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Browse subject: forest inventory
Number of records: 197

Forest statistics for southwest Arkansas counties
About this Resource: This report tabulates information from a new forest survey of southwest Arkansas, completed in 1969 by the Southern Forest Experiment Station. The tables are intended for use as source data in compiling estimates for groups of counties. Because the Arkansas sampling procedure is intended primarily to furnish inventory data for the State as a whole, estimates for individual counties have limited and variable accuracy.

Forest statistics for middle Tennessee counties
About this Resource: This report tabulates information from a new forest inventory of counties of central and west-central regions of Tennessee, completed in 1971 by the Southern Forest Experiment Station. The tables are intended for use as source data in compiling estimates for groups of counties. Because the sampling procedure is intended primarily to furnish inventory data for the State as a whole, estimates for individual counties have limited and variable accuracy.

Forest statistics for south delta parishes of Louisiana
About this Resource: Commercial forest area and timber inventory as of 1974

Forest statistics for southeast Louisiana parishes
About this Resource: Commercial forest area and timber inventory as of 1974.

Forest statistics for southwest Louisiana parishes
About this Resource: Commercial forest area and timber inventory as of 1974.

Forest statistics for the Delta and Ouachita regions of Arkansas
About this Resource: This report tabulates information from a new forest survey of the Delta and Ouachita regions of Arkansas, completely in 1969 by the Southern Forest Experimental Station. The tables are intended for use as source data in compiling estimates for groups of counties. Because the Arkansas sampling procedure is intended primarily to furnish inventory data for the State as a whole, estimates for individual counties have limited and variable accuracy.

Forest Statistics for Southeast Georgia 1971
About this Resource: Since 1960, acreage of commercial forest has declined by 6 percent, or about one-half million acres, in this 35-county area and now totals 7.4 million acres. During this period, volume of growing stock increased by 616 million cubic feet, to 7.3 billion cubic feet. Hard- woods accounted for almo s t two-thirds of the net gain. About 1 million acres have been artificially regenerated since 1960, over 70 percent of which is located south of the Altamaha River. In 1970, net growth of growing stock totaled 414 million cubic feet and exceeded removals by 11 percent. South of the Altamaha River removals of pine exceeded growth by 26 percent, and softwood-inventory in this area has been reduced by 12 percent during the remeasurement period.

National Forestry Database Program
About this Resource: The National Forestry Database Program is used to compile national statistics provided by provincial or territorial resource management organizations and federal departments. The site provides links to the Compendium of Canadian Forestry Statistics, REGEN: a program for reporting regeneration results, and the framework for national reporting on wood supply. There are lists of forest inventory and silvicultural terms in Canada.

Forest Inventory and Analysis National Program | USDA-Forest Service
About this Resource: A link to the research and development organization within USDA's forest Service responsible for assessing the America's forests. Presents information that allows site visitors to develop, analyze and maintain forest resource information. The program allows for projections into how the National firest system will appear in the future. Visitors can develop upon specific indices. The website features various tools and databases, data tables and data services. The FIA Library is a source for a publications; fact sheets; briefings; summaries; overviews; scientific papers; presentations; maps and field guides. External links are also online.

Swedish University of Agricultural Sciences, Department of Forest Resource Management and Geomatics
About this Resource: The Department of Forest Resource Management and Geomatics focuses on education and research in the fields of statistics, forest management planning, remote sensing, forest inventory, and environmental monitoring. Courses are offered in statistics, computer science, forest management planning, forest inventry, remote sensing, GIS, and environmental monitoring. There is information about the program on the site. There are links to the Swedish National Forest Inventory and the National Inventory of Landscapes in Sweden, which is a national program for the monitoring of biodiversity.

The Components of Change for an Annual Forest Inventory Design
About this Resource: The sample design of the USDA Forest Service's Forest Inventory and Analysis Program (FIA) with respect to a three-dimensional population (forest area x time) of tree attributes is formally defined and evaluated. The definitions for both the traditional components of growth, as presented by Meyer (1953, Forest Mensuration), and a discrete analog to the time invariant redefinition of the components of change given by Eriksson (1995, Forest Sci. 41(4):796-822), are compared and contrasted. Special problems in the application of the traditional definitions due to the continuous and overlapping temporal intervals featured in the sample design are explored. This exploration supports a contention that the traditional definitions are at a theoretical disadvantage because they are not based purely on the population(s) of interest, while the redefinitions dubbed the components of change by Eriksson (1995) were based solely on population attributes. The temporally discrete analog to the Eriksson definitions are used in this article to define the three-dimensional populations in terms of a set of mutually exclusive component matrices that can be summed to represent the entire population, independently of the sample design.

The value of timber inventory information for management planning
About this Resource: Timber inventory data is the basis for many monetary transactions related to timber and timberland sale and (or) purchase as well as for development of timber management plans. The value of such data is well known and much appreciated for sale and (or) purchase of standing merchantable timber. Unfortunately, the value of timber inventory data for planning purposes is less well understood. We report on the results of a large simulation study that was undertaken to evaluate the utility and value of timber inventory data for timber management plan development for a typical timberland ownership in the southern United States. Our results indicate that timberland managers are likely producing management plans that do not maximize the profitability of their timberland holdings. Specifically, our results indicate it is likely that timber management organizations that develop timber management plans with stand level data that has a sampling error of 25% are experiencing expected losses in net present value in excess of 170 US$·ha-1 on a large proportion of the acreage found on typical timberland parcels in the southern United States.

Regional Height-Diameter Equations for Major Tree Species of Southwest Oregon.
About this Resource: Selected tree height and diameter functions were evaluated for their predictive abilities for major tree species of southwest Oregon. Two sets of equations were evaluated. The first set included four base equations for estimating height as a function of individual tree diameter, and the remaining 16 equations enhanced the four base equations with alternative measures of stand density and relative position. The inclusion of the crown competition factor in larger trees (CCFL) and basal area (BA), which simultaneously indicates the relative position of a tree and stand density, into the base height-diameter equations increased the accuracy of prediction for all species. On the average, root mean square error values were reduced by 45 cm (15% improvement). On the basis of the residual plots and fit statistics, two equations are recommended for estimating tree heights for major tree species in southwest Oregon. The equation coefficients are documented for future use.

Measurement variability error for estimates of volume change
About this Resource: Using quality assurance data, measurement variability distributions were developed for attributes that affect tree volume prediction. Random deviations from the measurement variability distributions were applied to 19 381 remeasured sample trees in Maine. The additional error due to measurement variation and measurement bias was estimated via a simulation study for various components of volume change. In comparison with sampling error, the error due to measurement variation was relatively small. When biases in measurements had contradictory effects on the calculation of individual tree volume, there was little additional error, however, systematic biases produced substantial error increases. The proportion of measurement variation error attributable to diameter at breast height and tree species classification was small relative to that attributable to bole (merchantable) height and percent cull attributes, which composed the preponderance of uncertainty due to measurement variation. The greatest impacts were associated with the accretion component, which was subject to measurement variation and bias at both the initial and subsequent measurements.

Fates of live trees retained in forest cutting units, western Cascade Range, Oregon
About this Resource: Live trees, standing dead trees, and downed logs have been retained in some forest harvest sites in the Pacific Northwest to fulfill various ecological objectives. To assess the fates of retained trees following partial cutting of mature forests in the central western Cascade Range in Oregon, we inventoried standing live and dead trees and toppled trees in 21 cutting units in 1993 and 2001. In 1993, 1-10 years after cutting, an average of 65% of the initially retained trees (average of counts for all sites) were alive and standing, 12% had been toppled or topped by wind, 13% had become snags by natural processes, and 10% were converted to snags by management action, including cutting, blasting, girdling, and inoculation with fungi. By 2001, when cutting-unit ages ranged from 9 to 18 years, 54% of the retained trees were alive and standing, 10%-21% had been toppled or topped by wind, 11%-22% had become snags by natural processes, and 14% had been converted to snags by management action. The highest levels of mortality occurred at sites with abundant intentional snag creation and (or) prescribed fire following harvest. The rate of mortality due to windthrow declined over time, possibly because the remaining trees were more windfirm.

Forest Resources of Tennessee - 1972
About this Resource: This report states the principal findings of a new forest survey of Tennessee. Data for growth and cut are given for 1970, and the inventory is reported for January 1, 1971. A canvass of forest products output in 1970 also contributed information.

Forest Statistics for North Georgia 1972
About this Resource: Commercial forests occupy 3.2 million acres, or 75 percent of the total land in the 21-county area of North Georgia. There has been less forestry activity in this area than in any other part of the State. In the latest Forest Survey, 7 out of every:10 acres now classified as commercial forest showed no evidence of treatment or major disturbance over the past 11 years. Since 1961, area of commercial forest has decreased by less than 3 percent, while the inventory of softwood and hardwood growing stock has increased by 67 and 32 percent, respectively. Net annual growth averages 55 cubic feet per acre of commercial forest land, almost double the volume of annual timber removals.

Estimating Ownerships and Parcels of Nonindustrial Private Forestland in Massachusetts.
About this Resource: Woodland ownership for three regions of Massachusetts is estimated using property tax assessor data. These data are nonspatially explicit and are based on commercial, industrial, residential, or other activity rather than actual land cover. A heuristic was used to aggregate similar parcels to provide an estimate of actual landownership. The estimated average statewide ownership is 17.9 ac, and when properties less than 10 ac are excluded, the average rises to 42.5 ac. The median ownership varies from east to west in the state across the spectrum of suburban development radiating from the metropolitan Boston area, with the median being 4.8, 7.8, and 8.6 ac in the eastern, central, and western part of the state, respectively. These results are compared with ownership estimates generated by the US Forest Service Forest Inventory and Analysis.

Global Fire Monitoring Center (GFMC)
About this Resource: The GFMC is an activity of the International Strategy for Disaster Reduction and contains information about fire and fire prevention. The site provides information about the Center, global current fire status, international assistance in wildland fire emergencies, global wildland fire network, global fire inventories and models, international fire management programs, fire meetings, fire management training courses, jobs, and international fire research programs. The site also contains a calender of events, fire glossaries, literature, and software, International Forest Fire News, and links to international organizations.

Habitat classification modeling with incomplete data: pushing the habitat envelope
About this Resource: Habitat classification models (HCMs) are invaluable tools for species conservation, land-use planning, reserve design, and metapopulation assessments, particularly at broad spatial scales. However, species occurrence data are often lacking and typically limited to presence points at broad scales. This lack of absence data precludes the use of many statistical techniques for HCMs. One option is to generate pseudo-absence points so that the many available statistical modeling tools can be used. Traditional techniques generate pseudo-absence points at random across broadly defined species ranges, often failing to include biological knowledge concerning the species-habitat relationship. We incorporated biological knowledge of the species-habitat relationship into pseudo-absence points by creating habitat envelopes that constrain the region from which points were randomly selected. We define a habitat envelope as an ecological representation of a species, or species feature's (e.g., nest) observed distribution (i.e., realized niche) based on a single attribute, or the spatial intersection of multiple attributes. We created HCMs for Northern Goshawk (Accipiter gentilis atricapillus) nest habitat during the breeding season across Utah forests with extant nest presence points and ecologically based pseudo-absence points using logistic regression. Predictor variables were derived from 30-m USDA Landfire and 250-m Forest Inventory and Analysis (FIA) map products. These habitat-envelope-based models were then compared to null envelope models which use traditional practices for generating pseudo-absences. Models were assessed for fit and predictive capability using metrics such as kappa, threshold-independent receiver operating characteristic (ROC) plots, adjusted deviance, and cross-validation, and were also assessed for ecological relevance. For all cases, habitat envelope-based models outperformed null envelope models and were more ecologically relevant, suggesting that incorporating biological knowledge into pseudo-absence point generation is a powerful tool for species habitat assessments. Furthermore, given some a priori knowledge of the species-habitat relationship, ecologically based pseudo-absence points can be applied to any species, ecosystem, data resolution, and spatial extent.

Decision support systems for forest management: A financial analysis for South Carolina's state forests
About this Resource: Decision support systems (DSS), also known as forest resource information systems, focus on providing forest managers information to make better decisions. DSS in forestry organizations have evolved from the integration of geographic information systems and database management systems with common forestry applications. These types of systems are becoming widely used within forestry organizations as the planning and documentation of activities become ever more critical due to forest certification activities and increased public scrutiny. While methods to define the cost of these types of technologies are relatively straightforward, defining the benefits associated with system implementation is more difficult. A benefit/cost analysis of a DSS for South Carolina's state forests is presented. This analysis derives the majority of the benefits from improvements in business process, not the effects of individual applications or functions. Process alternatives currently available to forest managers and the benefits and cost of these alternatives are identified. While results presented apply specifically to South Carolina's state forests system, the alternatives and methodology have broad implications to medium and large forest landowners.

Forest Environmental Investments and Implications for Climate Change Mitigation
About this Resource: Forest environmental conditions are affected by climate change, but investments in forest environmental quality can be used as part of the climate change mitigation strategy. A key question involving the potential use of forests to store more carbon as part of climate change mitigation is the impact of forest investments on the timing and quantity of forest volumes that affect carbon storage. Using an economic optimization model, we project levels of U.S. forest volumes as indicators of carbon storage for a wide range of private forest investment scenarios. Results show that economic opportunities exist to further intensify timber management on some hectares and reduce the average timber rotation length such that the national volume of standing timber stocks could be reduced relative to projections reflecting historical trends. The national amount of timber volume is projected to increase over the next 50 yr, but then is projected to decline if private owners follow an economic optimization path, such as with more forest type conversions and shorter timber rotations. With perfect foresight, future forest investments can affect current timber harvest levels, with intertemporal linkages based on adjustments through markets. Forest investments that boost regenerated timber yields per hectare would act to enhance ecosystem services (e.g., forest carbon storage) if they are related to the rate of growth and extent of growing stock inventory.

The forest vegetation simulator: a review of its structure, content, and applications
About this Resource: The Forest Vegetation Simulator (FVS) is a distance-independent, individual-tree forest growth model widely used in the United States to support management decisionmaking. Stands are the basic projection unit, but the spatial scope can be many thousands of stands. The temporal scope is several hundred years at a resolution of 5-10 years. Projections start with a summary of current conditions evident in the input inventory data. FVS contains a self-calibration feature that uses measured growth rates to modify predictions for local conditions. Component models predict the growth and mortality of individual trees, and extensions to the base model represent disturbance agents including insects, pathogens, and fire. The component models differ depending on the geographic region represented by regionally specific model variants. The differences are due to data availability and the applicability of existing models. The model supports specification of management rules in the input, such as thinning if density is too high. The rules can be extended to represent other factors. For example, the effect of climate change on stand development by entering rules that specify how growth and mortality will change in response to changing climate. Applications range from development of silvicultural prescription for single stands to landscape and large regional assessments. Key issues addressed with FVS include forest development, wildlife habitat, pest outbreaks, and fuels management. The predictions are used to gain insights into how forested environments will respond to alternative management actions. Broad-scale forest management policies have been studied with FVS. For the 30 years since the model was initially introduced, the development team has anticipated and provided needed enhancements and maintained a commitment to working with and training users. The existence of an adequate user interface and the continued use of the original programming language are often overlooked factors for the success of this model. Future work will focus on improving FVS by adopting recent biometric techniques and including new information linking geomorphology to mortality and growth. Extending the model to more closely represent biophysical processes and adapting the model so that it is more relevant to management questions related to predicted climate change are also foci. Providing ways to dynamically link FVS to other models is our current strategy for providing major new capabilities.

Conterminous U.S. and Alaska Forest Type Mapping Using Forest Inventory and Analysis Data
About this Resource: Classification-trees were used to model forest type groups and forest types for the conterminous United States and Alaska. The predictor data were a geospatial data set with a spatial resolution of 250 m developed by the U.S. Department of Agriculture Forest Service (USFS). The response data were plot data from the USFS Forest Inventory and Analysis program. Overall accuracies for the conterminous U.S. for the forest type group and forest type were 69 percent (Kappa = 0.66) and 50 percent (Kappa = 0.57), respectively. The overall accuracies for Alaska for the forest type group and forest type were 78 percent (Kappa = 0.69) and 67 percent (Kappa = 0.61), respectively. This is the first forest type map produced for the U.S. The forest type group map is an update of a previous forest type group map created by Zhu and Evans (1994).

Forest Carbon Management in the United States--1600-2100
About this Resource: This paper reviews the effects of past forest management on carbon stocks in the United States, and the challenges for managing forest carbon resources in the 21st century. Forests in the United States were in approximate carbon balance with the atmosphere from 1600-1800. Utilization and land clearing caused a large pulse of forest carbon emissions during the 19th century, followed by regrowth and net forest carbon sequestration in the 20th century. Recent data and knowledge of the general behavior of forests after disturbance suggest that the rate of forest carbon sequestration is declining. A goal of an additional 100 to 200 Tg C/yr of forest carbon sequestration is achievable, but would require investment in inventory and monitoring, development of technology and practices, and assistance for land managers.

Relative abundance, habitat use, and long-term population changes of wintering and resident landbirds on St. John, U.S. Virgin Islands
About this Resource: St. John, U.S. Virgin Islands, is one of the most forested islands in the West Indies and provides an opportunity to conserve both resident birds and wintering neotropical migrants. We conducted double-observer point counts of landbirds in December 2005 and 2006 in Forest Inventory and Analysis (FIA) plots and National Park Service (NPS) trails in Virgin Islands National Park (VINP) to assess population trends of birds in subtropical dry and moist forests. We recorded 2,270 individual birds representing 35 species at 150 point count stations in 2005, and 3,092 individuals of 32 species at 143 of these stations in 2006. The increase in birds per point from 2005 (15.1) to 2006 (21.6) was due to resident species, 17 of which were recorded more frequently in 2006. The 17 species of neotropical migrants composed 11.8% of all registrations in 2005 and 2006. Subtropical moist and dry forest habitats differed strongly in vegetation characteristics and plant species, but no species of birds exhibited a strong affiliation with either habitat type on FIA plots. Data from NPS trails showed that most migrant species were detected more often in moist, mature forest. The resident Bridled Quail-Dove (Geotrygon mystacea) also was correlated with mature forest. Plant and bird species co-occurrence with positive correlations that may carry a signal of preferred frugivory included Guettarda odorata (Rubiaceae) with Bridled Quail-Dove, and Myrciaria floribunda (Myrtaceae) with Pearly-eyed Thrasher (Margarops fuscatus). Migrant species did not exhibit strong long-term changes in relative abundance since founding of VINP in 1957, but four open-country resident species declined significantly between 1957 and 2006 as the forest matured. Forest maturation should continue on St. John, yielding a bright future for most of its landbirds barring catastrophic hurricanes, pathogens, or invasive plants.

Effects of height imputation strategies on stand volume estimation
About this Resource: Subsampling and subsequent imputation of tree heights can improve the predictive performance of stand volume estimation but may also introduce biases. Using coastal Douglas-fir data from southwest Oregon, USA, the predictive performance of several height imputation strategies for estimating stand volume was evaluated. A subsample of 1-15 trees was randomly selected per stand, and missing heights were imputed using a regional Chapman-Richards function with diameter only and diameter plus stand density measures, fitted using a nonlinear least-squares model (NFEM) and a nonlinear mixed-effects model (NMEM). Missing heights were imputed using the regional height-diameter equation and by adjusting the equation with a correction factor (NFEM) or with predicted random effects (NMEM) to calibrate the height-diameter relationship to each stand. Differences in actual stand volumes, calculated with measured heights, and predicted stand volumes, calculated using measured heights for the subsampled trees and predicted heights for those with missing heights, were used to compare the alternative height imputation methods. Precision and bias were poorest for the regional models, especially NMEM, and best for the adjusted models also using NMEM. Results suggest that a similar subsample of heights (n = 4) is required for precise stand volume estimation as has been reported for height.

A method for integrating multiple components in a decision support system
About this Resource: We present a flexible, extensible method for integrating multiple tools into a single large decision support system (DSS) using a forest ecosystem management DSS (NED-2) as an example. In our approach, a rich ontology for the target domain is developed and implemented in the internal data model for the DSS. Semi-autonomous agents control external components and communicate using a blackboard. We illustrate how this multi-agent approach with its blackboard architecture supports the expansion of a DSS (in this case, NED-2) to incorporate new models and decision support tools as they become available. The exemplar NED-2 DSS developed using this method is a goal-driven DSS that integrates a sophisticated inventory system, treatment plan development, growth-and-yield models, wildlife models, fire risk models, knowledge based systems for goal satisfaction analysis, and a powerful report generation system.

Separating Duff and Litter for Improved Mass and Carbon Estimates.
About this Resource: Mass and carbon load estimates, such as those from forest soil organic matter (duff and litter), inform forestry decisions. The US Forest Inventory and Analysis (FIA) Program systematically collects data nationwide: a down woody material protocol specifies discrete duff and litter depth measurements, and a soils protocol specifies mass and carbon of duff and litter combined. Sampling duff and litter separately via the soils protocol would increase accuracy of subsequent bulk density calculations and mass and carbon estimates that use them. At 57 locations in North Carolina, Virginia, and West Virginia, we measured depth, mass, and carbon of duff and litter separately. Duff depth divided by total depth varied from 20% to 56%, duff was 1-4 times denser than litter, and the calculated median carbon-to-mass ratio for hardwood duff (0.37) was less than that for litter (0.45). Using FIA depth measurements, we calculated mass from (1) our mean density values, (2) a mass versus depth regression model we developed, and (3) published density values. Model mass calculations were lower than those using our mean densities, possibly because the latter ignore density differences with layer thickness. Our model could provide valuable mass and carbon estimates if fully developed with future FIA data (duff and litter separated).

Development of a basal area growth system for maritime pine in northwestern Spain using the generalized algebraic difference approach
About this Resource: A basal area growth system for single-species, even-aged maritime pine (Pinus pinaster Ait.) stands in Galicia (northwestern Spain) was developed from data of 212 plots measured between one and four times. Six dynamic equations were considered for analysis, and both numerical and graphical methods were used to compare alternative models. The double cross-validation approach was used to assess the predictive ability of the models. The data were best described by a dynamic equation derived from the Korf growth function using the generalized algebraic difference approach (GADA) by considering two parameters to be site specific. The equation was fitted in one stage using the base-age-invariant dummy variables method. In addition, the system incorporates a function for predicting initial stand basal area, in which the site-related variable was expressed as a power function of site index. This function can be used to establish the starting point for the projection equation when no inventory data are available. The two equations are compatible. The effect of thinning on basal area growth was examined; the results showed that there was no need to use a different equation to reliably predict postthinning basal area development. The nonlinear extra sum of squares method indicated differences in the model parameters for the two ecoregions (coastal and interior) defined for this species in the area of study.

Phytosociology of Vascular Plants on an International Biosphere Reserve: Virgin Islands National Park, St. John, US Virgin Islands
About this Resource: We investigated the relationships of vegetation communities to environmental variables and compared the relative contribution of native and introduced species in extant forest communities on St. John, US Virgin Islands, using an island-wide forest vegetation inventory and monitoring network of permanent plots. We detected 2,415 individuals of 203 species, 5 percent of which were introduced. Cluster analysis, Indicator Species Analysis, and Nonmetric Multidimensional Scaling (NMS) ordination detected four broad species communities divided primarily by moisture and disturbance gradients. Group 1 was characterized by rocky, low-to-mid elevation dry scrub forest on soils with fairly low soil nutrient content; Group 2 was distinguished by low soil nutrient content, high-elevation moist basin forests on steep slopes; Group 3 was indicative of disturbed communities on a wide range of elevations with gentle or no slope across a range of soil types; and Group 4 represented mid-elevation moist forests across a range of steep slopes on nutrientrich soils.Though introduced species are present and widespread on the island, they do not appear to be dominating most plant communities. Exceptions may be those communities with long-standing histories of human disturbance. Achieving an adequate sample of forest types of limited extent or linear spatial patterns such as mangroves and gallery moist forests is difficult with a systematic design. Future sampling should consider some form of stratification targeting these under-sampled forest types.

Effects of forest cover, topography, and sampling extent on the measured density of shallow, translational landslides
About this Resource: We use regionally available digital elevation models and land cover data, calibrated with ground- and photo-based landslide inventories, to produce spatially distributed estimates of shallow, translational landslide density (number/unit area). To discern effects of land use, we focus on resolving landslide density relationships with forest cover. We account for topographic variability between sites and landslide detection bias in air photo mapping. Even so, for sites in the Oregon Coast Range, we find great variability in the ratios of landslide density in forest classes among sites. We present strategies for subsampling available data to quantify this variability. For these data, we find that older forests, when sampled over tens of square kilometers, commonly exhibited the highest landslide densities but over hundreds of square kilometers always exhibited the lowest densities, averaging 30% of that in recently harvested areas and 79% of that in younger, managed forests.

Farmers' objectives toward their woodlands in the upper Midwest of the United States: implications for woodland volumes and diversity
About this Resource: This paper reports the results of a study that explores the relationship between farm woodland owners' stated intentions for owning woodland, and the structure and composition of these woodlands in the states of Illinois, Indiana and Iowa in the upper Midwest of the United States. Data from two sample-based inventories conducted by the USDA Forest Service, Forest Inventory and Analysis (FIA) program were combined for this analysis--the FIA forest resources inventory and the National Woodland Owner Survey (NWOS). We looked for relationships between product value and investment in woodlands, as reflected in volumes and tree quality. We also examined whether measures of diversity reflected specific management focus. Our results partially supported our hypotheses. Woodland-focused ownership reasons were found to have larger volumes and individual tree sizes. We found that a passive woodland ownership reason--that woods were “part of the farm”--generally had lower volumes per hectare. Although we were not able to differentiate between different forest product classes and measures of volume, we did find that those landowners who harvested veneer had more volume than those who harvested for firewood. Woodland owners who salvage-harvested their woodlands--a harvesting reason that is more reactive than proactive--exhibited lower volumes per hectare than those who harvested for more proactive, product-focused reasons. Biodiversity was also found to be related to the ownership focus and harvest intent. Generally, there was lower diversity in overstory species when the woodland was viewed merely as “part of the farm,” when the product harvested was fence posts and when timber was harvested for salvage or land clearing. The small sample size limits our analysis, but we can conclude that focusing the woodland owners on management of their woodlands--regardless of what the specific management goals might be--should increase productivity and biodiversity of those woodlands.

Regional Applicability of Forest Height and Aboveground Biomass Models for the Geoscience Laser Altimeter System.
About this Resource: Accurate estimates of forest aboveground biomass are needed to reduce uncertainties in global and regional terrestrial carbon fluxes. In this study we investigated the utility of the Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land Elevation Satellite for large-scale biomass inventories. GLAS is the first spaceborne lidar sensor that will provide global estimates of forest height. We compared accuracy and regional variability of GLAS height estimates with data from the US Forest Service Inventory and Analysis (FIA) program and found that current GLAS algorithms provided generally accurate estimates of height. GLAS heights were on average 2-3 m lower than FIA estimates. To translate GLAS-estimated heights into forest biomass will require general allometric equations. Analysis of the regional variability of forest height-biomass relationships using FIA field data indicates that general nonspecies specific equations are applicable without a significant loss of prediction accuracy. We developed biomass models from FIA data and applied them to the GLAS-estimated heights. Regional estimates of forest biomass from GLAS differed between 39.7 and 58.2 Mg ha-1 compared with FIA.

Assessment of Forest Fuel Loadings in Puerto Rico and the US Virgin Islands
About this Resource: Quantification of the downed woody materials that comprise forest fuels has gained importance in Caribbean forest ecosystems due to the increasing incidence and severity of wildfires on island ecosystems. Because large-scale assessments of forest fuels have rarely been conducted for these ecosystems, forest fuels were assessed at 121 US Department of Agriculture forest service inventory plots on Puerto Rico, Vieques, and the US Virgin Islands. Results indicated that fuel loadings averaged 24.05 Mg ha-1 in 2004-2006. Forest litter decreased from wetter to drier forest life zones. These island forests showed a paucity of coarse woody fuels (CWD) (2.91 Mg ha-1) and relatively greater quantities of smaller-sized fine woody fuels (FWD) (10.18 Mg ha-1 for FWD and 10.82 Mg ha-1 for duff/litter) when compared to continental tropical forests. Between 2001 and 2006, CWD fuel loads decreased, while fine fuels and litter increased, such that total fuel loads remained constant on a subset of plots on Puerto Rico. This trend indicates that continued decomposition of CWD deposited by the last severe hurricane is balanced by increasing inputs of FWD from recovering and maturing secondary forests. Forest disturbance cycles and successional development must be taken into account by agencies charged with fire protection and risk assessment.

Forest Statistics for Mississippi Counties
About this Resource: Commercial forest-land areas, timber inventory, growth, and cut, as of 1967.","This report tabulates information from a new forest survey of Mississippi, completed in 1967 by the Southern Forest Experiment Station. The tables are intended for use as source data in compiling estimates for groups of counties. Because the sampling procedure used in Mississippi was intended primarily to furnish inventory data for the State as a whole, estimates for individual counties have limited and variable accuracy.

Using Airborne Light Detection and Ranging (LIDAR) to Characterize Forest Stand Condition on the Kenai Peninsula of Alaska.
About this Resource: Airborne laser scanning (also known as light detection and ranging or LIDAR) data were used to estimate three fundamental forest stand condition classes (forest stand size, land cover type, and canopy closure) at 32 Forest Inventory Analysis (FIA) plots distributed over the Kenai Peninsula of Alaska. Individual tree crown segment attributes (height, area, and species type) were derived from the three-dimensional LIDAR point cloud, LIDAR-based canopy height models, and LIDAR return intensity information. The LIDAR-based crown segment and canopy cover information was then used to estimate condition classes at each 10-m grid cell on a 300 x 300-m area surrounding each FIA plot. A quantitative comparison of the LIDAR- and field-based condition classifications at the subplot centers indicates that LIDAR has potential as a useful sampling tool in an operational forest inventory program.

Snag longevity under alternative silvicultural regimes in mixed-species forests of central Maine.
About this Resource: Predictions of snag longevity, defined here as the probability of snag survival to a given age, are key to designing silvicultural regimes that ensure their availability for wildlife and form an important component of carbon flow models. Species, diameter at breast height, stand density, management regime, and agent of tree mortality were assessed for their effect on snag longevity in a long-term silvicultural study on the Penobscot Experimental Forest in central Maine. Snag recruitment and fall data from USDA Forest Service inventories between 1981 and 1997 were analyzed using parametric survival analysis. A Weibull model fit the data best, indicating a significant lag time followed by rapid fall rates. Half-times varied among species, with Thuja occidentalis L. having the longest (10 years) and Picea species the shortest (6 years). Snag longevity was significantly greater with increasing diameter and decreased with increasing stand density. Agent of mortality and silvicultural treatment were also significant. Two models were developed for estimating probability of snag survival over time, one that included predictor variables unique to the silvicultural systems study on the Penobscot Experimental Forest and one using predictor variables available in most standard inventories. Snag survival models can easily be incorporated into comprehensive forest dynamics models to facilitate estimates of wildlife habitat structure and carbon flow.

Modeling potential future individual tree-species distributions in the eastern United States under a climate change scenario: a case study with Pinus virginiana
About this Resource: We are using a deterministic regression tree analysis model (DISTRIB) and a stochastic migration model (SHIFT) to examine potential distributions of approximately 66 individual species of eastern US trees under a 2xCO2 climate change scenario. This process is demonstrated for Virginia pine (Pinus virginiana). USDA Forest Service Forest Inventory and Analysis data for more than 100 000 plots and nearly 3 million trees east of the 100th meridian were analyzed and aggregated to the county level to provide species importance values for each of more than 2100 counties. County-level data also were compiled on climate, soils, land use, elevation, and spatial pattern. Regression tree analysis (RTA) was used to devise prediction rules from current species-environment relationships, which were then used to replicate the current distribution and predict the potential future distributions under two scenarios of climate change (2xCO2). RTA allows different variables to control importance value predictions at different regions, e.g. at the northern versus southern range limits of a species. RTA outputs represent the potential 'environmental envelope' shifts required by species, while the migration model predicts the more realistic shifts based on colonization probabilities from varying species abundances within a fragmented landscape. The model shows severely limited migration in regions of high forest fragmentation, particularly when the species is low in abundance near the range boundary. These tools are providing mechanisms for evaluating the relationships among various environmental and landscape factors associated with tree-species importance and potential migration in a changing global climate.

Newer Classification and Regression Tree Techniques: Bagging and Random Forests for Ecological Prediction
About this Resource: The task of modeling the distribution of a large number of tree species under future climate scenarios presents unique challenges. First, the model must be robust enough to handle climate data outside the current range without producing unacceptable instability in the output. In addition, the technique should have automatic search mechanisms built in to select the most appropriate values for input model parameters for each species so that minimal effort is required when these parameters are fine-tuned for individual tree species. We evaluated four statistical models--Regression Tree Analysis (RTA), Bagging Trees (BT), Random Forests (RF), and Multivariate Adaptive Regression Splines (MARS)--for predictive vegetation mapping under current and future climate scenarios according to the Canadian Climate Centre global circulation model. To test, we applied these techniques to four tree species common in the eastern United States: loblolly pine (Pinus taeda), sugar maple (Acer saccharum), American beech (Fagus grandifolia), and white oak (Quercus alba). When the four techniques were assessed with Kappa and fuzzy Kappa statistics, RF and BT were superior in reproducing current importance value (a measure of basal area in addition to abundance) distributions for the four tree species, as derived from approximately 100,000 USDA Forest Service's Forest Inventory and Analysis plots. Future estimates of suitable habitat after climate change were visually more reasonable with BT and RF, with slightly better performance by RF as assessed by Kappa statistics, correlation estimates, and spatial distribution of importance values. Although RTA did not perform as well as BT and RF, it provided interpretive models for species whose distributions were captured well by our current set of predictors. MARS was adequate for predicting current distributions but unacceptable for future climate. We consider RTA, BT, and RF modeling approaches, especially when used together to take advantage of their individual strengths, to be robust for predictive mapping and recommend their inclusion in the ecological toolbox.

Forest statistics for Arkansas counties (1970)
About this Resource: Commercial forest-land areas, timber inventory, growth, and cut, as of 1969.

Forest Statistics for Tennessee Counties (1971)
About this Resource: Commercial forest-land areas, timber inventory, growth, and cut as of 1971.

Calibrating and testing a gap model for simulating forest management in the Oregon Coast Range
About this Resource: The complex mix of economic and ecological objectives facing today's forest managers necessitates the development of growth models with a capacity for simulating a wide range of forest conditions while producing outputs useful for economic analyses. We calibrated the gap model ZELIG to simulate stand-level forest development in the Oregon Coast Range as part of a landscape-scale assessment of different forest management strategies. Our goal was to incorporate the predictive ability of an empirical model with the flexibility of a forest succession model. We emphasized the development of commercial-aged stands of Douglas-fir, the dominant tree species in the study area and primary source of timber. In addition, we judged that the ecological approach of ZELIG would be robust to the variety of other forest conditions and practices encountered in the Coast Range, including mixed-species stands, small-scale gap formation, innovative silvicultural methods, and reserve areas where forests grow unmanaged for long periods of time. We parameterized the model to distinguish forest development among two ecoregions, three forest types and two site productivity classes using three data sources: chronosequences of forest inventory data, long-term research data, and simulations from an empirical growth-and-yield model. The calibrated model was tested with independent, long-term measurements from 11 Douglas-fir plots (6 unthinned, 5 thinned), 3 spruce-hemlock plots, and 1 red alder plot. ZELIG closely approximated developmental trajectories of basal area and large trees in the Douglas-fir plots. Differences between simulated and observed conifer basal area for these plots ranged from -2.6 to 2.4m²/ha; differences in the number of trees/ha >=50cmdbh ranged from -8.8 to 7.3tph. Achieving these results required the use of a diameter-growth multiplier, suggesting some underlying constraints on tree growth such as the temperature response function. ZELIG also tended to overestimate regeneration of shade-tolerant trees and underestimate total tree density (i.e., higher rates of tree mortality). However, comparisons with the chronosequences of forest inventory data indicated that the simulated data are within the range of variability observed in the Coast Range. Further exploration and improvement of ZELIG is warranted in three key areas: (1) modeling rapid rates of conifer tree growth without the need for a diameter-growth multiplier; (2) understanding and remedying rates of tree mortality that were higher than those observed in the independent data; and (3) improving the tree regeneration module to account for competition with understory vegetation.

Spatio-Temporal Analysis of Xyleborus glabratus (Coleoptera: Circulionidae: Scolytinae) Invasion in Eastern U.S. Forests
About this Resource: The non-native redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), has recently emerged as a significant pest of southeastern U.S. coastal forests. Specifically, a fungal symbiont (Raffaelea sp.) of X. glabratus has caused mortality of redbay (Persea borbonia) and sassafras (Sassafras albidum) trees in the region; several other Lauraceae species also seem susceptible. Although the range of X. glabratus continues to expand rapidly, little is known about the species' biology and behavior. In turn, there has been no broad-scale assessment of the threat it poses to eastern U.S. forests. To provide a basic information framework, we performed analyses exploiting relevant spatio-temporal data available for X. glabratus. First, we mapped the densities of redbay and sassafras from forest inventory data. Second, we used climate matching to delineate potential geographic limits for X. glabratus. Third, we used county infestation data to estimate the rate of spread and modeled spread through time, incorporating host density as a weighting factor. Our results suggest that (1) key areas with high concentrations of redbay have yet to be invaded, but some are immediately threatened; (2) climatic conditions may serve to constrain X. glabratus to the southeastern U.S. coastal region; and (3) if unchecked, X. glabratus may spread throughout the range of redbay in <40 yr. Disruption of anthropogenic, long-distance dispersal could reduce the likelihood of this outcome.

Assessment of C-band synthetic aperture radar data for mapping and monitoring Coastal Plain forested wetlands in the Mid-Atlantic Region, U.S.A.
About this Resource: Multi-temporal C-band SAR data (C-HH and C-VV), collected by ERS-2 and ENVISAT satellite systems, are compared with field observations of hydrology (i.e., inundation and soil moisture) and National Wetland Inventory maps (U.S. Fish and Wildlife Service) of a large forested wetland complex adjacent to the Patuxent and Middle Patuxent Rivers, tributaries of the Chesapeake Bay. Multi-temporal C-band SAR data were shown to be capable of mapping forested wetlands and monitoring hydroperiod (i.e., temporal fluctuations in inundation and soil moisture) at the study site, and the discrimination of wetland from upland was improved with 10 m digital elevation data. Principal component analysis was used to summarize the multi-temporal SAR data sets and to isolate the dominant temporal trend in inundation and soil moisture (i.e., relative hydroperiod). Significant positive, linear correlations were found between the first principal component and percent area flooded and soil moisture. The correlation (r2) between the first principal component (PC1) of multi-temporal C-HH SAR data and average soil moisture was 0.88 (p = < .0001) during the leaf-off season and 0.87 (p = < .0001) during the leaf-on season, while the correlation between PC1 and average percent area inundated was 0.82 (p = < .0001) and 0.47 (p = .0016) during the leaf-off and leaf-on seasons, respectively. When compared to field data, the SAR forested wetland maps identified areas that were flooded for 25% of the time with 63-96% agreement and areas flooded for 5% of the time with 44-89% agreement, depending on polarization and time of year. The results are encouraging and justify further studies to attempt to quantify the relative SAR-derived hydroperiod classes in terms of physical variables and also to test the application of SAR data to more diverse landscapes at a broader scale. The present evidence suggests that the SAR data will significantly improve routine wooded wetland mapping.

Southern Research Station | USDA Forest Service
About this Resource: The Southern Research Station creates the science and technology needed to sustain and enhance forest ecosystems in southern regions of the U.S. This link, which connects to the Research Station's homepage is a source for identifying publications; work units; employees and background on the Station. The Homepage features: current highlights; scientists' and their research; new additions; the Stations' strategic framework and the ten most recent publications added to the site. A section for "additional information" points to glossaries; educational products and photo galleries. Additional web features include a publications electronic mailing list, employment information, online videos and relevant external links.

Field efficiency and bias of snag inventory methods.
About this Resource: Snags and cavity trees are important components of forests, but can be difficult to inventory precisely and are not always included in inventories because of limited resources. We tested the application of N-tree distance sampling as a time-saving snag sampling method and compared N-tree distance sampling to fixed-area sampling and modified horizontal line sampling in mixed pine-hardwood forests of southern Maine and New Hampshire. We also present a novel modification of N-tree distance sampling that limits the distance from plot center that an observer must search to find tally trees. A field test shows N-tree to be quick, but generally biased and characterized by high variability. Distance-limited N-tree sampling mitigates these problems, but not completely. We give recommendations for operational snag inventory in similar forest types.

Decision support tools to improve the effectiveness of hazardous fuel reduction treatments in the New Jersey Pine Barrens
About this Resource: Our goal is to assist the New Jersey Forest Fire Service and federal wildland fire managers in the New Jersey Pine Barrens evaluate where and when to conduct hazardous fuel reduction treatments. We used remotely sensed LIDAR (Light Detection and Ranging System) data and field sampling to estimate fuel loads and consumption during prescribed fire treatments. This information was integrated with data on prescribed fire treatments conducted by the New Jersey Forest Fire Service over the last 15 years to produce and interpret maps of current fuel loads. Forest productivity measurements and models were then used to estimate rates of fuel accumulation through time. We could then calculate return intervals for desired fuel load conditions. Through formal workshops and frequent discussions with state and federal fire managers, our results enhance the ability of these agencies to make key decisions regarding the effectiveness and longevity of hazardous fuels treatments.

Predicting past and future diameter growth for trees in the northeastern United States
About this Resource: Tree diameter growth models are widely used in forestry applications, often to predict tree size at a future point in time. Also, there are instances where projections of past diameters are needed. A relative diameter growth model was developed to allow prediction of both future and past growth rates. Coefficients were estimated for 15 species groups that cover most tree species in the northeastern United States. Application of the model to independent data generally showed slight underprediction of growth, although the bias was negligible. Correlated observations were accounted for via a mixed-effects modeling approach, and an error function was specified to address heterogeneous variance. The models use a minimum amount of field-collected data, thus keeping data acquisition costs low and facilitating use in many forest growth applications.

Secondary Forest Succession and Tree Planting at the Laguna Cartagena and Cabo Rojo Wildlife Refuges in Southwestern Puerto Rico
About this Resource: Secondary forest succession and tree planting are contributing to the recovery of the Cabo Rojo refuge (Headquarters and Salinas tracts) and Laguna Cartagena refuge (Lagoon and Tinaja tracts) of the Fish and Wildlife Service in southwestern Puerto Rico. About 80 species, mainly natives, have been planted on 44 ha during the past 25 y in an effort to reduce the threat of grass fires and to restore wildlife habitat. A 2007 survey of 9-y-old tree plantings on the Lagoon tract showed satisfactory growth rates for 16 native species. Multiple stems from individual trees at ground level were common. A sampling of secondary forest on the entire 109 ha Tinaja tract disclosed 141 native tree species, or 25% of Puerto Rico's native tree flora, along with 20 exotics. Five tree species made up about 58% of the total basal area, and seven species were island endemics. Between 1998 and 2003, tree numbers and basal area, as well as tree heights and diameter at breast height values (diameter at 1.4 m above the ground), increased on the lower 30 ha of the Tinaja tract. In this area, much of it subject to fires and grazing through 1996, exotic trees made up 25% of the species. Dry forest throughout the tropics is an endangered habitat, and its recovery (i.e., in biomass, structure, and species composition) at Tinaja may exceed 500 y. Future forests, however, will likely contain some exotics.