellite loci in rangewide samples of the endangered coral, Acropora palmata (n = 3352). Colonies harboured 342 unique mutations in 147 genets. Genet age ranged from 30 to 838 years assuming a mutation rate of 1.195 -04 per locus per year based on colony growth rates and 236 to 6500 years assuming a mutation rate of 1.542 -05 per locus per year based on sea level changes to habitat availability. Long-lived A. palmata genets imply a large capacity to tolerate past environmental change, and yet recent mass mortality events in A. palmata suggest that capacity is now being frequently exceeded. © 2016 John Wiley & Sons Ltd.

Pendugaan Dinamika Struktur Tegakan Hutan Alam Bekas Tebangan (Estimation of Stand Structure Dynamics of Logged-over Natural Forests

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Muhdin .

2011-07-01

Full Text Available Dynamics of stand structure (DST, which could indicate the growth performance of logged-over forests, mayvary depending on various factors, e.g. stand density, initial stand structure, species composition, time afterlogging, and environmental factors (rainfall, elevation, etc..  The variations of such factors could result in thevariations of DST’s components (e.g. proportion of trees upgrowth and staying. However, this study, which used75 permanent sample plots data of lowland and dryland natural forests in Kalimantan, showed that the proportionof trees upgrowth and staying could not be predicted satisfactorily using the number of trees, stand basal area,time after logging, and elevation as independent variables in multiple linear regression models. The regressionmodels produced unrealistic projections of stand structures.  In contrast, the projection of stand structures usingthe DST’s components that were calculated using arithmetic mean was better than that of the regression models.Keywords: stand structure projection, upgrowth, natural forest, logged-over area

Chemodiversity in terpene emissions at a boreal Scots pine stand

Science.gov (United States)

Bäck, J.; Aalto, J.; Henriksson, M.; Hakola, H.; He, Q.; Boy, M.

2011-10-01

Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Coniferous forests are known to produce large quantities of volatile vapors, especially terpenes to the surrounding air. These compounds are reactive in the atmosphere, and contribute to the formation and growth of atmospheric new particles. Our aim was to analyze the variability of mono- and sesquiterpene emissions between Scots pine trees, in order to clarify the potential errors caused by using emission data obtained from only a few trees in atmospheric chemistry models. We also aimed at testing if stand history and seed origin has an influence on the chemotypic diversity. The inherited, chemotypic variability in mono- and sesquiterpene emission was studied in a seemingly homogeneous 47-yr-old stand in Southern Finland, where two areas differing in their stand regeneration history could be distinguished. Sampling was conducted in August 2009. Terpene concentrations in the air had been measured at the same site for seven years prior to branch sampling for chemotypes. Two main compounds, α-pinene and Δ3-carene formed together 40-97% of the monoterpene proportions in both the branch emissions and in the air concentrations. The data showed a bimodal distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees emitted mainly α-pinene and no Δ3-carene at all, whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total emitted monoterpene spectrum). An intermediate group of trees emitted equal amounts of both α-pinene and Δ3-carene. The emission pattern of trees at the area established using seeding as the artificial regeneration method differed from the naturally regenerated or planted trees, being mainly high Δ3-carene emitters. Some differences were also seen in e.g. camphene and limonene emissions between chemotypes, but sesquiterpene emissions did not differ

Effects of plantation and juvenile spacing on tree and stand development.

Science.gov (United States)

J. Harry G. Smith; Donald L. Reukema

1986-01-01

The aim of this paper is to summarize current knowledge of effects of initial spacing and respacing of plantations and natural stands on early growth until the time of first commercial entry—for coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), concentrating on conclusions that can be drawn from the literature and the authors...

The ratio of NPP to GPP: evidence of change over the course of stand development

Science.gov (United States)

Annikki Makela; Harry T. Valentine

2001-01-01

Using Scots pine (Pinus sylvestris L.) in Fenno-Scandia as a case study, we investigate whether net primary production (NPP) and maintenance respiration are constant fractions of gross primary production (GPP) as even-aged mono-specific stands progress from initiation to old age. A model of the ratio of NPP to GPP is developed based on (1) the...

Biomass yielding potential of naturally regenerated Prosopis juliflora tree stands at three varied ecosystems in southern districts of Tamil Nadu, India.

Science.gov (United States)

Saraswathi, K; Chandrasekaran, S

2016-05-01

Fuel energy demand is of great concern in recent times due to the depletion of fossil fuel resources. Biomass serves as widely available primary renewable energy source. Hence, a study was performed to assess the above-ground biomass yielding capability of fuel wood tree Prosopis juliflora in three varied ecosystems viz., coastal, fallow land and riparian ecosystems in southern districts of Tamil Nadu. The results showed that the biomass production potential and above-ground net primary productivity of P. juliflora depend on the age of the tree stands and the nature of ecosystem. A higher biomass yield was observed for P. juliflora trees with 5 to 10 years old when compared to less than 5 years of their age. Among the three ecosystems, the maximum biomass production was recorded in riparian ecosystem. The stands with less than 5-year-old P. juliflora trees gave 1.40 t/ha, and 5- to 10-year-old tree stands produced 27.69 t/ha in riparian ecosystem. Above-ground net primary productivity of both the age groups was high in fallow land ecosystem. In riparian ecosystem, the wood showed high density and low sulphur content than the other two ecosystems. Hence, P. juliflora biomass can serve as an environmentally and economically feasible fuel as well as their utilization proffers an effective means to control its invasiveness.

Development of prolonged standing strain index to quantify risk levels of standing jobs.

Science.gov (United States)

Halim, Isa; Omar, Abdul Rahman

2012-01-01

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.

Seasonal photosynthesis and water relations of juvenile loblolly pine relative to stand density and canopy position

Science.gov (United States)

Zhenmin Tang; Jim L. Chambers; Mary A. Sword Sayer; James P. Barnett

2003-01-01

To assess the effects of stand density and canopy environment on tree physiology, we measured gas exchange responses of the same needle age class of 16-year-old loblolly pines (Pinus taeda L.) in thinned (512 trees ha-1) and non-thinned treatment plots (2,863 trees ha-1) in central Louisiana....

Site and stand analysis for growth prediction of Eucalyptus grandis ...

African Journals Online (AJOL)

The integration of site information with that of tree growth is of special importance in Zululand, where sustainable supply of timber is essential for local processing and export commitments. Site prediction growth models need to be based on easily attainable input variables that are suitable for operational implementation by ...

Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

Science.gov (United States)

Miles Hemstrom; Martin G. Raphael

2000-01-01

This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

The one-leg standing radiograph

OpenAIRE

Pinsornsak, P.; Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

2016-01-01

Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis wa...