John R. Mills

Forest Sector Impacts from Changes in Forest Productivity Under Climate Change

The consequences of elevated carbon dioxide and climate change on forest systems and the role that economics could play in timber harvest and vegetation change have not been addressed together. A framework was developed to link climate change scenarios, an ecosystem model, a forest sector model and a carbon accounting model. Four climate scenarios were used to estimate net primary productivity (NPP) for forests in the United States. Changes in NPP were estimated using TEM, the Terrestrial Ecosystem Model which uses spatially referenced information on climate, soils and vegetation to estimate important carbon and nitrogen fluxes and pool sizes within ecosystems at the continental scale. Changes in NPP under climate change were used to modify timber growth within the Aggregate Timberland Assessment Model (ATLAS), which is a part of the forest sector model (TAMMATLAS) used by the Forest Service to examine timber policy questions. The changes in timber inventories were then translated into changes in the amount of carbon stored on private timberlands using a national carbon model (FORCARB). Regional changes in productivity filter through the forest sector and result in changes in land use and timber consumption. Long-term changes in carbon storage indicate that these private timberlands will be a source of carbon dioxide for all but the most optimistic climate change scenario.

The 2005 RPA timber assessment update.

This update reports changes in the Nations timber resource since the Analysis of the Timber Situation in the United States was completed in 2003. Prospective trends in demands for and supplies of timber, and the factors that affect these trends are examined. These trends include changes in the U.S. economy, increased salvage of British Columbia beetle-killed timber, and a stronger U.S. dollar. Other prospective trends that might alter the future timber situation are discussed including changes in U.S. timberland area, reductions in southern pine plantation establishment, impacts of climate change on forest productivity, increased restoration thinning on Western public lands, and the impact of programs to increase carbon sequestration through afforestation. Various management implications such as the influence of prices on forest management, concerns about changes in forest area, the emerging open space issue, forests as a set of commons, seeking to find greater compatibility in forest management, and the stewardship agenda are discussed.

FORCARB2: An updated version of the U.S. Forest Carbon Budget Model

FORCARB2, an updated version of the U.S. FORest CARBon Budget Model (FORCARB), produces estimates of carbon stocks and stock changes for forest ecosystems and forest products at 5-year intervals. FORCARB2 includes a new methodology for carbon in harvested wood products, updated initial inventory data, a revised algorithm for dead wood, and now includes public forest land, reserved forest land, and forest land of low productivity. The model has been used to provide estimates and projections for policy-related needs, including the Resources Planning Act timber resource assessment and forest-related greenhouse gas inventories of the United States, and has provided the basis for an analysis of forest carbon for Ontario, Canada. The program is written in FORTRAN and is text based, though virtually every parameter is defined by input text-based files that can be modified or built by the user. We expect users who are fairly advanced in terms of knowledge about computers will be most capable in using this model. Step-by-step instructions for running the program, input and output files, and codes used are included, and input files for public forest lands of the United States are provided as an example. All electronic files for download, including the model source code, executable files, and input and output files are available at http://nrs.fs.fed.us/pubs/35613.

Contemporary Management Regimes in the Pacific Northwest: Balancing Biophysical and Economic Concerns

For almost a century timberland in Oregon and Washington (especially in western Oregon and Washington) has been managed with increasing intensity to support a forest products sector that has grown in both size and complexity. Various forest management regimes evolved as landowner objectives, regulatory conditions, and the markets for (and utilization of) harvested timber changed and silvicultural knowledge (including growth and yield information) advanced. The region is characterized by diverse ownerships (Table 1) that have led to a patchwork mosaic of management regimes. Unlike other U.S. regions, however, these ownerships tend to consist of large and relatively contiguous blocks of timberland, leading to an interest in landscape scale management approaches within individual ownerships. This chapter discusses the evolving mix of management regimes, the conditions that influence their adoption, expected trends in forest management, and the effects of these trends on timber harvest potential.

Bioeconomic and market models

The United States has a century of experience with the development of models that describe markets for forest products and trends in resource conditions. In the last four decades, increasing rigor in policy debates has stimulated the development of models to support policy analysis. Increasingly, research has evolved (often relying on computer-based models) to increase understanding of consumer demands, producer behavior, landowner behavior, and conditions of the timber resource. Greater computational power available since the mid 1970s has allowed the evolution of bioeconomic models that combine economic and resource models. These are used in the United States to provide the basis for forecasting future resource and market trends and to inform policy analysis. These more complex models have also extended options for policy analysis using approaches such as scenario planning to help decision makers gauge uncertainty.

Timber Inventory and Management—ATLAS

The ATLAS model is a framework that allows development of multi- scale, customized growth and yield modules. In the Timber Assessment Projection System these modules represent aggregates of stands across a region and owner- ship with multiple management regimes. ATLAS employs an age class structure to represent the timber inventory for areas managed on both even- and uneven- aged silvicultural systems. Inventory is represented by means of strata or units which are aggregations of basic plot-level data to some higher geographic or other descriptive level. Yield projections are derived from type-specific growth models in some regions and from empirical yield relations derived from basic inventory data in other instances. Yield projections are adapted to reflect both even-aged and partial cutting regimes. Allocation of private lands to various levels of manage- ment intensity depends on a model of management investment based on estimated land expectations values. Section 6.4 contrasts ATLAS with inventory projection approaches employed in other recent forest sector models.