"Adjacency" and "Green-up" are headings describing sub-projects that are parts of the main 3-year project, sponsored by TIP3 funding, titled: "Long-term sustainability analysis of forest resources in Georgia and assessment of potential effects of riparian zones and other regulatory and business constraints".  The purpose of these two sub-projects is to estimate the impact of regulatory constraints associated with a potential implementation of a mandatory Forestry Practices Code in Georgia that might be introduced in the future.  

The analysis of "Adjacency" and "Green-up" constraints impacts on the Fiber Supply in Georgia are scheduled for the year 2003/2004, and the the results of this research will be published in the later part of 2004 and thereafter on this web pages and in other outlets.  Please see the description of the relevant to these analyzes main project below.


Long-term sustainability analysis of forest resources in Georgia and assessment of potential effects of riparian zones and other regulatory and business constraints


Forest product industry, owners, and policy makers heavily rely on the information to be inferred from the data collected in the FIA program. Many of the analyses relying on these data are very simplistic, and some of the inferences produced from such analyses are incomplete and may be questionable. For example, no reliable answer to the question whether or not our natural resources are utilized on a sustainable basis, and what would be the potential impact of various regulatory constraints on forest resources in the state of Georgia. To answer resource sustainability questions, one needs to conduct a much more complex analysis involving modeling of changes over time, that are nonlinear in nature. This includes using explicit assumptions concerning regeneration dynamics and management activities, clear assumptions regarding future land use changes, and also by taking into account supply and demand of forest products.

At the same time with the growing concern of modern societies about the welfare of natural resources, even private landowners face the possibility of dramatic regulatory constraints imposed by forces acting in the name of preservation and sustainability. Furthermore, the claims of threat to sustainability are commonly based on inadequate information, arbitrary assumptions, and oversimplified analyses (as, e.g., growth/removals ratio). Through the proposed project we want to provide a scientific basis for realistic analyses of the long-term considerations of sustainability of natural resources in Georgia.

In so doing we want to develop a responsible methodology for analysis of the effects of various regulatory conditions, such as the introduction of riparian zones, or buffers around water resources, maximum harvest areas, and adjacency and green-up constraints. In addition, we want to include in the analyses a basic modeling of supply and demand conditions, urban and suburban developments, and land use changes.

Description of the Problem

Forestry is one of the most important industries in Georgia. According to the newest data (Riall 2002) the business of forestry contributes about $30 billion annually to Georgia's economy. In addition to the direct economic benefit, Georgia's forests provide hunting, fishing, hiking, and other outdoor recreational opportunities, help to maintain a clean water supply, conserve soil and provide habitat for many fish and wildlife species, some of which are presently endangered.

As the state becomes more populated, urban/suburban expansion will result in fewer acres available for production forestry and recreation. Furthermore, as the population of the state increases we will face greater demand for clean water as well as non-timber forest uses such as hiking and camping. This will further reduce the number of acres available for production forestry. Concurrent to this reduction in the number of acres devoted to production forestry, we will experience an increase in demand for various wood products from our forests. Thus, we will have a decreasing land base from which an increasing supply of wood products will be required (e.g., Wear and Greis 2001). This may lead to a situation in which the standing timber inventory may not meet the needs of the citizens of the state of Georgia. Since policy makers and business leaders make decisions that affect our forests, we must have a tool to evaluate the potential effects their decisions will have on this valuable resource. For example, how will the standing inventory of merchantable trees be affected by environmental constraints (such as SMZs of various sizes along roads, streams and rivers, or adjacency and green-up constraints). At this point in time, the tools available to answer these types of questions are rudimentary at best.

In the project we acquired the most recently available FIA inventory data for Georgia and initiated an acquisition of additional GIS spatial data. We have acquired spatial data for such non-forest features as roads, streams, rivers, lakes, etc. All of the spatial data are being brought into OPTIONS so that the current inventory data for Georgia can be displayed numerically, graphically or spatially (i.e. maps). We will then show how the current and future inventory available for harvest is affected by various assumptions about how the inventory is distributed in space as well as how supply, demand, growth and regeneration are defined. The analyses will compare several scenarios and sets of assumptions with the current USFS methodology for spatial distribution of inventory and changes over time.

Description of the Project

Forest resources managers make economic and policy related decisions based on current and anticipated timber supply. Current estimates of regional and national timber supply are based on data obtained by the Forest Inventory and Analysis (FIA) unit of the USDA Forest Service. Future estimates of timber supply are obtained with regional timber supply projection algorithms (Adams and Haynes 1996, Pacheco et al. 1996, Cubbage et al. 1990). These timber supply projection algorithms use supply/demand relationships along with anticipated growth and harvest of timber to project timber supply and prices into the future. To date, most growth projection algorithms used in regional and national timber supply models use ad hoc methods that have not been well documented. Furthermore, these models tend to be very simplistic in that they do not take into account the spatial distribution of timber and other resources and how their proximity to one another may impact available inventory. With current models, it is very difficult or impossible to impose realistic restrictions on harvesting and regeneration that may be associated with environmental regulations that currently exist or may be put into effect. Consequently, the projections made with such models are at best very crude approximations of future fiber supply. The technical approach of this study is based on realistic, long-term simulations of the inventory information in Georgia. In the first year, the project started with non-spatial analysis of long-term sustainability of fiber supply resources. This analysis was based on large-scale aggregation based on data from FIA/SAFIS inventory. All data were processed to a common format and examined for quality assurance. In the second year the project's database was complemented by assumptions with respect to intensive management practices and by additional GIS information that came from available sources describing, among other things, water resources data and road locations (Georgia GIS clearinghouse, GAP, NARSAL, etc . To reliably conduct long-term analyses for fiber supply assessment, we prepared yield tables with various adjustments suitable for low-resolution analyses of different scenarios that we considered. At the time of writing this proposal the second year is still in progress. We started the spatial analysis of long-term sustainability of fiber supply resources using various management options, including riparian zones, road beautifying buffers, and intensive management practices. We assessed the impact of intensive management practices assuming various harvesting levels and proportions of land transferred into intensive management after harvest. During the analysis we'll use a database developed in the previous steps with the most up-to-date inventory information in southeastern Georgia using spatially explicit inventory data from industrial cooperators in conjunction with other spatially explicit data (e.g., water resources, roads, urban/suburban areas). The emphasis will be put into being able to produce high-resolution results that allow evaluation of the effects of specific environmental constraints (e.g. riparian zones, road beautifying buffers, maximum clear-cut size, adjacency and green-up constraints, etc.) on the structure and development of the timber inventory in any considered region. In order to do that, we would have to revise yield and regeneration tables used in previous phases to assure that they are suitable for long-term, high resolution, fiber supply analyses including that of wood quality components. The data and analyses mentioned above will be the base on which to develop OPTIONS scenarios for the high-resolution analysis of the effect of regulatory constraints on fiber supply.


Adams, D.M. and R.W. Haynes. 1996. The 1993 timber assessment market model: structure, projections and policy implications. USDA Forest Service. GTR-PNW-368. 58pp.

Cubbage, F.W., D.W. Hogg, T.G. Harris, and R.J. Alig. 1990. Inventory projection with the Georgia regional timber supply (GRITS) model. South. J.Appl. For. 14(3):124-133.

Pacheco, G., R.C. Abt, and F.W. Cubbage. 1996. Southwide timber supply projection and assessment. In: Proceedings of the Southern Forest Economics Workshop. Gatlinburg, TN. 418pp.

Riall, W.B. 2002. Economic Benefits of the Forestry Industry in Georgia: 2001. Report of the Georgia Tech Research Corporation, Atlanta, GA, prepared for the Georgia Forestry Commission.

Wear, D.N., J.G. Greis. 2002. Southern forest resource assessment. Gen. Tech. Rep. SRS-53. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 635p.

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