Forest Stand Segmentation Using Airborne LIDAR Data and Very High Resolution Multispectral Imagery

Science.gov (United States)

Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet, Valérie; Hervieu, Alexandre

2016-06-01

Forest stands are the basic units for forest inventory and mapping. Stands are large forested areas (e.g., ≥ 2 ha) of homogeneous tree species composition. The accurate delineation of forest stands is usually performed by visual analysis of human operators on very high resolution (VHR) optical images. This work is highly time consuming and should be automated for scalability purposes. In this paper, a method based on the fusion of airborne laser scanning data (or lidar) and very high resolution multispectral imagery for automatic forest stand delineation and forest land-cover database update is proposed. The multispectral images give access to the tree species whereas 3D lidar point clouds provide geometric information on the trees. Therefore, multi-modal features are computed, both at pixel and object levels. The objects are individual trees extracted from lidar data. A supervised classification is performed at the object level on the computed features in order to coarsely discriminate the existing tree species in the area of interest. The analysis at tree level is particularly relevant since it significantly improves the tree species classification. A probability map is generated through the tree species classification and inserted with the pixel-based features map in an energetical framework. The proposed energy is then minimized using a standard graph-cut method (namely QPBO with α-expansion) in order to produce a segmentation map with a controlled level of details. Comparison with an existing forest land cover database shows that our method provides satisfactory results both in terms of stand labelling and delineation (matching ranges between 94% and 99%).

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...

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.

[Carbon storage of forest stands in Shandong Province estimated by forestry inventory data].

Science.gov (United States)

Li, Shi-Mei; Yang, Chuan-Qiang; Wang, Hong-Nian; Ge, Li-Qiang

2014-08-01

Based on the 7th forestry inventory data of Shandong Province, this paper estimated the carbon storage and carbon density of forest stands, and analyzed their distribution characteristics according to dominant tree species, age groups and forest category using the volume-derived biomass method and average-biomass method. In 2007, the total carbon storage of the forest stands was 25. 27 Tg, of which the coniferous forests, mixed conifer broad-leaved forests, and broad-leaved forests accounted for 8.6%, 2.0% and 89.4%, respectively. The carbon storage of forest age groups followed the sequence of young forests > middle-aged forests > mature forests > near-mature forests > over-mature forests. The carbon storage of young forests and middle-aged forests accounted for 69.3% of the total carbon storage. Timber forest, non-timber product forest and protection forests accounted for 37.1%, 36.3% and 24.8% of the total carbon storage, respectively. The average carbon density of forest stands in Shandong Province was 10.59 t x hm(-2), which was lower than the national average level. This phenomenon was attributed to the imperfect structure of forest types and age groups, i. e., the notably higher percentage of timber forests and non-timber product forest and the excessively higher percentage of young forests and middle-aged forest than mature forests.

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)....

Minnesota DNR Forest Stand Inventory Version 2

Data.gov (United States)

Minnesota Department of Natural Resources — This layer is a digital inventory of individual forest stands. The data is collected by DNR Foresters in each DNR Forestry Administrative Area, and is updated on a...

Throughfall in different forest stands of Iperó, São Paulo

Directory of Open Access Journals (Sweden)

Esthevan Augusto Goes Gasparoto

2014-06-01

Full Text Available In forestry, throughfall (Pi is that fraction of rainfall that runs directly through the tree canopy and reaches the ground. It is characterized as the main source of water supply in a watershed. This study aimed to analyze the dynamics of throughfall in three types of forest stands, namely Eucalyptus cloeziana, Pinus sp. and seasonal semideciduous forest (FES, all located in Ipanema National Forest, in the municipality of Iperó-SP. In each stand, a 300 m² plot was established in which ten rain gauges were installed for monitoring throughfall, and three rain gauges were installed in an open area adjacent to the stand for measuring gross precipitation (P. At the end of 25 observations, it was observed that, relative to P values, Pi values were 76.2% in semideciduous forest (FES, 85.1% in E.cloeziana forest and 84.0% in Pinus sp forest. In addition, comparing these stands, a larger leaf canopy coverage and consequently greater capability for water retention was noted in the semideciduous forest. However, no statistical differences were observed (P<0.05 between the stands of interest regarding throughfall.

The long-term hydrological effect of forest stands on the stability of slopes

Science.gov (United States)

Bogaard, T. A.; Meng, W.; van Beek, L. P. H.

2012-04-01

Forest is widely known to improve slope stability as a result of mechanical and hydrological effects. While the mechanics underlying the stabilizing process of root reinforcement are well understood and quantified, the influence of forest on the occurrence of critical hydrological conditions in terms of suction or pore pressure remains uncertain. Due to seasonal and inter-annual fluctuations, the stabilizing influence of evaporation and transpiration is difficult to isolate from the overall noise of the hydrological signal. More long-term effects of forest stands on soil development are highly variable and thus difficult to observe and quantify. Often these effects are ambivalent, having potentially a stabilizing or destabilizing influence on a slope under particular conditions (e.g., more structured soils leading to both rapid infiltration and drainage). Consequently, it can be postulated that forests will hydrologically influence the magnitude-frequency distribution of landsliding, not only at the stand level but also on a regional scale through the groundwater system. The overall aim of this research is to understand and quantify the stabilizing hydrological effect of forests on potentially unstable slopes. To this end, we focus on the changes in the magnitude-frequency distribution of landsliding that arise as a result of variations in evapotranspiration losses over the life cycle of stands. Temporal variations in evapotranspiration comprise first of all the interception that can account for an important amount of evaporation from a forest, and that changes with seasonal and annual variations in the interception capacity of the canopy and forest floor. Transpiration also represents an important loss that varies over the various growth stages of a forest stand. Based on a literature review of water consumption by tree species and water balance studies of forested catchments we defined the potential transpiration for different growth stages. This information we

Neural network modelling of rainfall interception in four different forest stands

OpenAIRE

Ibrahim Yurtseven; Mustafa Zengin

2013-01-01

The objective of this study is to reveal whether it is possible to predict rainfall, throughfall and stemflow in forest ecosystems with less effort, using several measurements of rainfall interception (hereafter interception) and an artificial neural network based linear regression model (ANN model). To this end, the Kerpe Research Forest in the province of Kocaeli, which houses stands of mixed deciduous-broadleaf forest (Castanea sativa Mill., Fagus orientalis Lipsky, Quercus spp.), black pi...

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.

Landscape perception based on personal attributes in determining the scenic beauty of in-stand natural secondary forests

Directory of Open Access Journals (Sweden)

Yong Chen

2016-06-01

Full Text Available The aim of this paper was to validate factors affecting the in-stand landscape quality and how important each factor was in determining scenic beauty of natural secondary forests. The study was limited to 23 stand-level cases of natural secondary forests in Shen Zhen city in southern China. Typical samples of photographs and public estimations were applied to evaluate scenic beauty inside the natural secondary forests. The major factors were then selected by multiple linear-regression analysis and a model between scenic beauty estimation (SBE values and in-stand landscape features was established. Rise in crown density, fall in plant litter, glow in color of trunk, fall in arbor richness, and rise in visible distance increased scenic beauty values of in-stand landscape. These five factors significantly explained the differences in scenic beauty, and together accounted for 45% of total variance in SBEs. Personal factors (e.g. gender, age and education did not significantly affect the ratings of landscape photos, although variations of landscape quality were affected by some personal factors. Results of this study will assist policymakers, silviculturists and planners in landscape design and management of natural secondary forests in Shenzhen city. People can improve the scenic beauty values by pruning branches and clearing plant litter, which subsequently improve the forest health and contribute to forest recreation.

Incorporating stand level risk management options into forest decision support systems

Directory of Open Access Journals (Sweden)

Kyle Eyvindson

2018-01-01

Full Text Available Aim of study: To examine methods of incorporating risk and uncertainty to stand level forest decisions. Area of study: A case study examines a small forest holding from Jönköping, Sweden. Material and methods: We incorporate empirically estimated uncertainty into the simulation through a Monte Carlo approach when simulating the forest stands for the next 100 years. For the iterations of the Monte Carlo approach, errors were incorporated into the input data which was simulated according to the Heureka decision support system. Both the Value at Risk and the Conditional Value at Risk of the net present value are evaluated for each simulated stand. Main results: Visual representation of the errors can be used to highlight which decision would be most beneficial dependent on the decision maker’s opinion of the forest inventory results. At a stand level, risk preferences can be rather easily incorporated into the current forest decision support software. Research highlights: Forest management operates under uncertainty and risk. Methods are available to describe this risk in an understandable fashion for the decision maker.

Estimating Stand Volume and Above-Ground Biomass of Urban Forests Using LiDAR

Directory of Open Access Journals (Sweden)

Vincenzo Giannico

2016-04-01

Full Text Available Assessing forest stand conditions in urban and peri-urban areas is essential to support ecosystem service planning and management, as most of the ecosystem services provided are a consequence of forest stand characteristics. However, collecting data for assessing forest stand conditions is time consuming and labor intensive. A plausible approach for addressing this issue is to establish a relationship between in situ measurements of stand characteristics and data from airborne laser scanning (LiDAR. In this study we assessed forest stand volume and above-ground biomass (AGB in a broadleaved urban forest, using a combination of LiDAR-derived metrics, which takes the form of a forest allometric model. We tested various methods for extracting proxies of basal area (BA and mean stand height (H from the LiDAR point-cloud distribution and evaluated the performance of different models in estimating forest stand volume and AGB. The best predictors for both models were the scale parameters of the Weibull distribution of all returns (except the first (proxy of BA and the 95th percentile of the distribution of all first returns (proxy of H. The R2 were 0.81 (p < 0.01 for the stand volume model and 0.77 (p < 0.01 for the AGB model with a RMSE of 23.66 m3·ha−1 (23.3% and 19.59 Mg·ha−1 (23.9%, respectively. We found that a combination of two LiDAR-derived variables (i.e., proxy of BA and proxy of H, which take the form of a forest allometric model, can be used to estimate stand volume and above-ground biomass in broadleaved urban forest areas. Our results can be compared to other studies conducted using LiDAR in broadleaved forests with similar methods.

Facilitating the recovery of natural evergreen forests in South Africa via invader plant stands

Directory of Open Access Journals (Sweden)

Coert J. Geldenhuys

2017-11-01

Full Text Available Contrary to general belief, planted and naturalized stands of introduced species facilitate the recovery of natural evergreen forests and their diversity. Forest rehabilitation actions are often performed at great cost: mature forest species are planted, while species with adaptations to recover effectively and quickly after severe disturbance are ignored; or stands are cleared of invasive alien species before native tree species are planted. By contrast, cost-effective commercial plantation forestry systems generally use fast-growing pioneer tree species introduced from other natural forest regions. Such planted tree stands often facilitate the recovery of shade-tolerant native forest species. This paper provides a brief overview of disturbance-recovery processes at landscape level, and how pioneer stands of both native and introduced tree species develop from monocultures to diverse mature forest communities. It uses one example of a study of how natural forest species from small forest patches of 3 ha in total invaded a 90-ha stand of the invasive Black wattle, Acacia mearnsii, over a distance of 3.1 ha at Swellendam near Cape Town, South Africa. The study recorded 329 forest species clusters across the wattle stand: more large clusters closer to and more smaller clusters further away from natural forest patches. The 28 recorded forest species (of potentially 40 species in the surrounding forest patches included 79% tree and 21% shrub species. Colonizing forest species had mostly larger fleshy fruit and softer small seeds, and were dispersed by mostly birds and primate species. Maturing forest trees within developing clusters in the wattle stand became a source for forest regeneration away from the clusters, showing different expansion patterns. Four sets of fenced-unfenced plots in the wattle stand showed the impact of browsing by livestock, antelope, rodents and insects on the successful establishment of regenerating forest species, and the

Potential change in forest types and stand heights in central Siberia in a warming climate

International Nuclear Information System (INIS)

Tchebakova, N M; Parfenova, E I; Korets, M A; Conard, S G

2016-01-01

Previous regional studies in Siberia have demonstrated climate warming and associated changes in distribution of vegetation and forest types, starting at the end of the 20th century. In this study we used two regional bioclimatic envelope models to simulate potential changes in forest types distribution and developed new regression models to simulate changes in stand height in tablelands and southern mountains of central Siberia under warming 21st century climate. Stand height models were based on forest inventory data (2850 plots). The forest type and stand height maps were superimposed to identify how heights would change in different forest types in future climates. Climate projections from the general circulation model Hadley HadCM3 for emission scenarios B1 and A2 for 2080s were paired with the regional bioclimatic models. Under the harsh A2 scenario, simulated changes included: a 80%–90% decrease in forest-tundra and tundra, a 30% decrease in forest area, a ∼400% increase in forest-steppe, and a 2200% increase in steppe, forest-steppe and steppe would cover 55% of central Siberia. Under sufficiently moist conditions, the southern and middle taiga were simulated to benefit from 21st century climate warming. Habitats suitable for highly-productive forests (≥30–40 m stand height) were simulated to increase at the expense of less productive forests (10–20 m). In response to the more extreme A2 climate the area of these highly-productive forests would increase 10%–25%. Stand height increases of 10 m were simulated over 35%–50% of the current forest area in central Siberia. In the extremely warm A2 climate scenario, the tall trees (25–30 m) would occur over 8%–12% of area in all forest types except forest-tundra by the end of the century. In forest-steppe, trees of 30–40 m may cover some 15% of the area under sufficient moisture. (letter)

Forest stand structure, productivity, and age mediate climatic effects on aspen decline

Science.gov (United States)

Bell, David M.; Bradford, John B.; Lauenroth, William K.

2014-01-01

Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

Relationships between net primary productivity and forest stand age in U.S. forests

Science.gov (United States)

Liming He; Jing M. Chen; Yude Pan; Richard Birdsey; Jens. Kattge

2012-01-01

Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four...

The role of forest stand density in controlling soil erosion: implications to sediment-related disasters in Japan.

Science.gov (United States)

Razafindrabe, Bam H N; He, Bin; Inoue, Shoji; Ezaki, Tsugio; Shaw, Rajib

2010-01-01

The role of forest stand density in controlling soil erosion was investigated in Ehime Prefecture, Japan. The main objective was to compare soil erosion under different forest conditions including forest type, species composition, and stand density as influenced by thinning operations. Relative yield index (Ry) was used as an indicator of stand density to reflect the degree of management operations in the watershed. Eleven treatments were established based on the above forest conditions. Soil loss was collected in each of the 11 treatments after each rainfall event for a period of 1 year. The paper presents summary data on soil loss as affected by forest conditions and rainfall patterns. Findings showed that an appropriate forest management operation, which can be insured by stand density control, is needed to reduce soil loss. The present study plays an important role in clarifying technical processes related to soil erosion, while it helps linking these elements to current Japanese forestry issues and bringing new inputs to reducing sediment-related disasters in Japan.

A method of forest management for the planned introduction of intensive husbandry in virgin forest stands

Science.gov (United States)

B. Dolezal

1978-01-01

The method proposed is derived from long experience of intensive management in forest stands of Central Europe and from our proposal for management in virgin Iranian forests of the Caspian Region. The method establishes the need for systematic planning of stand conversion to insure both sustained yield and the harvesting of sufficient timber to sustain economic...

Changes of forest stands vulnerability to future wind damage resulting from different management methods

DEFF Research Database (Denmark)

Panferov, O.; Sogachev, Andrey; Ahrends, B.

2010-01-01

The structure of forests stands changes continuously as a result of forest growth and both natural and anthropogenic disturbances like windthrow or management activities – planting/cutting of trees. These structure changes can stabilize or destabilize forest stands in terms of their resistance...... to wind damage. The driving force behind the damage is the climate, but the magnitude and sign of resulting effect depend on tree species, management method and soil conditions. The projected increasing frequency of weather extremes in the whole and severe storms in particular might produce wide area...... damage in European forest ecosystems during the 21st century. To assess the possible wind damage and stabilization/destabilization effects of forest management a number of numeric experiments are carried out for the region of Solling, Germany. The coupled small-scale process-based model combining Brook90...

Modelling canopy fuel and forest stand variables and characterizing the influence of thinning in the stand structure using airborne LiDAR

Directory of Open Access Journals (Sweden)

A. Hevia

2016-02-01

Full Text Available Forest fires are a major threat in NW Spain. The importance and frequency of these events in the area suggests the need for fuel management programs to reduce the spread and severity of forest fires. Thinning treatments can contribute for fire risk reduction, because they cut off the horizontal continuity of forest fuels. Besides, it is necessary to conduct a fire risk management based on the knowledge of fuel allocation, since fire behaviour and fire spread study is dependent on the spatial factor. Therefore, mapping fuel for different silvicultural scenarios is essential. Modelling forest variables and forest structure parameters from LiDAR technology is the starting point for developing spatially explicit maps. This is essential in the generation of fuel maps since field measurements of canopy fuel variables is not feasible. In the present study, we evaluated the potential of LiDAR technology to estimate canopy fuel variables and other stand variables, as well as to identify structural differences between silvicultural managed and unmanaged P. pinaster Ait. stands. Independent variables (LiDAR metrics of greater explanatory significance were identified and regression analyses indicated strong relationships between those and field-derived variables (R2 varied between 0.86 and 0.97. Significant differences were found in some LiDAR metrics when compared thinned and unthinned stands. Results showed that LiDAR technology allows to model canopy fuel and stand variables with high precision in this species, and provides useful information for identifying areas with and without silvicultural management.

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

Science.gov (United States)

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.

Simulating boreal forest carbon dynamics after stand-replacing fire disturbance : Insights from a global process-based vegetation model

NARCIS (Netherlands)

Yue, Chao; Ciais, P.; Luyssaert, S.; Cadule, Patricia; Harden, J. L.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S.L.; Poulter, B.; Viovy, N.

2013-01-01

Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and

Stand, species, and individual traits impact transpiration in historically disturbed forests.

Science.gov (United States)

Blakely, B.; Rocha, A. V.; McLachlan, J. S.

2017-12-01

Historic logging disturbances have changed the structure and species composition of most Northern temperate forests. These changes impact the process of transpiration - which in turn impacts canopy surface temperature - but the links among structure, composition, and transpiration remain unclear. For this reason, ecosystem models typically use simplified structure and composition to simulate the impact of disturbances on forest transpiration. However, such simplifications ignore real variability among stands, species, and individual trees that may strongly influence transpiration across spatial and temporal scales. To capture this variability, we monitored transpiration in 48 individual trees of multiple species in both undisturbed (400+ yr) and historically logged (80 - 120 yr) forests. Using modern and historic forest surveys, we upscaled our observations to stand and regional scales to identify the key changes impacting transpiration. We extended these inferences by establishing a relationship between transpiration and measured surface temperature, linking disturbance-induced changes in structure and composition to local and regional climate. Despite greater potential evapotranspiration and basal area, undisturbed forest transpired less than disturbed (logged) forest. Transpiration was a strong predictor of surface temperature, and the canopy surface was warmer in undisturbed forest. Transpiration differences among disturbed and undisturbed forests resulted from (1) lesser transpiration and dampened seasonality in evergreen species (2) greater transpiration in younger individuals within a species, and (3) strong transpiration by large individuals. When transpiration was scaled to the stand or regional level in a simplified manner (e.g. a single transpiration rate for all deciduous individuals), the resulting estimates differed markedly from the original. Stand- species- and individual-level traits are therefore essential for understanding how transpiration and

A forest simulation approach using weighted Voronoi diagrams. An application to Mediterranean fir Abies pinsapo Boiss stands

Energy Technology Data Exchange (ETDEWEB)

Abellanas, B.; Abellanas, M.; Pommerening, A.; Lodares, D.; Cuadros, S.

2016-07-01

Aim of the study. a) To present a new version of the forest simulator Vorest, an individual-based spatially explicit model that uses weighted Voronoi diagrams to simulate the natural dynamics of forest stands with closed canopies. b) To apply the model to the current dynamics of a Grazalema pinsapo stand to identify the nature of its competition regime and the stagnation risks it is currently facing. Area of study: Sierra del Pinar de Grazalema (S Spain) Material and methods: Two large plots representative of Grazalema pinsapo stands were used to fit and validate the model (plus 6 accesory plots to increase the availability of mortality data). Two inventories were carried out in 1998 and 2007 producing tree size and location data. We developed a forest simulator based on three submodels: growth, competition and mortality. The model was fitted, evaluated and validated for Grazalema plots. The simulation outputs were used to infer the expected evolution of structural diversity of forest stands. Main results: Vorest has proved to be a good tool for simulating dynamics of natural closed stands. The application to Grazalema pinsapo stands has allowed assessing the nature of the main processes that are driving its development pathway. We have found that the prevailing size-asymmetric competition dominates the self-thinning process in small-sized trees. At the same time, there is an active tree-size differentiation process. Research highlights: Vorest has proved to be a good tool for simulating natural stands with closed canopies. The Grazalema pinsapo stand under consideration is currently undergoing a natural process of differentiation, avoiding long-term stagnation. (Author)

Forest volume-to-biomass models and estimates of mass for live and standing dead trees of U.S. forests.

Science.gov (United States)

James E. Smith; Linda S. Heath; Jennifer C. Jenkins

2003-01-01

Includes methods and equations for nationally consistent estimates of tree-mass density at the stand level (Mg/ha) as predicted by growing-stock volumes reported by the USDA Forest Service for forests of the conterminous United States. Developed for use in FORCARB, a carbon budget model for U.S. forests, the equations also are useful for converting plot-, stand- and...

Woodland: dynamics of average diameters of coniferous tree stands of the principal forest types

Directory of Open Access Journals (Sweden)

R. A. Ziganshin

2016-08-01

Full Text Available The analysis of age dynamics of average diameters of deciduous tree stands of different forest types at Highland Khamar-Daban (natural woodland in South-East Baikal Lake region has been done. The aggregate data of average tree, the analysis of age dynamics of average diameters of a deciduous tree stands of stand diameters by age classes, as well as tree stand current periodic and overall average increment are presented and discussed in the paper. Forest management appraisal is done. The most representative forest types have been selected to be analyzed. There were nine of them including three Siberian stone pine Pinus sibirica Du Tour stands, three Siberian fir Abies sibirica Ledeb. stands, one Siberian spruce Picea obovata Ledeb. stand, and two dwarf Siberian pine Pinus pumila (Pallas Regel stands. The whole high-altitude range of mountain taiga has been evaluated. Mathematical and statistic indicators have been calculated for every forest type. Stone pine stands are the largest. Dynamics of mean diameters of forest stands have been examined by dominant species for every forest type. Quite a number of interesting facts have been elicited. Generally, all species have maximal values of periodic annual increment that is typical for young stands, but further decrease of increment is going on differently and connects to the different lifetime of wood species. It is curious that annual increment of the dwarf Siberian pine stands almost does not decrease with aging. As for mean annual increment, it is more stable than periodic annual increment. From the fifth age class (age of stand approaching maturity mean annual increment of cedar stands varies from 0.20 to 0.24 cm per year; from 0.12–0.15 to 0.18–0.21 cm per year – in fir stands; from 0.18 to 0.24 cm per year – in spruce stands; and from 0.02–0.03 to 0.05–0.06 cm per year – in draft pine stands. Mean annual increment of dwarf Siberian pine increases with aging and increment of other

A 3D stand generator for central Appalachian hardwood forests

Science.gov (United States)

Jingxin Wang; Yaoxiang Li; Gary W. Miller

2002-01-01

A 3-dimensional (3D) stand generator was developed for central Appalachian hardwood forests. It was designed for a harvesting simulator to examine the interactions of stand, harvest, and machine. The Component Object Model (COM) was used to design and implement the program. Input to the generator includes species composition, stand density, and spatial pattern. Output...

Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

African Journals Online (AJOL)

The importance of data analysis in quantitative assessment of natural resources remains significant in the sustainable management of complex tropical forest resources. Analyses of data from complex tropical forest stands have not been easy or clear due to improper data management. It is pivotal to practical researches ...

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.

Forest bioenergy or forest carbon? Assessing trade-offs in greenhouse gas mitigation with wood-based fuels.

Science.gov (United States)

McKechnie, Jon; Colombo, Steve; Chen, Jiaxin; Mabee, Warren; MacLean, Heather L

2011-01-15

The potential of forest-based bioenergy to reduce greenhouse gas (GHG) emissions when displacing fossil-based energy must be balanced with forest carbon implications related to biomass harvest. We integrate life cycle assessment (LCA) and forest carbon analysis to assess total GHG emissions of forest bioenergy over time. Application of the method to case studies of wood pellet and ethanol production from forest biomass reveals a substantial reduction in forest carbon due to bioenergy production. For all cases, harvest-related forest carbon reductions and associated GHG emissions initially exceed avoided fossil fuel-related emissions, temporarily increasing overall emissions. In the long term, electricity generation from pellets reduces overall emissions relative to coal, although forest carbon losses delay net GHG mitigation by 16-38 years, depending on biomass source (harvest residues/standing trees). Ethanol produced from standing trees increases overall emissions throughout 100 years of continuous production: ethanol from residues achieves reductions after a 74 year delay. Forest carbon more significantly affects bioenergy emissions when biomass is sourced from standing trees compared to residues and when less GHG-intensive fuels are displaced. In all cases, forest carbon dynamics are significant. Although study results are not generalizable to all forests, we suggest the integrated LCA/forest carbon approach be undertaken for bioenergy studies.

Stand and within-stand factors influencing Golden-winged Warbler use of regenerating stands in the central Appalachian Mountains

Directory of Open Access Journals (Sweden)

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

Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species.

Science.gov (United States)

Lima, Robson B DE; Bufalino, Lina; Alves, Francisco T; Silva, José A A DA; Ferreira, Rinaldo L C

2017-01-01

Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

Patterns of covariance between forest stand and canopy structure in the Pacific Northwest.

Science.gov (United States)

Michael A. Lefsky; Andrew T. Hudak; Warren B. Cohen; S.A. Acker

2005-01-01

In the past decade, LIDAR (light detection and ranging) has emerged as a powerful tool for remotely sensing forest canopy and stand structure, including the estimation of aboveground biomass and carbon storage. Numerous papers have documented the use of LIDAR measurements to predict important aspects of forest stand structure, including aboveground biomass. Other...

Regional Instability in the Abundance of Open Stands in the Boreal Forest of Eastern Canada

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Rija Rapanoela

2016-05-01

Full Text Available Fires are a key disturbance of boreal forests. In fact, they are the main source of renewal and evolution for forest stands. The variability of fire through space and time results in a diversified forest mosaic, altering their species composition, structure and productivity. A resilient forest is assumed to be in a state of dynamic equilibrium with the fire regime, so that the composition, age structure and succession stages of forests should be consistent with the fire regime. Dense spruce-moss stands tend, however, to diminish in favour of more open stands similar to spruce-lichen stands when subjected to more frequent and recurring disturbances. This study therefore focused on the effects of spatial and temporal variations in burn rates on the proportion of open stands over a large geographic area (175,000 km2 covered by black spruce (Picea mariana (Mill. Britton, Sterns, Poggenb.. The study area was divided into 10 different zones according to burn rates, as measured using fire-related data collected between 1940 and 2006. To test if the abundance of open stands was unstable over time and not in equilibrium with the current fire regime, forest succession was simulated using a landscape dynamics model that showed that the abundance of open stands should increase progressively over time in zones where the average burn rate is high. The proportion of open stands generated during a specific historical period is correlated with the burn rate observed during the same period. Rising annual burn rates over the past two decades have thereby resulted in an immediate increase in the proportion of open stands. There is therefore a difference between the current proportion of open stands and the one expected if vegetation was in equilibrium with the disturbance regime, reflecting an instability that may significantly impact the way forest resources are managed. It is apparent from this study that forestry planning should consider the risks associated

Effect of different tree mortality patterns on stand development in the forest model SIBYLA

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Trombik Jiří

2016-09-01

Full Text Available Forest mortality critically affects stand structure and the quality of ecosystem services provided by forests. Spruce bark beetle (Ips typographus generates rather complex infestation and mortality patterns, and implementation of such patterns in forest models is challenging. We present here the procedure, which allows to simulate the bark beetle-related tree mortality in the forest dynamics model Sibyla. We explored how sensitive various production and stand structure indicators are to tree mortality patterns, which can be generated by bark beetles. We compared the simulation outputs for three unmanaged forest stands with 40, 70 and 100% proportion of spruce as affected by the disturbance-related mortality that occurred in a random pattern and in a patchy pattern. The used tree species and age class-specific mortality rates were derived from the disturbance-related mortality records from Slovakia. The proposed algorithm was developed in the SQLite using the Python language, and the algorithm allowed us to define the degree of spatial clustering of dead trees ranging from a random distribution to a completely clustered distribution; a number of trees that died in either mode is set to remain equal. We found significant differences between the long-term developments of the three investigated forest stands, but we found very little effect of the tested mortality modes on stand increment, tree species composition and diversity, and tree size diversity. Hence, our hypothesis that the different pattern of dead trees emergence should affect the competitive interactions between trees and regeneration, and thus affect selected productivity and stand structure indicators was not confirmed.

Object-oriented classification of forest structure from light detection and ranging data for stand mapping

Science.gov (United States)

Alicia A. Sullivan; Robert J. McGaughey; Hans-Erik Andersen; Peter. Schiess

2009-01-01

Stand delineation is an important step in the process of establishing a forest inventory and provides the spatial framework for many forest management decisions. Many methods for extracting forest structure characteristics for stand delineation and other purposes have been researched in the past, primarily focusing on high-resolution imagery and satellite data. High-...

Public Preferences Across Europe for Different Forest Stand Types as Sites for Recreation

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David M. Edwards

2012-03-01

Full Text Available A Delphi survey involving experts in forest preference research was carried out to derive scores for the recreational value of 240 forest stand types across Europe. The survey was organized around four regional panels: Great Britain, Nordic Region, Central Europe, and Iberia. In each region, 60 forest stand types were defined according to five forest management alternatives (FMAs on a continuum of management intensity, four phases of development (establishment, young, medium, and adult, and three tree species types (conifer, broadleaved, and mixed stands of conifer and broadleaved. The resulting scores were examined using conjoint analysis to determine the relative importance of the three structural attributes (FMA, phase of development, and tree species type, and each level or component of the attributes. The findings quantify the extent to which forest visitors prefer a degree of management to unmanaged forest nature reserves across the four regions. Phase of development was shown to make the highest contribution to the recreational value of forests while the contribution of tree species type was shown to be relatively unimportant. While the results are indicative, they provide evidence to support long-term retention and low-impact silviculture in forests where recreation is a primary objective of management.

Long-term monitoring of diversity and structure of two stands of an Atlantic Tropical Forest.

Science.gov (United States)

Diniz, Écio Souza; Carvalho, Warley Augusto Caldas; Santos, Rubens Manoel; Gastauer, Markus; Garcia, Paulo Oswaldo; Fontes, Marco Aurélio Leite; Coelho, Polyanne Aparecida; Moreira, Aline Martins; Menino, Gisele Cristina Oliveira; Oliveira-Filho, Ary Teixeira

2017-01-01

This study aimed to report the long-term monitoring of diversity and structure of the tree community in a protected semideciduous Atlantic Forest in the South of Minas Gerais State, Southeast Brazil. The study was conducted in two stands (B and C), each with 26 and 38 10 m x 30 m plots. Censuses of stand B were conducted in 2000, 2005 and 2011, and stand C in 2001, 2006 and 2011. In both stands, the most abundant and important species for biomass accumulation over the inventories were trees larger than 20 cm of diameter, which characterize advanced successional stage within the forest. The two surveyed stands within the studied forest presented differences in structure, diversity and species richness over the time.

Predicting forested catchment evapotranspiration and streamflow from stand sapwood area and Aridity Index

Science.gov (United States)

Lane, Patrick

2016-04-01

Estimating the water balance of ungauged catchments has been the subject of decades of research. An extension of the fundamental problem of estimating the hydrology is then understanding how do changes in catchment attributes affect the water balance component? This is a particular issue in forest hydrology where vegetation exerts such a strong influence on evapotranspiration (ET), and consequent streamflow (Q). Given the primacy of trees in the water balance, and the potential for change to species and density through logging, fire, pests and diseases and drought, methods that directly relate ET/Q to vegetation structure, species, and stand density are very powerful. Plot studies on tree water use routinely use sapwood area (SA) to calculate transpiration and upscale to the stand/catchment scale. Recent work in south eastern Australian forests have found stand-wide SA to be linearly correlated (R2 = 0.89) with long term mean annual loss (P-Q), and hence, long term mean annual catchment streamflow. Robust relationships can be built between basal area (BA), tree density and stand SA. BA and density are common forest inventory measurements. Until now, no research has related the fundamental stand attribute of SA to streamflow. The data sets include catchments that have been thinned and with varying age classes. Thus far these analyses have been for energy limited systems in wetter forest types. SA has proven to be a more robust biometric than leaf area index which varies seasonally. That long term ET/Q is correlated with vegetation conforms to the Budyko framework. Use of a downscaled (20 m) Aridity Index (AI) has shown distinct correlations with stand SA, and therefore T. Structural patterns at a the hillslope scale not only correlate with SA and T, but also with interception (I) and forest floor evaporation (Es). These correlations between AI and I and Es have given R2 > 0.8. The result of these studies suggest an ability to estimate mean annual ET fluxes at sub

Application of Lidar remote sensing to the estimation of forest canopy and stand structure

Science.gov (United States)

Lefsky, Michael Andrew

A new remote sensing instrument, SLICER (Scanning Lidar Imager of Canopies by Echo Recovery), has been applied to the problem of remote sensing the canopy and stand structure of two groups of deciduous forests, Tulip Poplar-Oak stands in the vicinity of Annapolis, MD. and bottomland hardwood stands near Williamston, NC. The ability of the SLICER instrument to remotely sense the vertical distribution of canopy structure (Canopy Height Profile), bulk canopy transmittance, and several indices of canopy height has been successfully validated using twelve stands with coincident field and SLICER estimates of canopy structure. Principal components analysis has been applied to canopy height profiles from both field sites, and three significant factors were identified, each closely related to the amount of foliage in a recognizable layer of the forest, either understory, midstory, or overstory. The distribution of canopy structure to these layers is significantly correlated with the size and number of stems supporting them. The same layered structure was shown to apply to both field and SLICER remotely sensed canopy height profiles, and to apply to SLICER remotely sensed canopy profiles from both the bottomland hardwood stands in the coastal plain of North Carolina, and to mesic Tulip-Poplars stands in the upland coastal plain of Maryland. Linear regressions have demonstrated that canopy and stand structure are correlated to both a statistically significant and useful degree. Stand age and stem density is more highly correlated to stand height, while stand basal area and aboveground biomass are more closely related to a new measure of canopy structure, the quadratic mean canopy height. A geometric model of canopy structure has been shown to explain the differing relationships between canopy structure and stand basal area for stands of Eastern Deciduous Forest and Douglas Fir Forest.

The role of forest stand structure as biodiversity indicator

DEFF Research Database (Denmark)

Gao, Tian; Hedblom, Marcus; Emilsson, Tobias

2014-01-01

be achieved if indicators are derived from existing data. In this study, a model for classifying forest stand structures was developed and tested as an indicator of overall plant species diversity at stand level. The model combines four stand structure parameters: canopy coverage, age of canopy trees, tree...... species composition and canopy stratification. Using data from the National Inventory of Landscapes in Sweden and General Linear Mixed Model, plant species diversity (Shannon diversity index, SHDI) and composition (Sørensen-Dice index, SDI) were tested between 26 different stand structure types and nine...... soil classes. The results showed that mature stands with a stratified canopy had the highest plant species diversity across the soil classes, particularly if they comprised mixed coniferous and broadleaved species with a semi-open canopy. In contrast, young (...

Energy balance and evaporation of a short-rotation willow forest. Variation with season and stand development

Energy Technology Data Exchange (ETDEWEB)

Iritz, Z.

1996-10-01

Energy balance and evaporation of a short-rotation willow (Salix viminalis L.) forest was studied in relation to season and stand development. The developmental stage of the forest stand considerably influenced how the energy, received as net radiation, was partitioned between the connective fluxes and the storage components. The main part of the available energy was utilised for evaporation during most of the season. Only at the beginning of the season did the willow forest supply heat to the atmosphere. Later in the season, energy was taken from air and utilised for evaporation, which resulted in negative sensible heat fluxes. Soil heat storage was also a significant term in the energy balance and also strongly depended on canopy development. Changes in energy partitioning relative to leaf area indices indicated the existence of a threshold value for leaf area index of the developing canopy. The analysis suggested that the canopy of the willow forest could be considered as closed at a leaf area index of 2. It was further found that evaporation from well-irrigated willow forest occurred also during night-time, particularly in windy and dry weather conditions. The sources of nocturnal evaporation were both the canopy, i.e. indicating non-closed stomata, and the soil surface. Partitioning of the total evaporation into components was investigated using a physically-based model with a two-layer aboveground representation and a two-layer soil module. The model estimates evaporation with respect to developmental stage of the willow stand and also takes into account the interaction between the fluxes from the canopy and the soil surface. Good performance of the model indicated that, after further testing in drier conditions, it could be used as a tool for analysing the prerequisites for energy-forest establishment, and practical management of energy forest stands. 37 refs, 9 figs

Stand structure and dead wood characterization in cork forest of Calabria region (southern Italy

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Barreca L

2010-07-01

Full Text Available The cork forests are one the most interesting forest ecosystems in the Mediterranean area. Their distribution and ecological characteristics have undergone a significant transformation after the significant changes following the development and establishment of agricultural crops. Currently, only a few stands, which survive in hard to reach places, prove the wide spread distribution of this species was also in the recent past. This study describes the stand structure of some cork forests in Calabria region (southern Italy. In order, to characterize the vertical structure Latham index has been applied, while for the description of the horizontal distribution NBSI group indices has been used. Detailed surveys on dead wood were also conducted determining the occurring volume and its decay stage according to the decay classes system proposed by Hunter. The aim of this study is to provide guidelines for sustainable management of cork forests, improving and promoting the structural complexity and functional efficiency of these forest stands.

CpDNA haplotype variation reveals strong human influence on oak stands of the Veluwe forest in the Netherlands

NARCIS (Netherlands)

Buiteveld, J.; Koelewijn, H.P.

2006-01-01

We examined chloroplast DNA (cpDNA) variation in 78 oak stands of an important forest complex (the Veluwe) in The Netherlands. Based on historical maps and information oak stands were classified as planted or autochthonous. A genetic study by means of cpDNA haplotype characterisation was carried out

Vegetation diversity of the Scots pine stands in different forest sites in the Turawa Forest District

OpenAIRE

Stefańska-Krzaczek, Ewa; Pech, Paweł

2014-01-01

The utility of phytocenotic indices in the diagnosis and classification of forest sites might be limited because of vegetation degeneration in managed forests. However, even in secondary communities it may be possible to determine indicator species, although these may differ from typical and well known plant indicators. The aim of this work was to assess the vegetation diversity of Scots pine stands in representative forest site types along a moisture and fertility gradient. In total ...

Tree Diversity Enhances Stand Carbon Storage but Not Leaf Area in a Subtropical Forest.

Science.gov (United States)

Castro-Izaguirre, Nadia; Chi, Xiulian; Baruffol, Martin; Tang, Zhiyao; Ma, Keping; Schmid, Bernhard; Niklaus, Pascal A

2016-01-01

Research about biodiversity-productivity relationships has focused on herbaceous ecosystems, with results from tree field studies only recently beginning to emerge. Also, the latter are concentrated largely in the temperate zone. Tree species diversity generally is much higher in subtropical and tropical than in temperate or boreal forests, with reasons not fully understood. Niche overlap and thus complementarity in the use of resources that support productivity may be lower in forests than in herbaceous ecosystems, suggesting weaker productivity responses to diversity change in forests. We studied stand basal area, vertical structure, leaf area, and their relationship with tree species richness in a subtropical forest in south-east China. Permanent forest plots of 30 x 30 m were selected to span largely independent gradients in tree species richness and secondary successional age. Plots with higher tree species richness had a higher stand basal area. Also, stand basal area increases over a 4-year census interval were larger at high than at low diversity. These effects translated into increased carbon stocks in aboveground phytomass (estimated using allometric equations). A higher variability in tree height in more diverse plots suggested that these effects were facilitated by denser canopy packing due to architectural complementarity between species. In contrast, leaf area was not or even negatively affected by tree diversity, indicating a decoupling of carbon accumulation from leaf area. Alternatively, the same community leaf area might have assimilated more C per time interval in more than in less diverse plots because of differences in leaf turnover and productivity or because of differences in the display of leaves in vertical and horizontal space. Overall, our study suggests that in species-rich forests niche-based processes support a positive diversity-productivity relationship and that this translates into increased carbon storage in long-lived woody

A stand-replacing fire history in upper montane forests of the southern Rocky Mountains

Science.gov (United States)

Margolis, E.Q.; Swetnam, T.W.; Allen, Craig D.

2007-01-01

Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842–1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines of evidence were (i) quaking aspen (Populus tremuloides Michx.) inner-ring dates, (ii) fire-killed conifer bark-ring dates, (iii) tree-ring width changes or other morphological indicators of injury, and (iv) fire scars. The annual precision of dating allowed the identification of synchronous stand-replacing fire years among the sites, and co-occurrence with regional surface fire events previously reconstructed from a network of fire scar collections in lower elevation pine forests across the southwestern United States. Nearly all of the synchronous stand-replacing and surface fire years coincided with severe droughts, because climate variability created regional conditions where stand-replacing fires and surface fires burned across ecosystems. Reconstructed stand-replacing fires that predate substantial Anglo-American settlement in this region provide direct evidence that stand-replacing fires were a feature of high-elevation forests before extensive and intensive land-use practices (e.g., logging, railroad, and mining) began in the late 19th century.

Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America.

Directory of Open Access Journals (Sweden)

Jens T Stevens

Full Text Available Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA program reflects the timing of historical high-severity (i.e. stand-replacing fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1 the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2 recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.

Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America.

Science.gov (United States)

Stevens, Jens T; Safford, Hugh D; North, Malcolm P; Fried, Jeremy S; Gray, Andrew N; Brown, Peter M; Dolanc, Christopher R; Dobrowski, Solomon Z; Falk, Donald A; Farris, Calvin A; Franklin, Jerry F; Fulé, Peter Z; Hagmann, R Keala; Knapp, Eric E; Miller, Jay D; Smith, Douglas F; Swetnam, Thomas W; Taylor, Alan H

Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.

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.

Science.gov (United States)

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.

The frequency of forest fires in Scots pine stands of Tuva, Russia

Energy Technology Data Exchange (ETDEWEB)

Ivanova, G A; Kukavskaya, E A [Russian Academy of Sciences, Siberian Branch, V N Sukachev Institute of Forest, Akademgorodok, Krasnoyarsk, 660036 (Russian Federation); Ivanov, V A [Siberian State Technological University, Krasnoyarsk, 660049 (Russian Federation); Soja, A J, E-mail: GAIvanova@ksc.krasn.r [National Institute of Aerospace, Resident at NASA Langley Research Center, MS 420, Hampton, VA 23681-2199 (United States)

2010-01-15

Forest fires resulting from long periods of drought cause extensive forest ecosystem destruction and can impact on the carbon balance and air quality and feed back to the climate system, regionally and globally. Past fire frequency is reconstructed for Tuvan Scots pine stands using dendrochronology and statistics. Central Tuvan Scots pine (Pinus sylvestris) stands are subject to annual fire regimes; however high intensity fires are rare but they are responsible for most of the damage. Low, medium, and high severity fires have shaped the multi-story Scots pine communities, locally and regionally. Fire type and frequency are directly related to weather and climate and are also dependent on anthropogenic influences. The primary dry period, which promotes fire ignition and spread, in Tuva occurs in April and May. In some years, the precipitation deficit combined with high air temperatures induces long periods of drought. Unlike the typical surface fire regime, forest fires that burn during these extreme droughts often become crown fires that result in substantial forest damage and carbon release. The mean fire interval (MFI) is found to be 10.4 years in Balgazyn stands, and the landscape-scale MFI is 22.4 years. High severity, stand-replacing crown fires have a longer MFI. The warmer and dryer weather that is predicted by global climate models is evident in Tuva, and we believe that these changes in weather and climate have resulted in increased fire intensity and severity, rather than fire frequency in the Tuvan region.

The frequency of forest fires in Scots pine stands of Tuva, Russia

International Nuclear Information System (INIS)

Ivanova, G A; Kukavskaya, E A; Ivanov, V A; Soja, A J

2010-01-01

Forest fires resulting from long periods of drought cause extensive forest ecosystem destruction and can impact on the carbon balance and air quality and feed back to the climate system, regionally and globally. Past fire frequency is reconstructed for Tuvan Scots pine stands using dendrochronology and statistics. Central Tuvan Scots pine (Pinus sylvestris) stands are subject to annual fire regimes; however high intensity fires are rare but they are responsible for most of the damage. Low, medium, and high severity fires have shaped the multi-story Scots pine communities, locally and regionally. Fire type and frequency are directly related to weather and climate and are also dependent on anthropogenic influences. The primary dry period, which promotes fire ignition and spread, in Tuva occurs in April and May. In some years, the precipitation deficit combined with high air temperatures induces long periods of drought. Unlike the typical surface fire regime, forest fires that burn during these extreme droughts often become crown fires that result in substantial forest damage and carbon release. The mean fire interval (MFI) is found to be 10.4 years in Balgazyn stands, and the landscape-scale MFI is 22.4 years. High severity, stand-replacing crown fires have a longer MFI. The warmer and dryer weather that is predicted by global climate models is evident in Tuva, and we believe that these changes in weather and climate have resulted in increased fire intensity and severity, rather than fire frequency in the Tuvan region.

Accounting for density reduction and structural loss in standing dead trees: Implications for forest biomass and carbon stock estimates in the United States

Directory of Open Access Journals (Sweden)

Domke Grant M

2011-11-01

Full Text Available Abstract Background Standing dead trees are one component of forest ecosystem dead wood carbon (C pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas Inventory. Initiated in 1998, the USDA Forest Service's Forest Inventory and Analysis program (responsible for compiling the Nation's forest C estimates began consistent nationwide sampling of standing dead trees, which may now supplant previous purely model-based approaches to standing dead biomass and C stock estimation. A substantial hurdle to estimating standing dead tree biomass and C attributes is that traditional estimation procedures are based on merchantability paradigms that may not reflect density reductions or structural loss due to decomposition common in standing dead trees. The goal of this study was to incorporate standing dead tree adjustments into the current estimation procedures and assess how biomass and C stocks change at multiple spatial scales. Results Accounting for decay and structural loss in standing dead trees significantly decreased tree- and plot-level C stock estimates (and subsequent C stocks by decay class and tree component. At a regional scale, incorporating adjustment factors decreased standing dead quaking aspen biomass estimates by almost 50 percent in the Lake States and Douglas-fir estimates by more than 36 percent in the Pacific Northwest. Conclusions Substantial overestimates of standing dead tree biomass and C stocks occur when one does not account for density reductions or structural loss. Forest inventory estimation procedures that are descended from merchantability standards may need to be revised toward a more holistic approach to determining standing dead tree biomass and C attributes (i.e., attributes of tree biomass outside of sawlog

An experimental test of the causes of forest growth decline with stand age.

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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...

The main forest inventory characteristics of the stands damaged by hurricane winds in the southern taiga subzone (Kostroma Oblast

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I. N. Petukhov

2016-08-01

Full Text Available In June and July 2010 in Yaroslavl, Vologda and Kostroma regions, as a result of exposure to hurricane winds, recorded several violations of extensive forest cover in the form of windfalls and windbreaks (Krylov et al., 2012; Petukhov, Nemchinova, 2014. Retrospective analysis on the basis of remote sensing data for the period 1984–2011’s was conducted. It showed, that among the 21st dedicated mass windfall within the Kostroma region and border areas, windfall July 2010 is unique in the magnitude of the total area of disturbed forest cover. According to our estimates, derived from the analysis of remote sensing (RS, its area was more than 60 thousand Ha, which is four times the average annual area of clear felling, in particular, in the Kostroma region (Petukhov, Nemchinova, 2014. In addition to determining the areas of windfall violations of forest cover, based on forest inventory data and remote sensing data analyzed taxation characteristics of forest stands affected by the impact of the seven gale-force winds within the territory of the Kostroma region. The analysis revealed the following trends in hurricane-force winds damaged trees: for parameters such as completeness, forest type and site class is observed relatively uniform stands hurricane wind damage; I.e., we have not found an association between the degree (probability of forest stands damaged data and taxation values data. An exception is the age, height, and in some cases, the predominant species plantations. Plantations dominated by spruce in the stand proved to be somewhat less, but with a predominance of pine – more resistant to hurricane winds, compared to other tree species. Selectivity is also observed for breach of stands older than 40 years and a height of over 16 meters, which is possibly related to the morphological and physiological features of the trees of a given age and height.

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

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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

Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

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Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

2011-06-01

Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

Semantic segmentation of forest stands of pure species combining airborne lidar data and very high resolution multispectral imagery

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Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet-Brunet, Valérie

2017-04-01

Forest stands are the basic units for forest inventory and mapping. Stands are defined as large forested areas (e.g., ⩾ 2 ha) of homogeneous tree species composition and age. Their accurate delineation is usually performed by human operators through visual analysis of very high resolution (VHR) infra-red images. This task is tedious, highly time consuming, and should be automated for scalability and efficient updating purposes. In this paper, a method based on the fusion of airborne lidar data and VHR multispectral images is proposed for the automatic delineation of forest stands containing one dominant species (purity superior to 75%). This is the key preliminary task for forest land-cover database update. The multispectral images give information about the tree species whereas 3D lidar point clouds provide geometric information on the trees and allow their individual extraction. Multi-modal features are computed, both at pixel and object levels: the objects are individual trees extracted from lidar data. A supervised classification is then performed at the object level in order to coarsely discriminate the existing tree species in each area of interest. The classification results are further processed to obtain homogeneous areas with smooth borders by employing an energy minimum framework, where additional constraints are joined to form the energy function. The experimental results show that the proposed method provides very satisfactory results both in terms of stand labeling and delineation (overall accuracy ranges between 84 % and 99 %).

Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure.

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Miquelajauregui, Yosune; Cumming, Steven G; Gauthier, Sylvie

2016-01-01

It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity.

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

Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management

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Doug P. Aubrey; David R. Coyle; Mark D. Coleman

2012-01-01

Background and aims Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus...

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

Temporal changes in radiocesium deposition in various forest stands following the Fukushima Dai-ichi Nuclear Power Plant accident.

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Kato, Hiroaki; Onda, Yuichi; Hisadome, Keigo; Loffredo, Nicolas; Kawamori, Ayumi

2017-01-01

In this study, we investigated the transfer of canopy-intercepted radiocesium to the forest floor following the Fukushima Dai-ichi Nuclear Power Plant accident. The 137 Cs content of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantations of Japanese cedar) and a deciduous mixed broad-leaved forest stand (oak with red pine) from July 2011 to December 2012. The forest floor of cedar stands had received higher levels of additional 137 Cs deposition compared with the mixed broad-leaved stand during the sampling period. The cumulative 137 Cs deposition during the study period was 119 kBq m -2 for the mature cedar stand, 105 kBq m -2 for the young cedar stand, and 41.5 kBq m -2 for the broad-leaved stand. The deposition of 137 Cs to the forest floor occurred mainly in throughfall during the first rainy season, from July to September 2011 (<200 d after the initial fallout); thereafter, the transfer of 137 Cs from the canopy to forest floor occurred mainly through litterfall. A double exponential field-loss model, which was used to simulate the removal of 137 Cs from canopies, was the best fit for the temporal changes in the canopy 137 Cs inventory. Copyright © 2015 Elsevier Ltd. All rights reserved.

Occurrence of termites (Isoptera on living and standing dead trees in a tropical dry forest in Mexico

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Nancy Calderón-Cortés

2018-05-01

Full Text Available Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60–98% of standing dead trees and 23–59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057–0.066 trees/m2 than in riparian forests (0.022 and 0.027 trees/m2, even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01–0.09 trees/m2 than in larger class sizes (0–0.02 trees/m2. Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil.

Occurrence of termites (Isoptera) on living and standing dead trees in a tropical dry forest in Mexico.

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Calderón-Cortés, Nancy; Escalera-Vázquez, Luis H; Oyama, Ken

2018-01-01

Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60-98% of standing dead trees and 23-59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057-0.066 trees/m 2 ) than in riparian forests (0.022 and 0.027 trees/m 2 ), even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01-0.09 trees/m 2 ) than in larger class sizes (0-0.02 trees/m 2 ). Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil.

Mapping of past stand-level forest disturbances and estimation of time since disturbance using simulated spaceborne LiDAR data

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Sanchez Lopez, N.; Hudak, A. T.; Boschetti, L.

2017-12-01

Explicit information on the location, the size or the time since disturbance (TSD) at the forest stand level complements field inventories, improves the monitoring of forest attributes and the estimation of biomass and carbon stocks. Even-aged stands display homogenous structural parameters that have often been used as a proxy of stand age. Consequently, performing object-oriented analysis on Light Detection and Ranging (LiDAR) data has potential to detect historical stand-replacing disturbances. Recent research has shown good results in the delineation of forest stands as well as in the prediction of disturbance occurrence and TSD using airborne LiDAR data. Nevertheless, the use of airborne LiDAR for systematic monitoring of forest stands is limited by the sporadic availability of data and its high cost compared to satellite instruments. NASA's forthcoming Global Ecosystem Dynamics Investigations (GEDI) mission will provide systematically data on the vertical structure of the vegetation, but its use presents some challenges compared to the common discrete-return airborne LiDAR. GEDI will be a waveform instrument, hence the summary metrics will be different to those obtained with airborne LiDAR, and the sampling configuration could limit the utility of the data, especially on heterogeneous landscapes. The potential use of GEDI data for forest characterization at the stand level would therefore depend on the predictive power of the GEDI footprint metrics, and on the density of point samples relative to forest stand size (i.e. the number of observation/footprints per stand).In this study, we assess the performance of simulated GEDI-derived metrics for stand characterization and estimation of TSD, and the point density needed to adequately identify forest stands, which translates - due to the fixed sampling configuration - into the minimum temporal interval needed to collect a sufficient number of points. The study area was located in the Clear Creek, Selway River

Structura unor arborete exploatabile din regiunea de munte [Structure of some exploitable forest stands from the mountainous area

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Prodan M

2005-07-01

Full Text Available The paper presents one of the first scientific works of the prof. dr. dr. h. c. Michail Prodan, published in the Romanian forestry journal “Viaţa forestieră” (“The forestry life”, in 1940, before starting his prodigious career in Germany. The used data - as in some of his next papers - are from the forest inventories performed in the forest districts of the Romanian Orthodox Religion Found from Bucovina (Eastern Carpathians with the occasion of the forest management plans renewal. Some details: (natural, almost primeval forest stands between 100-200 years, pure or mixed from species Norway spruce, Silver fir, Beech, in total 200,000 records. The analyzed stands were grouped based on Feistmantel class fertility and the basic analysis were the distribution of tree diameters, for these tree species and fertility classes. were computed the theoretical distribution for the diameter classes, using the Charlier approach

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

Relating demographic characteristics of a small mammal to remotely sensed forest-stand condition.

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Hania Lada

Full Text Available Many ecological systems around the world are changing rapidly in response to direct (land-use change and indirect (climate change human actions. We need tools to assess dynamically, and over appropriate management scales, condition of ecosystems and their responses to potential mitigation of pressures. Using a validated model, we determined whether stand condition of floodplain forests is related to densities of a small mammal (a carnivorous marsupial, Antechinus flavipes in 60,000 ha of extant river red gum (Eucalyptus camaldulensis forests in south-eastern Australia in 2004, 2005 and 2011. Stand condition was assessed remotely using models built from ground assessments of stand condition and satellite-derived reflectance. Other covariates, such as volumes of fallen timber, distances to floods, rainfall and life stages were included in the model. Trapping of animals was conducted at 272 plots (0.25 ha across the region. Densities of second-year females (i.e. females that had survived to a second breeding year and of second-year females with suckled teats (i.e. inferred to have been successful mothers were higher in stands with the highest condition. There was no evidence of a relationship with stand condition for males or all females. These outcomes show that remotely-sensed estimates of stand condition (here floodplain forests are relatable to some demographic characteristics of a small mammal species, and may provide useful information about the capacity of ecosystems to support animal populations. Over-regulation of large, lowland rivers has led to declines in many facets of floodplain function. If management of water resources continues as it has in recent decades, then our results suggest that there will be further deterioration in stand condition and a decreased capacity for female yellow-footed antechinuses to breed multiple times.

Forest structure and plant diversity in maritime pine (Pinus pinaster Ait.) stands in central Spain

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Osorio, L. F.; Bravo, F.; Zaldivar, P.; Pando, V.

2009-07-01

The relationship between forest structure and plant diversity in Mediterranean Maritime pine stands (Pinus pinaster Ait.) in the Iberian Range (Spain) was studied. Forty eight stands were sampled. In each, a circular plot (15 m radius) and a transect (25*1 m{sup 2}) were established to estimate stand variables and record presence and abundance of vascular species respectively. Canonical correlation analysis (CCA), simple correlations and multiple stepwise linear regressions were used to explore the relationship between plant diversity and forest structure. Correlation between diversity measurements and stand variables is very weak, but significant correlations were found when evaluating each set of variables separately. Presence and cover of some species (for instance, Veronica arvensis L. or Micropyrum tenellum (L.) Link) is correlated with stand variables; however, determination coefficients found in step-by-step regression are not significant. (Author) 34 refs.

Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon.

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Michelle C Agne

Full Text Available Lodgepole pine (Pinus contorta forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes. Dwarf mistletoe (Arceuthobium americanum also influences stand structure and occurs frequently in post-mountain pine beetle epidemic lodgepole pine forests. Few studies have incorporated both disturbances simultaneously although they co-occur frequently on the landscape. The aim of this study is to investigate the stand structure of lodgepole pine forests 21-28 years after a mountain pine beetle epidemic with varying levels of dwarf mistletoe infection in the Deschutes National Forest in central Oregon. We compared stand density, stand basal area, canopy volume, proportion of the stand in dominant/codominant, intermediate, and suppressed cohorts, average height and average diameter of each cohort, across the range of dwarf mistletoe ratings to address differences in stand structure. We found strong evidence of a decrease in canopy volume, suppressed cohort height, and dominant/codominant cohort diameter with increasing stand-level dwarf mistletoe rating. There was strong evidence that as dwarf mistletoe rating increases, proportion of the stand in the dominant/codominant cohort decreases while proportion of the stand in the suppressed cohort increases. Structural differences associated with variable dwarf mistletoe severity create heterogeneity in this forest type and may have a significant influence on stand productivity and the resistance and resilience of these stands to future biotic and abiotic disturbances. Our findings show that it is imperative to incorporate dwarf mistletoe when studying stand productivity and ecosystem recovery processes in lodgepole pine forests because of its

Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon.

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Agne, Michelle C; Shaw, David C; Woolley, Travis J; Queijeiro-Bolaños, Mónica E

2014-01-01

Lodgepole pine (Pinus contorta) forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes. Dwarf mistletoe (Arceuthobium americanum) also influences stand structure and occurs frequently in post-mountain pine beetle epidemic lodgepole pine forests. Few studies have incorporated both disturbances simultaneously although they co-occur frequently on the landscape. The aim of this study is to investigate the stand structure of lodgepole pine forests 21-28 years after a mountain pine beetle epidemic with varying levels of dwarf mistletoe infection in the Deschutes National Forest in central Oregon. We compared stand density, stand basal area, canopy volume, proportion of the stand in dominant/codominant, intermediate, and suppressed cohorts, average height and average diameter of each cohort, across the range of dwarf mistletoe ratings to address differences in stand structure. We found strong evidence of a decrease in canopy volume, suppressed cohort height, and dominant/codominant cohort diameter with increasing stand-level dwarf mistletoe rating. There was strong evidence that as dwarf mistletoe rating increases, proportion of the stand in the dominant/codominant cohort decreases while proportion of the stand in the suppressed cohort increases. Structural differences associated with variable dwarf mistletoe severity create heterogeneity in this forest type and may have a significant influence on stand productivity and the resistance and resilience of these stands to future biotic and abiotic disturbances. Our findings show that it is imperative to incorporate dwarf mistletoe when studying stand productivity and ecosystem recovery processes in lodgepole pine forests because of its potential to

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

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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.

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

Evaluation of three classifiers in mapping forest stand types using ...

African Journals Online (AJOL)

EJIRO

applied for classification of the image. Supervised classification technique using maximum likelihood algorithm is the most commonly and widely used method for land cover classification (Jia and Richards, 2006). In Australia, the maximum likelihood classifier was effectively used to map different forest stand types with high.

Interactions of changing climate and shifts in forest composition on stand carbon balance

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Chiang Jyh-Min; Louis Iverson; Anantha Prasad; Kim Brown

2006-01-01

Given that climate influences forest biogeographic distribution, many researchers have created models predicting shifts in tree species range with future climate change scenarios. The objective of this study is to investigate the forest carbon consequences of shifts in stand species composition with current and future climate scenarios using such a model.

How fast will trees die? A transition matrix model of ash decline in forest stands infested by emerald ash borer

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Kathleen S. Knight; Robert P. Long; Joanne Rebbeck; Annemarie Smith; Kamal Gandhi; Daniel A. Herms

2008-01-01

We recorded Fraxinus spp. tree health and other forest stand characteristics for 68 plots in 21 EAB-infested forest stands in Michigan and Ohio in 2005 and 2007. Fraxinus spp. were a dominant component of these stands, with more than 900 ash trees (including Fraxinus americana, Fraxinus pennsylvanica, Fraxinus profunda...

Stand-level variation in evapotranspiration in non-water-limited eucalypt forests

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Benyon, Richard G.; Nolan, Rachael H.; Hawthorn, Sandra N. D.; Lane, Patrick N. J.

2017-08-01

To better understand water and energy cycles in forests over years to decades, measurements of spatial and long-term temporal variability in evapotranspiration (Ea) are needed. In mountainous terrain, plot-level measurements are important to achieving this. Forest inventory data including tree density and size measurements, often collected repeatedly over decades, sample the variability occurring within the geographic and topographic range of specific forest types. Using simple allometric relationships, tree stocking and size data can be used to estimate variables including sapwood area index (SAI), which may be strongly correlated with annual Ea. This study analysed plot-level variability in SAI and its relationship with overstorey and understorey transpiration, interception and evaporation over a 670 m elevation gradient, in non-water-limited, even-aged stands of Eucalyptus regnans F. Muell. to determine how well spatial variation in annual Ea from forests can be mapped using SAI. Over the 3 year study, mean sap velocity in five E. regnans stands was uncorrelated with overstorey sapwood area index (SAI) or elevation: annual transpiration was predicted well by SAI (R2 0.98). Overstorey and total annual interception were positively correlated with SAI (R2 0.90 and 0.75). Ea from the understorey was strongly correlated with vapour pressure deficit (VPD) and net radiation (Rn) measured just above the understorey, but relationships between understorey Ea and VPD and Rn differed between understorey types and understorey annual Ea was not correlated with SAI. Annual total Ea was also strongly correlated with SAI: the relationship being similar to two previous studies in the same region, despite differences in stand age and species. Thus, spatial variation in annual Ea can be reliably mapped using measurements of SAI.

Grapevine dynamics after manual tending of juvenile stands on the Hoosier National Forest, Indiana

Science.gov (United States)

Robert C. Morrissey; Martin-Michel Gauthier; John A., Jr. Kershaw; Douglass F. Jacobs; Burnell C. Fischer; John R. Siefert

2008-01-01

Large woody vines, most notably grapevines, are a source of great concern for forest and wildlife managers in many parts of the Central Hardwood Forest Region of the United States. We examined grapevine dynamics in stands aged 21 - 35 years. The plots, located in regenerated clearcuts in the Hoosier National Forest (HNF), were evaluated for vine control, site, and tree...

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

The nature of the beast: examining climate adaptation options in forests with stand-replacing fire regimes

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Joshua S. Halofsky; Daniel C. Donato; Jerry F. Franklin; Jessica E. Halofsky; David L. Peterson; Brian J. Harvey

2018-01-01

Building resilience to natural disturbances is a key to managing forests for adaptation to climate change. To date, most climate adaptation guidance has focused on recommendations for frequent-fire forests, leaving few published guidelines for forests that naturally experience infrequent, stand-replacing wildfires. Because most such forests are inherently resilient to...

Tree Regeneration Spatial Patterns in Ponderosa Pine Forests Following Stand-Replacing Fire: Influence of Topography and Neighbors

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Justin P. Ziegler

2017-10-01

Full Text Available Shifting fire regimes alter forest structure assembly in ponderosa pine forests and may produce structural heterogeneity following stand-replacing fire due, in part, to fine-scale variability in growing environments. We mapped tree regeneration in eighteen plots 11 to 15 years after stand-replacing fire in Colorado and South Dakota, USA. We used point pattern analyses to examine the spatial pattern of tree locations and heights as well as the influence of tree interactions and topography on tree patterns. In these sparse, early-seral forests, we found that all species were spatially aggregated, partly attributable to the influence of (1 aspect and slope on conifers; (2 topographic position on quaking aspen; and (3 interspecific attraction between ponderosa pine and other species. Specifically, tree interactions were related to finer-scale patterns whereas topographic effects influenced coarse-scale patterns. Spatial structures of heights revealed conspecific size hierarchies with taller trees in denser neighborhoods. Topography and heterospecific tree interactions had nominal effect on tree height spatial structure. Our results demonstrate how stand-replacing fires create heterogeneous forest structures and suggest that scale-dependent, and often facilitatory, rather than competitive, processes act on regenerating trees. These early-seral processes will establish potential pathways of stand development, affecting future forest dynamics and management options.

Automatic Mapping of Forest Stands Based on Three-Dimensional Point Clouds Derived from Terrestrial Laser-Scanning

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Tim Ritter

2017-07-01

Full Text Available Mapping of exact tree positions can be regarded as a crucial task of field work associated with forest monitoring, especially on intensive research plots. We propose a two-stage density clustering approach for the automatic mapping of tree positions, and an algorithm for automatic tree diameter estimates based on terrestrial laser-scanning (TLS point cloud data sampled under limited sighting conditions. We show that our novel approach is able to detect tree positions in a mixed and vertically structured stand with an overall accuracy of 91.6%, and with omission- and commission error of only 5.7% and 2.7% respectively. Moreover, we were able to reproduce the stand’s diameter in breast height (DBH distribution, and to estimate single trees DBH with a mean average deviation of ±2.90 cm compared with tape measurements as reference.

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

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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.

Methods for registration laser scanner point clouds in forest stands

International Nuclear Information System (INIS)

Bienert, A.; Pech, K.; Maas, H.-G.

2011-01-01

Laser scanning is a fast and efficient 3-D measurement technique to capture surface points describing the geometry of a complex object in an accurate and reliable way. Besides airborne laser scanning, terrestrial laser scanning finds growing interest for forestry applications. These two different recording platforms show large differences in resolution, recording area and scan viewing direction. Using both datasets for a combined point cloud analysis may yield advantages because of their largely complementary information. In this paper, methods will be presented to automatically register airborne and terrestrial laser scanner point clouds of a forest stand. In a first step, tree detection is performed in both datasets in an automatic manner. In a second step, corresponding tree positions are determined using RANSAC. Finally, the geometric transformation is performed, divided in a coarse and fine registration. After a coarse registration, the fine registration is done in an iterative manner (ICP) using the point clouds itself. The methods are tested and validated with a dataset of a forest stand. The presented registration results provide accuracies which fulfill the forestry requirements [de

Carbon content of forest floor and mineral soil in Mediterranean Pinus spp. and Oak stands in acid soils in Northern Spain

Energy Technology Data Exchange (ETDEWEB)

Herrero, C.; Turrión, M.B.; Pando, V.; Bravo, F.

2016-07-01

Aim of the study: The aim of the study was to determine the baseline carbon stock in forest floor and mineral soils in pine and oak stands in acid soils in Northern Spain. Area of study: The study area is situated in northern Spain (42° N, 4° W) on “Paramos y Valles” region of Palencia. aterial and methods: An extensive monitoring composed of 48 plots (31 in pine and 17 in oak stands) was carried out. Litter layers and mineral soil samples, at depths of 0-30 cm and 30-60 cm, were taken in each plot. An intensive monitoring was also performed by sampling 12 of these 48 plots selected taken in account species forest composition and their stand development stage. Microbial biomass C (CMB), C mineralization (CRB), and soil organic C balance at stand level were determined in surface soil samples of intensive monitoring. Main results: No differences in soil C content were detected in the two forest ecosystems up to 60 cm depth (53.0±25.8 Mg C ha-1 in Pinus spp. plantations and 60.3±43.8 Mg C ha-1 in oak stands). However, differences in total C (CT), CMB and CRB were found in the upper 10 cm of the soils depending on the stand development stage in each species forest composition (Pinus nigra, Pinus pinaster, Pinus sylvestris and Quercus pyrenaica). Plots with high development stage exhibited significant lower metabolic quotient (qCO2), so, meant more efficient utilization of C by the microbial community. The C content in the forest floor was higher in pine stands (13.7±0.9 Mg C ha-1) than in oak stands (5.4±0.7 Mg C ha-1). A greater turnover time was found in pine ecosystems vs. oak stands. In contrast, forest floor H layer was nonexistent in oak stands. Research highlights: Results about litterfall, forest floor and mineral soil dynamics in this paper can be used strategically to reach environmental goals in new afforestation programs and sustainable forest management approaches. (Author)

Effects of Initial Stand Density and Climate on Red Pine Productivity within Huron National Forest, Michigan, USA

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Joseph O'Brien

2012-12-01

Full Text Available Changes in climate are predicted to significantly affect the productivity of trees in the Great Lakes region over the next century. Forest management decisions, such as initial stand density, can promote climatic resiliency and moderate decreased productivity through the reduction of tree competition. The influences of climate (temperature and precipitation and forest management (initial stand density on the productivity of red pine (Pinus resinosa across multiple sites within Huron National Forest, Michigan, were examined using dendrochronological methods. Two common planting regimes were compared in this analysis; low initial density (1977 trees per hectare. Low initial density stands were found to have a higher climatic resilience by combining equal or greater measures of productivity, while having a reduced sensitivity to monthly and seasonal climate, particularly to summer drought.

Effect of forest structural change on carbon storage in a coastal Metasequoia glyptostroboides stand.

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Cheng, Xiangrong; Yu, Mukui; Wu, Tonggui

2013-01-01

Forest structural change affects the forest's growth and the carbon storage. Two treatments, thinning (30% thinning intensity) and underplanting plus thinning, are being implemented in a coastal Metasequoia glyptostroboides forest shelterbelt in Eastern China. The vegetation carbon storage significantly increased in the underplanted and thinned treatments compared with that in the unthinned treatment (P 0.05). The soil light fraction organic carbon (LFOC) was significantly higher at the 0-15 cm soil layer in the thinned and underplanted stands compared with that in the unthinned stand (P < 0.05). The soil respiration of the underplanted treatment was significantly higher than that of the unthinned treatment only in July (P < 0.05). This study concludes that 30% thinning and underplanting after thinning could be more favorable to carbon sequestration for M. glyptostroboides plantations in the coastal areas of Eastern China.

Effects of climate, CO2 concentration, nitrogen deposition, and stand age changes on the carbon budget of China's forests

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Zhang, C.; Ju, W.; Zhang, F.; Mao, D.; Wang, X.

2017-12-01

Forests play an irreplaceable role in the Earth's terrestrial carbon budget which retard the atmospheric CO2 buildup. Understanding the factors controlling forest carbon budget is critical for reducing uncertainties in projections of future climate. The relative importance of climate, atmospheric CO2 concentration, nitrogen deposition, and stand age changes on carbon budget, however, remains unclear for China's forests. In this study, we quantify individual contribution of these drivers to the trends of forest carbon budget in China from 1901 to 2012 by integrating national datasets, the updated Integrated Terrestrial Ecosystem Carbon Cycle (InTEC) model and factorial simulations. Results showed that the average carbon sink in China's forests from 1982 to 2012 was 186.9 Tg C yr-1 with 68% (127.6 Tg C yr-1) of the sink in living biomass because of the integrated effects of climate, atmospheric CO2 concentration, nitrogen deposition, and stand age factors. Compared with the simulation of all factors combined, the estimated carbon sink during 1901-2012 would be reduced by 41.8 Tg C yr-1 if climate change, atmospheric CO2 concentration and nitrogen deposition factors were omitted, and reduced by 25.0 Tg C yr-1 if stand age factor was omitted. In most decades, these factors increased forest carbon sinks with the largest of 101.3, 62.9, and 44.0 Tg C yr-1 from 2000 to 2012 contributed by stand age, CO2 concentration and nitrogen deposition, respectively. During 1901-2012, climate change, CO2 concentration, nitrogen deposition and stand age contributed -13.3, 21.4, 15.4 and 25.0 Tg C yr-1 to the averaged carbon sink of China's forests, respectively. Our study also showed diverse regional patterns of forest carbon budget related to the importance of driving factors. Stand age effect was the largest in most regions, but the effects of CO2 concentration and nitrogen deposition were dominant in southern China.

Coupled effects of wind-storms and drought on tree mortality across 115 forest stands from the Western Alps and the Jura mountains.

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Csilléry, Katalin; Kunstler, Georges; Courbaud, Benoît; Allard, Denis; Lassègues, Pierre; Haslinger, Klaus; Gardiner, Barry

2017-12-01

Damage due to wind-storms and droughts is increasing in many temperate forests, yet little is known about the long-term roles of these key climatic factors in forest dynamics and in the carbon budget. The objective of this study was to estimate individual and coupled effects of droughts and wind-storms on adult tree mortality across a 31-year period in 115 managed, mixed coniferous forest stands from the Western Alps and the Jura mountains. For each stand, yearly mortality was inferred from management records, yearly drought from interpolated fields of monthly temperature, precipitation and soil water holding capacity, and wind-storms from interpolated fields of daily maximum wind speed. We performed a thorough model selection based on a leave-one-out cross-validation of the time series. We compared different critical wind speeds (CWSs) for damage, wind-storm, and stand variables and statistical models. We found that a model including stand characteristics, drought, and storm strength using a CWS of 25 ms -1 performed the best across most stands. Using this best model, we found that drought increased damage risk only in the most southerly forests, and its effect is generally maintained for up to 2 years. Storm strength increased damage risk in all forests in a relatively uniform way. In some stands, we found positive interaction between drought and storm strength most likely because drought weakens trees, and they became more prone to stem breakage under wind-loading. In other stands, we found negative interaction between drought and storm strength, where excessive rain likely leads to soil water saturation making trees more susceptible to overturning in a wind-storm. Our results stress that temporal data are essential to make valid inferences about ecological impacts of disturbance events, and that making inferences about disturbance agents separately can be of limited validity. Under projected future climatic conditions, the direction and strength of these

Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

Science.gov (United States)

Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

2015-01-01

Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (R A) and heterotrophic (R H) in total soil (R T) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of R H and R A to R T for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to R T, accounted for over 63% of R H. 3) AT and ST were significantly positively correlated with R T and its components (psoil respiration. 4) Components of soil respiration were significantly different between two forest stands (psoil respiration and its components. PMID:25680112

Near-natural forests in southern Sweden. Palaeoecological and silvicultural aspects on nature-based silviculture

Energy Technology Data Exchange (ETDEWEB)

Bjoerse, Gisela [Swedish Univ. of Agricultural Sciences, Alnarp (Sweden). Southern Swedish Forest Research Centre

2000-07-01

Timber production and protection of biodiversity are two main issues in south Swedish forestry. This thesis explores the possibilities of combining the two issues in a nature-based silviculture. Different branches of science, palaeoecology, silviculture and forest vegetation ecology, were combined to give a multidisciplinary approach to the subject. Mimicking the historical forest composition and processes in the silvicultural measures for the benefit of both biodiversity protection and timber production was identified as one possible way of developing a nature-based silviculture. The long period of human influence on the landscape in southern Sweden has effectively removed all the remnants of natural forest that could have been used as references in the mimicking procedure. Consequently, historical references were searched. A method to describe former forest conditions was developed using palaeoecological data and methods. It was found that the historical deciduous dominance was pronounced. Over 2000 years southern Sweden has been transformed from a deciduous to a coniferous landscape. Human activities were shown to be a major driving force in this change. Several detected historical forest types were possible as references for the mimicking approach, but forest types common in the past and rare today were suggested for maximal efficiency in obtaining high biodiversity. Mixed nemoral deciduous forests were pointed out as a historically widespread forest type with very little resemblance in the present landscape. The small fragments left are important for present biodiversity and from many other aspects. Development of a nature-based silvicultural system for the management of mixed nemoral forest stands based on the theory of mimicking was begun. A silvicultural experiment was established in a near-natural, mixed nemoral forest stand in southern Sweden and the early effects of the silvicultural treatments tested were evaluated with regard to floristic diversity

Contributions to the phytocoenologic study in pure european beech stand forests in Codru-Moma Mountains (North-Western Romania

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Călin-Gheorghe PĂŞCUŢ

2010-05-01

Full Text Available In the present work we present a phytocoenologic study on the associations found in pure European beech stand forests in Codru-Moma Mountains namely: Festuco drymejae-Fagetum Morariu et al. 1968, Luzulo albidae-Fagetum sylvaticae Zólyomi 1955.Characterization of the associations we studied and presentation of the tables have been made considering the selection of the most representative relevées of pure European beech forests belonging to Codru-Moma Mountains.The phytocoenoses of pure forest stands of European beech forests belonging to the two associations were analyzed in terms of floristic composition, life forms spectrum, spectrum chart of the floral elements and ecological indices.

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,...

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...

[Soil quality assessment of forest stand in different plantation esosystems].

Science.gov (United States)

Huang, Yu; Wang, Silong; Feng, Zongwei; Gao, Hong; Wang, Qingkui; Hu, Yalin; Yan, Shaokui

2004-12-01

After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982, three plantation ecosystems, pure Michelia macclurei stand (PMS), pure Chinese-fir stand (PCS) and their mixed stand, were established in spring 1983, and their effects on soil characteristics were evaluated by measuring some soil physical, chemical, microbiological and biochemical parameters. After 20 years' plantation, all test indices showed differences among different forest management models. Both PMS and MCM had a favorable effect on soil fertility maintenance. Soil quality assessment showed that some soil functions, e.g., water availability, nutrient availability, root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands, whereas in a relatively lower level under successive PCS stand. The results also showed that there existed close correlations between soil total organic C (TOC), cation exchange capacity (CEC), microbial biomass-C (Cmic) and other soil physical, chemical and biological indices. Therefore, TOC, CEC and Cmic could be used as the indicators in assessing soil quality in this study area. In addition, there were also positive correlations between soil microbial biomass-C and TOC, soil microbial biomass-N and total N, and soil microbial biomass-P and total P in the present study.

Aggregating pixel-level basal area predictions derived from LiDAR data to industrial forest stands in North-Central Idaho

Science.gov (United States)

Andrew T. Hudak; Jeffrey S. Evans; Nicholas L. Crookston; Michael J. Falkowski; Brant K. Steigers; Rob Taylor; Halli Hemingway

2008-01-01

Stand exams are the principal means by which timber companies monitor and manage their forested lands. Airborne LiDAR surveys sample forest stands at much finer spatial resolution and broader spatial extent than is practical on the ground. In this paper, we developed models that leverage spatially intensive and extensive LiDAR data and a stratified random sample of...

Surface albedo in relation to disturbance and early stand dynamics in the boreal forest: Implications for climate models

Science.gov (United States)

Halim, M. A.; Thomas, S. C.

2017-12-01

Surface albedo is the most important biophysical radiative forcing in the boreal forest. General Circulation Model studies have suggested that harvesting of boreal forest has a net cooling effect, in contrast to other terrestrial biomes, by increasing surface albedo. However, albedo estimation in these models has been achieved by simplifying processes governing albedo at a coarse scale (both spatial and temporal). Biophysical processes that determine albedo likely operate on small spatial and temporal scales, requiring more direct estimates of effects of landcover change on net radiation. We established a chronosequence study in post-fire and post-clearcut sites (2013, 2006, 1998), logging data from July 2013 to July 2017 in boreal forest sites in northwestern Ontario, Canada. Each age-class X disturbance had 3 three replicates, matched to 18 permanent circular plots (10-m radius) each with an instrumented tower measuring surface albedo, air and soil temperature, and soil moisture. We also measured leaf area index, species composition and soil organic matter content at each site. BRDF-corrected surface albedo was calculated from daily 30m x 30m reflectance data fused from the MODIS MOD09GA product and Landsat 7 reflectance data. Calculated albedo was verified using ground-based measurements. Results show that fire sites generally had lower (15-25%) albedo than clearcut sites in all seasons. Because of rapid forest regrowth, large perturbations of clearcut harvests on forest albedo started to fade out within a year. Albedo differences between fire and clearcut sites also declined sharply with stand age. Younger stands generally had higher albedo than older stands mainly due to the presence of broadleaf species (for example, Populus tremuloides). In spring, snow melted 10-12 days earlier in recent (2013) clearcut sites compared to closed-canopy sites, causing a sharp reduction in surface albedo in comparison to old clearcut/fire sites (2006 and 1998). Snow melted

Estimating canopy bulk density and canopy base height for conifer stands in the interior Western United States using the Forest Vegetation Simulator Fire and Fuels Extension.

Science.gov (United States)

Seth Ex; Frederick Smith; Tara Keyser; Stephanie Rebain

2017-01-01

The Forest Vegetation Simulator Fire and Fuels Extension (FFE-FVS) is often used to estimate canopy bulk density (CBD) and canopy base height (CBH), which are key indicators of crown fire hazard for conifer stands in the Western United States. Estimated CBD from FFE-FVS is calculated as the maximum 4 m running mean bulk density of predefined 0.3 m thick canopy layers (...

Beetle-killed stands in the South Carolina piedmont: from fuel hazards to regenerating oak forests

Science.gov (United States)

Aaron D. Stottlemyer; G. Geoff Wang; Thomas A. Waldrop

2012-01-01

Impacts of spring prescribed fire, mechanical mastication, and no-treatment (control) on fuels and natural hardwood tree regeneration were examined in beetle-killed stands in the South Carolina Piedmont. Mechanical mastication ground the down and standing dead trees and live vegetation into mulch and deposited it onto the forest floor. The masticated debris layer had...

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

Directory of Open Access Journals (Sweden)

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.

Aerodynamic resistance of spruce forest stand in relation to roughness length and airflow

Czech Academy of Sciences Publication Activity Database

Hurtalová, T.; Matějka, F.; Rožnovský, J.; Janouš, Dalibor

2003-01-01

Roč. 33, č. 3 (2003), s. 147-160 ISSN 1335-2806 R&D Projects: GA ČR(CZ) GA526/03/1104 Keywords : aerodynamic resistance * spruce forest stand * roughness length Subject RIV: DG - Athmosphere Sciences, Meteorology

Chemical composition of the humus layer, mineral soil and soil solution of 150 forest stands in the Netherlands in 1990

NARCIS (Netherlands)

Vries, de W.; Leeters, E.E.J.M.

2001-01-01

A nationwide assessment of the chemical composition of the humus layer, mineral topsoil (0-30 cm) and soil solution in both topsoil and subsoil (60-100 cm) was made for 150 forest stands in the year 1990. The stands, which were part of the national forest inventory on vitality, included seven tree

Traditional silvopastoral management and its effects on forest stand structure in northern Zagros, Iran

DEFF Research Database (Denmark)

Valipour, Ahmad; Plieninger, Tobias; Shakeri, Zahed

2014-01-01

and to investigate the effects of these practices on forest stand structure. To understand how the traditional forest management system works, empirical survey methods, in particular face to face interviews and participation in traditional practices have been employed. In general, local livelihoods depend on three......Oak forests of Iran are managed for soil conservation, water quality and other non-market ecosystem services. Nationalization policies in 1963 implied shifts from private ownership and informal traditional management to public ownership and state forest management. In spite of the nationalization......, informal practices and conventional ownership have been continued which has caused considerable conflicts between local people and the state forest administration. The aim of the study was to systematically gather the components of traditional silvopastoral management in these oak forests...

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

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

Science.gov (United States)

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

Environmental Impacts to Residual Stand Damage due to Logging Operations in Hyrcanian Forest

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Meghdad JOURGHOLAMI

2012-08-01

Full Text Available The development of harvesting systems aims to provide physically feasible, economically viable, and environmentally sound solutions. Residual stand-damage data have been collected from a mixed broadleaved stand in Kheyrud area in Hyrcanian forest in the northern of Iran. After the harvesting operations, for all trees, damage to the bole, roots, extent of the damage, wounding patterns, size and distribution was assessed using stratified systematic sampling with a random start and fixed area plots. Results show that wounding occurred on 16.4% of the remaining trees, but the severity of wounding varied significantly by species. Forty-six percent of wounding for all species combined was considered as small size. The greatest average amount of damage, to a bole, occurred along the first 1m up from the ground and also within 3m of the skid trail centerline (86.4%. Gouges were present on 79% of all scars. The stratification of the study unit would effectively improve accuracy of stand damage surveys. Selection of the appropriate method for damage reduction to trees adjacent skid trails was crucial. According to the results, skidding damage cannot be completely avoided in practice. We suggest that the education and the entertainment of the foresters and workers in forest would be enhanced and the injuries could be explained before the harvesting to the workers. In such a way the damages would be less in the future.

Abundance of juvenile eastern box turtles in manages forest stands

Science.gov (United States)

Z. Felix; Y. Wang; H. Czech; C. Schweitzer

2008-01-01

Between 2002 and 2005, we used drift fences and artificial pools to sample juvenile eastern box turtles (Terrapene carolina) in northeastern Alabama in forest stands experimentally treated to retain various amounts of overstory trees—clear-cuts and those with 25%–50% and 75%–100% of trees retained.We captured juvenile turtles only in clear-cut and 25%–50% retention...

Chemical composition of the humus layer, mineral soil and soil solution of 200 forest stands in the Netherlands in 1995

NARCIS (Netherlands)

Leeters, E.E.J.M.; Vries, de W.

2001-01-01

A nationwide assessment of the chemical composition of the soil solid phase and the soil solution in the humus layer and two mineral layers (0-10 cm and 10-30 cm) was made for 200 forest stands in the year 1995. The stands were part of the national forest inventory on vitality, included seven tree

Stand density index as a tool to assess the maximization of forest carbon and biomass

Science.gov (United States)

Christopher W. Woodall; Anthony W. D’Amato; John B. Bradford; Andrew O. Finley

2012-01-01

Given the ability of forests to mitigate greenhouse gas emissions and provide feedstocks to energy utilities, there is an emerging need to assess forest biomass/carbon accretion opportunities over large areas. Techniques for objectively quantifying stand stocking of biomass/carbon are lacking for large areas given the complexity of tree species composition in the U.S....

Stand Structure, Productivity and Carbon Sequestration Potential of Oak Dominated Forests in Kumaun Himalaya

OpenAIRE

Bijendra Lal; L.S. Lodhiyal

2016-01-01

Present study deals with stand structure, biomass, productivity and carbon sequestration in oak dominated forests mixed with other broad leaved tree species. The sites of studied forests were located in Nainital region between 29058’ N lat. and 79028’ E long at 1500-2150 m elevation. Tree density of forests ranged from 980-1100 ind.ha-1. Of this, oak trees shared 69-97%. The basal area of trees was 31.81 to 63.93 m2 ha-1. R. arboreum and Q. floribunda shared maximum basal area 16.45 and 16.32...

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

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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.

Stand-replacing wildfires increase nitrification for decades in southwestern ponderosa pine forests.

Science.gov (United States)

Kurth, Valerie J; Hart, Stephen C; Ross, Christopher S; Kaye, Jason P; Fulé, Peter Z

2014-05-01

Stand-replacing wildfires are a novel disturbance within ponderosa pine (Pinus ponderosa) forests of the southwestern United States, and they can convert forests to grasslands or shrublands for decades. While most research shows that soil inorganic N pools and fluxes return to pre-fire levels within a few years, we wondered if vegetation conversion (ponderosa pine to bunchgrass) following stand-replacing fires might be accompanied by a long-term shift in N cycling processes. Using a 34-year stand-replacing wildfire chronosequence with paired, adjacent unburned patches, we examined the long-term dynamics of net and gross nitrogen (N) transformations. We hypothesized that N availability in burned patches would become more similar to those in unburned patches over time after fire as these areas become re-vegetated. Burned patches had higher net and gross nitrification rates than unburned patches (P < 0.01 for both), and nitrification accounted for a greater proportion of N mineralization in burned patches for both net (P < 0.01) and gross (P < 0.04) N transformation measurements. However, trends with time-after-fire were not observed for any other variables. Our findings contrast with previous work, which suggested that high nitrification rates are a short-term response to disturbance. Furthermore, high nitrification rates at our site were not simply correlated with the presence of herbaceous vegetation. Instead, we suggest that stand-replacing wildfire triggers a shift in N cycling that is maintained for at least three decades by various factors, including a shift from a woody to an herbaceous ecosystem and the presence of fire-deposited charcoal.

An economic valuation of the recreational benefits associated with nature-based forest management practices

DEFF Research Database (Denmark)

Nielsen, Anders Busse; Olsen, Søren Bøye; Lundhede, Thomas Hedemark

2007-01-01

The presented study aimed at identifying and assessing public preferences for variations in tree species composition, tree height structure, and presence of dead trees left for natural decay – forest characteristics which are likely to be affected when subjecting stands to nature-based forest...... of the mentioned three forest characteristics. The highest WTP (1939 DKK, approx. 262 EUR) was found for a scenario of replacing the baseline case stand of even-aged conifers with no dead trees left for natural decay with a mixture of conifers and broadleaves of varying heights, and leaving a few dead trees...

Comparison of riparian and upland forest stand structure and fuel loads in beetle infested watersheds, southern Rocky Mountains

Science.gov (United States)

Kathleen A. Dwire; Robert Hubbard; Roberto Bazan

2015-01-01

Extensive outbreaks of mountain pine beetle (MPB), spruce beetle (SB), and other insects are altering forest stand structure throughout western North America, and thereby contributing to the heterogeneity of fuel distribution. In forested watersheds, conifer-dominated riparian forests frequently occur as narrow linear features in the landscape mosaic and contribute to...

Floristic Study of Buxus hyrcana Stands in the Western Forests of Haraz District, Amol

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S. Hosseinzadeh

2017-06-01

Full Text Available Floristic composition of boxwood (Buxus hyrcana Pojark stands in the forests of Western Haraz, distributed at the altitudinal range of 250 to 1,200 m asl, was investigated by field-walk method. Results showed that the flora of this area includes 50 families, 69 genera, and 78 plant species. Rosaceae, Orchidaceae, Dryopteridaceae, Lamiaceae and Aspleniaceae are the greatest families in this area. Chorological studies showed that the largest proportion of the flora is related to Euro-Siberian region (56.4%. Cryptophytes (32 species, Phanerophytes (26 sp. and Hemicryptophytes (16 sp., which are compromising 44%, 33.3% and 20.5% of the flora, were the most important structure groups of the biological spectrum. Abundance of Cryptophytes with Phanerophytes and Hemicryptophytes in these forests implys that there is a temperate climate with cold winter, frequently rainfall and relatively cool summer, which are suitable for growing temperate forest. Frequent occurrence of Prunus Laurocerasus trees with Daneae racemosa as a woody understory species especially in the upper parts of the studied area accompany by absence of Therophytes and relatively well distribution of ferns species, especially Asplenium scolopendrium, also implys high, favorable, moisture conditions without any disturbances in Box tree stands of these forests.

Valuation of Forest Amenities: A Macro Approach

Science.gov (United States)

Ronald Raunikar; Joseph Buongiorno

2001-01-01

A method of estimating forest amenity value based on macroeconomic growth theory is presented. It relies on the assumption that more valuable forest amenities are provided by a forest with a more natural stand structure. We construct a forest naturalness index from stand data that provides a relative measure of the forest amenity provided regionally. This naturalness...

Specifics of stands formation at coalmine dumps in forest-steppe zone

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R. T. Murzakmаtov

2018-02-01

Full Text Available Rock dumps of coalmines have high potential for forest regeneration and environmental capacity, which are dependent on the technology of reclamation and the properties of technogenic soils and grounds. Traditional forestry methods for obtaining the main criteria of biological indicators of woody vegetation were used in the study as follows: ground seed germination, seedling planting technology, composition and increment of tree stands, root structure, care harvesting of undergrowth, biotopic classification. Natural overgrowing of dumps is dependent on the availability of seeds and conditions for their germination and subsequent growth. Most of the zonal tree and shrub species are able to colonize and grow on the coalmine dumps. Mineralization of the dumps surfaces without rich soil stratum, porosity of the upper horizon of lithostratum, and low nutrient content (nitrogen give benefits in the growth and subsequent formation of birch, pine and sea-buckthorn stands. Afforestation is the cheapest and most effective method of biological reclamation. The analysis of artificial reforestation shows the probability of targeted plantation cultivation of various tree species. The use of a wide range of tree and shrub species make it possible to create biologically diverse intrazonal technogenic ecosystems with high recreational and economic productivity. Wildfires spreading out in spring season on herbaceous rags limit the overgrowth of the dumps by forest vegetation. Two-year cyclical increment decline of trees due to provocative spring warming takes place. The zoogenic factor, especially zoo chores distribution of berry plants, has essential value for forest forming process. By the results of forest formation analysis at rock dumps, alveolate-hilly technology of mine reclamation was developed, which allows to significantly improve dumps’ afforestation capacity, their biological posttechnogenic diversity and productivity.

Cisovka - the relic population of Abies alba and its relationship to man-made silver-fir stands in Białowieża primeval forest

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Leon Mejnartowicz

2014-01-01

Full Text Available In Białowieża Primeval Forest, in 1823 Stanisław Górski discovered on the Cisovka Hag, a relic population of European silver-fir (Abies alba Mill.. This population is isolated and most away, 120 km to the North-East, from the border of European-silver-fir distribution. Besides the natural population Cisovka, there are also man-made silver fir stands and clumps in the Polish and Belorussian part of Białowieża Primeval Forest. In the Polish part there are four such artificial stands. If the seed-producing silver-fir stands really originated from the Cisovka population, then they are a very valuable part of the declining population and an easy accessible seed source. However, if these populations were introduced to the Białowieża Primeval Forest, then they are a potential source of dangerous genetic pollution of the Cisovka population. The relationship of the genetic structure of the Cisovka population to man-made silver-fir-stands in Białowieża Forest was investigated with the help of 17 loci of 1 1 enzyme systems. Genetic diversity of Cisovka population is characterized by the smallest mean number of alleles per locus (Mal= 1.353, includes all loci studied and per polimorphic locus Malp = 2.00. In Cisovka population there is very low-grade of polimorphic loci (Pp = 11.765 with the mean 37.255 for all studied populations. Expected heterozygosity, He = 0.079 revealed very low-grade of genetic diversity in the population. The observed heterozygosity (Ho = 0.123 was similar to this characterictic in other populations. A dendrogram based on Neis genetic distance coefficient (D among 9 silver-fir populations was constructed. Cisovka in the UPGMA dendrogram is a distinct population separated from other ones by a very great genetic distance (D = 0.06. Also two man-made silver-fir (B I and 132 stands are separated from others. Only populations B3 and B4 are combined into one subgroup linked to the population Tomaszów Lubelski. Basing on the

Quantification of ozone uptake at the stand level in a Pinus canariensis forest in Tenerife, Canary Islands: An approach based on sap flow measurements

International Nuclear Information System (INIS)

Wieser, Gerhard; Luis, Vanessa C.; Cuevas, Emilio

2006-01-01

Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance significantly decreased with soil water availability and vapour pressure deficit. Mean daily ozone uptake averaged 1.9 nmol m -2 s -1 during the wet and cold season, and 1.5 nmol m -2 s -1 during the warm and dry period. The corresponding daily mean ambient ozone concentrations were 42 and 51 nl l -1 , respectively. Thus we conclude that in Mediterranean type forest ecosystems the flux based approach is more capable for risk assessment than an external, concentration based approach. - Sap flow measurements can be used for estimating ozone uptake at the stand level and for parameterisation of O 3 uptake models

Timber, Browse, and Herbage on Selected Loblolly-Shortleaf Pine-Hardwood Forest Stands

Science.gov (United States)

Gale L. Wolters; Alton Martin; Warren P. Clary

1977-01-01

A thorough vegetation inventory was made on loblolly-shortleaf pine-hardwood stands scheduled by forest industry for clearcutting, site preparation, and planting to pine in north central Louisiana and southern Arkansas. Overstory timber, on the average, contained about equal proportions of softwood and hardwood basal area. Browse plants ranged from 5,500 to over 70,...

Breeding avifauna of mature forest stands in the Borki Forest and its dynamics at the turn of the 21st century

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Rąkowski Grzegorz

2016-09-01

Full Text Available The composition and structure of the breeding bird community in the Borki Forest in north-eastern Poland were investigated during two separate periods: 1994–1996 and 2012–2014. Bird censuses were carried out in three plots located in mature oak-hornbeam, ash-alder and mixed coniferous forest stands. A standard combined mapping technique for estimating the number of breeding birds was applied. A total of 74 bird species bred at least once within any plot during 1994–1996 or 2012–2014. The structure of the bird assemblages on particular plots displayed a high degree of similarity, exceeding 75%, which means that they represent essentially the same bird community. However, the investigated assemblages have changed substantially over the 20 years. Both, the number of breeding bird species and the population densities on all plots, were much higher in 2012–2014 than in 1994–1996. The mean number of breeding species on all plots was over 50% higher in 2012–2014 than in 1994–1996, whereas the mean total density of breeding pairs increased by more than 60%. Total population densities on the plots increased as a result of an increase in population densities of individual bird species combined with an increase in the number of breeding species. Due to different rates of population growth for certain species, also the composition of dominating species group have changed. The observed changes in the avifauna of the Borki Forest were most probably due to an enrichment of the forest habitats structure, which was caused by natural factors, such as ageing of forest stands, forest succession and a change in water regime by beaver dams, as well as by forest management, including group felling within or in the vicinity of plots and uncovering of the forest edge.

Tree microhabitat structures as indicators of biodiversity in Douglas-fir forests of different stand ages and management histories in the Pacific Northwest, U.S.A.

Science.gov (United States)

Alexa K. Michel; Susanne. Winter

2009-01-01

In this study, microhabitat structures in Douglas-fir (Pseudotsuga menziesii) forests were defined and their frequency and abundance in natural stands and stands of varying active management histories and stand ages was compared. Indicator microhabitat structures for natural forests were determined and the relationship of the abundance of...

Combining sap flow and eddy covariance approaches to derive stomatal and non-stomatal O3 fluxes in a forest stand

International Nuclear Information System (INIS)

Nunn, A.J.; Cieslik, S.; Metzger, U.; Wieser, G.; Matyssek, R.

2010-01-01

Stomatal O 3 fluxes to a mixed beech/spruce stand (Fagus sylvatica/Picea abies) in Central Europe were determined using two different approaches. The sap flow technique yielded the tree-level transpiration, whereas the eddy covariance method provided the stand-level evapotranspiration. Both data were then converted into stomatal ozone fluxes, exemplifying this novel concept for July 2007. Sap flow-based stomatal O 3 flux was 33% of the total O 3 flux, whereas derivation from evapotranspiration rates in combination with the Penman-Monteith algorithm amounted to 47%. In addition to this proportional difference, the sap flow-based assessment yielded lower levels of stomatal O 3 flux and reflected stomatal regulation rather than O 3 exposure, paralleling the daily courses of canopy conductance for water vapor and eddy covariance-based total stand-level O 3 flux. The demonstrated combination of sap flow and eddy covariance approaches supports the development of O 3 risk assessment in forests from O 3 exposure towards flux-based concepts. - Combined tree sap flow and eddy covariance-based methodologies yield stomatal O 3 flux as 33% in total stand flux.

Soil microbial biomass under pine forests in the north-western Spain: influence of stand age, site index and parent material

Energy Technology Data Exchange (ETDEWEB)

Mahia, J.; Perez-Ventura, L.; Cabaneiro, A.; Diaz-Ravina, M.

2006-07-01

The effects of stand age, site index and parent material on soil biochemical properties related to biomass (extractable C, microbial C and metabolic quotient) were examined in the 0-15 cm mineral soil layers of Pinus pinaster and Pinus sylvestris stand from NW Spain. Two productivity levels (low and high site index), two ages (young and old) and two parent soil materials (granite and acid schists) were considered. The data indicated that there were differences in microbial parameters in soils under different species. In general in P. pinaster forest higher values of biochemical parameters expressed on organic C basis, were observed in the stands of high site index as compared with the low ones; in contrast, in P. sylvestris no differences among stand site index were detected. In both species different results were also observed depending on parent material and a significant effect of stand age was detected for extractable C and microbial C in P. pinaster forest developed over granite. The data seem to indicate that measured parameters may have the potential to be used as indicators of the effect of forest management on soil organic matter quality. (Author) 25 refs.

Nitrogen, phosphorus, and cation use efficiency in stands of regenerating tropical dry forest.

Science.gov (United States)

Waring, Bonnie G; Becknell, Justin M; Powers, Jennifer S

2015-07-01

Plants on infertile soils exhibit physiological and morphological traits that support conservative internal nutrient cycling. However, potential trade-offs among use efficiencies for N, P, and cations are not well explored in species-rich habitats where multiple elements may limit plant production. We examined uptake efficiency and use efficiency of N, P, K, Ca, Mg, Al, and Na in plots of regenerating tropical dry forests spanning a gradient of soil fertility. Our aim was to determine whether plant responses to multiple elements are correlated, or whether there are trade-offs among exploitation strategies across stands varying in community composition, soil quality, and successional stage. For all elements, both uptake efficiency and use efficiency decreased as availability of the corresponding element increased. Plant responses to N, Na, and Al were uncoupled from uptake and use efficiencies for P and essential base cations, which were tightly correlated. N and P use efficiencies were associated with shifts in plant species composition along the soil fertility gradient, and there was also a trend towards increasing N use efficiency with stand age. N uptake efficiency was positively correlated with the abundance of tree species that associate with ectomycorrhizal fungi. Taken together, our results suggest that successional processes and local species composition interact to regulate plant responses to availability of multiple resources. Successional tropical dry forests appear to employ different strategies to maximize response to N vs. P and K.

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...

Effect of Forest Structural Change on Carbon Storage in a Coastal Metasequoia glyptostroboides Stand

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Xiangrong Cheng

2013-01-01

Full Text Available Forest structural change affects the forest’s growth and the carbon storage. Two treatments, thinning (30% thinning intensity and underplanting plus thinning, are being implemented in a coastal Metasequoia glyptostroboides forest shelterbelt in Eastern China. The vegetation carbon storage significantly increased in the underplanted and thinned treatments compared with that in the unthinned treatment (P0.05. The soil light fraction organic carbon (LFOC was significantly higher at the 0–15 cm soil layer in the thinned and underplanted stands compared with that in the unthinned stand (P<0.05. The soil respiration of the underplanted treatment was significantly higher than that of the unthinned treatment only in July (P<0.05. This study concludes that 30% thinning and underplanting after thinning could be more favorable to carbon sequestration for M. glyptostroboides plantations in the coastal areas of Eastern China.

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.

Detecting Multi-layered Forest Stands Using High Density Airborne LiDAR Data. GI_Forum|GI_Forum 2015 – Geospatial Minds for Society|

OpenAIRE

Schultz, Alfred; Mund, Jan-Peter; Körner, Michael; Wilke, Robert

2016-01-01

Since two decades, the use of terrestrial laser scanning (TLS) and Airborne Light Detection and Ranging (LIDAR) has become very prominent in analysing 3D forest structures (AKAY et al. 2009). The potential of full waveform analysis of high density Airborne LiDAR data (ALS) for the detection and structural analysis of multi-layered forest stands is not yet well investigated (JASKIERNIAK et al. 2011), although ALS data provide exact information on tree heights of multi-layered forest stands usi...

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...

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

Impact of professional foresters on timber harvests on West Virginia nonindustrial private forests

Science.gov (United States)

Stuart A. Moss; Eric. Heitzman

2013-01-01

Timber harvests conducted on 90 nonindustrial private forest properties in West Virginia were investigated to determine the effects that professional foresters have on harvest and residual stand attributes. Harvests were classified based on the type of forester involved: (1) consulting/state service foresters representing landowners, (2) industry foresters representing...

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, ...

Quantification of ozone uptake at the stand level in a Pinus canariensis forest in Tenerife, Canary Islands: An approach based on sap flow measurements

Energy Technology Data Exchange (ETDEWEB)

Wieser, Gerhard [Division of Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Rennweg 1, A-6020 Innsbruck (Austria)]. E-mail: gerhard.wieser@uibk.ac.at; Luis, Vanessa C. [Department of Plant Biology, Plant Physiology, University of La Laguna, Avda. Astrofisico Francisco Sanchez s/n, E-38207 La Laguna, Tenerife (Spain); Cuevas, Emilio [Izana Atmospheric Observatory, National Institute of Meteorology, La Marina, E-38071 Santa Cruz de Tenerife (Spain)

2006-04-15

Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance significantly decreased with soil water availability and vapour pressure deficit. Mean daily ozone uptake averaged 1.9 nmol m{sup -2} s{sup -1} during the wet and cold season, and 1.5 nmol m{sup -2} s{sup -1} during the warm and dry period. The corresponding daily mean ambient ozone concentrations were 42 and 51 nl l{sup -1}, respectively. Thus we conclude that in Mediterranean type forest ecosystems the flux based approach is more capable for risk assessment than an external, concentration based approach. - Sap flow measurements can be used for estimating ozone uptake at the stand level and for parameterisation of O{sub 3} uptake models.

The Sylview graphical interface to the SYLVAN STAND STRUCTURE model with examples from southern bottomland hardwood forests

Science.gov (United States)

David R. Larsen; Ian Scott

2010-01-01

In the field of forestry, the output of forest growth models provide a wealth of detailed information that can often be difficult to analyze and perceive due to presentation either as plain text summary tables or static stand visualizations. This paper describes the design and implementation of a cross-platform computer application for dynamic and interactive forest...

Optimization Forest Thinning Measures for Carbon Budget in a Mixed Pine-Oak Stand of the Qingling Mountains, China: A Case Study

Directory of Open Access Journals (Sweden)

Lin Hou

2016-11-01

Full Text Available Forest thinning is a silviculture treatment for sustainable forest management. It may promote growth of the remaining individuals by decreasing stand density, reducing competition, and increasing light and nutrient availability to increase carbon sequestration in the forest ecosystem. However, the action also increases carbon loss simultaneously by reducing carbon and other nutrient inputs as well as exacerbating soil CO2 efflux. To achieve a maximum forest carbon budget, the central composite design with two independent variables (thinning intensity and thinning residual removal rate was explored in a natural pine-oak mixed stand in the Qinling Mountains, China. The net primary productivity of living trees was estimated and soil CO2 efflux was stimulated by the Yasso07 model. Based on two years observation, the preliminary results indicated the following. Evidently chemical compounds of the litter of the tree species affected soil CO2 efflux stimulation. The thinning residual removal rate had a larger effect than thinning intensity on the net ecosystem productivity. When the selective thinning intensity and residual removal rate was 12.59% and 66.62% concurrently, the net ecosystem productivity reached its maximum 53.93 t·ha−1·year−1. The lower thinning intensity and higher thinning residual removal rated benefited the net ecosystem productivity.

Ground beetle (Coleoptera, Carabidae) assemblages inhabiting Scots pine stands of Puszcza Piska Forest: six-year responses to a tornado impact.

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Skłodowski, Jarosław; Garbalińska, Paulina

2011-01-01

Ground beetle assemblages were studied during 2003-08 in the Pisz Forest by comparing stands disturbed by a tornado to undisturbed control stands. The following exploratory questions were put forward. (1) How do the carabid assemblages change during six years following the tornado impact? (2) Does the carabid assemblage recovery begin during the six first post-tornado years? To assess the state of carabid assemblages we used two indices: the MIB (Mean Individual Biomass) and the SPC (Sum of Progressive Characteristics). Carabid assemblages in the disturbed and in the control stands, as expressed by these two indices, were compared using the length of a regression distance (sample distance in a MIB:SPC coordinate system). A cluster analysis revealed that the assemblages of the disturbed and the control stands were different. The tornado-impacted stands produced lower carabid catch rates, but species richness was significantly higher there than in the control stands. They hosted lower proportions of individuals of European species, of large zoophages, and of forest and brachypterous species, than the control stands. The observed reduction in SPC and MIB, and an increase in the regression distances may indicate that the carabid assemblages had not started to recover from the tornado-caused disturbance. Carabid assemblages apparently responded to the tornado in two steps. Firstly, the first three years were characterized by moderate decreases of index values. Secondly, from the fourth to the sixth year after the tornado, many observed changes became magnified. We did not observe clear signals of the recovery of forest carabid assemblages during the six follow-up years.

Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

Science.gov (United States)

Polo, John A.; Hallgren, S.W.; Leslie,, David M.

2013-01-01

Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20 years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7 Mg ha-1) and carbon stocks (11.7 Mg ha-1) were distributed among standing dead (22%), coarse woody debris (CWD, dia. > 7.5 cm., 12%), fine woody debris (FWD, dia. prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory prescribed burning. Second, fire suppression during the first one-half of the

Compensating effect of sap velocity for stand density leads to uniform hillslope-scale forest transpiration across a steep valley cross-section

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Renner, Maik; Hassler, Sibylle; Blume, Theresa; Weiler, Markus; Hildebrandt, Anke; Guderle, Marcus; Schymanski, Stan; Kleidon, Axel

2016-04-01

Roberts (1983) found that forest transpiration is relatively uniform across different climatic conditions and suggested that forest transpiration is a conservative process compensating for environmental heterogeneity. Here we test this hypothesis at a steep valley cross-section composed of European Beech in the Attert basin in Luxemburg. We use sapflow, soil moisture, biometric and meteorological data from 6 sites along a transect to estimate site scale transpiration rates. Despite opposing hillslope orientation, different slope angles and forest stand structures, we estimated relatively similar transpiration responses to atmospheric demand and seasonal transpiration totals. This similarity is related to a negative correlation between sap velocity and site-average sapwood area. At the south facing sites with an old, even-aged stand structure and closed canopy layer, we observe significantly lower sap velocities but similar stand-average transpiration rates compared to the north-facing sites with open canopy structure, tall dominant trees and dense understorey. This suggests that plant hydraulic co-ordination allows for flexible responses to environmental conditions leading to similar transpiration rates close to the water and energy limits despite the apparent heterogeneity in exposition, stand density and soil moisture. References Roberts, J. (1983). Forest transpiration: A conservative hydrological process? Journal of Hydrology 66, 133-141.

Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

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McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

2010-01-01

Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

Directory of Open Access Journals (Sweden)

Eloise G Zimbelman

Full Text Available Real-time positioning on mobile devices using global navigation satellite system (GNSS technology paired with radio frequency (RF transmission (GNSS-RF may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1 the odds of missed GNSS-RF signals, (2 the root mean squared error (RMSE of Atlas PTs, and (3 the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

Science.gov (United States)

Zimbelman, Eloise G; Keefe, Robert F

2018-01-01

Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

Studies of wood fuel systems with raw material from young forest stands. Final report; Systemstudier ungskogsbraensle. Slutrapport

Energy Technology Data Exchange (ETDEWEB)

Liss, J.E. [Dalarna Univ., Falun (Sweden)

2001-12-01

The three-year project 'Studies of wood fuel systems with raw material from young forest stands' has been carried out during the period March 1998 to February 2001. New technology for harvesting small trees has created a possibility to develop efficient wood fuel systems using raw material from young forest stands. This possibility coincides with a great demand for tending of young stands from a silvicultural point of view. The main aim of the project has been to analyse and assess wood fuel systems based on this concept. The spectrum of criteria for assessment has been broad, including productivity, profitability, safety and health aspects, employment and environmental impact. As an example of a new technology which has been developed and studied during the project period can be mentioned a new felling head which can be used for cutting and handling several trees at the same time. The weight of the felling head is only about 270 kg, which has done it possible to use it on smaller base-machines as well as larger machines. The productivity has shown to be about 150-250 trees/hour in stands with a diameter of 5-10 cm. The productivity, expressed as biomass, is about 2-3 tonnes dry substance/hour. In the design of production system, bundling of trees early in the process is considered to be especially promising. The development of such a system is ongoing, but is not at the market yet. Some experimental studies have been done on transportation, storing and chipping of such bundles with varying size and varying tree-species. The calculated cost of this system will be lower then for traditional chipping-systems, because of the higher density for the handle units. It is much easier to handle bundles than small non-bundled trees, the chipping-productivity will be high and the transportation can be done with regular timber trucks. The calculation cost for the bundle-system will be about 120-130 SEK/MWh in stands with a diameter of some 7-10 cm, which can be

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

Sustainability assessment in forest management based on individual preferences.

Science.gov (United States)

Martín-Fernández, Susana; Martinez-Falero, Eugenio

2018-01-15

This paper presents a methodology to elicit the preferences of any individual in the assessment of sustainable forest management at the stand level. The elicitation procedure was based on the comparison of the sustainability of pairs of forest locations. A sustainability map of the whole territory was obtained according to the individual's preferences. Three forest sustainability indicators were pre-calculated for each point in a study area in a Scots pine forest in the National Park of Sierra de Guadarrama in the Madrid Region in Spain to obtain the best management plan with the sustainability map. We followed a participatory process involving fifty people to assess the sustainability of the forest management and the methodology. The results highlighted the demand for conservative forest management, the usefulness of the methodology for managers, and the importance and necessity of incorporating stakeholders into forestry decision-making processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Landsat-based Analysis of Mountain Forest-tundra Ecotone Response to Climate Trends in Sayan Mountains

Science.gov (United States)

Kharuk, Viatcheslav I.; Im, Sergey T.; Ranson, K. Jon

2007-01-01

observations of temperatures Siberia has shown a several degree warming over the past 30 years. It is expected that forest will respond to warming at high latitudes through increased tree growth and northward or upward slope migration. migration. Tree response to climate trends is most likely observable in the forest-tundra ecotone, where temperature mainly limits tree growth. Making repeated satellite observations over several decades provides an opportunity to track vegetation response to climate change. Based on Landsat data of the Sayan Mountains, Siberia, there was an increase in forest stand crown closure and an upward tree-line shift in the of the forest-tundra ecotone during the last quarter of the 2oth century,. On-ground observations, supporting these results, also showed regeneration of Siberian pine in the alpine tundra, and the transformation of prostrate Siberian pine and fir into arboreal (upright) forms. During this time period sparse stands transformed into closed stands, with existing closed stands increasing in area at a rate of approx. 1 %/yr, and advancing their upper border at a vertical rate of approx. 1.0 m/yr. In addition, the vertical rate of regeneration propagation is approx. 5 m/yr. It was also found that these changes correlated positively with temperature trends

Trace gas emissions from a chronosequence of bark beetle-infested lodgepole pine (Pinus contorta) forest stands

Science.gov (United States)

Norton, U.; Pendall, E.; Ewers, B. E.; Borkhuu, B.

2011-12-01

Severe outbreak of mountain pine beetle (MPB) and associated blue stain fungi have killed millions of hectares of coniferous forests in Western North America. This unprecedented disturbance has critically impacted ecosystem biogeochemistry and net carbon (C) and nitrogen (N) fluxes. However, the effects on greenhouse gas (GHG) emissions and drivers of biogeochemical processes that trigger GHG emissions following MPB infestations are not well understood. Such information can help assess regional-level changes in ecosystem C and N budgets and large-scale disturbance impacts on gas exchange between the atmosphere and terrestrial ecosystem. The overall objective of this research was to assess the immediate responses of GHG fluxes and soil C and N mineralization rates along a chronosequence of recently infested (1-yr, 3-yr and 4-yr ago) and uninfested (150-yr, 20-yr and 15-yr old) lodgepole pine stands in Medicine Bow National Forest in southeastern Wyoming. We hypothesize that MPB-induced tree mortality significantly changes stand-level hydrology, soil organic matter quality and chemistry of aboveground and belowground plant inputs. Consequently, these modifications influence nitrous oxide (N2O) emissions and methane (CH4) assimilation. Biweekly GHG measurements using static chambers were carried out during three consecutive snow-free growing seasons. Our results suggest that a stand infested within a year already shows a 20% increase in spring N2O production and a small decline in summer CH4 assimilation when compared to uninfested stands. Stands infested three and four years prior to our measurements produce over three times more N2O and assimilate three to five times less CH4 when compared to uninfested stands. In addition, a notable increase in soil moisture content and soil mineral N concentrations following early onset of the MPB infestation was also observed. An overall increase in N2O production and decline in CH4 assimilation following MPB infestation may

Modeling biophysical properties of broad-leaved stands in the hyrcanian forests of Iran using fused airborne laser scanner data and ultraCam-D images

Science.gov (United States)

Mohammadi, Jahangir; Shataee, Shaban; Namiranian, Manochehr; Næsset, Erik

2017-09-01

Inventories of mixed broad-leaved forests of Iran mainly rely on terrestrial measurements. Due to rapid changes and disturbances and great complexity of the silvicultural systems of these multilayer forests, frequent repetition of conventional ground-based plot surveys is often cost prohibitive. Airborne laser scanning (ALS) and multispectral data offer an alternative or supplement to conventional inventories in the Hyrcanian forests of Iran. In this study, the capability of a combination of ALS and UltraCam-D data to model stand volume, tree density, and basal area using random forest (RF) algorithm was evaluated. Systematic sampling was applied to collect field plot data on a 150 m × 200 m sampling grid within a 1100 ha study area located at 36°38‧- 36°42‧N and 54°24‧-54°25‧E. A total of 308 circular plots (0.1 ha) were measured for calculation of stand volume, tree density, and basal area per hectare. For each plot, a set of variables was extracted from both ALS and multispectral data. The RF algorithm was used for modeling of the biophysical properties using ALS and UltraCam-D data separately and combined. The results showed that combining the ALS data and UltraCam-D images provided a slight increase in prediction accuracy compared to separate modeling. The RMSE as percentage of the mean, the mean difference between observed and predicted values, and standard deviation of the differences using a combination of ALS data and UltraCam-D images in an independent validation at 0.1-ha plot level were 31.7%, 1.1%, and 84 m3 ha-1 for stand volume; 27.2%, 0.86%, and 6.5 m2 ha-1 for basal area, and 35.8%, -4.6%, and 77.9 n ha-1 for tree density, respectively. Based on the results, we conclude that fusion of ALS and UltraCam-D data may be useful for modeling of stand volume, basal area, and tree density and thus gain insights into structural characteristics in the complex Hyrcanian forests.

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)

Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

Science.gov (United States)

Reinikainen, Michael; D’Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

2014-01-01

Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain

Using a standing-tree acoustic tool to identify forest stands for the production of mechanically-graded lumber.

Science.gov (United States)

Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

2013-03-12

This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber.

[Wood transformation in dead-standing trees in the forest-tundra of Central Siberia].

Science.gov (United States)

Mukhortova, L V; Kirdianov, A V; Myglan, V S; Guggenberger, G

2009-01-01

Changes in the composition of wood organic matter in dead-standing spruce and larch trees depending on the period after their death have been studied in the north of Central Siberia. The period after tree death has been estimated by means of cross-dating. The results show that changes in the composition of wood organic matter in 63% of cases are contingent on tree species. Wood decomposition in dead-standing trees is accompanied by an increase in the contents of alkali-soluble organic compounds. Lignin oxidation in larch begins approximately 80 years after tree death, whereas its transformation in spruce begins not earlier than after 100 years. In the forest-tundra of Central Siberia, the rate of wood organic matter transformation in dead-standing trees is one to two orders of magnitude lower than in fallen wood, which accounts for their role as a long-term store of carbon and mineral elements in these ecosystems.

Updating stand-level forest inventories using airborne laser scanning and Landsat time series data

Science.gov (United States)

Bolton, Douglas K.; White, Joanne C.; Wulder, Michael A.; Coops, Nicholas C.; Hermosilla, Txomin; Yuan, Xiaoping

2018-04-01

Vertical forest structure can be mapped over large areas by combining samples of airborne laser scanning (ALS) data with wall-to-wall spatial data, such as Landsat imagery. Here, we use samples of ALS data and Landsat time-series metrics to produce estimates of top height, basal area, and net stem volume for two timber supply areas near Kamloops, British Columbia, Canada, using an imputation approach. Both single-year and time series metrics were calculated from annual, gap-free Landsat reflectance composites representing 1984-2014. Metrics included long-term means of vegetation indices, as well as measures of the variance and slope of the indices through time. Terrain metrics, generated from a 30 m digital elevation model, were also included as predictors. We found that imputation models improved with the inclusion of Landsat time series metrics when compared to single-year Landsat metrics (relative RMSE decreased from 22.8% to 16.5% for top height, from 32.1% to 23.3% for basal area, and from 45.6% to 34.1% for net stem volume). Landsat metrics that characterized 30-years of stand history resulted in more accurate models (for all three structural attributes) than Landsat metrics that characterized only the most recent 10 or 20 years of stand history. To test model transferability, we compared imputed attributes against ALS-based estimates in nearby forest blocks (>150,000 ha) that were not included in model training or testing. Landsat-imputed attributes correlated strongly to ALS-based estimates in these blocks (R2 = 0.62 and relative RMSE = 13.1% for top height, R2 = 0.75 and relative RMSE = 17.8% for basal area, and R2 = 0.67 and relative RMSE = 26.5% for net stem volume), indicating model transferability. These findings suggest that in areas containing spatially-limited ALS data acquisitions, imputation models, and Landsat time series and terrain metrics can be effectively used to produce wall-to-wall estimates of key inventory attributes, providing an

Investigations into the fungal flora of forest stands under severe stress from immissions

International Nuclear Information System (INIS)

Butin, H.

1992-01-01

This finalized research project on the fungal flora of forest stands under severe stress form immissions looked into the question of the contribution of fungi to the triggering of topical forest damage and investigated whether correlations between certain symptoms and needle yellowing or root damage can be established. The main tree species selected were spruce and pine; but spot sample checks were also carried out on other tree species. Fungal flora was determined both qualitatively and quantitatively, and the pathogenic significance of the individual species was determined. Further, it was investigated whether fungal species are correlated to certain symptoms of damage, and which fungal species are. For selected fungal species, their pathogenicity was investigated by infection experiments. (RHE) [de

Required sample size for monitoring stand dynamics in strict forest reserves: a case study

Science.gov (United States)

Diego Van Den Meersschaut; Bart De Cuyper; Kris Vandekerkhove; Noel Lust

2000-01-01

Stand dynamics in European strict forest reserves are commonly monitored using inventory densities of 5 to 15 percent of the total surface. The assumption that these densities guarantee a representative image of certain parameters is critically analyzed in a case study for the parameters basal area and stem number. The required sample sizes for different accuracy and...

Post-fire diversity and abundance in pine and eucalipt stands in Portugal: effects of biogeography, topography, forest type and post-fire management

OpenAIRE

Maia, P.; Keizer, J.; Vasques, A.; Abrantes, N.; Roxo, L.; Fernandes, P.; Ferreira, A.; Moreira, F.

2014-01-01

This study concerned the mid-term regeneration of the woody understory vegetation of pure and mixed stands of Pinus pinaster Ait. and Eucalyptus globulus Labill. in northern and central Portugal following wildfires in 2005 and 2006. Pine and eucalypt stands are the most widespread and most fire-prone forest types in Portugal. The main aim was to investigate the importance of biogeography, topography, forest type and post-fire management operations in explaining the patterns in shr...

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

Science.gov (United States)

Brad Oberle; Kiona Ogle; Amy E. Zanne; Christopher W. Woodall

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests...

Remote sensing estimates of stand-replacement fires in Russia, 2002–2011

International Nuclear Information System (INIS)

Krylov, Alexander; Potapov, Peter; Loboda, Tatiana; Tyukavina, Alexandra; Turubanova, Svetlana; Hansen, Matthew C; McCarty, Jessica L

2014-01-01

The presented study quantifies the proportion of stand-replacement fires in Russian forests through the integrated analysis of Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) data products. We employed 30 m Landsat Enhanced Thematic Mapper Plus derived tree canopy cover and decadal (2001–2012) forest cover loss (Hansen et al 2013 High-resolution global maps of 21st-century forest cover change Science 342 850–53) to identify forest extent and disturbance. These data were overlaid with 1 km MODIS active fire (earthdata.nasa.gov/data/near-real-time-data/firms) and 500 m regional burned area data (Loboda et al 2007 Regionally adaptable dNBR-based algorithm for burned area mapping from MODIS data Remote Sens. Environ. 109 429–42 and Loboda et al 2011 Mapping burned area in Alaska using MODIS data: a data limitations-driven modification to the regional burned area algorithm Int. J. Wildl. Fire 20 487–96) to differentiate stand-replacement disturbances due to fire versus other causes. Total stand replacement forest fire area within the Russian Federation from 2002 to 2011 was estimated to be 17.6 million ha (Mha). The smallest stand-replacement fire loss occurred in 2004 (0.4 Mha) and the largest annual loss in 2003 (3.3 Mha). Of total burned area within forests, 33.6% resulted in stand-replacement. Light conifer stands comprised 65% of all non-stand-replacement and 79% of all stand-replacement fire in Russia. Stand-replacement area for the study period is estimated to be two times higher than the reported logging area. Results of this analysis can be used with historical fire regime estimations to develop effective fire management policy, increase accuracy of carbon calculations, and improve fire behavior and climate change modeling efforts. (paper)

Development, succession, and stand dynamics of upland oak forests in the Wisconsin Driftless Area: Implications for oak regeneration and management

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Megan L. Buchanan; Kurt F. Kipfmueller; Anthony W. D' Amato

2017-01-01

Throughout the deciduous forests of the eastern United States, oak (Quercus) regeneration has declined in stands historically dominated by oak species. In the Wisconsin Driftless Area, the level of decline in oak regeneration is variable and influenced by stand structural development, historical disturbance regime, abiotic site characteristics, and...

Standing crop and aboveground biomass partitioning of a dwarf mangrove forest in Taylor River Slough, Florida

Science.gov (United States)

Coronado-Molina, C.; Day, J.W.; Reyes, E.; Perez, B.C.

2004-01-01

The structure and standing crop biomass of a dwarf mangrove forest, located in the salinity transition zone ofTaylor River Slough in the Everglades National Park, were studied. Although the four mangrove species reported for Florida occurred at the study site, dwarf Rhizophora mangle trees dominated the forest. The structural characteristics of the mangrove forest were relatively simple: tree height varied from 0.9 to 1.2 meters, and tree density ranged from 7062 to 23 778 stems haa??1. An allometric relationship was developed to estimate leaf, branch, prop root, and total aboveground biomass of dwarf Rhizophora mangle trees. Total aboveground biomass and their components were best estimated as a power function of the crown area times number of prop roots as an independent variable (Y = B ?? Xa??0.5083). The allometric equation for each tree component was highly significant (pRhizophora mangle contributed 85% of total standing crop biomass. Conocarpus erectus, Laguncularia racemosa, and Avicennia germinans contributed the remaining biomass. Average aboveground biomass allocation was 69% for prop roots, 25% for stem and branches, and 6% for leaves. This aboveground biomass partitioning pattern, which gives a major role to prop roots that have the potential to produce an extensive root system, may be an important biological strategy in response to low phosphorus availability and relatively reduced soils that characterize mangrove forests in South Florida.

Overland flow generation processes in sub-humid Mediterranean forest stands

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Ferreira, A. J. D.; Ferreira, C. S. S.; Coelho, C. O. A.; Walsh, R. P. D.; Shakesby, R. A.

2012-04-01

Forest soils in north and central Portugal have suffered and continue to suffer major structural changes as a result of forest management techniques, such as clear-felling and as a result of wildfire and rip-ploughing, which is carried out to prepare the ground for planting tree seedlings. In soils that have undergone these changes, the characteristics tend to be different for coniferous plantations, where the root system tends to die when the trees are cut following fire and subsequently may be consumed by fire to form a macropore network, and other types of tree plantations where the root system remains alive and allows regrowth from the sawn tree stumps. Overland flow thresholds decrease sharply as a result of rip-ploughing and forest fires and increase following clear-felling. The time taken for trees to reach maturity after wildfire differs markedly betwen the two main species (Pinus pinaster Aiton and Eucalyptus globulus Labill.) stands. In this paper, overland flow is considered in relation to rainfall, throughfall and throughflow, both in terms of hydrology and hydrochemistry in an attempt to understand overland flow generation mechanisms for a variety of forest land uses (mature pine and eucalyptus, pine seedling regrowth and eucalyptus regrowth from tree stumps, eucalyptus plantations and burned pine). Overland flow generation processes change sharply, even within a single rainfall event, as reflected in the soil hydrological processes and the hydrochemical fingerprints. These effects result from the different contact times for water and soil, which cause differences in the absorption and exhudation processes for the two species

Developments to the Sylvan stand structure model to describe wood quality changes in southern bottomland hardwood forests because of forest management

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Ian R. Scott

2009-01-01

Growth models can produce a wealth of detailed information that is often very difficult to perceive because it is frequently presented either as summary tables, stand view or landscape view visualizations. We have developed new tools for use with the Sylvan model (Larsen 1994) that allow the analysis of wood-quality changes as a consequence of forest management....

Stand-scale soil respiration estimates based on chamber methods in a Bornean tropical rainforest

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Kume, T.; Katayama, A.; Komatsu, H.; Ohashi, M.; Nakagawa, M.; Yamashita, M.; Otsuki, K.; Suzuki, M.; Kumagai, T.

2009-12-01

This study was undertaken to estimate stand-scale soil respiration in an aseasonal tropical rainforest on Borneo Island. To this aim, we identified critical and practical factors explaining spatial variations in soil respiration based on the soil respiration measurements conducted at 25 points in a 40 × 40 m subplot of a 4 ha study plot for five years in relation to soil, root, and forest structural factors. Consequently, we found significant positive correlation between the soil respiration and forest structural parameters. The most important factor was the mean DBH within 6 m of the measurement points, which had a significant linear relationship with soil respiration. Using the derived linear regression and an inventory dataset, we estimated the 4 ha-scale soil respiration. The 4 ha-scale estimation (6.0 μmol m-2 s-1) was nearly identical to the subplot scale measurements (5.7 μmol m-2 s-1), which were roughly comparable to the nocturnal CO2 fluxes calculated using the eddy covariance technique. To confirm the spatial representativeness of soil respiration estimates in the subplot, we performed variogram analysis. Semivariance of DBH(6) in the 4 ha plot showed that there was autocorrelation within the separation distance of about 20 m, and that the spatial dependence was unclear at a separation distance of greater than 20 m. This ascertained that the 40 × 40 m subplot could represent the whole forest structure in the 4 ha plot. In addition, we discuss characteristics of the stand-scale soil respiration at this site by comparing with those of other forests reported in previous literature in terms of the soil C balance. Soil respiration at our site was noticeably greater, relative to the incident litterfall amount, than soil respiration in other tropical and temperate forests probably owing to the larger total belowground C allocation by emergent trees. Overall, this study suggests the arrangement of emergent trees and their bellow ground C allocation could be

Dissimilar responses of larch stands in northern Siberia to increasing temperatures-a field and simulation based study.

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Wieczorek, Mareike; Kruse, Stefan; Epp, Laura S; Kolmogorov, Alexei; Nikolaev, Anatoly N; Heinrich, Ingo; Jeltsch, Florian; Pestryakova, Lyudmila A; Zibulski, Romy; Herzschuh, Ulrike

2017-09-01

Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field- and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming. Using information on stand structure, tree age, and seed quality and quantity from seven sites, we investigate effects of intra-specific competition and seed availability on the specific impact of recent climate warming on larch stands. Field data show that tree density is highest in the forest-tundra, and average tree size decreases from closed forest to single-tree tundra. Age-structure analyses indicate that the trees in the closed forest and forest-tundra have been present for at least ~240 yr. At all sites except the most southerly ones, past establishment is positively correlated with regional temperature increase. In the single-tree tundra, however, a change in growth form from krummholz to erect trees, beginning ~130 yr ago, rather than establishment date has been recorded. Seed mass decreases from south to north, while seed quantity increases. Simulations with LAVESI (Larix Vegetation Simulator) further suggest that relative density changes strongly in response to a warming signal in the forest-tundra while intra-specific competition limits densification in the closed forest and seed limitation hinders densification in the single-tree tundra. We find striking differences in strength and timing of responses to recent climate warming. While forest-tundra stands recently densified, recruitment is almost non-existent at the southern and northern end of the ecotone due to autecological processes. Palaeo-treelines may therefore

Assessing wildfire occurrence probability in Pinus pinaster Ait. stands in Portugal

Energy Technology Data Exchange (ETDEWEB)

Marques, S.; Garcia-Gonzalo, J.; Botequim, B.; Ricardo, A.; Borges, J. G.; Tome, M.; Oliveira, M. M.

2012-11-01

Maritime pine (Pinus pinaster Ait.) is an important conifer from the western Mediterranean Basin extending over 22% of the forest area in Portugal. In the last three decades nearly 4% of Maritime pine area has been burned by wildfires. Yet no wildfire occurrence probability models are available and forest and fire management planning activities are thus carried out mostly independently of each other. This paper presents research to address this gap. Specifically, it presents a model to assess wildfire occurrence probability in regular and pure Maritime pine stands in Portugal. Emphasis was in developing a model based on easily available inventory data so that it might be useful to forest managers. For that purpose, data from the last two Portuguese National Forest Inventories (NFI) and data from wildfire perimeters in the years from 1998 to 2004 and from 2006 to 2007 were used. A binary logistic regression model was build using biometrics data from the NFI. Biometric data included indicators that might be changed by operations prescribed in forest planning. Results showed that the probability of wildfire occurrence in a stand increases in stand located at steeper slopes and with high shrubs load while it decreases with precipitation and with stand basal area. These results are instrumental for assessing the impact of forest management options on wildfire probability thus helping forest managers to reduce the risk of wildfires. (Author) 57 refs.

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

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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.

Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

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Fyllas, N. M.; Gloor, E.; Mercado, L. M.; Sitch, S.; Quesada, C. A.; Domingues, T. F.; Galbraith, D. R.; Torre-Lezama, A.; Vilanova, E.; Ramírez-Angulo, H.; Higuchi, N.; Neill, D. A.; Silveira, M.; Ferreira, L.; Aymard C., G. A.; Malhi, Y.; Phillips, O. L.; Lloyd, J.

2014-07-01

Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits - leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree - in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status

Detection of Spatio-Temporal Changes of Norway Spruce Forest Stands in Ore Mountains Using Landsat Time Series and Airborne Hyperspectral Imagery

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Jan Mišurec

2016-01-01

Full Text Available The study focuses on spatio-temporal changes in the physiological status of the Norway spruce forests located at the central and western parts of the Ore Mountains (northwestern part of the Czech Republic, which suffered from severe environmental pollution from the 1970s to the 1990s. The situation started improving after the pollution loads decreased significantly at the end of the 1990s. The general trends in forest recovery were studied using the tasseled cap transformation and disturbance index (DI extracted from the 1985–2015 time series of Landsat data. In addition, 16 vegetation indices (VIs extracted from airborne hyperspectral (HS data acquired in 1998 using the Advanced Solid-State Array Spectroradiometer (ASAS and in 2013 using the Airborne Prism Experiment (APEX were used to study changes in forest health. The forest health status analysis of HS image data was performed at two levels of spatial resolution; at a tree level (original 2.0 m spatial resolution, as well as at a forest stand level (generalized to 6.0 m spatial resolution. The temporal changes were studied primarily using the VOG1 vegetation index (VI as it was showing high and stable sensitivity to forest damage for both spatial resolutions considered. In 1998, significant differences between the moderately to heavily damaged (central Ore Mountains and initially damaged (western Ore Mountains stands were detected for all the VIs tested. In 2013, the stands in the central Ore Mountains exhibited VI values much closer to the global mean, indicating an improvement in their health status. This result fully confirms the finding of the Landsat time series analysis. The greatest difference in Disturbance Index (DI values between the central (1998: 0.37 and western Ore Mountains stands (1998: −1.21 could be seen at the end of the 1990s. Nonetheless, levelling of the physiological status of Norway spruce was observed for the central and western parts of the Ore Mountains in

A web-based application to simulate alternatives for sustainable forest management: SIMANFOR

Energy Technology Data Exchange (ETDEWEB)

Bravo, F.; Rodriguez, F.; Ordonez, C.

2012-11-01

Growth and yield models at different scales are useful tools for forest stake holders. Adequate simulation of forest stand conditions after different silviculture scenarios allows stake holders to adopt appropriate actions to maintain forest integrity while forest products and services are obtained to benefit society as a whole. SIMANFOR is a platform to simulate sustainable forest management alternatives, integrating different modules to manage forest inventories, simulate and project stand conditions and maintain systems security and integrity. SIMANFOR output is compatible with an Office environment (Microsoft or Open), allowing users to exchange data and files between SIMANFOR and their own software. New developments are being planned under a web 2.0 environment to take advantage of user input to improve SIMANFOR in the future. (Author) 9 refs.

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

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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.

Using Lidar and color infrared imagery to successfully measure stand characteristics on the William B. Bankhead National Forest, Alabama

Science.gov (United States)

Jeffrey Stephens; Luben Dimov; Callie Schweitzer; Wubishet Tadesse

2008-01-01

Light detection and ranging (Lidar) and color infrared imagery (CIR) were used to quantify forest structure and to distinguish deciduous from coniferous trees for selected stands on the William B. Bankhead National Forest in Alabama. Lidar bare ground and vegetation point clouds were used to determine tree heights and tree locations. Lidar accuracy was assessed by...

The zero inflation of standing dead tree carbon stocks

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Christopher W. Woodall; David W. MacFarlane

2012-01-01

Given the importance of standing dead trees in numerous forest ecosystem attributes/processes such as carbon (C) stocks, the USDA Forest Service’s Forest Inventory and Analysis (FIA) program began consistent nationwide sampling of standing dead trees in 1999. Modeled estimates of standing dead tree C stocks are currently used as the official C stock estimates for the...

Are Bavarian Forests (southern Germany) at risk from ground-level ozone? Assessment using exposure and flux based ozone indices

International Nuclear Information System (INIS)

Baumgarten, Manuela; Huber, Christian; Bueker, Patrick; Emberson, Lisa; Dietrich, Hans-Peter; Nunn, Angela J.; Heerdt, Christian; Beudert, Burkhard; Matyssek, Rainer

2009-01-01

Exposure and flux-based indices of O 3 risk were compared, at 19 forest locations across Bavaria in southern Germany from 2002 to 2005; leaf symptoms on mature beech trees found at these locations were also examined for O 3 injury. O 3 flux modelling was performed using continuously recorded O 3 concentrations in combination with meteorological and soil moisture data collected from Level II forest sites. O 3 measurements at nearby rural open-field sites proved appropriate as surrogates in cases where O 3 data were lacking at forest sites (with altitude-dependent average differences of about 10% between O 3 concentrations). Operational thresholds of biomass loss for both O 3 indices were exceeded at the majority of the forest locations, suggesting similar risk under long-term average climate conditions. However, exposure-based indices estimated higher O 3 risk during dry years as compared to the flux-based approach. In comparison, minor O 3 -like leaf injury symptoms were detected only at a few of the forest sites investigated. Relationships between flux-based risk thresholds and tree response need to be established for mature forest stands for validation of predicted growth reductions under the prevailing O 3 regimes. - Exposure- and flux-based ozone indices suggest Bavarian forests to be at risk from ozone; the flux-based index offers a means of incorporating stand-specific and ecological variables that influence risk.

An individual-based growth and competition model for coastal redwood forest restoration

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van Mantgem, Phillip J.; Das, Adrian J.

2014-01-01

Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

Severity of a mountain pine beetle outbreak across a range of stand conditions in Fraser Experimental Forest, Colorado, United States

Science.gov (United States)

Anthony G. Vorster; Paul H. Evangelista; Thomas J. Stohlgren; Sunil Kumar; Charles C. Rhoades; Robert M. Hubbard; Antony S. Cheng; Kelly Elder

2017-01-01

The recent mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks had unprecedented effects on lodgepole pine (Pinus contorta var. latifolia) in western North America. We used data from 165 forest inventory plots to analyze stand conditions that regulate lodgepole pine mortality across a wide range of stand structure and species composition at the Fraser...

Productivity of aboveground coarse wood biomass and stand age related to soil hydrology of Amazonian forests in the Purus-Madeira interfluvial area

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Cintra, B. B. L.; Schietti, J.; Emillio, T.; Martins, D.; Moulatlet, G.; Souza, P.; Levis, C.; Quesada, C. A.; Schöngart, J.

2013-04-01

The ongoing demand for information on forest productivity has increased the number of permanent monitoring plots across the Amazon. Those plots, however, do not comprise the whole diversity of forest types in the Amazon. The complex effects of soil, climate and hydrology on the productivity of seasonally waterlogged interfluvial wetland forests are still poorly understood. The presented study is the first field-based estimate for tree ages and wood biomass productivity in the vast interfluvial region between the Purus and Madeira rivers. We estimate stand age and wood biomass productivity by a combination of tree-ring data and allometric equations for biomass stocks of eight plots distributed along 600 km in the Purus-Madeira interfluvial area that is crossed by the BR-319 highway. We relate stand age and wood biomass productivity to hydrological and edaphic conditions. Mean productivity and stand age were 5.6 ± 1.1 Mg ha-1 yr-1 and 102 ± 18 yr, respectively. There is a strong relationship between tree age and diameter, as well as between mean diameter increment and mean wood density within a plot. Regarding the soil hydromorphic properties we find a positive correlation with wood biomass productivity and a negative relationship with stand age. Productivity also shows a positive correlation with the superficial phosphorus concentration. In addition, superficial phosphorus concentration increases with enhanced soil hydromorphic condition. We raise three hypotheses to explain these results: (1) the reduction of iron molecules on the saturated soils with plinthite layers close to the surface releases available phosphorous for the plants; (2) the poor structure of the saturated soils creates an environmental filter selecting tree species of faster growth rates and shorter life spans and (3) plant growth on saturated soil is favored during the dry season, since there should be low restrictions for soil water availability.

Inventory of aspen trees in spruce dominated stands in conservation area

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Matti Maltamo

2015-05-01

Full Text Available Background The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots (5–10 to values of 25%–50% with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our

Information system of forest growth and productivity by site quality type and elements of forest

Science.gov (United States)

Khlyustov, V.

2012-04-01

Information system of forest growth and productivity by site quality type and elements of forest V.K. Khlustov Head of the Forestry Department of Russian State Agrarian University named after K.A.Timiryazev doctor of agricultural sciences, professor The efficiency of forest management can be improved substantially by development and introduction of principally new models of forest growth and productivity dynamics based on regionalized site specific parameters. Therefore an innovative information system was developed. It describes the current state and gives a forecast for forest stand parameters: growth, structure, commercial and biological productivity depend on type of site quality. In contrast to existing yield tables, the new system has environmental basis: site quality type. The information system contains set of multivariate statistical models and can work at the level of individual trees or at the stand level. The system provides a graphical visualization, as well as export of the emulation results. The System is able to calculate detailed description of any forest stand based on five initial indicators: site quality type, site index, stocking, composition, and tree age by elements of the forest. The results of the model run are following parameters: average diameter and height, top height, number of trees, basal area, growing stock (total, commercial with distribution by size, firewood and residuals), live biomass (stem, bark, branches, foliage). The system also provides the distribution of mentioned above forest stand parameters by tree diameter classes. To predict the future forest stand dynamics the system require in addition the time slot only. Full set of forest parameters mention above will be provided by the System. The most conservative initial parameters (site quality type and site index) can be kept in the form of geo referenced polygons. In this case the system would need only 3 dynamic initial parameters (stocking, composition and age) to

Changes in standing stocks and fluxes of carbon due to salinization: tidal freshwater wetland forest retreat to marsh

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Krauss, K.; Noe, G. B.; Duberstein, J. A.; Conner, W. H.; Stagg, C. L.; Jones, M.; Bernhardt, C. E.; Cormier, N.

2017-12-01

Assessments of organic carbon (C) standing stocks and fluxes as wetland ecosystems transition from tidally influenced freshwater forested wetlands to low-salinity marshes are not typically included in "blue carbon" accounting. However, these ecosystems have the potential to store and convey large quantities of C. Here, we report on data collected from eight riverine sites along salinity and hydro-edaphic gradients in South Carolina and Georgia to provide the first complete estimates of C storage, flux, and burial, including estimation of C export to aquatic environments, in tidal freshwater forested wetlands undergoing transition to oligohaline marsh. Total standing stocks of C ranged from 280 to 891 Mg C/ha along both rivers but with no consistent trend in standing stock shifts along salinity gradients between the two rivers. Soil C standing stocks were most variable among sites. Furthermore, we assessed input (litterfall, woody growth, herbaceous growth, root growth and surface sediment C accretion) in comparison with output (surface litter decomposition, root decomposition and gaseous C) fluxes over periods ranging from 2 to 11 years. C sequestration from mass balance calculations ranged from 103 to 728 g C/m2/year among sites, with generally greater C sequestration on sites with prominent salinity-mediated conversion to oligohaline marsh. Dissolved C export was estimated as the difference between C sequestration and soil C burial using 14C dating of cores, and ranged from 144 to 404 g C/m2/year, representing a large amount of C export to feed aquatic biogeochemical transformations and secondary productivity. Along with C accounting, these sites also differed in how N and P were mineralized in soils, with considerable N mineralization on salinity-stressed (2.4-4.3 parts per thousand) forested sites with newly encroached marsh plants and considerable P mineralization on slightly higher salinity marshes. In all, C storage from tidal freshwater forested wetlands

OpCost: an open-source system for estimating costs of stand-level forest operations

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Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

2017-01-01

This report describes and documents the OpCost forest operations cost model, a key component of the BioSum analysis framework. OpCost is available in two editions: as a callable module for use with BioSum, and in a stand-alone edition that can be run directly from R. OpCost model logic and assumptions for this open-source tool are explained, references to the...

Evaluarea naturalității și a structurii arboretelor în rezervațiile Pădurea Voievodeasa și Codrul Secular Loben din Obcinile Bucovinei [Evaluation of stand naturalness and structure in forest reserves Pădurea Voievodeasa and Codrul Secular Loben from Obcinele Bucovinei

Directory of Open Access Journals (Sweden)

Marius Teodosiu

2014-12-01

Full Text Available The paper presents the results of a naturalness assessments, and also of the first inventory in two newly established forest reserves (Voievodeasa and Loben from North of Romanian Eastern Carpathians. The evaluation of naturalness used the historical data concerning the wood extraction, as were recorded in the forest management plans. In selected stands of higher local naturalness was further conducted an inventory, following the methodology recommended by COST E4 and based on a systematic grid with circular plots of 500 m2 . Expected, the results showed that extraction impacted the structural characteristics of stands, esspecially the standing/downing trees volume. The comparison of structural data resulted from inventory (density and volume of both alive and dead standing trees and coarse woody debris with local references - “virgin“ forests located about 40 km apart of the forest reserves under study - suggested a degree of correspondence between 20-40%. The same data, compared with published information available from mixed forest of beech-fir-spruce accross temperate zone of Europe confirmed the departure of selected stands from the references of naturalness and their distinct grouping, compared with other forest reserves.

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...

The Role of Tree Mortality in Vitality Assessment of Sessile Oak Forests

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Imre Berki

2016-12-01

Full Text Available Background and Purpose: The drought-induced vitality loss of sessile oak (Quercus petraea (Matt. Liebl. has been continuously observed in Hungary for more than three decades. The decrease in stand density as a consequence of drought-induced mortality has not been taken into consideration in most of the monitoring methods. Materials and Methods: Forest stands without any forest intervention during the last 30 years were selected. Quadrats were designated for the analysis in 18 sessile oak stands along a climatic transect in which foliage transparency and stand density were measured. Drought stress was defined by the water balance approach. By combining the foliage transparency and the relative stand density, a new cumulative assessment method of stand level vitality was introduced to get a more realistic picture about the effects of long-term drought (lasting for several decades on the sessile oak forests in South-East Europe. Results: The calculated health status (100% - vital; 0% - dead of the sessile oak stands was between 70-90% in the moist South-West Hungary and below 50% close to its xeric limit. The individual tree-based vitality assessment method gave considerably higher values on 17 out of 18 sites. Conclusions: Forest monitoring should also consider stand level-based tree mortality in oak forests while assessing health condition especially close to its xeric limit. The proposed new method provides a more realistic picture about the effects of climate change on sessile oak stands particularly for forest managers interested in changing in the wood stock of forests.

Southern pine beetle infestations in relation to forest stand conditions, previous thinning, and prescribed burning: evaluation of the Southern Pine Beetle Prevention Program

Science.gov (United States)

John T. Nowak; James R. Meeker; David R. Coyle; Chris A. Steiner; Cavell Brownie

2015-01-01

Since 2003, the Southern Pine Beetle Prevention Program (SPBPP) (a joint effort of the USDA Forest Service and Southern Group of State Foresters) has encouraged and provided cost-share assistance for silvicultural treatments to reduce stand/forest susceptibility to the southern pine beetle (SPB)(Dendroctonus frontalis Zimmermann) in the southeastern United States....

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 .

Present state and future trends of pine forests of malam jabba, swat district, Pakistan

International Nuclear Information System (INIS)

Siddiqui, M. F.; Arsalan, M.; Hussain, M. I.; Iqbal, J.; Wahab, M.

2015-01-01

Present state and future trend of pine forests of Malam Jabba, Swat district, Pakistan explored. We focused on vegetation composition, structure, diversity and forests dynamics. Thirteen stands were sampled by Point Centered Quarter method. Among all stands four monospecific forests of Pinus wallichiana attained highest density ha-1 except in one stand where Picea smithiana attained 401 trees ha-1. Unlike density, the basal area m2 ha-1 of these stands varies stand to stand. Based on floristic composition and importance value index, five different communities viz Pinus wallichiana-Picea smithiana; Picea smithiana-Pinus wallichiana; Abies pindrow-Pinus wallichiana; Pinus wallichiana-Abies pindrow; Abies pindrow-Picea smithiana and 4 monospecific forests of Pinus wallichiana were recognized. Size class structure of forests showed marked influence of anthropogenic disturbance because not a single stand showed ideal regeneration pattern (inverse J shape distribution). Future of these forests is worst due to absence trees in small size classes. Gaps are also evident in most of the forest stands. Stand diversity, richness, equitability and Simpson dominance values formulated on single stand basis. Diversity of Abides pindrow and Pinus wallichiana stand was highest because these stand occupied dominant species, while lowest diversity observed in some Pinus wallichiana and Picea smithiana stand as these stands have mark difference between the dominance of two species. In the monospecific forests, the diversity level was zero, suggesting the monopolization of resources by one species or elimination of other tree species in these stands. (author)

Predictive Modeling of Black Spruce (Picea mariana (Mill. B.S.P. Wood Density Using Stand Structure Variables Derived from Airborne LiDAR Data in Boreal Forests of Ontario

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Bharat Pokharel

2016-12-01

Full Text Available Our objective was to model the average wood density in black spruce trees in representative stands across a boreal forest landscape based on relationships with predictor variables extracted from airborne light detection and ranging (LiDAR point cloud data. Increment core samples were collected from dominant or co-dominant black spruce trees in a network of 400 m2 plots distributed among forest stands representing the full range of species composition and stand development across a 1,231,707 ha forest management unit in northeastern Ontario, Canada. Wood quality data were generated from optical microscopy, image analysis, X-ray densitometry and diffractometry as employed in SilviScan™. Each increment core was associated with a set of field measurements at the plot level as well as a suite of LiDAR-derived variables calculated on a 20 × 20 m raster from a wall-to-wall coverage at a resolution of ~1 point m−2. We used a multiple linear regression approach to identify important predictor variables and describe relationships between stand structure and wood density for average black spruce trees in the stands we observed. A hierarchical classification model was then fitted using random forests to make spatial predictions of mean wood density for average trees in black spruce stands. The model explained 39 percent of the variance in the response variable, with an estimated root mean square error of 38.8 (kg·m−3. Among the predictor variables, P20 (second decile LiDAR height in m and quadratic mean diameter were most important. Other predictors describing canopy depth and cover were of secondary importance and differed according to the modeling approach. LiDAR-derived variables appear to capture differences in stand structure that reflect different constraints on growth rates, determining the proportion of thin-walled earlywood cells in black spruce stems, and ultimately influencing the pattern of variation in important wood quality attributes

The Missouri Ozark Forest Ecosystem Project: the effects of forest management on the forest ecosystem

Science.gov (United States)

Brian Brookshire; Carl Hauser

1993-01-01

The effects of forest management on non-timber resources are of growing concern to forest managers and the public. While many previous studies have reported effects of stand-level treatments (less than 15 ha) on various stand-level attributes, few studies have attempted to document the influence of forest management on the biotic and abiotic characteristics of entire...

Biogeographical patterns of biomass allocation in leaves, stems, and roots in China's forests.

Science.gov (United States)

Zhang, Hao; Wang, Kelin; Xu, Xianli; Song, Tongqing; Xu, Yanfang; Zeng, Fuping

2015-11-03

To test whether there are general patterns in biomass partitioning in relation to environmental variation when stand biomass is considered, we investigated biomass allocation in leaves, stems, and roots in China's forests using both the national forest inventory data (2004-2008) and our field measurements (2011-2012). Distribution patterns of leaf, stem, and root biomass showed significantly different trends according to latitude, longitude, and altitude, and were positively and significantly correlated with stand age and mean annual precipitation. Trade-offs among leaves, stems, and roots varied with forest type and origin and were mainly explained by stand biomass. Based on the constraints of stand biomass, biomass allocation was also influenced by forest type, origin, stand age, stand density, mean annual temperature, precipitation, and maximum temperature in the growing season. Therefore, after stand biomass was accounted for, the residual variation in biomass allocation could be partially explained by stand characteristics and environmental factors, which may aid in quantifying carbon cycling in forest ecosystems and assessing the impacts of climate change on forest carbon dynamics in China.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests.

Science.gov (United States)

Oberle, Brad; Ogle, Kiona; Zanne, Amy E; Woodall, Christopher W

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

ORGEST: Regional guidelines and silvicultural models for sustainable forest management

Energy Technology Data Exchange (ETDEWEB)

Piqué, Míriam; Vericat, Pau; Beltrán, Mario

2017-11-01

Aim of the study: To develop regional guidelines for sustainable forest management. Area of the study: Forests of Catalonia (NE Spain). Material and methods: The process of developing the forest management guidelines (FMG) started by establishing a thorough classification of forest types at stand level. This classification hinges on two attributes: tree species composition and site quality based on ecological variables, which together determine potential productivity. From there, the management guidelines establish certain objectives and silvicultural models for each forest type. The forest type classifications, like the silvicultural models, were produced using both existing and newly-built growth models based on data from the National Forest Inventory (NFI) and expert knowledge. The effort involved over 20 expert working groups in order to better integrate the expertise and vision of different sectorial agents. Main results: The FMG consist in quantitative silvicultural models that include typical silvicultural variables, technical descriptions of treatments and codes of good practice. Guidelines now cover almost all forest types in Catalonia (spanning up to 90% of the Catalan forest area). Different silvicultural models have been developed for pure and mixed stands, different site quality classes (2–3 classes per species), and even- and multi-aged stands. Research highlights: FMG: i) orient the management of private and public forests, (ii) provide a technical scaffold for efficient allocation/investment of public subsidies in forest management, and (iii) bridge forest planning instruments at regional (strategic-tactical) and stand (operational) level.

ORGEST: Regional guidelines and silvicultural models for sustainable forest management

International Nuclear Information System (INIS)

Piqué, Míriam; Vericat, Pau; Beltrán, Mario

2017-01-01

Aim of the study: To develop regional guidelines for sustainable forest management. Area of the study: Forests of Catalonia (NE Spain). Material and methods: The process of developing the forest management guidelines (FMG) started by establishing a thorough classification of forest types at stand level. This classification hinges on two attributes: tree species composition and site quality based on ecological variables, which together determine potential productivity. From there, the management guidelines establish certain objectives and silvicultural models for each forest type. The forest type classifications, like the silvicultural models, were produced using both existing and newly-built growth models based on data from the National Forest Inventory (NFI) and expert knowledge. The effort involved over 20 expert working groups in order to better integrate the expertise and vision of different sectorial agents. Main results: The FMG consist in quantitative silvicultural models that include typical silvicultural variables, technical descriptions of treatments and codes of good practice. Guidelines now cover almost all forest types in Catalonia (spanning up to 90% of the Catalan forest area). Different silvicultural models have been developed for pure and mixed stands, different site quality classes (2–3 classes per species), and even- and multi-aged stands. Research highlights: FMG: i) orient the management of private and public forests, (ii) provide a technical scaffold for efficient allocation/investment of public subsidies in forest management, and (iii) bridge forest planning instruments at regional (strategic-tactical) and stand (operational) level.

Radionuclides in forest ecosystems

International Nuclear Information System (INIS)

Strebl, F.; Bossew, P.; Kienzl, K.; Hiesel, E.

2000-01-01

Some regions within Austria were highly contaminated (> 50 kBq m -2 ) with radiocaesium by the deposition event following the Chernobyl reactor accident in 1986. Monitoring carried out by several Austrian institutions showed that in contrast to agricultural products radiocaesium levels in wild berries, mushrooms and game meat from forest ecosystems remained considerably higher over the years. To find reasons for this contrasting radioecological behavior and for the derivation of model input parameters, an extended study about the distribution of 137 Cs within three Austrian forest stands was carried out between 1987 and 1997. Results of this and subsequent studies are summarized and include the following ecosystem compartments: forest soils, litter, trees, bilberry, mushrooms, mosses, ferns, lichen, other vegetation, insects, small mammals, game animals and surface water. Besides the investigation of radioecological behavior an estimation of pool sizes and transfer rates as well as radioecological residence half times for 137 Cs in different forest species was used to compile a radiocaesium balance for the years 1988 and 1996. Soil proved to be an effective sink for radiocaesium contamination, but in long-term perspective it can act as a source for the contamination of vegetation and higher levels of the food-chain as well. Due to the high standing biomass trees represent the largest 'living' radiocaesium pool within the investigated forest stand. Dose estimations based on average consume habits gave no significant increase (less than 0.4 %) of the annual average population radiation dose due to the ingestion of forest products from the investigated forest stands. (author)

Changes in carbon pool and stand structure of a native subtropical mangrove forest after inter-planting with exotic species Sonneratia apetala.

Science.gov (United States)

Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

2014-01-01

In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration.

Variability of sun-induced chlorophyll fluorescence according to stand age-related processes in a managed loblolly pine forest.

Science.gov (United States)

Colombo, Roberto; Celesti, Marco; Bianchi, Remo; Campbell, Petya K E; Cogliati, Sergio; Cook, Bruce D; Corp, Lawrence A; Damm, Alexander; Domec, Jean-Christophe; Guanter, Luis; Julitta, Tommaso; Middleton, Elizabeth M; Noormets, Asko; Panigada, Cinzia; Pinto, Francisco; Rascher, Uwe; Rossini, Micol; Schickling, Anke

2018-02-20

Leaf fluorescence can be used to track plant development and stress, and is considered the most direct measurement of photosynthetic activity available from remote sensing techniques. Red and far-red sun-induced chlorophyll fluorescence (SIF) maps were generated from high spatial resolution images collected with the HyPlant airborne spectrometer over even-aged loblolly pine plantations in North Carolina (United States). Canopy fluorescence yield (i.e., the fluorescence flux normalized by the light absorbed) in the red and far-red peaks was computed. This quantifies the fluorescence emission efficiencies that are more directly linked to canopy function compared to SIF radiances. Fluorescence fluxes and yields were investigated in relation to tree age to infer new insights on the potential of those measurements in better describing ecosystem processes. The results showed that red fluorescence yield varies with stand age. Young stands exhibited a nearly twofold higher red fluorescence yield than mature forest plantations, while the far-red fluorescence yield remained constant. We interpreted this finding in a context of photosynthetic stomatal limitation in aging loblolly pine stands. Current and future satellite missions provide global datasets of SIF at coarse spatial resolution, resulting in intrapixel mixture effects, which could be a confounding factor for fluorescence signal interpretation. To mitigate this effect, we propose a surrogate of the fluorescence yield, namely the Canopy Cover Fluorescence Index (CCFI) that accounts for the spatial variability in canopy structure by exploiting the vegetation fractional cover. It was found that spatial aggregation tended to mask the effective relationships, while the CCFI was still able to maintain this link. This study is a first attempt in interpreting the fluorescence variability in aging forest stands and it may open new perspectives in understanding long-term forest dynamics in response to future climatic

Forest attributes and fuel loads of riparian vs. upland stands in mountain pine beetle infested watersheds, southern Rocky Mountains [Chapter 13

Science.gov (United States)

Kathleen A. Dwire; Roberto A. Bazan; Robert Hubbard

2015-01-01

Extensive outbreaks of mountain pine beetle (MPB), spruce beetle (SB), and other insects are altering forest stand structure throughout the Western United States, and thereby increasing the natural heterogeneity of fuel distribution. Riparian forests frequently occur as narrow linear features in the landscape mosaic and can contribute to the spatial complexity of...

Forests and Forest Cover - MDC_NaturalForestCommunity

Data.gov (United States)

NSGIC Local Govt | GIS Inventory — A point feature class of NFCs - Natural Forest Communities. Natural Forest Community shall mean all stands of trees (including their associated understory) which...

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

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.)

Biodiversity of animals that are living on the surface of soil under the forest stands surrounding Japan Cave of BKPH Nglerak, North Lawu, Karanganyar

Directory of Open Access Journals (Sweden)

DHINI WIJAYA

2002-01-01

Full Text Available The study of animal biodiversity that lived on the surface of soil under the stands forest surround Japan Cave BKPH Nglerak, North Lawu, Karanganyar has bee done. Observations were conducted in 6 stations of different stands of forest. Animals were caught by pit fall trap method. In each catching was found about 22 animals consisting of 6 families with Simpson’s diversity index of 0.5. The result of identification indicates that those animals belong to 4 classes: Insects (9 orders, Arachnids (2 orders, Diplopods (2 orders, and Crustacean (1 order. The most diverse animals was found in the habitat of pine stands while the lowest one found in the habitat of cultivated plants.

Analysis of tree stand horizontal structure using random point field methods

Directory of Open Access Journals (Sweden)

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.

Biogeographical patterns of biomass allocation in leaves, stems, and roots in China’s forests

Science.gov (United States)

Zhang, Hao; Wang, Kelin; Xu, Xianli; Song, Tongqing; Xu, Yanfang; Zeng, Fuping

2015-01-01

To test whether there are general patterns in biomass partitioning in relation to environmental variation when stand biomass is considered, we investigated biomass allocation in leaves, stems, and roots in China’s forests using both the national forest inventory data (2004–2008) and our field measurements (2011–2012). Distribution patterns of leaf, stem, and root biomass showed significantly different trends according to latitude, longitude, and altitude, and were positively and significantly correlated with stand age and mean annual precipitation. Trade-offs among leaves, stems, and roots varied with forest type and origin and were mainly explained by stand biomass. Based on the constraints of stand biomass, biomass allocation was also influenced by forest type, origin, stand age, stand density, mean annual temperature, precipitation, and maximum temperature in the growing season. Therefore, after stand biomass was accounted for, the residual variation in biomass allocation could be partially explained by stand characteristics and environmental factors, which may aid in quantifying carbon cycling in forest ecosystems and assessing the impacts of climate change on forest carbon dynamics in China. PMID:26525117

Forests

Science.gov (United States)

Louis R. Iverson; Mark W. Schwartz

1994-01-01

Originally diminished by development, forests are coming back: forest biomass is accumulating. Forests are repositories for many threatened species. Even with increased standing timber, however, biodiversity is threatened by increased forest fragmentation and by exotic species.

Liming with powdered oil-shale ash in a heavily damaged forest ecosystem. 1.The effect on forest soil in a pine stand

International Nuclear Information System (INIS)

Terasmaa, T.; Sepp, S.

1994-01-01

A fertilization and liming experiment with mineral fertilizers and powdered oil-shale ash was carried out in a heavily damaged 50-year-old Scots pine ecosystem in South Estonia. In Estonia, where electric power is produced mainly in big oil-shale-fired power plants, huge quantities of SO 2 are flying into the atmosphere through the chimneys of the plants. However, it is characteristic of Estonia that simultaneously with comparatively high SO 2 pollution the proton load has been quite low because of big amounts of alkali c ash emitted together with SO 2 into the atmosphere through the chimneys of the thermal power plants. Therefore, acid rains are not frequent in Estonia. Acid precipitation here is caused mainly by SO 2 released in the central part of Europe. In Estonia acid rains are most frequently registered in the southern area of the country. At times rains with pH values below 5.1 (even 4.0 and lower) have been registered there. This is also the region where quite severely damaged pine forests can be found. As a rule, these forests grow on acid sandy soils poor in nutrients and bases. The aim of the present study was to investigate the possibility of using oil shale ash as a liming agent in a forest ecosystem for protecting forest soils from acidification and, together with some mineral fertilizers, for improving the health of injured pine stands. In Estonia the most easily available liming agent is powdered oil-shale ash, which has been widely used as a lime fertilizer for agricultural crops but so far has not been tested for liming forests on mineral soils. The comparison of the present study with the liming experiments carried out with limestone in Finland shows that the effect of oil-shale ash treatment of acid sandy soils to raise pH values and to reduce other characteristics of soil acidity was more effective than limestone liming of mineral soils in Finnish forests. The present study demonstrates that powdered oil-shale ash is highly effective in short

Habitat use by forest bats in South Carolina in relation to local, stand, and landscape characteristics

Science.gov (United States)

Susan C. Loeb; Joy M. O' Keefe

2006-01-01

Knowledge and understanding of bat habitat associations and the responses of bats to forest management are critical for effective bat conservation and management. Few studies have been conducted on bat habitat use in the southeast, despite the high number of endangered and sensitive species in the region. Our objective was to identify important local, stand, and...

Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

Directory of Open Access Journals (Sweden)

Weili Kou

2015-01-01

Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

Selection of roosting habitat by forest bats in a diverse forested landscape

Science.gov (United States)

Roger W. Perry; Ronald E. Thill; David M. Leslie

2007-01-01

Many studies of roost selection by forest-dwelling bats have concentrated on microhabitat surrounding roosts without providing forest stand level preferences of bats; thus, those studies have provided only part of the information needed by managers. We evaluated diurnal summer roost selection by the bat community at the forest-stand level in a diversely forested...

Retrieving forest stand parameters from SAR backscatter data using a neural network trained by a canopy backscatter model

International Nuclear Information System (INIS)

Wang, Y.; Dong, D.

1997-01-01

It was possible to retrieve the stand mean dbh (tree trunk diameter at breast height) and stand density from the Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) backscatter data by using threelayered perceptron neural networks (NNs). Two sets of NNs were trained by the Santa Barbara microwave canopy backscatter model. One set of the trained NNs was used to retrieve the stand mean dbh, and the other to retrieve the stand density. Each set of the NNs consisted of seven individual NNs for all possible combinations of one, two, and three radar wavelengths. Ground and multiple wavelength AIRSAR backscatter data from two ponderosa pine forest stands near Mt. Shasta, California (U.S.A.) were used to evaluate the accuracy of the retrievals. The r.m.s. and relative errors of the retrieval for stand mean dbh were 6.1 cm and 15.6 per cent for one stand (St2), and 3.1 cm and 6.7 per cent for the other stand (St11). The r.m.s. and relative errors of the retrieval for stand density were 71.2 treesha-1 and 23.0 per cent for St2, and 49.7 treesha-1 and 21.3 per cent for St11. (author)

Climatic factors controlling the productivity of pine stands. A model-based analysis

International Nuclear Information System (INIS)

McMurtrie, R.E.; Gholz, H.L.; Linder, S.; Gower, S.T.

1994-01-01

A process-based forest growth model, BIOMASS, is applied to stands of four pine species (Pinus elliottii, P. radiata, P. resinosa, and P. sylvestris) growing in five sub-tropical, temperate and boreal environments (in Australia, New Zealand, Florida, Sweden and Wisconsin). Measured annual above-ground net primary production (ANPP) at these sites ranges from 0.2 to 1.6 kg C m -2 . After establishing that simulated ANPP closely matches biomass production measured for the various stands, we analyse model runs to relate simulated productivity to absorbed photosynthetically-active radiation (APAR). Annual photosynthetic productivity (or gross primary production, GPP) simulated for the five stands is linearly related to utilizable APAR, derived by estimating the extent to which photosynthesis is limited by soil water deficit, high air saturation vapor deficit or low temperature. The reduction of GPP due to incomplete radiation interception is 10 to 25% for stands with high leaf area index (LAI) in Australia, New Zealand and Wisconsin and 50 to 60% for low LAI stands in Florida and Sweden. Gross carbon gain is reduced by a further 50 to 70% at sites experiencing cold winters (Sweden and Wisconsin), summer drought (Australia) or high summer humidity deficits (Australia and Wisconsin). Simulated carbon losses due to above-ground respiration average 50% of GPP, but are highly variable among the sites due to large differences in live biomass and tissue nitrogen concentrations. This results in a weaker relationship between simulated NPP and APAR. (au) 93 refs

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.

Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

Science.gov (United States)

CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

2013-12-01

Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

An integer programming model for a forest harvest problem in Pinus pinaster stands

Energy Technology Data Exchange (ETDEWEB)

Fonseca, T. F.; Cerveira, A.; Mota, A.

2012-11-01

The study addresses the special case of a management plan for maritime pine (Pinus pinaster Ait.) in common lands. The study area refers to 4,432 ha of maritime pine stands in North Portugal (Perimetro Florestal do Barroso in the county of Ribeira de Pena), distributed among five common lands called baldio areas. Those lands are co-managed by the Official Forest Services and the local communities, essentially for timber production, using empirical guidance. As the current procedure does not guarantee the best thinning and clear-cutting scheduling, it was considered important to develop easy-to-use models, supported by optimization techniques, to be employed by the forest managers in the harvest planning of these communitarian forests. Planning of the thinning and clear-cutting operations involved certain conditions, such as: (1) the optimal age for harvesting; (2) the maximum stand density permitted; (3) the minimum volume to be cut; (4) the guarantee of incomes for each of the five baldios in at least a two year period; (5) balanced incomes during the length of the projection period. In order to evaluate the sustainability of the wood resources, a set of constraints lower bounding the average ending age was additionally tested. The problem was formulated as an integer linear programming model where the incomes from thinning and clear-cutting are maximized while considering the constraints mentioned above. Five major scenarios were simulated. The simplest one allows for silvicultural constraints only, whereas the other four consider these constraints besides different management options. Two of them introduce joint management of all common areas with or without constraints addressing balanced distribution of incomes during the plan horizon, whilst the other two consider the same options but for individual management of the baldios. The proposed model is easy to apply, providing immediate advantages for short and mid-term planning periods compared to the empirical

An Old-Growth Definition for Southern Mixed Hardwood Forests

Science.gov (United States)

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...

Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon

Science.gov (United States)

Michelle C. Agne; David C. Shaw; Travis J. Woolley; Mónica E. Queijeiro-Bolaños; Mai-He. Li

2014-01-01

Lodgepole pine (Pinus contorta) forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes....

Exploiting Growing Stock Volume Maps for Large Scale Forest Resource Assessment: Cross-Comparisons of ASAR- and PALSAR-Based GSV Estimates with Forest Inventory in Central Siberia

Directory of Open Access Journals (Sweden)

Christian Hüttich

2014-07-01

Full Text Available Growing stock volume is an important biophysical parameter describing the state and dynamics of the Boreal zone. Validation of growing stock volume (GSV maps based on satellite remote sensing is challenging due to the lack of consistent ground reference data. The monitoring and assessment of the remote Russian forest resources of Siberia can only be done by integrating remote sensing techniques and interdisciplinary collaboration. In this paper, we assess the information content of GSV estimates in Central Siberian forests obtained at 25 m from ALOS-PALSAR and 1 km from ENVISAT-ASAR backscatter data. The estimates have been cross-compared with respect to forest inventory data showing 34% relative RMSE for the ASAR-based GSV retrievals and 39.4% for the PALSAR-based estimates of GSV. Fragmentation analyses using a MODIS-based land cover dataset revealed an increase of retrieval error with increasing fragmentation of the landscape. Cross-comparisons of multiple SAR-based GSV estimates helped to detect inconsistencies in the forest inventory data and can support an update of outdated forest inventory stands.

Indirect estimations and spatial variation in leaf area index of coniferous, deciduous and mixed forest stands in Forsmark and Laxemar

International Nuclear Information System (INIS)

Tagesson, Torbern

2006-12-01

Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57 deg 5 min N, 16 deg 7 min E) and the Forsmark investigation area (60 deg 4 min N, 18 deg 2 min E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosphere takes place, and leaf area index (LAI) of the vegetation cover is an important variable correlated to a number of ecophysiological parameters and hereby an important parameter in ecosystem models. In the investigation areas, LAI of boreal and temperate ecosystems were therefore estimated indirectly through optical measurements using the LAI-2000 (LI-COR, Cambridge UK) and TRAC (Tracing Radiation and Architecture of Canopies). On average, measured maximum LAI was 3.40 in Laxemar and 3.43 in Forsmark; minimum LAI was 1.65 in Laxemar and 1.97 in Forsmark. Forest inventory data showed that LAI is positively correlated with basal area, stand height, stand volume and breast height tree diameter. For the coniferous stands, there was also a linearly negative relationship with age. In the Laxemar investigation area, there were no significant relationships for LAI with a satellite derived kNN (kNearest Neighbor) data set with stand height, stand volume and stand age. The kNN data set can therefore not be used to extrapolate measured LAI over the Laxemar investigation area. There were significant relationships between LAI and the normalized difference vegetation index (NDVI) for coniferous, deciduous and mixed forest stands in the Laxemar investigation area. A NDVI image could be used to extrapolate LAI over the entire investigation area. For the Forsmark investigation area, effective LAI for all stands were correlated to NDVI and this relationship could then be used for extrapolation. The effective LAI image was afterwards corrected for average

Indirect estimations and spatial variation in leaf area index of coniferous, deciduous and mixed forest stands in Forsmark and Laxemar

Energy Technology Data Exchange (ETDEWEB)

Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Analysis, Lund Univ., Lund (Sweden)

2006-12-15

Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57 deg 5 min N, 16 deg 7 min E) and the Forsmark investigation area (60 deg 4 min N, 18 deg 2 min E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosphere takes place, and leaf area index (LAI) of the vegetation cover is an important variable correlated to a number of ecophysiological parameters and hereby an important parameter in ecosystem models. In the investigation areas, LAI of boreal and temperate ecosystems were therefore estimated indirectly through optical measurements using the LAI-2000 (LI-COR, Cambridge UK) and TRAC (Tracing Radiation and Architecture of Canopies). On average, measured maximum LAI was 3.40 in Laxemar and 3.43 in Forsmark; minimum LAI was 1.65 in Laxemar and 1.97 in Forsmark. Forest inventory data showed that LAI is positively correlated with basal area, stand height, stand volume and breast height tree diameter. For the coniferous stands, there was also a linearly negative relationship with age. In the Laxemar investigation area, there were no significant relationships for LAI with a satellite derived kNN (kNearest Neighbor) data set with stand height, stand volume and stand age. The kNN data set can therefore not be used to extrapolate measured LAI over the Laxemar investigation area. There were significant relationships between LAI and the normalized difference vegetation index (NDVI) for coniferous, deciduous and mixed forest stands in the Laxemar investigation area. A NDVI image could be used to extrapolate LAI over the entire investigation area. For the Forsmark investigation area, effective LAI for all stands were correlated to NDVI and this relationship could then be used for extrapolation. The effective LAI image was afterwards corrected for average

Quantitative retrieving forest ecological parameters based on remote sensing in Liping County of China

Science.gov (United States)

Tian, Qingjiu; Chen, Jing M.; Zheng, Guang; Xia, Xueqi; Chen, Junying

2006-09-01

Forest ecosystem is an important component of terrestrial ecosystem and plays an important role in global changes. Aboveground biomass (AGB) of forest ecosystem is an important factor in global carbon cycle studies. The purpose of this study was to retrieve the yearly Net Primary Productivity (NPP) of forest from the 8-days-interval MODIS-LAI images of a year and produce a yearly NPP distribution map. The LAI, DBH (diameter at breast height), tree height, and tree age field were measured in different 80 plots for Chinese fir, Masson pine, bamboo, broadleaf, mix forest in Liping County. Based on the DEM image and Landsat TM images acquired on May 14th, 2000, the geometric correction and terrain correction were taken. In addition, the "6S"model was used to gain the surface reflectance image. Then the correlation between Leaf Area Index (LAI) and Reduced Simple Ratio (RSR) was built. Combined with the Landcover map, forest stand map, the LAI, aboveground biomass, tree age map were produced respectively. After that, the 8-days- interval LAI images of a year, meteorology data, soil data, forest stand image and Landcover image were inputted into the BEPS model to get the NPP spatial distribution. At last, the yearly NPP spatial distribution map with 30m spatial resolution was produced. The values in those forest ecological parameters distribution maps were quite consistent with those of field measurements. So it's possible, feasible and time-saving to estimate forest ecological parameters at a large scale by using remote sensing.

Reducing uncertainty for estimating forest carbon stocks and dynamics using integrated remote sensing, forest inventory and process-based modeling

Science.gov (United States)

Poulter, B.; Ciais, P.; Joetzjer, E.; Maignan, F.; Luyssaert, S.; Barichivich, J.

2015-12-01

Accurately estimating forest biomass and forest carbon dynamics requires new integrated remote sensing, forest inventory, and carbon cycle modeling approaches. Presently, there is an increasing and urgent need to reduce forest biomass uncertainty in order to meet the requirements of carbon mitigation treaties, such as Reducing Emissions from Deforestation and forest Degradation (REDD+). Here we describe a new parameterization and assimilation methodology used to estimate tropical forest biomass using the ORCHIDEE-CAN dynamic global vegetation model. ORCHIDEE-CAN simulates carbon uptake and allocation to individual trees using a mechanistic representation of photosynthesis, respiration and other first-order processes. The model is first parameterized using forest inventory data to constrain background mortality rates, i.e., self-thinning, and productivity. Satellite remote sensing data for forest structure, i.e., canopy height, is used to constrain simulated forest stand conditions using a look-up table approach to match canopy height distributions. The resulting forest biomass estimates are provided for spatial grids that match REDD+ project boundaries and aim to provide carbon estimates for the criteria described in the IPCC Good Practice Guidelines Tier 3 category. With the increasing availability of forest structure variables derived from high-resolution LIDAR, RADAR, and optical imagery, new methodologies and applications with process-based carbon cycle models are becoming more readily available to inform land management.

NDE of logs and standing trees using new acoustic tools : technical application and results

Science.gov (United States)

Peter Carter; Xiping Wang; Robert J. Ross; David Briggs

2005-01-01

The new Director ST300 provides a means to efficiently assess stands for stiffness and related wood properties based on standing tree acoustic velocily measures, and can be easily integrated with pre-harvest and earlier stand assessments. This provides for effective valuation for forest sale, stumpage purchase, harvest planning, and ranking of progeny or clones in tree...

Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - I. Recently Cutover Natural Stands

Science.gov (United States)

James B. Baker; Michael G. Shelton

1998-01-01

A 1988 USDA Forest Service report indicated that 22% (40 million ac) of the commercial timberland in the South was understocked (less than 60% stocking) with desirable tree species for timber production (USDA Forest Service 1988). The understocked stands are usually the result of past har-vesting practices, natural catastrophes, or regeneration fail-ures. Understocked...

Foliar free polyamine and inorganic ion content in relation to soil and soil solution chemistry in two fertilized forest stands at the Harvard Forest, Massachusetts

Science.gov (United States)

Rakesh Minocha; Stephanie Long; Alison H. Magill; John Aber; William H. McDowell

2000-01-01

Polyamines (putrescine, spermidine, and spermine) are low molecular weight, open-chained, organic polycations which are found in all organisms and have been linked with stress responses in plants. The objectives of our study were to investigate the effects of chronic N additions to pine and hardwood stands at Harvard Forest, Petersham, MA on foliar polyamine and...

Can Forest Transformation Help Reducing Floods in Forested Watersheds?

DEFF Research Database (Denmark)

Wahl, Niels Arne; Wöllecke, B.; Benz, O.

2005-01-01

of the management practice of forest transformation in forested areas on soil hydraulic properties is presented and discussed as a means of preventing such disasters at a reasonable cost and during a foreseeable period. Investigations were carried out in northeastern Germany on forest stands differing in tree...... populations and stand structure. It was found that infiltration capacity and hydraulic conductivity K exhibit overall low values nevertheless the tree species. This finding appears to be related to water repellency, the predominating texture, and a poor macroporosity. During the different stages of forest...

Volume and weight characteristics of a typical Douglas-fir/ western larch stand, Coram Experimental Forest, Montana

Science.gov (United States)

Robert E. Benson; Joyce A. Schlieter

1980-01-01

An over-mature Douglas-fir/western larch stand on the Coram Experimental Forest in Montana averaged about 7,300 ft3/acre (511 rn3/ha) of wood over 3 inches (7.62 cm) in diameter, and an additional 57 tons/acre (128/ha) of fine material, before harvest. After logging, using three different cutting methods and four different levels of utilization, wood residues ranged...

Species Composition, Tree Quality and Wood Properties of Southern Pine Stands Under Ecosystemm Management on National Forests in the Peidmont and Coastal Plain

Science.gov (United States)

Alexander Clark; James W. McMinn

1999-01-01

National Forests in the United States are under sustainable ecosystem management to conserve biodiversity, achieve sustainable conditions and improve the balance among forest values. This paper reports on a study established to identify the implications of ecosystem management strategies on natural stands in the Piedmont and Coastal Plain. The impact of partial...

Estimation of crown biomass of Pinus pinaster stands and shrubland above-ground biomass using forest inventory data, remotely sensed imagery and spatial prediction models

Science.gov (United States)

H. Viana; J. Aranha; D. Lopes; Warren B. Cohen

2012-01-01

Spatially crown biomass of Pinus pinaster stands and shrubland above-ground biomass (AGB) estimation was carried-out in a region located in Centre-North Portugal, by means of different approaches including forest inventory data, remotely sensed imagery and spatial prediction models. Two cover types (pine stands and shrubland) were inventoried and...

Impact of Nitrogen Fertilization on Forest Carbon Sequestration and Water Loss in a Chronosequence of Three Douglas-Fir Stands in the Pacific Northwest

Directory of Open Access Journals (Sweden)

Xianming Dou

2015-05-01

Full Text Available To examine the effect of nitrogen (N fertilization on forest carbon (C sequestration and water loss, we used an artificial neural network model to estimate C fluxes and evapotranspiration (ET in response to N fertilization during four post-fertilization years in a Pacific Northwest chronosequence of three Douglas-fir stands aged 61, 22 and 10 years old in 2010 (DF49, HDF88 and HDF00, respectively. Results showed that N fertilization increased gross primary productivity (GPP for all three sites in all four years with the largest absolute increase at HDF00 followed by HDF88. Ecosystem respiration increased in all four years at HDF00, but decreased over the last three years at HDF88 and over all four years at DF49. As a result, fertilization increased the net ecosystem productivity of all three stands with the largest increase at HDF88, followed by DF49. Fertilization had no discernible effect on ET in any of the stands. Consequently, fertilization increased water use efficiency (WUE in all four post-fertilization years at all three sites and also increased light use efficiency (LUE of all the stands, especially HDF00. Our results suggest that the effects of fertilization on forest C sequestration and water loss may be associated with stand age and fertilization; the two younger stands appeared to be more efficient than the older stand with respect to GPP, WUE and LUE.

Cycling of acid and base cations in deciduous stands of Huntington Forest, New York, and Turkey Lakes, Ontario

Energy Technology Data Exchange (ETDEWEB)

Foster, N W; Morrison, I K [Forestry Canada, Sault Ste. Marie, ON (Canada); Mitchell, M J [State Univ. of New York, Syracuse, NY (USA); Shepard, J P [National Council of the Paper Industry for Air and Stream Improvement, Gainesville, FL (USA)

1992-01-01

Annual nutrient fluxes within two forests exposed to acidic deposition were compared for a 1-year period. Calcium (Ca{sup 2+}) was the dominant cation in throughfall and soil solutions from tolerant hardwood dominated Spodosols (Podzols) at both Huntington Forest (HF), New York, and the Turkey Lakes watershed (TLW), Ontario. There was a net annual export of Ca{sup 2+} and Mg{sup 2+} from the TLW soil, whereas base cation inputs in precipitation equalled outputs at HF. In 1986, leaching losses of base cations were five times greater at TLW than at HF. A higher percentage of the base cation reserves was leached from the soil at TLW (5%) than at HF (1%). Relative to throughfall, aluminum concentrations increased in forest-floor and mineral-soil solutions, especially at HF. The TLW soil appears more sensitive to soil acidification. Deposited atmospheric acidity, however, was small in comparison with native soil acidity (total and exchangeable) and the reserves of base cations in each soil. Soil acidity and base saturation, therefore, are likely only to change slowly. 57 refs., 1 fig., 5 tabs.

Spectral Similarity and PRI Variations for a Boreal Forest Stand Using Multi-angular Airborne Imagery

Directory of Open Access Journals (Sweden)

Vincent Markiet

2017-09-01

Full Text Available The photochemical reflectance index (PRI is a proxy for light use efficiency (LUE, and is used in remote sensing to measure plant stress and photosynthetic downregulation in plant canopies. It is known to depend on local light conditions within a canopy indicating non-photosynthetic quenching of incident radiation. Additionally, when measured from a distance, canopy PRI depends on shadow fraction—the fraction of shaded foliage in the instantaneous field of view of the sensor—due to observation geometry. Our aim is to quantify the extent to which sunlit fraction alone can describe variations in PRI so that it would be possible to correct for its variation and identify other possible factors affecting the PRI–sunlit fraction relationship. We used a high spatial and spectral resolution Aisa Eagle airborne imaging spectrometer above a boreal Scots pine site in Finland (Hyytiälä forest research station, 61°50′N, 24°17′E, with the sensor looking in nadir and tilted (off-nadir directions. The spectral resolution of the data was 4.6 nm, and the spatial resolution was 0.6 m. We compared the PRI for three different scatter angles ( β = 19 ° , 55 ° and 76 °, defined as the angle between sensor and solar directions at the forest stand level, and observed a small (0.006 but statistically significant (p < 0.01 difference in stand PRI. We found that stand mean PRI was not a direct function of sunlit fraction. However, for each scatter angle separately, we found a clear non-linear relationship between PRI and sunlit fraction. The relationship was systematic and had a similar shape for all of the scatter angles. As the PRI–sunlit fraction curves for the different scatter angles were shifted with respect to each other, no universal curve could be found causing the observed independence of canopy PRI from the average sunlit fraction of each view direction. We found the shifts of the curves to be related to a leaf structural effect on canopy

Assessing the effects of management on forest growth across France: insights from a new functional-structural model.

Science.gov (United States)

Guillemot, Joannès; Delpierre, Nicolas; Vallet, Patrick; François, Christophe; Martin-StPaul, Nicolas K; Soudani, Kamel; Nicolas, Manuel; Badeau, Vincent; Dufrêne, Eric

2014-09-01

The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional-structural model is presented and is used to assess the effects of management on forest functioning at a national scale. The stand process-based model (PBM) CASTANEA was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled CASTANEA-SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth. The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the CASTANEA PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale. This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield.

Test of four stand growth simulators for the northeastern United States

Science.gov (United States)

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...

Proceedings from a workshop on Sustainable forest management in tropical forests of Guyana

Energy Technology Data Exchange (ETDEWEB)

Hagner, Mats [ed.] [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Silviculture; Maluenda, J. [ed.] [ORGUT Consulting AB, Stockholm (Sweden)

1998-12-31

Guyana officials were certain that an efficient forest management could yield economic benefits to the country, while still allowing for the sustainability of its forest resources. Standards will be set in a Code of Practice (COP). Lectures, presented in the proceeding, were mixed with group discussions and finally the 26 participants gave their written view of `What has to be done in Guyana and by whom?`. Amerindians wanted their own foresters should be recruited to oversee the activities on their own land. Bushmilling need to be controlled but not banned. Monitoring timber products and control of hunting should be stricter. COP should set standards for the residual stand. Environmental Protection Agency wanted more research and training, with aim of self-monitoring capability for forest users. Forest Products Association recommended government to co-operate for refinement of: training, mapping of resources, harvesting plans, concession agreements, road building, and bushmilling. Forestry Commission wanted concession allocation procedures to be reviewed: zonation of chainsaw activities, protection of small-scale operators, management plans. COP should be revised and tested in practice. Suggestion about standards for residual stand should be considered. ORGUT Lecturers recommended a standard for residual stand, a vertical and horizontal spot density measure. Based on that the concession holder could harvest what, where and when be preferred and chose the most efficient technique

Proceedings from a workshop on Sustainable forest management in tropical forests of Guyana

Energy Technology Data Exchange (ETDEWEB)

Hagner, Mats [ed.; Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Silviculture; Maluenda, J [ed.; ORGUT Consulting AB, Stockholm (Sweden)

1999-12-31

Guyana officials were certain that an efficient forest management could yield economic benefits to the country, while still allowing for the sustainability of its forest resources. Standards will be set in a Code of Practice (COP). Lectures, presented in the proceeding, were mixed with group discussions and finally the 26 participants gave their written view of `What has to be done in Guyana and by whom?`. Amerindians wanted their own foresters should be recruited to oversee the activities on their own land. Bushmilling need to be controlled but not banned. Monitoring timber products and control of hunting should be stricter. COP should set standards for the residual stand. Environmental Protection Agency wanted more research and training, with aim of self-monitoring capability for forest users. Forest Products Association recommended government to co-operate for refinement of: training, mapping of resources, harvesting plans, concession agreements, road building, and bushmilling. Forestry Commission wanted concession allocation procedures to be reviewed: zonation of chainsaw activities, protection of small-scale operators, management plans. COP should be revised and tested in practice. Suggestion about standards for residual stand should be considered. ORGUT Lecturers recommended a standard for residual stand, a vertical and horizontal spot density measure. Based on that the concession holder could harvest what, where and when be preferred and chose the most efficient technique

Carbon Storage and Allocation Pattern in Plant Biomass among Different Forest Plantation Stands in Guangdong, China

Directory of Open Access Journals (Sweden)

Yuanqi Chen

2015-03-01

Full Text Available In order to understand how carbon storage and allocation patterns vary among plantation types, we estimated carbon allocation between above- and below-ground compartments in four subtropical plantations and a naturally recovered shrubland (as a control. Results indicated that the carbon storage and allocation pattern varied greatly among forest types and was highly dependent on specific traits of trees and understory vegetation. The fast-growing species, such as Eucalyptus urophylla, accumulated more carbon in plant biomass. The biomass carbon was about 1.9- and 2.2-times greater than the 10-species mixed plantation and Castanopsis hystrix plantations, respectively. Meanwhile, the plantations sequestered 1.5- to 3-times more carbon in biomass than naturally recovered shrubland. The carbon allocation pattern between above- and below-ground compartments also varied with plantation type and stand age. The ratio of tree root carbon to tree aboveground carbon decreased with stand age for Eucalyptus urophylla and the 10-species mixed plantation. In contrast, the ratio increased for Acacia crassicarpa. Our data suggested that planting the fast-growing species in the degraded land of subtropical China was an effective choice in terms of carbon sequestration. The information about carbon allocation patterns was also valuable for decision making in sustainable forest management and climate change mitigation.

Does nitrogen and sulfur deposition affect forest productivity?

Science.gov (United States)

Brittany A. Johnson; Kathryn B. Piatek; Mary Beth Adams; John R. Brooks

2010-01-01

We studied the effects of atmospheric nitrogen and sulfur deposition on forest productivity in a 10-year-old, aggrading forest stand at the Fernow Experimental Forest in Tucker County, WV. Forest productivity was expressed as total aboveground wood biomass, which included stem and branch weight of standing live trees. Ten years after stand regeneration and treatment...

Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

Directory of Open Access Journals (Sweden)

F. J. Bohn

2018-03-01

Full Text Available Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP. It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q and a species distribution index (ΩAWP. ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length. The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a

Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

Science.gov (United States)

Bohn, Friedrich J.; May, Felix; Huth, Andreas

2018-03-01

Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant

Influence of timber harvesting costs on the layout of cuttings and economic return in forest planning based on dynamic treatment units

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Adrián Pascual

2018-05-01

Full Text Available Aim of study: To analyze the influence of harvesting costs on the distribution and type of cuttings when forest management planning is based on the dynamic treatment units (DTUs approach. Area of study: A Mediterranean pine forest in Central Spain. Materials and methods: Airborne laser scanning data were used in area-based approach to predict stand attributes and delineate segments that were used as calculation units. Predicted stand attributes and existing models for diameter distribution and individual-tree growth were used to simulate alternative management schedules for each segment for a 60-year planning horizon divided into three 20-year periods. Three alternative forest planning problems were formulated. They aimed to maximize or minimize net income, or maximize timber production with a constant flow of harvested timber. Spatial goals were used in all cases to enhance the clustering of treatments. Main results: Maxizing timber production without considering harvesting costs can be costly, even close to the plan that minimized net incomes. Maximizing net incomes led to frequent use of final felling instead of thinnings, placing cuttings near forest roads and creating more compact DTUs than obtained in the plan that maximized timber production. Research highlights: Compared to previous studies on DTUs, this study integrated felling and forwarding costs, which depended on distance to road and stand attributes, in the process of creating DTUs by means of spatial optimization.

Using wood-based structural products as forest management tools to improve forest health, sustainability and reduce forest fuels : a research program of the USDA Forest Service under the National Fire Plan

Science.gov (United States)

John F. Hunt; Jerrold E. Winandy

2002-01-01

Currently, after logging or thinning operations much of the low value timber is either left standing or is felled and left on the ground, chipped, or burned because most North American mills are not equipped to handle this material. In many areas of Western U.S., this forest residue does not decompose if felled and it soon becomes susceptible to forest insect or...

Nutrient cycling in Huntington Forest and Turkey Lakes deciduous stands: Nitrogen and sulfur

Energy Technology Data Exchange (ETDEWEB)

Mitchell, M J [State Univ. of New York, Syracuse, NY (USA); Foster, N W; Morrison, I K [Forestry Canada, Sault Ste. Marie, ON (Canada); Shepard, J P [National Council of the Paper Industry for Air and Stream Improvement, Gainsville, FL (USA)

1992-01-01

A study was conducted to analyze two tolerant hardwood forests that are exhibiting different levels of nitrate and sulfate leaching. Fluxes of N and S at the two sites were compared, and the fluxes of nitrate and sulfate through the forest canopy, forest floor, and mineral soil were determined in order to ascertain whether differences in these fluxes could be explained using information on the N, S, and C biogeochemistry of each site. One site is in the Adirondack region, where the impacts of acidic deposition have been noted; the other site is in central Ontario, and has geological, pedological, and hydrological characteristics that make it potentially sensitive to acidic deposition. An increase in concentration of sulfate and nitrate was noted after passage through the canopy at both sites. The Ontario site showed much greater leaching of nitrate. At the Adirondack site only, there was a marked increase in sulfate flux when water leached from the forest floor through the soil. The mineral soil was the largest pool of N and S for both sites. The Ontario soil had a C/N ratio of 16:1, narrower than the 34:1 ratio of the soil at the other site. The former ratio should favor accumulation of ammonium and nitrate ions, and subsequent nitrate leaching. Laboratory measurements suggest that the forest floor at the Ontario site may have higher N mineralization rates. Fluxes of N and S within the vegetation were generally similar at both sites. The higher nitrate leaching at the Ontario site may be attributed mostly to stand maturity coupled with tree mortality, but the absence of slow decomposing beech leaf litter and lower C/N ratio in the soil may also be contributing factors. 50 refs., 3 figs., 6 tabs.

Red-cockaded woodpecker male/female foraging differences in young forest stands.

Energy Technology Data Exchange (ETDEWEB)

Franzreb, Kathleen, E.

2010-07-01

ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering seven woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.

Modelling mixed forest growth : a review of models for forest management

NARCIS (Netherlands)

Porte, A.; Bartelink, H.H.

2002-01-01

Most forests today are multi-specific and heterogeneous forests (`mixed forests'). However, forest modelling has been focusing on mono-specific stands for a long time, only recently have models been developed for mixed forests. Previous reviews of mixed forest modelling were restricted to certain

Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

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R. Poyatos

2005-01-01

Full Text Available Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L. and a pubescent oak (Quercus pubescens Willd. forests located in a montane area of the Eastern Pyrenees (NE Spain. The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand (Ec was only 110 mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0 in the oak stand compares well with the expected values predicted for low leaf area index (LAI oak forests in southern Europe. Scots pine showed a strong reduction in (Ec/ET0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interannual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September in 2003 was almost 40% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dd and soil water status.

Soil moisture in sessile oak forest gaps

Science.gov (United States)

Zagyvainé Kiss, Katalin Anita; Vastag, Viktor; Gribovszki, Zoltán; Kalicz, Péter

2015-04-01

By social demands are being promoted the aspects of the natural forest management. In forestry the concept of continuous forest has been an accepted principle also in Hungary since the last decades. The first step from even-aged stand to continuous forest can be the forest regeneration based on gap cutting, so small openings are formed in a forest due to forestry interventions. This new stand structure modifies the hydrological conditions for the regrowth. Without canopy and due to the decreasing amounts of forest litter the interception is less significant so higher amount of precipitation reaching the soil. This research focuses on soil moisture patterns caused by gaps. The spatio-temporal variability of soil water content is measured in gaps and in surrounding sessile oak (Quercus petraea) forest stand. Soil moisture was determined with manual soil moisture meter which use Time-Domain Reflectometry (TDR) technology. The three different sizes gaps (G1: 10m, G2: 20m, G3: 30m) was opened next to Sopron on the Dalos Hill in Hungary. First, it was determined that there is difference in soil moisture between forest stand and gaps. Second, it was defined that how the gap size influences the soil moisture content. To explore the short term variability of soil moisture, two 24-hour (in growing season) and a 48-hour (in dormant season) field campaign were also performed in case of the medium-sized G2 gap along two/four transects. Subdaily changes of soil moisture were performed. The measured soil moisture pattern was compared with the radiation pattern. It was found that the non-illuminated areas were wetter and in the dormant season the subdaily changes cease. According to our measurements, in the gap there is more available water than under the forest stand due to the less evaporation and interception loss. Acknowledgements: The research was supported by TÁMOP-4.2.2.A-11/1/KONV-2012-0004 and AGRARKLIMA.2 VKSZ_12-1-2013-0034.

Further Studies of Forest Structure Parameter Retrievals Using the Echidna® Ground-Based Lidar

Science.gov (United States)

Strahler, A. H.; Yao, T.; Zhao, F.; Yang, X.; Schaaf, C.; Wang, Z.; Li, Z.; Woodcock, C. E.; Culvenor, D.; Jupp, D.; Newnham, G.; Lovell, J.

2012-12-01

Ongoing work with the Echidna® Validation Instrument (EVI), a full-waveform, ground-based scanning lidar (1064 nm) developed by Australia's CSIRO and deployed by Boston University in California conifers (2008) and New England hardwood and softwood (conifer) stands (2007, 2009, 2010), confirms the importance of slope correction in forest structural parameter retrieval; detects growth and disturbance over periods of 2-3 years; provides a new way to measure the between-crown clumping factor in leaf area index retrieval using lidar range; and retrieves foliage profiles with more lower-canopy detail than a large-footprint aircraft scanner (LVIS), while simulating LVIS foliage profiles accurately from a nadir viewpoint using a 3-D point cloud. Slope correction is important for accurate retrieval of forest canopy structural parameters, such as mean diameter at breast height (DBH), stem count density, basal area, and above-ground biomass. Topographic slope can induce errors in parameter retrievals because the horizontal plane of the instrument scan, which is used to identify, measure, and count tree trunks, will intersect trunks below breast height in the uphill direction and above breast height in the downhill direction. A test of three methods at southern Sierra Nevada conifer sites improved the range of correlations of these EVI-retrieved parameters with field measurements from 0.53-0.68 to 0.85-0.93 for the best method. EVI scans can detect change, including both growth and disturbance, in periods of two to three years. We revisited three New England forest sites scanned in 2007-2009 or 2007-2010. A shelterwood stand at the Howland Experimental Forest, Howland, Maine, showed increased mean DBH, above-ground biomass and leaf area index between 2007 and 2009. Two stands at the Harvard Forest, Petersham, Massachusetts, suffered reduced leaf area index and reduced stem count density as the result of an ice storm that damaged the stands. At one stand, broken tops were

Influence of Forest-Canopy Morphology and Relief on Spectral Characteristics of Taiga Forests

Science.gov (United States)

Zhirin, V. M.; Knyazeva, S. V.; Eydlina, S. P.

2017-12-01

The article deals with the results of a statistical analysis reflecting tendencies (trends) of the relationship between spectral characteristics of taiga forests, indicators of the morphological structure of forest canopy and illumination of the territory. The study was carried out on the example of the model forest territory of the Priangarskiy taiga region of Eastern Siberia (Krasnoyarsk krai) using historical data (forest inventory 1992, Landsat 5 TM 16.06.1989) and the digital elevation model. This article describes a method for determining the quantitative indicator of morphological structure of forest canopy based on taxation data, and the authors propose to subdivide the morphological structure into high complexity, medium complexity, and relatively simple. As a result of the research, dependences of average values of spectral brightness in near and short-wave infrared channels of a Landsat 5 TM image for dark-coniferous, light-coniferous and deciduous forests from the degree of complexity of the forest-canopy structure are received. A high level of variance and maximum brightness average values are marked in green moss (hilocominosa) dark-coniferous and various-grass (larioherbosa) dark-coniferous forests and light-coniferous forests with a complex structure of canopy. The parvifoliate forests are characterized by high values of brightness in stands with a relatively simple structure of the canopy and by a small variance in brightness of any degree of the structure of the canopy complexity. The increase in brightness for the lit slopes in comparison with shaded ones in all stands with a difficult morphological canopy structure is revealed. However, the brightness values of the lit and shaded slopes do not differ for stands with a medium complexity of the structure. It is noted that, in addition to the indicator of the forest-canopy structure, the possible impact on increasing the variance of spectral brightness for the taxation plot has a variability of the

Converting partially-stocked aspen stands to fully-stocked stands in the Lake States: an economic analysis.

Science.gov (United States)

Jeffrey T. Olson; Allen L. Lundgren

1978-01-01

The 1968 Wisconsin Forest Survey showed large areas of aspen type that are not considered fully stocked. The economic feasibility of converting partially-stocked stands to full stocking is examined, and a rule presented for determining when a partially-stocked stand should be harvested to maximize its present value.

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.

Genetic variability and health of Norway spruce stands in the Regional Directorate of the State Forests in Krosno

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Gutkowska Justyna

2017-03-01

Full Text Available The study was conducted in 2015 in six spruce stands situated in different forest districts administratively belonging to the Regional Directorate of State Forests in Krosno. Each spruce population was represented by 30 trees and assessed in terms of their current health status. Genetic analyses were performed on shoot samples from each tree using nine nuclear DNA markers and one mitochondrial DNA marker (nad1. The health status of the trees was described according to the classification developed by Szczepkowski and Tarasiuk (2005 and the correlation between health classes and the level of genetic variability was computed with STATISTICA (α = 0.05.

Production and standing crop of litter and humus in a forest exposed to chronic gamma irradiation for twelve years

International Nuclear Information System (INIS)

Armentano, T.V.; Woodwell, G.M.

1976-01-01

Continuous exposure since 1961 of an oak-pine forest at Brookhaven National Laboratory to chronic gamma irradiation has shown: (1) progressive reduction in litter production from the first year through 1965; (2) greater litter production in 1973 compared to 1965 at exposure rates below 9 R/day primarily because of the prolific sprouting of the oaks, especially Quercus alba; (3) further reduction in litter production in intermediate zones (14-49 R/day) from 1965 to 1973 as a result of replacement of the forest by a Carex pensylvanica mat; (4) increased litter production in the high exposure zone (125 R/day) in 1973 as a result of colonization by adventive species; (5) reduction in the standing crop of litter by 1973 at the lowest exposure rate studied (3.5 R/day) although in 1965 there was no reduction at exposure rates up to 15 R/day; (6) decline in humus content at 4.6 R/day and above with the standing crop in the Carex zone exceeding that of the shrub and damaged forest zones of lower exposures. Both further losses and partial recovery in the production and storage of organic matter have occurred since 1965. These changes constitute a portion of the long-term response of the forest to chronic disturbance. The pattern of response is the result of ecosystem processes that are still not in equilibrium with the chronic disturbance and which were not predictable from short-term studies, even those spanning as much as 4 yr

Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

Science.gov (United States)

Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

2008-12-01

Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels.

Features of secondary birch young stands in low mountain Pokuttya (Ukrainian Carpathian Mts. )

OpenAIRE

MILEVSKAYA S.Y.

2015-01-01

Forest landscapes of the region during the last 3–5 centuries undergone the profound anthropogenic transformation. Secondary young stands occupy 25% of the total forest area. The problem of derivatives is particularly relevant for the modern forest typology in the Carpathian region. It requires the reflection in its dynamic trends shaping the stands, especially mixed young stands. The aim of our study consisted in getting the knowledge of the structural features of the secondary phytocoenosis...

Species Diversity of Oak Stands and Its Significance for Drought Resistance

Directory of Open Access Journals (Sweden)

Jan Kotlarz

2018-03-01

Full Text Available Drought periods have an adverse impact on the condition of oak stands. Research on different types of ecosystems has confirmed a correlation between plant species diversity and the adverse effects of droughts. The purpose of this study was to investigate the changes that occurred in an oak stand (Krotoszyn Plateau, Poland under the impact of the summer drought in 2015. We used a method based on remote sensing indices from satellite images in order to detect changes in the vegetation in 2014 and 2015. A positive difference was interpreted as an improvement, whereas a negative one was treated as a deterioration of the stand condition. The Shannon-Wiener species diversity was estimated using an iterative principal component analysis (PCA algorithm based on aerial images. We observed a relationship between the species indices of the individual forest divisions and their response to drought. The highest correlation between the index differences and the Shannon-Wiener indices was found for the Green Normalized Difference Vegetation Index (GNDVI index (+0.74. In addition, correlations were observed between the mean index difference and the percentage shares in the forest divisions of species such as Pinus sylvestris L. (P. sylvestris (+0.67 ± 0.08 and Quercus robur L. (Q. robur (−0.65 ± 0.10. Our results lead us to infer that forest management based on highly diverse habitats is more suitable to meet the challenges in the context of global climatic changes, characterized by increasingly frequent droughts.

Methods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States

Science.gov (United States)

James E. Smith; Linda S. Heath; Kenneth E. Skog; Richard A. Birdsey

2006-01-01

This study presents techniques for calculating average net annual additions to carbon in forests and in forest products. Forest ecosystem carbon yield tables, representing stand-level merchantable volume and carbon pools as a function of stand age, were developed for 51 forest types within 10 regions of the United States. Separate tables were developed for...

EUFODOS: European Forest Downstream Services - Improved Information on Forest Structure and Damage

Science.gov (United States)

Hirschmugl, M.; Gallaun, H.; Wack, R.; Granica, K.; Schardt, M.

2013-05-01

Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs) thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i) the forest border line, (ii) the segmentation of forest stands and (iii) the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R) of 0.79.

Do Pine Trees in Aspen Stands Increase Bird Diversity

OpenAIRE

Rumble, Mark A; Mills, Todd R; Dystra, Brian L; Flake, Lester D

2001-01-01

In the Black Hills of South Dakota, quaking aspen (Populus tremuloides) is being replaced by conifers through fire suppression and successional processes. Al- though the Black Hills National forest is removing conifers (primarily ponderosa pine [Pinus ponderosa])toincreasetheaspencommunitiesinsomemixedstands,ForestPlan guidelines allow four conifers per hectare to remain to increase diversity in the remaining aspen stand. We compared bird species richness in pure ponderosa pine, mixed stands ...

Data Assimilation in Forest Inventory: First Empirical Results

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Mattias Nyström

2015-12-01

Full Text Available Data assimilation techniques were used to estimate forest stand data in 2011 by sequentially combining remote sensing based estimates of forest variables with predictions from growth models. Estimates of stand data, based on canopy height models obtained from image matching of digital aerial images at six different time-points between 2003 and 2011, served as input to the data assimilation. The assimilation routines were built on the extended Kalman filter. The study was conducted in hemi-boreal forest at the Remningstorp test site in southern Sweden (lat. 13°37′ N; long. 58°28′ E. The assimilation results were compared with two other methods used in practice for estimation of forest variables: the first was to use only the most recent estimate obtained from remotely sensed data (2011 and the second was to forecast the first estimate (2003 to the endpoint (2011. All three approaches were validated using nine 40 m radius validation plots, which were carefully measured in the field. The results showed that the data assimilation approach provided better results than the two alternative methods. Data assimilation of remote sensing time series has been used previously for calibrating forest ecosystem models, but, to our knowledge, this is the first study with real data where data assimilation has been used for estimating forest inventory data. The study constitutes a starting point for the development of a framework useful for sequentially utilizing all types of remote sensing data in order to provide precise and up-to-date estimates of forest stand parameters.

13C-isotopic fingerprint of Pinus pinaster Ait. and Pinus sylvestris L. wood related to the quality of standing tree mass in forests from NW Spain.

Science.gov (United States)

Fernandez, Irene; González-Prieto, Serafin J; Cabaneiro, Ana

2005-01-01

Pine forest plantations of Pinus pinaster Ait. and P. sylvestris L. located in Galicia, NW Spain, were selected to study the 13C/12C-isotopic fingerprint in wood core samples in order to find possible relationships between the delta(13)C at natural abundance levels and the quality of the standing tree mass. For each pine species, 24 forests growing on acidic soils were studied: half developed over granite and half over schists. Two dominant trees from each plot, corresponding to all possible combinations of forest stands with high or low site index and with adults or young trees, were drilled at the basal part of trunks using a Pressler drill to obtain tree ring samples. The C-isotopic compositions of the litter and the soil organic matter from different soil depths were also determined and statistically significant correlations between these values and the 13C content of the wood were observed. Despite internal variations due to the influence of site index, tree age and parent material, the isotopic fingerprint of P. pinaster wood (mean value delta13C=-26.2+/-0.8 per thousand) significantly differed (Ppinaster stands (r=-0.667, Ppinaster growing over schists (r=-0.833, Ppinaster trees is higher when plots over granite or schists are separately considered. A similar fact occurs for adult P. sylvestris trees from schists stands, high quality specimens being 13C-depleted compared with low quality ones. On the other hand, 13C natural abundance of wood from P. sylvestris trees seems to be also strongly influenced by the underlying parent material, young trees from granite stands having a statistically higher 13C-isotopic composition (P<0.05) than young trees from schists stands. Copyright (c) 2005 John Wiley & Sons, Ltd.

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.

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.

Spatial Structure Indices of Mature Pedunculate Oak Stands in NW Croatia

Directory of Open Access Journals (Sweden)

Krunoslav Indir

2013-06-01

was 1.02 to 1.51. This indicated a tendency to a regular distribution of trees. The species mingling index that considered three nearest neighbouring trees was 0.395 to 0.620. When observing four nearest neighbouring trees, the index values showed slight decreases in all age classes. The diameter differentiation index (0.407-0.424 when three or four nearest neighbour trees were taken into account, showed almost the same differentiation in the 5th, 6th and 7th age class. Conclusion: Though they contained the component of distance between the trees and were based on individual trees parameters, the three analysed stand structure indicators were a useful tool in further categorizing of forest stands.

Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

Science.gov (United States)

Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

2015-04-01

Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

Fuels planning: science synthesis and integration; forest structure and fire hazard fact sheet 03: visualizing forest structure and fuels

Science.gov (United States)

Rocky Mountain Research Station USDA Forest Service

2004-01-01

The software described in this fact sheet provides managers with tools for visualizing forest and fuels information. Computer-based landscape simulations can help visualize stand and landscape conditions and the effects of different management treatments and fuel changes over time. These visualizations can assist forest planning by considering a range of management...

Structural attributes of stand overstory and light under the canopy

Directory of Open Access Journals (Sweden)

Alice Angelini

2015-02-01

Full Text Available  This paper reviews the literature relating to the relationship between light availability in the understory and the main qualitative and quantitative attributes of stand overstory usually considered in forest management and planning (species composition, density, tree sizes, etc. as well as their changes as consequences of harvesting. The paper is divided in two sections: the first one reviews studies which investigated the influence of species composition on understory light conditions; the second part examines research on the relationships among stand parameters determined from dendrometric field data and the radiation on understory layer. The objective was to highlight which are the most significant stand traits and management features to build more practical models for predicting light regimes in any forest stand and, in more general terms, to support forest managers in planning and designing silvicultural treatments that retain structure in different way in order to meet different objectives.

Effects of intermediate-severity disturbance on composition and structure in mixed Pinus-hardwood stands

Science.gov (United States)

Benjamin Trammell; Justin Hart; Callie Schweitzer; Daniel C. Dey; Michael Steinberg

2017-01-01

Increasingly, forest managers intend to create or maintain mixed Pinus-hardwood stands. This stand assemblage may be driven by a variety of objectives but is often motivated by the desire to enhance native forest diversity and promote resilience to perturbations. Documenting the effects of natural disturbances on species composition and stand...

Examining conifer canopy structural complexity across forest ages and elevations with LiDAR data

Science.gov (United States)

Van R. Kane; Jonathan D. Bakker; Robert J. McGaughey; James A. Lutz; Rolf F. Gersonde; Jerry F. Franklin

2010-01-01

LiDAR measurements of canopy structure can be used to classify forest stands into structural stages to study spatial patterns of canopy structure, identify habitat, or plan management actions. A key assumption in this process is that differences in canopy structure based on forest age and elevation are consistent with predictions from models of stand development. Three...

Acute and long-term effects of irradiation on pine (Pinus silvestris) stands post-Chernobyl

International Nuclear Information System (INIS)

Arkhipov, N.P.; Kuchma, N.D.; Askbrant, S.; Pasternak, P.S.; Musica, V.V.

1994-01-01

The effect of ionizing irradiation on the viability of pine stands after the fallout from the damaged nuclear energy plant at Chernobyl (ChNPP) was shown within the territory of the 10-km zone. During the period 1986-1991, irradiated and damaged forest stands, so-called 'red forest', located in this area were systematically classified by observation. Mortality rate, re-establishment, development of tree canopies, reproduction anomalies and stand viability were shown to be dependent on absorbed irradiation dose, on the age of the stand and on forest composition. For pine stands in the acutely affected zone, doses of more than 60 Gy resulted in a massive mortality and no regeneration of pine trees since 1987. The injured trees had burned or had dried-up. The drying process was accelerated by a massive production of pathogenic insects invading the dying trees. Specifically, irradiation doses of 10-60 Gy, 1-10 Gy and 0.1-1 Gy caused high, medium and low injury to the forest stands, respectively. Doses of less than 0.1 Gy did not cause any visible damage to the trees. In 1987, repair processes were displayed by the tree canopies and practically the entire viability of the forest stands had recovered except for trees in the acute and highly affected zones. The young forest was reestablished in the same place as the perished trees and new pine saplings were planted on the reclaimed areas

Acute and long-term effects of irradiation on pine (Pinus silvestris) stands post-Chernobyl

Energy Technology Data Exchange (ETDEWEB)

Arkhipov, N.P.; Kuchma, N.D. (Department of Radiology and Land Restoration, Pripyat Research and Industrial Association, Chernobyl (Ukraine)); Askbrant, S. (National Radiation Protection Institute, Stockholm (Sweden)); Pasternak, P.S.; Musica, V.V. (Lyes Research and Industrial Association, Kharykov (Ukraine))

1994-10-14

The effect of ionizing irradiation on the viability of pine stands after the fallout from the damaged nuclear energy plant at Chernobyl (ChNPP) was shown within the territory of the 10-km zone. During the period 1986-1991, irradiated and damaged forest stands, so-called 'red forest', located in this area were systematically classified by observation. Mortality rate, re-establishment, development of tree canopies, reproduction anomalies and stand viability were shown to be dependent on absorbed irradiation dose, on the age of the stand and on forest composition. For pine stands in the acutely affected zone, doses of more than 60 Gy resulted in a massive mortality and no regeneration of pine trees since 1987. The injured trees had burned or had dried-up. The drying process was accelerated by a massive production of pathogenic insects invading the dying trees. Specifically, irradiation doses of 10-60 Gy, 1-10 Gy and 0.1-1 Gy caused high, medium and low injury to the forest stands, respectively. Doses of less than 0.1 Gy did not cause any visible damage to the trees. In 1987, repair processes were displayed by the tree canopies and practically the entire viability of the forest stands had recovered except for trees in the acute and highly affected zones. The young forest was reestablished in the same place as the perished trees and new pine saplings were planted on the reclaimed areas.

Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics.

Science.gov (United States)

Itter, Malcolm S; Finley, Andrew O; D'Amato, Anthony W; Foster, Jane R; Bradford, John B

2017-06-01

Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

Science.gov (United States)

Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.

2017-01-01

Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

EUFODOS: European Forest Downstream Services – Improved Information on Forest Structure and Damage

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M. Hirschmugl

2013-05-01

Full Text Available Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i the forest border line, (ii the segmentation of forest stands and (iii the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R of 0.79.

Carbon Flux of Down Woody Materials in Forests of the North Central United States

International Nuclear Information System (INIS)

Woodall, C.W.

2010-01-01

Across large scales, the carbon (C) flux of down woody material (DWM) detrital pools has largely been simulated based on forest stand attributes (e.g., stand age and forest type). The annual change in forest DWM C stocks and other attributes (e.g., size and decay class changes) was assessed using a forest inventory in the north central United States to provide an empirical assessment of strategic-scale DWM C flux. Using DWM inventory data from the USDA Forest Service's Forest Inventory and Analysis program, DWM C stocks were found to be relatively static across the study region with an annual flux rate not statistically different from zero. Mean C flux rates across the study area were -0.25, -0.12, -0.01, and -0.04 (Mg/ha/yr) for standing live trees, standing dead trees, coarse woody debris, and fine woody debris, respectively. Flux rates varied in their both magnitude and status (emission/sequestration) by forest types, latitude, and DWM component size. Given the complex dynamics of DWM C flux, early implementation of inventory re measurement, and relatively low sample size, numerous future research directions are suggested.

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

Economic analysis of replacement regeneration and coppice regeneration in eucalyptus stands under risk conditions

Directory of Open Access Journals (Sweden)

Isabel Carolina de Lima Guedes

2011-09-01

Full Text Available Projects are by their very nature subject to conditions of uncertainty that obstruct the decision-making process. Uncertainties involving forestry projects are even greater, as they are combined with time of return on capital invested, being medium to long term. For successful forest planning, it is necessary to quantify uncertainties by converting them into risks. The decision on whether to adopt replacement regeneration or coppice regeneration in a forest stand is influenced by several factors, which include land availability for new forest crops, changes in project end use, oscillations in demand and technological advancement. This study analyzed the economic feasibility of replacement regeneration and coppice regeneration of eucalyptus stands, under deterministic and under risk conditions. Information was gathered about costs and revenues for charcoal production in order to structure the cash flow used in the economic analysis, adopting the Net Present Value method (VPL. Risk assessment was based on simulations running the Monte Carlo method. Results led to the following conclusions: replacement regeneration is economically viable, even if the future stand has the same productivity as the original stand; coppice regeneration is an economically viable option even if productivity is a mere 70% of the original stand (high-tree planted stand, the best risk-return ratio option is restocking the stand (replacement regeneration by one that is 20% more productive; the probabilistic analysis running the Monte Carlo method revealed that invariably there is economic viability for the various replacement and coppice regeneration options being studied, minimizing uncertainties and consequently increasing confidence in decision-making.

Litterfall and litter decomposition in chestnut high forest stands in northern Portugal

Energy Technology Data Exchange (ETDEWEB)

Patricio, M. S.; Nunes, L. F.; Pereira, E. L.

2012-11-01

This research aimed to: estimate the inputs of litterfall; model the decomposition process and assess the rates of litter decay and turnover; study the litter decomposition process and dynamics of nutrients in old chestnut high forests. This study aimed to fill a gap in the knowledge of chestnut decomposition process as this type of ecosystems have never been modeled and studied from this point of view in Portugal. The study sites are located in the mountains of Marao, Padrela and Bornes in a west-to-east transect, across northern Portugal, from a more-Atlantic-to-lessmaritime influence. This research was developed on old chestnut high forests for quality timber production submitted to a silviculture management close-to-nature. We collected litterfall using littertraps and studied decomposition of leaf and bur litter by the nylon net bag technique. Simple and double exponential models were used to describe the decomposition of chestnut litterfall incubated in situ during 559 days. The results of the decomposition are discussed in relation to the initial litter quality (C, N, P, K, Ca, Mg) and the decomposition rates. Annually, the mature chestnut high-forest stands (density 360-1,260 tree ha1, age 55-73 years old) restore 4.9 Mg DM ha–1 of litter and 2.6 Mg ha{sup -}1 yr{sup -}1 of carbon to the soil. The two-component litter decay model proved to be more biologically realistic, providing a decay rate for the fast initial stage (46-58 yr{sup -}1for the leaves and 38-42 yr{sup -}1for the burs) and a decay rate related to the recalcitrant pool (0.45-0.60 yr{sup -}1for the leaves and 0.22-0.36 yr{sup -}1for the burs). This study pointed to some decay patterns and release of bioelements by the litterfall which can be useful for calibrating existing models and indicators of sustainability to improve both silvicultural and environmental approaches for the management of chestnut forests. (Author) 45 refs.

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

Directory of Open Access Journals (Sweden)

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.

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

Stand-volume estimation from multi-source data for coppiced and high forest Eucalyptus spp. silvicultural systems in KwaZulu-Natal, South Africa

Science.gov (United States)

Dube, Timothy; Sibanda, Mbulisi; Shoko, Cletah; Mutanga, Onisimo

2017-10-01

Forest stand volume is one of the crucial stand parameters, which influences the ability of these forests to provide ecosystem goods and services. This study thus aimed at examining the potential of integrating multispectral SPOT 5 image, with ancillary data (forest age and rainfall metrics) in estimating stand volume between coppiced and planted Eucalyptus spp. in KwaZulu-Natal, South Africa. To achieve this objective, Partial Least Squares Regression (PLSR) algorithm was used. The PLSR algorithm was implemented by applying three tier analysis stages: stage I: using ancillary data as an independent dataset, stage II: SPOT 5 spectral bands as an independent dataset and stage III: combined SPOT 5 spectral bands and ancillary data. The results of the study showed that the use of an independent ancillary dataset better explained the volume of Eucalyptus spp. growing from coppices (adjusted R2 (R2Adj) = 0.54, RMSEP = 44.08 m3/ha), when compared with those that were planted (R2Adj = 0.43, RMSEP = 53.29 m3/ha). Similar results were also observed when SPOT 5 spectral bands were applied as an independent dataset, whereas improved volume estimates were produced when using combined dataset. For instance, planted Eucalyptus spp. were better predicted adjusted R2 (R2Adj) = 0.77, adjusted R2Adj = 0.59, RMSEP = 36.02 m3/ha) when compared with those that grow from coppices (R2 = 0.76, R2Adj = 0.46, RMSEP = 40.63 m3/ha). Overall, the findings of this study demonstrated the relevance of multi-source data in ecosystems modelling.

impact of re-forestation of a re-growth secondary forest with

African Journals Online (AJOL)

BIG TIMMY

In general, the forest stand had more density of trees in each dbh class with a peak in .... Awolowo University Estate, Ile-Ife, Osun state, ... forest sub-type is dry deciduous forest (Onochie, ..... eastern Cascades, USA. .... Agriculture, Washington.

Preferences for variation in forest characteristics

DEFF Research Database (Denmark)

Filyushkina, Anna; Taye, Fitalew Agimass; Lundhede, Thomas

2017-01-01

. This study aims at evaluating the effects of variation both within and between stands on recreational values. A choice experiment (CE) was applied to elicit people's preferences for forest types on their next recreational visit. Each alternative is presented with drawings of three forest stands which differ...... with respect to tree species, height (age) and distance to the site, the latter representing the cost factor – willingness-to-travel. Respondents also compose their ideal recreational forest by selecting three types of stands from the catalogue of drawings. We find that mixed tree species are preferred...

The intrinsic periodic fluctuation of forest: a theoretical model based on diffusion equation

Science.gov (United States)

Zhou, J.; Lin, G., Sr.

2015-12-01

Most forest dynamic models predict the stable state of size structure as well as the total basal area and biomass in mature forest, the variation of forest stands are mainly driven by environmental factors after the equilibrium has been reached. However, although the predicted power-law size-frequency distribution does exist in analysis of many forest inventory data sets, the estimated distribution exponents are always shifting between -2 and -4, and has a positive correlation with the mean value of DBH. This regular pattern can not be explained by the effects of stochastic disturbances on forest stands. Here, we adopted the partial differential equation (PDE) approach to deduce the systematic behavior of an ideal forest, by solving the diffusion equation under the restricted condition of invariable resource occupation, a periodic solution was gotten to meet the variable performance of forest size structure while the former models with stable performance were just a special case of the periodic solution when the fluctuation frequency equals zero. In our results, the number of individuals in each size class was the function of individual growth rate(G), mortality(M), size(D) and time(T), by borrowing the conclusion of allometric theory on these parameters, the results perfectly reflected the observed "exponent-mean DBH" relationship and also gave a logically complete description to the time varying form of forest size-frequency distribution. Our model implies that the total biomass of a forest can never reach a stable equilibrium state even in the absence of disturbances and climate regime shift, we propose the idea of intrinsic fluctuation property of forest and hope to provide a new perspective on forest dynamics and carbon cycle research.

Detection of dead standing Eucalyptus camaldulensis without tree delineation for managing biodiversity in native Australian forest

Science.gov (United States)

Miltiadou, Milto; Campbell, Neil D. F.; Gonzalez Aracil, Susana; Brown, Tony; Grant, Michael G.

2018-05-01

In Australia, many birds and arboreal animals use hollows for shelters, but studies predict shortage of hollows in near future. Aged dead trees are more likely to contain hollows and therefore automated detection of them plays a substantial role in preserving biodiversity and consequently maintaining a resilient ecosystem. For this purpose full-waveform LiDAR data were acquired from a native Eucalypt forest in Southern Australia. The structure of the forest significantly varies in terms of tree density, age and height. Additionally, Eucalyptus camaldulensis have multiple trunk splits making tree delineation very challenging. For that reason, this paper investigates automated detection of dead standing Eucalyptus camaldulensis without tree delineation. It also presents the new feature of the open source software DASOS, which extracts features for 3D object detection in voxelised FW LiDAR. A random forest classifier, a weighted-distance KNN algorithm and a seed growth algorithm are used to create a 2D probabilistic field and to then predict potential positions of dead trees. It is shown that tree health assessment is possible without tree delineation but since it is a new research directions there are many improvements to be made.

[A comparative study on soil fauna in native secondary evergreen broad-leaved forest and Chinese fir plantation forests in subtropics].

Science.gov (United States)

Yan, Shaokui; Wang, Silong; Hu, Yalin; Gao, Hong; Zhang, Xiuyong

2004-10-01

In this study, we investigated the response of soil animal communities to the replacement of native secondary forest by Chinese fir plantation forest and successive rotation of Chinese fir in subtropics. Three adjacent forest stands, i.e., native secondary evergreen broad-leaved forest stand (control) and Chinese fir plantation stands of first (20 yr) and second (20 yr) rotations were selected for the comparison of soil fauna. All animals were extracted from the floor litter and 0-15 cm soil layer of the stands in Summer, 2003 by using Tullgren method, wet funnel method and hand-sorting method. Compared to two Chinese fir plantation forests, the native secondary evergreen broad-leaved forest had a higher abundance and a higher taxonomic diversity of animals in soil and litter, but there were no significant differences in the biomass and productivity of soil fauna between all study stands. The abundance or diversity did not differ significantly between the first rotation and second rotation stands, too. The results supported that vegetation cover might be one of the main forces driving the development of soil animal communities, and the effect of successive rotation of Chinese fir on the development of soil fauna was a slow-running process.

Climate-induced mortality of spruce stands in Belarus

Science.gov (United States)

Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

2015-12-01

The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

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.

The impact of nitrogen deposition on carbon sequestration in European forests and forest soils

DEFF Research Database (Denmark)

de Vries, Wim; Reinds, Gert Jan; Gundersen, Per

2006-01-01

for CO2 emissions because of harvest and forest fires, was assumed 33% of the overall C pool changes by growth. C sequestration in the soil were based on calculated nitrogen (N) retention (N deposition minus net N uptake minus N leaching) rates in soils, multiplied by the C/N ratio of the forest soils......An estimate of net carbon (C) pool changes and long-term C sequestration in trees and soils was made at more than 100 intensively monitored forest plots (level II plots) and scaled up to Europe based on data for more than 6000 forested plots in a systematic 16 km x 16 km grid (level I plots). C...... pool changes in trees at the level II plots were based on repeated forest growth surveys At the level I plots, an estimate of the mean annual C pool changes was derived from stand age and available site quality characteristics. C sequestration, being equal to the long-term C pool changes accounting...

Forest Classification Based on Forest texture in Northwest Yunnan Province

Science.gov (United States)

Wang, Jinliang; Gao, Yan; Wang, Xiaohua; Fu, Lei

2014-03-01

Forest texture is an intrinsic characteristic and an important visual feature of a forest ecological system. Full utilization of forest texture will be a great help in increasing the accuracy of forest classification based on remote sensed data. Taking Shangri-La as a study area, forest classification has been based on the texture. The results show that: (1) From the texture abundance, texture boundary, entropy as well as visual interpretation, the combination of Grayscale-gradient co-occurrence matrix and wavelet transformation is much better than either one of both ways of forest texture information extraction; (2) During the forest texture information extraction, the size of the texture-suitable window determined by the semi-variogram method depends on the forest type (evergreen broadleaf forest is 3×3, deciduous broadleaf forest is 5×5, etc.). (3)While classifying forest based on forest texture information, the texture factor assembly differs among forests: Variance Heterogeneity and Correlation should be selected when the window is between 3×3 and 5×5 Mean, Correlation, and Entropy should be used when the window in the range of 7×7 to 19×19 and Correlation, Second Moment, and Variance should be used when the range is larger than 21×21.

Forest Classification Based on Forest texture in Northwest Yunnan Province

International Nuclear Information System (INIS)

Wang, Jinliang; Gao, Yan; Fu, Lei; Wang, Xiaohua

2014-01-01

Forest texture is an intrinsic characteristic and an important visual feature of a forest ecological system. Full utilization of forest texture will be a great help in increasing the accuracy of forest classification based on remote sensed data. Taking Shangri-La as a study area, forest classification has been based on the texture. The results show that: (1) From the texture abundance, texture boundary, entropy as well as visual interpretation, the combination of Grayscale-gradient co-occurrence matrix and wavelet transformation is much better than either one of both ways of forest texture information extraction; (2) During the forest texture information extraction, the size of the texture-suitable window determined by the semi-variogram method depends on the forest type (evergreen broadleaf forest is 3×3, deciduous broadleaf forest is 5×5, etc.). (3)While classifying forest based on forest texture information, the texture factor assembly differs among forests: Variance Heterogeneity and Correlation should be selected when the window is between 3×3 and 5×5; Mean, Correlation, and Entropy should be used when the window in the range of 7×7 to 19×19; and Correlation, Second Moment, and Variance should be used when the range is larger than 21×21

Optimal uneven-aged stocking guides: an application to spruce-fir stands in New England

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Jeffrey H. Gove; Mark J. Ducey

2014-01-01

Management guides for uneven-aged forest stands periodically need to be revisited and updated based on new information and methods. The current silvicultural guide for uneven-aged spruce-fir management in Maine and the northeast (Frank, R.M. and Bjorkbom, J.C. 1973 A silvicultural guide for spruce-fir in the northeast. General Technical Report NE-6, Forest Service. U.S...

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.

Comparing MODIS Net Primary Production Estimates with Terrestrial National Forest Inventory Data in Austria

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Mathias Neumann

2015-04-01

Full Text Available The mission of this study is to compare Net Primary Productivity (NPP estimates using (i forest inventory data and (ii spatio-temporally continuous MODIS (MODerate resolution Imaging Spectroradiometer remote sensing data for Austria. While forest inventories assess the change in forest growth based on repeated individual tree measurements (DBH, height etc., the MODIS NPP estimates are based on ecophysiological processes such as photosynthesis, respiration and carbon allocation. We obtained repeated national forest inventory data from Austria, calculated a “ground-based” NPP estimate and compared the results with “space-based” MODIS NPP estimates using different daily climate data. The MODIS NPP estimates using local Austrian climate data exhibited better compliance with the forest inventory driven NPP estimates than the MODIS NPP predictions using global climate data sets. Stand density plays a key role in addressing the differences between MODIS driven NPP estimates versus terrestrial driven inventory NPP estimates. After addressing stand density, both results are comparable across different scales. As forest management changes stand density, these findings suggest that management issues are important in understanding the observed discrepancies between MODIS and terrestrial NPP.

A Basal Area Increment-Based Approach of Site Productivity Evaluation for Multi-Aged and Mixed Forests

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Liyong Fu

2017-04-01

Full Text Available Accurate estimates of forest site productivity are essential for environmental planning and forest management. In this study, we developed a new productivity index, hereafter termed basal area potential productivity index (BAPP, to estimate site productivity for irregular and complex forests characterized by multi-aged, multi-species, and multi-layer stands. We presented the biological relevance of BAPP with its computational details. We also compared BAPP against basal area realized productivity (BARP in order to verify the practicability and reliability of BAPP. Time-series data of the national forest inventory on 1912 permanent sample plots that were located in two main forest types and consisted of oak-dominated mixed forests and other broadleaf forests in northeast China were used to demonstrate the application of BAPP. The results showed that the value of BAPP for each sample plot was larger than or equal to the corresponding BARP value for each forest type. For appropriately managed stands with relatively better site conditions, the values of both BARP and BAPP were almost identical. The values of the difference between BAPP and BARP could therefore be used to effectively assess forest site productivity. Meanwhile, BAPP also provides much reliable and valuable information that can aid decision-making in forest management.

Effects of stand and inter-specific stocking on maximizing standing tree carbon stocks in the eastern United States

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Christopher W. Woodall; Anthony W. D' Amato; John B. Bradford; Andrew O. Finley

2011-01-01

There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a...

Atmospheric deposition in coniferous and deciduous tree stands in Poland

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Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

2016-05-01

The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

A significant carbon sink in temperate forests in Beijing: based on 20-year field measurements in three stands.

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Zhu, JianXiao; Hu, XueYang; Yao, Hui; Liu, GuoHua; Ji, ChenJun; Fang, JingYun

2015-11-01

Numerous efforts have been made to characterize forest carbon (C) cycles and stocks in various ecosystems. However, long-term observation on each component of the forest C cycle is still lacking. We measured C stocks and fluxes in three permanent temperate forest plots (birch, oak and pine forest) during 2011–2014, and calculated the changes of the components of the C cycle related to the measurements during 1992–1994 at Mt. Dongling, Beijing, China. Forest net primary production in birch, oak, and pine plots was 5.32, 4.53, and 6.73 Mg C ha-1 a-1, respectively. Corresponding net ecosystem production was 0.12, 0.43, and 3.53 Mg C ha-1 a-1. The C stocks and fluxes in 2011–2014 were significantly larger than those in 1992–1994 in which the biomass C densities in birch, oak, and pine plots increased from 50.0, 37.7, and 54.0 Mg C ha-1 in 1994 to 101.5, 77.3, and 110.9 Mg C ha-1 in 2014; soil organic C densities increased from 207.0, 239.1, and 231.7 Mg C ha-1 to 214.8, 241.7, and 238.4 Mg C ha-1; and soil heterotrophic respiration increased from 2.78, 3.49, and 1.81 Mg C ha-1 a-1 to 5.20, 4.10, and 3.20 Mg C ha-1 a-1. These results suggest that the mountainous temperate forest ecosystems in Beijing have served as a carbon sink in the last two decades. These observations of C stocks and fluxes provided field-based data for a long-term study of C cycling in temperate forest ecosystems.

Impacts of forest age on water use in Mountain ash forests

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Wood, Stephen A.; Beringer, Jason; Hutley, Lindsay B.; McGuire, A. David; Van Dijk, Albert; Kilinc, Musa

2008-01-01

Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire returning to pre-fire levels in the following centuries owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8mmday-1 with increasing forest age (an annual decrease of 657mm) the understorey ET contributed between 1.2 and 1.5mmday-1, 45% of the total ET (3mmday-1) at the old growth forest.

Analysis of forest structure using thematic mapper simulator data

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Peterson, D. L.; Westman, W. E.; Brass, J. A.; Stephenson, N. J.; Ambrosia, V. G.; Spanner, M. A.

1986-01-01

The potential of Thematic Mapper Simulator (TMS) data for sensing forest structure information has been explored by principal components and feature selection techniques. In a survey of forest structural properties conducted for 123 field sites of the Sequoia National Park, the canopy closure could be well estimated (r = 0.62 to 0.69) by a variety of channel bands and band ratios, without reference to the forest type. Estimation of the basal area was less successful (r = 0.51 or less) on the average, but could be improved for certain forest types when data were stratified by floristic composition. To achieve such a stratification, individual sites were ordinated by a detrended correspondence analysis based on the canopy of dominant species. The analysis of forest structure in the Sequoia data suggests that total basal area can be best predicted in stands of lower density, and in younger even-aged managed stands.

Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

Science.gov (United States)

Khansaritoreh, Elmira; Dulamsuren, Choimaa; Klinge, Michael; Ariunbaatar, Tumurbaatar; Bat-Enerel, Banzragch; Batsaikhan, Ganbaatar; Ganbaatar, Kherlenchimeg; Saindovdon, Davaadorj; Yeruult, Yolk; Tsogtbaatar, Jamsran; Tuya, Daramragchaa; Leuschner, Christoph; Hauck, Markus

2017-09-01

Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. © 2017 John Wiley & Sons Ltd.

Disease symptoms and their frequency of occurrence in sycamores (Acer pseudoplatanus L. in the Rymanów Forest Unit stands

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Tadeusz Kowalski

2012-12-01

Full Text Available Field studies were conducted in the years 2003 - 2005 in the Rymanów Forest Unit in 13 stands aged between 40 to 100 years, which had 10% - 60% of the sycamore in their species composition. They grew on a mountain forest site (12 stands and mountain riparian forest (1 stand. In each of them 100 trees were examined, growing next to each other in the central part of the stands. The disease symptoms, on trunks and in the crown area of each tree, and their intensity were determined according to the predefined symptomatic - developmental code. More than 80 fragments of wood and bark were collected from trunks of living and dead trees with local cankers and bark peeling off exposing wood. From the samples, 798 isolations were made on 2% malt - agar medium. The examined sycamores in the Rymanów Forest Unit showed a large variation in the disease symptoms and their occurrence frequency. Among 1300 analyzed trees, only 13.7% did not show external, macroscopic disease symptoms. There was a relatively large share of dead trees (15.0%, which in individual stands ranged 4.0 - 32.0%. The most frequent symptoms in crowns were as follows: top dying (6.3% trees, entire branch dying (16.2% or only their tops (9.6%, crown thinning (19.4%, leaf atrophy (10.8% and leaf discoloration (11.6%. On sycamores trunks, the following symptoms were found: plate-like and strip-like necrosis of bark that was breaking, falling off and exposing wood (8.6% trees, local bark cankers (14.7%, among which healed ones dominated (10.3%, bark cracks (14.3% and tree cancer symptoms (3.8%. Bark necrosis and wood exposure formed 1.5 times more frequently on the northern and western side than on the southern and eastern side, bark cracks appeared most frequently on the southern trunk side. On the cross sections of sycamore trunks, the following symptoms were found predominantly: T-shaped discolorations which appeared in the place of local healed cankers, dead wood regions in the places of

Stand structure, composition and illegal logging in selectively logged production forests of Myanmar: Comparison of two compartments subject to different cutting frequency

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Tual Cin Khai

2016-07-01

Full Text Available Appropriate cutting cycles and annual allowable cuts are crucial to ensure sustainability of tropical selective logging, but there have been limited field data to verify long-term effects of different cutting cycles. This study reveals some evidence of forest degradation in selectively logged production forests of Myanmar, which are subject to inappropriate cutting frequency. We compared stand structure, commercial species composition, and incidence of illegal logging between two compartments with low (LCF; 1 time and high (HCF; 5 times cutting frequency over a recent 18 years. Prior to the latest cutting, LCF had 176 trees ha−1 with an inverted-J shape distribution of diameter at breast height (DBH, including a substantial amount of teak (Tectona grandis and other commercially important species in each DBH class. HCF prior to the latest cut had only 41 trees ha−1 without many commercially important species. At HCF, nearly half the standing trees of various species and size were illegally cut following legal operations; this was for charcoal making in nearby kilns. At LCF, two species, teak and Xylia xylocarpa, were cut illegally and sawn for timber on the spot. More extensive and systematic surveys are needed to generalize the findings of forest degradation and illegal logging. However, our study calls for urgent reconsideration of logging practices with high cutting frequency, which can greatly degrade forests with accompanying illegal logging, and for rehabilitating strongly degraded, bamboo-dominated forests. To reduce illegal logging, it would be important to pay more attention on a MSS regulation stating that logging roads should be destroyed after logging operations.

Red Alder-Conifer Stands in Alaska: An Example of Mixed Species Management to Enhance Structural and Biological Complexity

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Robert L. Deal

2017-04-01

Full Text Available There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well-planned silvicultural systems containing a mixture of broadleaf-conifer species have potential to enhance stand diversity and provide other ecosystem services earlier than typical even-aged conifer plantations. Here, we use the example of mixed Sitka spruce/western hemlock and red alder in young, managed stands in southeast Alaska to achieve these goals. We briefly describe the silvics of Sitka spruce, western hemlock and red alder plantations as pure conifer stands or pure broadleaf stands. Then, we synthesize studies of mixed red alder-Sitka spruce/western hemlock stands in southeast Alaska and present their potential for improving stand structural complexity, biodiversity and other ecosystem services over pure conifer forests. Finally, we discuss some of the opportunities and potential tradeoffs for managing mixed broadleaf-conifer stands for providing a number of natural resources and the influence of these broadleaf-conifer forests on ecosystem linkages and processes.

Soil Respiration Changes after Prescribed Fires in Spanish Black Pine (Pinus nigra Arn. ssp. salzmannii Monospecific and Mixed Forest Stands

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Pedro Antonio Plaza-Álvarez

2017-07-01

Full Text Available Soil respiration is a major carbon pathway sensitive to environmental changes. Using prescribed burnings to reduce fuel accumulation and lower risks of large-scale wildfires has recently become more important. Prescribed burning can significantly alter the soil environment, but its effect in practice on soil respiration is not sufficiently understood. We evaluated the effects of prescribed burning on soil respiration before and after burning (May–July 2016. Prescribed burning was conducted in two natural pine areas by comparing a mixed stand of Pinus nigra Arn. ssp. salzmannii with Pinus pinaster Ait. to a pure stand of Pinus nigra Arn. ssp. salzmannii in the central Iberian Peninsula. Soil respiration was measured by an EGM-4 (Environmental Gas Monitor infrared gas analyser in both burned and unburned (control plots. Burnings were low-intensity, and slightly more energetic in the pure stand given its larger litter volume. Post-burning soil respiration followed a similar evolution to that in the control plots, but was greater in the pure stand burned zone and slightly lower in the burned plots in the mixed stand. No significant differences were found in any stand. Soil respiration significantly changed in temporal evolution due to increasing temperatures when summer began. We conclude that prescribed fire induces no changes in SR immediately after fire. This study helps understand how prescribed burnings can affect soil respiration in pure and mixed Spanish black pine forest stands.

Spatial distribution of carbon sources and sinks in Canada's forests

International Nuclear Information System (INIS)

Chen, Jing M.; Weimin, Ju; Liu, Jane; Cihlar, Josef; Chen, Wenjun

2003-01-01

Annual spatial distributions of carbon sources and sinks in Canada's forests at 1 km resolution are computed for the period from 1901 to 1998 using ecosystem models that integrate remote sensing images, gridded climate, soils and forest inventory data. GIS-based fire scar maps for most regions of Canada are used to develop a remote sensing algorithm for mapping and dating forest burned areas in the 25 yr prior to 1998. These mapped and dated burned areas are used in combination with inventory data to produce a complete image of forest stand age in 1998. Empirical NPP age relationships were used to simulate the annual variations of forest growth and carbon balance in 1 km pixels, each treated as a homogeneous forest stand. Annual CO 2 flux data from four sites were used for model validation. Averaged over the period 1990-1998, the carbon source and sink map for Canada's forests show the following features: (i) large spatial variations corresponding to the patchiness of recent fire scars and productive forests and (ii) a general south-to-north gradient of decreasing carbon sink strength and increasing source strength. This gradient results mostly from differential effects of temperature increase on growing season length, nutrient mineralization and heterotrophic respiration at different latitudes as well as from uneven nitrogen deposition. The results from the present study are compared with those of two previous studies. The comparison suggests that the overall positive effects of non-disturbance factors (climate, CO 2 and nitrogen) outweighed the effects of increased disturbances in the last two decades, making Canada's forests a carbon sink in the 1980s and 1990s. Comparisons of the modeled results with tower-based eddy covariance measurements of net ecosystem exchange at four forest stands indicate that the sink values from the present study may be underestimated

The incidence of dwarf mistletoe in Minnesota black spruce stands detected by operational inventories

Science.gov (United States)

Fred Baker; Mark Hansen; John D. Shaw; Manfred Mielke; Dixon Shelstad

2012-01-01

We surveyed black spruce stands within 0.5 miles of US Forest Service Forest Inventory and Analysis (FIA) plots and compared dwarf mistletoe status with that of the FIA and Minnesota Department of Natural Resources (DNR) forest inventories. Our results differed from FIA results in 3 of 16 stands with FIA plots, with FIA most often not recording dwarf mistletoe in...

Species composition and community structure of subtropical forest stands in western himalayan foothills of kashmir

International Nuclear Information System (INIS)

Shaheen, H.; Malik, N. M.; Dar, M. E. U. I.

2015-01-01

Lesser Himalayan subtropical forests have unique species composition due to diverse climatic and topographic factors which create numerous microhabitats. Phytosociological characteristics, structural attributes and biological spectrum of plant communities in the forests of Himalayan foothills in Kashmir were analyzed. A total of 65 species belonging to 26 plant families were recorded constituting 6 plant communities. Average value of diversity recorded for the communities was 2.44; species richness 4.01; whereas evenness was found to be 0.48. The species data indicated random distribution of species with a hump shaped diversity pattern directly correlated with increasing altitude. Themeda anathera was the dominant species with an importance value percentage of 14.7 percentage followed by Pinus roxburghii (9.6 percentage), Mallotus philippenensis (5.2 percentage), Malvastrum coromandelianum (5.1 percentage), Acacia modesta (5 percentage), Olea ferruginea (3.8 percentage) and Oxalis corniculata (3.2 percentage). Vegetation was dominated by Therophytes (30 percentage) and megaphanerophytes (23.3) with dominant leaf spectrum as leptophylls (31.6 percentage). Thirty seven percent plants had medicinal values followed by 31 percentage having fodder values where as 12 percentage used as fuel. Principal component analyses and cluster analyses revealed the association of dominant species with specific sites due to prevailing environmental conditions. The distribution of species in ordination diagrams indicated a continuous change in species composition along the altitudinal gradient. Key stone tree species were subject to immense tree felling resulting in deteriorating changes in forest structure. Visual indicators showed over grazing at all the studied sites evident from the dominance of unpalatable species. Local forest stands demand immediate attention of policy makers as well as forest management so that local diversity and floristic richness could be conserved and

Forest types of the "Argentino River Valley" Natural Reserve

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Bagnato S

2008-09-01

Full Text Available Forest classification is a fundamental target for understanding forest stand dynamics and for sustainable management strategy applications. In this paper the methodological approach of forest types, already used in other Italians region, was applied for the classification of the RNO "Argentino River Valley" (southern Apennine, Italy. This study has been organized in 4 steps: 1 bibliographic analysis and collection of the acquired knowledge; 2 preliminary verification of forest types in the field; 3 description of the different units; 4 final validation of typological units. Using this approach we have characterized 9 categories and 12 forest types units. The description of each units has been filed as cards, where information of different nature is summarized and related to the organization of the typological units, to its location, to the description of the qualitative indicators (disturbances, cohort, mortality, natural dynamic tendencies, SDT, CWD etc. and quantitative indicators (dbh, average height, current annual increment, etc., to the functioning and the current management. For a better understanding of types functioning, "sylvology models" based on the "Spatial Pattern of Relative Collective Interaction" (PSICR and on the principal characteristics influencing and characterizing forest stand dynamics (availability of resources, type and frequency of disturbances, stand development, etc. have been singled out and proposed. The "forest types map" and other maps useful for the management of forest resources have been obtained. Moreover, data collected did allow to formulate several hypotheses on sustainable management.

Effectiveness of management interventions on forest carbon stock in planted forests in Nepal.

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Dangal, Shambhu Prasad; Das, Abhoy Kumar; Paudel, Shyam Krishna

2017-07-01

Nepal has successfully established more than 370,000 ha of plantations, mostly with Pinus patula, in the last three and a half decades. However, intensive management of these planted forests is very limited. Despite the fact that the Kyoto Convention in 1997 recognized the role of plantations for forest-carbon sequestration, there is still limited knowledge on the effects of management practices and stand density on carbon-sequestration of popular plantation species (i.e. Pinus patula) in Nepal. We carried out case studies in four community forests planted between 1976 and 1990 to assess the impacts of management on forest carbon stocks. The study found that the average carbon stock in the pine plantations was 217 Mg C ha -1 , and was lower in forests with intensively managed plantations (214.3 Mg C ha -1 ) than in traditionally managed plantations (219 Mg C ha -1 ). However, it was the reverse in case of soil carbon, which was higher (78.65 Mg C ha -1 ) in the forests with intensive management. Though stand density was positively correlated with carbon stock, the proportionate increment in carbon stock was lower with increasing stand density, as carbon stock increased by less than 25% with a doubling of stand density (300-600). The total carbon stock was higher in plantations aged between 25 and 30 years compared to those aged between 30 and 35 years. Copyright © 2017 Elsevier Ltd. All rights reserved.

新疆森林资源动态分析%Dynamic analysis and evaluation of Xinjiang forest resources: based on RS and GIS

Institute of Scientific and Technical Information of China (English)

李虎; 王晓峰; 陈蜀疆

2005-01-01

The forest resources in Xinjiang were surveyed and analyzed based on RS and GIS. Satellite data interpretation was adopted to obtain the general situation of Xinjiang forest resources in assistance with the sampling method and on-the-spot investigations. Based on GIS, related data obtained from satellite remote sensing in 1996 and 2001 were studied through contrastive analysis. Moreover, the dynamic variation of Xinjiang forest resources was studied in an all-around way. In the past five years,the areas of the forestland, woodland, sparse woodland, nursery garden and the land usable for forestry in Xinjiang kept growing, moreover, the forest cover rate and the total standing stock volume increased correspondingly, showing that the wooded area and the amount of growing stock in Xinjiang were increasing. The forestland area in Xinjiang went up to 17,837 km2 from 17,331 km2, with an annual average increase of 101 km2. Accordingly, the forest vegetation came to 1.08% from 1.05%, up 0.03percentage point; the total standing stock volume went up to 289,985,200 m3 from 262,416,000 m3, a total increase of 27,569,200 m3, an annual average increase of 5,514,000 m3 and an annual average net growth rate of 2.00%. The analysis results showed that the forest resources in Xinjiang were increasing on the whole, however, there remained some problems, such as the sparse natural forests, low forest cover rate, imbalanced wood age structure, and mono tree species composition, etc.

Polarimetric SAR Interferometry based modeling for tree height and aboveground biomass retrieval in a tropical deciduous forest

Science.gov (United States)

Kumar, Shashi; Khati, Unmesh G.; Chandola, Shreya; Agrawal, Shefali; Kushwaha, Satya P. S.

2017-08-01

The regulation of the carbon cycle is a critical ecosystem service provided by forests globally. It is, therefore, necessary to have robust techniques for speedy assessment of forest biophysical parameters at the landscape level. It is arduous and time taking to monitor the status of vast forest landscapes using traditional field methods. Remote sensing and GIS techniques are efficient tools that can monitor the health of forests regularly. Biomass estimation is a key parameter in the assessment of forest health. Polarimetric SAR (PolSAR) remote sensing has already shown its potential for forest biophysical parameter retrieval. The current research work focuses on the retrieval of forest biophysical parameters of tropical deciduous forest, using fully polarimetric spaceborne C-band data with Polarimetric SAR Interferometry (PolInSAR) techniques. PolSAR based Interferometric Water Cloud Model (IWCM) has been used to estimate aboveground biomass (AGB). Input parameters to the IWCM have been extracted from the decomposition modeling of SAR data as well as PolInSAR coherence estimation. The technique of forest tree height retrieval utilized PolInSAR coherence based modeling approach. Two techniques - Coherence Amplitude Inversion (CAI) and Three Stage Inversion (TSI) - for forest height estimation are discussed, compared and validated. These techniques allow estimation of forest stand height and true ground topography. The accuracy of the forest height estimated is assessed using ground-based measurements. PolInSAR based forest height models showed enervation in the identification of forest vegetation and as a result height values were obtained in river channels and plain areas. Overestimation in forest height was also noticed at several patches of the forest. To overcome this problem, coherence and backscatter based threshold technique is introduced for forest area identification and accurate height estimation in non-forested regions. IWCM based modeling for forest

Fragmentation of forest communities in the eastern United States

Science.gov (United States)

Kurt Riitters; John Coulston; James Wickham

2011-01-01

Forest fragmentation threatens the sustainability of forest communities in the eastern United States. Forest communities exhibiting either a low total area or low percentage of intact forest are subject to relatively higher risk of shifts in stand composition towards edge-adapted and invasive species. Such changes in stand composition could result in local extirpation...

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...

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

Solar radiation measurements in forests - II. methods based on the principle of hemispherical photography

International Nuclear Information System (INIS)

Diaci, J.; Kolar, U.; Thormann, J.-J.

1999-01-01

The know-how in the field of solar radiation distribution in forests is important for basic ecological investigations and silvicultural practice. Three methods of solar radiation assessment based on hemispherical canopy photography are compared in the present article: a hemispherical photography by means of a fish-eye lens, a horizontoscope and the ALI-2000 Plant Canopy Analyzer. Experiences, improved methods and a drawing of a horizontoscope stand which was elaborated at the Chair of Silviculture are presented. Fairly good results with some limitations can be achieved with the improved stable horizontoscope in silvicultural work. Hemispherical photography is appropriate for the assessment of light conditions in all stand types and can thus be used in research work. The method has recently been undergoing intensive development. Digitalization of the entire system will speed up standardization. The ALI-2000 instrument is highly suitable for regeneration research in conditions of abundant plant vegetation, in reach sites and modified stands [sl

Feedbacks of windthrow for Norway spruce and Scots pine stands under changing climate

International Nuclear Information System (INIS)

Panferov, O; Rauch, E; Doering, C; Ahrends, B; Sogachev, A

2009-01-01

Wind damage is one of the major natural disturbances that can occur worldwide in most types of forests. Enhanced management using adequate decision support systems (DSS) can considerably reduce the risk of windthrow. The decision support system 'Forest and Climate Change' (DSS-WuK) which is currently being developed at Goettingen University aims at providing a tool for the quantitative assessment of biotic and abiotic risks for forest ecosystems under the conditions of changing climate. In order to assess the future risks of wind damage the system employs a coupled modelling approach combining the turbulence model SCAlar DIStribution (SCADIS) with the soil-vegetation-atmosphere-transfer (SVAT) model BROOK 90. The present study investigates projections of wind damage in Solling, Germany under climate scenarios A1B and B1, taking into account the windthrow feedbacks-changes of microclimate as a result of tree fall and consequent stabilization or destabilization of a forest stand. The results of the study indicate that in Solling the risk of windthrow for spruce and pine forest stands is likely to increase considerably during the 21st century. The general tendencies indicate that under A1B the probability of damage would be higher than under B1 and that under the same climate and soil conditions the risk for spruce stands would be higher than for pine stands of equal age. The degree of damage and feedback contribution as well as a sign of feedback in each particular case will strongly depend on the particular local or regional combination of climatic and soil factors with tree species, age and structure. For Solling the positive feedback to local climatic forcing is found. The feedback contributes considerably (up to 6% under given conditions) to the projected forest damage and cannot be neglected. Therefore, the adequate projection of future damage probabilities can be performed only with a process-based coupled soil-atmosphere model with corresponding high spatial

Interactive effects of historical logging and fire exclusion on ponderosa pine forest structure in the northern Rockies.

Science.gov (United States)

Naficy, Cameron; Sala, Anna; Keeling, Eric G; Graham, Jon; DeLuca, Thomas H

2010-10-01

Increased forest density resulting from decades of fire exclusion is often perceived as the leading cause of historically aberrant, severe, contemporary wildfires and insect outbreaks documented in some fire-prone forests of the western United States. Based on this notion, current U.S. forest policy directs managers to reduce stand density and restore historical conditions in fire-excluded forests to help minimize high-severity disturbances. Historical logging, however, has also caused widespread change in forest vegetation conditions, but its long-term effects on vegetation structure and composition have never been adequately quantified. We document that fire-excluded ponderosa pine forests of the northern Rocky Mountains logged prior to 1960 have much higher average stand density, greater homogeneity of stand structure, more standing dead trees and increased abundance of fire-intolerant trees than paired fire-excluded, unlogged counterparts. Notably, the magnitude of the interactive effect of fire exclusion and historical logging substantially exceeds the effects of fire exclusion alone. These differences suggest that historically logged sites are more prone to severe wildfires and insect outbreaks than unlogged, fire-excluded forests and should be considered a high priority for fuels reduction treatments. Furthermore, we propose that ponderosa pine forests with these distinct management histories likely require distinct restoration approaches. We also highlight potential long-term risks of mechanical stand manipulation in unlogged forests and emphasize the need for a long-term view of fuels management.

Uncertainty in Forest Net Present Value Estimations

Directory of Open Access Journals (Sweden)

Ilona Pietilä

2010-09-01

Full Text Available Uncertainty related to inventory data, growth models and timber price fluctuation was investigated in the assessment of forest property net present value (NPV. The degree of uncertainty associated with inventory data was obtained from previous area-based airborne laser scanning (ALS inventory studies. The study was performed, applying the Monte Carlo simulation, using stand-level growth and yield projection models and three alternative rates of interest (3, 4 and 5%. Timber price fluctuation was portrayed with geometric mean-reverting (GMR price models. The analysis was conducted for four alternative forest properties having varying compartment structures: (A a property having an even development class distribution, (B sapling stands, (C young thinning stands, and (D mature stands. Simulations resulted in predicted yield value (predicted NPV distributions at both stand and property levels. Our results showed that ALS inventory errors were the most prominent source of uncertainty, leading to a 5.1–7.5% relative deviation of property-level NPV when an interest rate of 3% was applied. Interestingly, ALS inventory led to significant biases at the property level, ranging from 8.9% to 14.1% (3% interest rate. ALS inventory-based bias was the most significant in mature stand properties. Errors related to the growth predictions led to a relative standard deviation in NPV, varying from 1.5% to 4.1%. Growth model-related uncertainty was most significant in sapling stand properties. Timber price fluctuation caused the relative standard deviations ranged from 3.4% to 6.4% (3% interest rate. The combined relative variation caused by inventory errors, growth model errors and timber price fluctuation varied, depending on the property type and applied rates of interest, from 6.4% to 12.6%. By applying the methodology described here, one may take into account the effects of various uncertainty factors in the prediction of forest yield value and to supply the

Low Tree-Growth Elasticity of Forest Biomass Indicated by an Individual-Based Model

Directory of Open Access Journals (Sweden)

Robbie A. Hember

2018-01-01

Full Text Available Environmental conditions and silviculture fundamentally alter the metabolism of individual trees and, therefore, need to be studied at that scale. However, changes in forest biomass density (Mg C ha−1 may be decoupled from changes in growth (kg C year−1 when the latter also accelerates the life cycle of trees and strains access to light, nutrients, and water. In this study, we refer to an individual-based model of forest biomass dynamics to constrain the magnitude of system feedbacks associated with ontogeny and competition and estimate the scaling relationship between changes in tree growth and forest biomass density. The model was driven by fitted equations of annual aboveground biomass growth (Gag, probability of recruitment (Pr, and probability of mortality (Pm parameterized against field observations of black spruce (Picea mariana (Mill. BSP, interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn. Franco, and western hemlock (Tsuga heterophylla (Raf. Sarg.. A hypothetical positive step-change in mean tree growth was imposed half way through the simulations and landscape-scale responses were then evaluated by comparing pre- and post-stimulus periods. Imposing a 100% increase in tree growth above calibrated predictions (i.e., contemporary rates only translated into 36% to 41% increases in forest biomass density. This corresponded with a tree-growth elasticity of forest biomass (εG,SB ranging from 0.33 to 0.55. The inelastic nature of stand biomass density was attributed to the dependence of mortality on intensity of competition and tree size, which decreased stand density by 353 to 495 trees ha−1, and decreased biomass residence time by 10 to 23 years. Values of εG,SB depended on the magnitude of the stimulus. For example, a retrospective scenario in which tree growth increased from 50% below contemporary rates up to contemporary rates indicated values of εG,SB ranging from 0.66 to 0.75. We conclude that: (1 effects of

Forest production dynamics along a wood density spectrum in eastern US forests

Science.gov (United States)

C.W. Woodall; M.B. Russell; B.F. Walters; A.W. D' Amato; K. Zhu; S.S. Saatchi

2015-01-01

Emerging plant economics spectrum theories were confirmed across temperate forest systems of the eastern US where the use of a forest stand's mean wood density elucidated forest volume and biomass production dynamics integrating aspects of climate, tree mortality/growth, and rates of site occupancy.

A new approach in the monitoring of the phytosanitary conditions of forests: the case of oak and beech stands in the Sicilian Regional Parks

Directory of Open Access Journals (Sweden)

Cinzia Rizza

2016-10-01

Full Text Available The objective of this study was to investigate the health conditions of oak and beech stands in the three Regional Parks of Sicily (Etna, Madonie and Nebrodi. A total of 81 sampling areas were investigated, 54 in oak stands and 27 in beech stands. The phytosanitary conditions of each tree within the respective sampling area was expressed with a synthetic index namely phytosanitary class (PC. Oak stands showed severe symptoms of decline, with 85% of the sampling areas including symptomatic trees. In general, beech stands were in better condition, with the exception of Nebrodi Park, where trees showed severe symptoms of decline. On oak trees, infections of fungal pathogens were also observed, including Biscogniauxia mediterranea, Polyporus sp., Fistulina hepatica, Mycrosphaera alphitoides and Armillaria sp. By contrast, on beech trees Biscogniauxia nummularia, Fomes fomentarius and Neonectria radicicola were recognized. Furthermore, twenty-two permanent sampling areas were delimited with the aim of monitoring regularly the health conditions of forests in these three parks.

Growth process and diameter structure of Pinus tabulaeformis forest ...

African Journals Online (AJOL)

STORAGESEVER

2009-10-19

Oct 19, 2009 ... and sunny slope Pinus tabulaeformis forest were investigated in hilly loess-gully ... tabulaeformis, the main species of tree for forestation, ... Biomass in different artificial P. tabulaformis stands ..... The change of plant diversity during natural ... elements and stand biomass in forest communities in Hilly Loess.

Can Airborne Laser Scanning (ALS and Forest Estimates Derived from Satellite Images Be Used to Predict Abundance and Species Richness of Birds and Beetles in Boreal Forest?

Directory of Open Access Journals (Sweden)

Eva Lindberg

2015-04-01

Full Text Available In managed landscapes, conservation planning requires effective methods to identify high-biodiversity areas. The objective of this study was to evaluate the potential of airborne laser scanning (ALS and forest estimates derived from satellite images extracted at two spatial scales for predicting the stand-scale abundance and species richness of birds and beetles in a managed boreal forest landscape. Multiple regression models based on forest data from a 50-m radius (i.e., corresponding to a homogenous forest stand had better explanatory power than those based on a 200-m radius (i.e., including also parts of adjacent stands. Bird abundance and species richness were best explained by the ALS variables “maximum vegetation height” and “vegetation cover between 0.5 and 3 m” (both positive. Flying beetle abundance and species richness, as well as epigaeic (i.e., ground-living beetle richness were best explained by a model including the ALS variable “maximum vegetation height” (positive and the satellite-derived variable “proportion of pine” (negative. Epigaeic beetle abundance was best explained by “maximum vegetation height” at 50 m (positive and “stem volume” at 200 m (positive. Our results show that forest estimates derived from satellite images and ALS data provide complementary information for explaining forest biodiversity patterns. We conclude that these types of remote sensing data may provide an efficient tool for conservation planning in managed boreal landscapes.

Forest as Underground-Closed Dendrocenoecosystem

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S. N. Sannikov

2014-02-01

Full Text Available As a result of quantitative «microecosystem» analysis of structural and functional relationships between biogeocenosis components in coniferous forests, the leading role of stand-edificator's root competition factor has been identified in determining the undergrowth and lower layer plant’s growth, compared with its «light» competition. Considering the dominant role of a tree stand root competition in the formation of other forest biogeocenosis components, new definition of «forest» as «underground-closed dendrocenoecosystem» have been proposed.

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

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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.

Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

Science.gov (United States)

Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

2009-04-01

Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

Forest Transpiration: Resolving Species-Specific Root Water Uptake Patterns

Science.gov (United States)

Blume, T.; Heidbuechel, I.; Simard, S.; Guntner, A.; Weiler, M.; Stewart, R. D.

2016-12-01

Transpiration and its spatio-temporal variability are still not fully understood, despite their importance for the global water cycle. This is in part due to our inability to measure transpiration comprehensively. Transpiration is usually either estimated with empirical equations based on climatic variables and crop factors, by measuring sap velocities, estimating sap wood area and scaling up to the forest stand based on a number of assumptions or by measuring the integral signal across a footprint with eddy flux towers. All these methods are focused on the cumulated loss of water to the atmosphere and do not provide information on where this water is coming from. In this study, spatio-temporal variability of root water uptake was investigated in a forest in the northeastern German lowlands. The soils are sandy and the depth of the unsaturated zone ranges from 1 to 30 m. We estimated root water uptake from different soil depths, from 0.1 m down to 2 m, based on diurnal fluctuations in soil moisture content during rain-free days. The 15 field sites cover different topographic positions and forest stands: 4 pure stands of both mature and young beech and pine and 9 mixed stands. The resulting daily data set of root water uptake shows that the forest stands differ in total amounts as well as in uptake depth distributions. Temporal dynamics of signal strength within the profile suggest a locally shifting spatial distribution of uptake that changes with water availability. The relationship of these depth-resolved uptake rates to overall soil water availability varies considerably between tree species. Using the physically-based soil hydrological model HYDRUS we investigated to what extent the observed patterns in uptake can be related to soil physical relationships alone and where tree species-specific aspects come into play. We furthermore used the model to test assumptions and estimate uncertainties of this soil moisture based estimation of plant water uptake. The

Higher stability in forest-atmosphere exchange observed in a structurally diverse forest.

Science.gov (United States)

Tamrakar, R.; Rayment, M.; Moyano, F.; Herbst, M.; Mund, M.; Knohl, A.

2016-12-01

We tested the hypothesis that structurally diverse forests have greater stability on exchange processes with the atmosphere compared to forests with less diverse structure. In a case study, we assessed how net ecosystem exchange (NEE) and normalized maximum assimilation (Amax) varied over time in two forests in Germany based on 11 years of continuous eddy flux measurements. The two sites differ in structure as well as in species composition: one (Hainich) is an unmanaged, uneven-aged and heterogeneous mixed beech forest (65% beech), the other (Leinefelde) is a managed, even-aged and homogeneous pure beech stand. The two selected forests are of similar mean ages (about 130 years old) and exposed to similar air temperatures and vapour pressure deficits. Even though Hainich (the unmanaged forest) received higher rainfall (720 ± 134 mm vs 599±166 mm), the soil water availability showed no significant difference between both sites. Based on detailed biomass inventory, trees in Hainich are well distributed in all diameter at breast height (dbh) classes (10 to 90cm dbh) whereas in Leinefelde (the managed forest) trees are mostly confined to dbh classes of 40 to 55 cm. Our results showed a strong difference in inter-annual variability of NEE, which was lower in the unmanaged than in the managed site (coefficient of variation (CV) of 0.13 and 0.27, respectively). The lowest NEE was observed in both sites in 2004, a mast year and a year after the strong summer drought of 2003. The variation in the inter-annual normalized maximum assimilation (Amax) was lower in Hainich (standard deviation of 2.5 compared to 3.9 µmol m-2 s-1). Also, the seasonal course of Amax differed between the two forests which could explain why the mixed forest was more affected by the late summer drought of 2003, despite showing a more conservative carbon budget than the pure stand in the long term. The interannual anomaly in Amax was correlated with fruit production, the latter being larger in

The Role of Remote Sensing in Assessing Forest Biomass in Appalachian South Carolina

Science.gov (United States)

Shain, W.; Nix, L.

1982-01-01

Information is presented on the use of color infrared aerial photographs and ground sampling methods to quantify standing forest biomass in Appalachian South Carolina. Local tree biomass equations are given and subsequent evaluation of stand density and size classes using remote sensing methods is presented. Methods of terrain analysis, environmental hazard rating, and subsequent determination of accessibility of forest biomass are discussed. Computer-based statistical analyses are used to expand individual cover-type specific ground sample data to area-wide cover type inventory figures based on aerial photographic interpretation and area measurement. Forest biomass data are presented for the study area in terms of discriminant size classes, merchantability limits, accessibility (as related to terrain and yield/harvest constraints), and potential environmental impact of harvest.

A contribution to the study of stand degradation process on the territory of Fruška Gora National Park

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Bobinac Martin T.

2003-01-01

Full Text Available We analyzed the process of stand degradation of individual forest ecosystems in the region of the zonal community Tilio-Carpino-Qurcetum robori-cerris Jov. 79 located in the western part of Fruška Gora National Park. Degradation occurred is consequence to regeneration felling and it progressed towards the extinction of oaks, first of all the valuable pedunculate oak and Vergilius's oak, and then also Turkey oak. The analyzed mature stands were degraded coppice and mainly predominated by the Turkey oak in the tree stratum. In juvenile stands, often initially well regenerated with Turkey oak, the dominant species in the tree stratum are lime, hornbeam, flowering ash, field maple and other secondary species, predominantly of coppice origin. Restitution of the degraded stands is possible by applying an adequate regeneration system. Taking into account the primarily protective function of the analyzed forest ecosystems and the fact that these are degraded and coppice stands, the system of regeneration should be based on combined restoration.

Natural decay resistance of heartwood from dead, standing yellow-cedar trees : laboratory evaluations

Science.gov (United States)

Rodney C. De Groot; Bessie Woodward; Paul E. Hennon

2000-01-01

Yellow-cedar trees have been mysteriously dying for more than a century in southeast Alaska. As these stems continue to stand for decades in the forest, foliage, twigs, and branches deteriorate. The sapwood in the stem degrades, leaving columns of essentially heartwood standing like ghosts in the forest until they eventually drop. To estimate the potential for...

Carbon storage as affected by different site preparation techniques two years after mixed forest stand installation

Energy Technology Data Exchange (ETDEWEB)

Fonseca, F.; Figueiredo, T. de; Martins, A.

2014-06-01

Aim of study: This study aims at evaluating the impact of site preparation techniques prior to plantation on carbon storage and distribution in a young mixed stand of Pseudotsuga menziesii (PM) and Castanea sativa (CS). Area of study: The experimental field was established near Macedo de Cavaleiros, Northern Portugal, at 700 m elevation, mean annual temperature 12 degree centigrade and mean annual rainfall 678 mm. Material and methods: The experimental layout includes three replicates, where the different treatments corresponding to different tillage intensities were randomly distributed (high, moderate and slight intensity), in plots with an area of 375 m{sup 2} each. Twenty six months after forest stand installation, samples of herbaceous vegetation (0.49 m{sup 2} quadrat), forest species (8 PM and 8 CS) and mineral soil (at 0-5, 5-15, 15-30 and 30-60 cm depth) were collected in 15 randomly selected points in each treatment, processed in laboratory and analyzed for carbon by elemental carbon analyzer. Main results: The results obtained showed that: (i) more than 90% of the total carbon stored in the system is located in the soil, increasing in depth with tillage intensity; (ii) the contribution of herbaceous vegetation and related roots to the carbon storage is very low; (iii) the amount of carbon per tree is higher in CS than in PM; (iv) the global carbon storage was affected by soil tillage generally decreasing with the increase of tillage intensity. Accordingly, carbon storage capacity as affected by the application of different site preparation techniques should be a decision support tool in afforestation schemes. (Author)

Impacts of fire on forest age and runoff in mountain ash forests

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Wood, S.A.; Beringer, J.; Hutley, L.B.; McGuire, A.D.; Van Dijk, A.; Kilinc, M.

2008-01-01

Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire - returning to pre-fire levels in the following centuries - owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8 mm day-1 with increasing forest age (an annual decrease of 657 mm) the understorey ET contributed between 1.2 and 1.5 mm day-1, 45% of the total ET (3 mm day-1) at the old growth forest. ?? CSIRO 2008.

Tropical forests are a net carbon source based on aboveground measurements of gain and loss

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Baccini, A.; Walker, W.; Carvalho, L.; Farina, M.; Sulla-Menashe, D.; Houghton, R. A.

2017-10-01

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year-1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year-1 and gains of 436.5 ± 31.0 Tg C year-1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses.

Dynamics of forest ecosystems regenerated on burned and harvested areas in mountain regions of Siberia: characteristics of biological diversity, structure and productivity

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I. M. Danilin

2016-12-01

Full Text Available Complex estimation of forest ecosystems dynamics based on detailing characteristics of structure, growth and productivity of the stands and describing general geographical and biological management options for preserving their biodiversity and sustaining stability are discussed in the paper by describing examples of tree stands restored on burned and logged areas in mountain regions of Siberia. On vast areas in Siberia, characterized as sub-boreal, subarid and with a strongly continental climate, forests grow on seasonally frozen soils and in many cases are surrounded by vast steppe and forest-steppe areas and uplands. Developing criteria for sustainability of mountain forest ecosystems is necessary for forest resource management and conservation. It is therefore important to obtain complex biometric characteristics on forest stands and landscapes and to thoroughly study their structure, biological diversity and productivity. Morphometric methods, Weibull simulation and allometric equations were used to determine the dimensional hierarchies of coenopopulation individuals. Structure and productivity of the aboveground stand components were also studied.

A comparison of structural characteristics and ecological factors between forest reserves and managed silver fir - Norway spruce forests in Slovenia

International Nuclear Information System (INIS)

Marinšek, A.; Diaci, J.

2011-01-01

In order to examine ecological, floristic and structural differences between the forest stands of managed and unmanaged silver fir - Norway spruce forests (Bazzanio trilobatae-Abietetum albae), twelve sample plots (25x25 m) were established in forest reserves and managed forests. Within the plots, subplots and microplots we conducted phytosociological and pedological surveys, analyses of the stand structure, natural regeneration and estimation of solar radiation. We determined that there are no significant differences in floristic composition and ecological factors between managed forest and forest reserve stands. The only variables that were significantly different were the solar radiation variables (ISF; TSF; DSF), vertical structure (cover indexes (CI)) and stand basal area. Small differences in the composition and the structure of the vegetation indicate that, as far as ecosystematic changes are concerned, managing these forests is not as significant as the soil conditions. Solar radiation had a major influence on natural regeneration. Indirect solar radiation seemed to be more important than direct solar radiation. We found a statistically significant positive correlation between silver fir and Norway spruce regeneration and indirect solar radiation and confirmed that the management of light is a significant factor in the management of regeneration. Another trend that was detected was an increase in the number of beech, which will have quite a large proportion in the upper tree layer of the next generation, especially in forest reserves

Assessing management effects on Oak forests in Austria

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Gautam, Sishir; Pietsch, Stephan A.; Hasenauer, Hubert

2010-05-01

Historic land use as well as silvicultural management practices have changed the structures and species composition of central European forests. Such changes have effects on the growth of forests and contribute to global warming. As insufficient information on historic forest management is available it is hard to explain the effect of management on forests growth and its possible consequences to the environment. In this situation, the BIOME-BGC model, which integrates the main physical, biological and physiological processes based on current understanding of ecophysiology is an option for assessing the management effects through tracking the cycling of energy, water, carbon and nutrients within a given ecosystems. Such models are increasingly employed to simulate current and future forest dynamics. This study first compares observed standing tree volume, carbon and nitrogen content in soil in the high forests and coppice with standards stands of Oak forests in Austria. Biome BGC is then used to assess the effects of management on forest growth and to explain the differences with measured parameters. Close positive correlations and unbiased results and statistically insignificant differences between predicted and observed volumes indicates the application of the model as a diagnostic tool to assess management effects in oak forests. The observed data in 2006 and 2009 was further compared with the results of respective model runs. Further analysis on simulated data shows that thinning leads to an increase in growth efficiency (GE), nitrogen use efficiency (NUE) and water use efficiency (WUE), and to a decrease in the radiation use efficiency (RUE) in both forests. Among all studied growth parameters, only the difference in the NUE was statistically significant. This indicates that the difference in the yield of forests is mainly governed by the NUE difference in stands due to thinning. The coppice with standards system produces an equal amount of net primary

Measurement and modeling of bryophyte evaporation in a boreal forest chronosequence

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Bond-Lamberty, Benjamin; Gower, Stith T.; Amiro, Brian; Ewers, Brent

2011-01-19

The effects of changing climate and disturbance on forest water cycling are not well understood. In particular bryophytes contribute significantly to forest evapotranspiration (ET) in poorly-drained boreal forests, but few studies have directly measured this flux and how it changes with stand age and soil drainage. We used large chambers to measure bryophyte evaporation (E) in Canadian Picea mariana forests of varying ages and soil drainages, as well under controlled laboratory conditions, and modeled daily E using site-specific meteorological data to drive a Penman-Monteith-based model. Field measurements of E averaged 0.37 mm day-1, and ranged from 0.03 (Pleurozium schreberii in a 77-year-old dry stand) to 1.43 mm day-1 (Sphagnum riparium in a 43-year-old bog). canopy resistance ranged from ~0 (at 25 °C, some values were <0) to ~1500 s m-1 for dry, cold (5 °C) mosses. In the laboratory, moss canopy resistance was constant until a moss water content of ~6 g g-1 and then climbed sharply with further drying; no difference was observed between the three moss groups (feather mosses, hollow mosses, and hummock mosses) tested. Modeled annual E fluxes from bryophytes ranged from 0.4 mm day-1, in the well-drained stands, to ~1 mm day-1 in the 43-year-old bog, during the growing season. Eddy covariance data imply that bryophytes contributed 18-31% and 49-69% to the total ET flux, at the well- and poorly-drained stands respectively. Bryophyte E was greater in bogs than in upland stands, was driven by low-lying mosses, and did not vary with stand age; this suggests that shifts in forest age due to increasing fire will have little effect on the bryophyte contribution to ET.

Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

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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.