Treesearch

This report is a scientific assessment of the current condition and likely future condition of forest resources in the United States relative to climatic variability and change. It serves as the U.S. Forest Service forest sector technical report for the National Climate Assessment and includes descriptions of key regional issues and examples of a risk-based framework for assessing climate-change effects. By the end of the 21st century, forest ecosystems in the United States will differ from those of today as a result of changing climate. Although increases in temperature, changes in...

The Integrated Landscape Assessment Project (ILAP) is a three-year effort that produces information, models, data, and tools to help land managers, policymakers, and others examine mid- to broad-scale (e.g., watersheds to states and larger areas) prioritization of land management actions, perform landscape assessments, and estimate potential effects of management actions for planning and other purposes. ILAP provides wall-to-wall, cross-ownership geospatial data and maps on existing, potential and future vegetation conditions, land ownership and management allocation classes, and other...

Many threats are jeopardizing the sagebrush steppe of the Columbia Basin, including the spread of invasive species such as cheatgrass (Bromus tectorum L.) and the expansion of western juniper (Juniperus occidentalis Hook.) into historic shrub steppe. Native sagebrush steppe provides productive grazing lands and important habitat for many wildlife species, and managers are in need of landscapescale tools to assess shrub steppe conversion risk and management options to maintain native shrub steppe. We used a state-and-transition modeling approach to project changes in sagebrush steppe...

This research explored the ecological consequences of rural residential development and different management regimes on a tract of former industrial timberland in central Oregon known as the Bull Springs. Forage quality and habitat suitability models for mule deer (Odocoileus hemionus) winter range were joined to the outputs of a spatially explicit vegetation dynamics model under two management scenarios. In one scenario, the tract was managed as a working forest excluding development, and in the other, development was allowed to occur at historical rates. Landscape pattern analysis was...

Wildlife conservation often is a central focus in planning for natural resource management. Evaluation of wildlife habitat involves balancing the desire for information about detailed habitat characteristics and the feasibility of completing analyses across large areas. Our objective is to describe tradeoffs made in assessments of wildlife habitat within a multiple-objective vegetation-based state-and-transition model (STM) framework. Species-habitat relationships derived from STM vegetation characteristics require careful interpretation for several reasons. First, the observational unit...

The Integrated Landscape Assessment Project (ILAP) uses spatial vegetation data and state and transition models (STM) to forecast future vegetation conditions and the interacting effects of natural disturbances and management activities. Results from ILAP will help land managers, planners, and policymakers evaluate management strategies that reduce fire risk, improve wildlife habitat, and benefit rural communities. This case study illustrates the methodology for modeling timber volume, biomass estimates, and the forest carbon over time with the output of STM simulations. It presents how...

Land managers commonly use FVS and VDDT as planning aids. Although complementary, the models differ in their approach to projection, spatial and temporal resolution, simulation units and required input. When both are used, comparison of the model projections helps to identify differences in the assumptions of the two models and hopefully will result in more consistent results across models. We used the transition probability matrix as the basis for comparing the two models, using side-by-side simulations with FVS and VDDT to project 250 mixed conifer stands. We designed and carried out a...

The Forest Vegetation Simulator (FVS) has been used to provide rates of natural growth transitions under endemic conditions for use in State and Transition Models (STMs). This process has previously been presented. This paper expands on that work by citing the methods used to capture resultant vegetation states following disturbance activities; be it of natural causes or human induced. Forest Inventory and Analysis (FIA) plots were stratified by representative Potential Natural Vegetation Types (PNVTs) of the southwestern United States. Structural states within the Vegetation Dynamics...

Understanding landscape vegetation dynamics often involves the use of scientifically-based modeling tools that are capable of testing alternative management scenarios given complex ecological, management, and social conditions. State-and-transition simulation model (STSM) frameworks and software such as PATH and VDDT are commonly used tools that simulate how landscapes might look and function in the future. Until recently, however, STSMs did not explicitly include climate change considerations. Yet the structure of STSMs makes them highly conducive to the incorporation of any probabilistic...

Interactions between landuse and ecosystem change are complex, especially in riparian zones. To date, few models are available to project the influence of alternative landuse practices, natural disturbance and plant succession on the likely future conditions of riparian zones and aquatic habitats across large spatial extents. A state and transition approach was used to model the effects of various management and restoration practices on conditions of riparian forests, channel morphology, and salmonid habitat. We present results of model analyses for the Wilson River in the Oregon Coast...