Treesearch

Between 1981 and 1985, the Austrian National Forest Inventory (ANF) established a set of 5,500 clusters, each with four permanent plots, covering all Austrian forests. After the first remeasurement between 1986 and 1990, models were developed to predict tree growth, mortality, and the behavior of forest owners in harvesting timber. A set of logistic equations describes the probability of a given stand exhibiting intermediate harvesting, single-tree selection, or final clearcutting. The independent variables were partly continuous and partly categorical, describing (l) regional units such...

The uncertainty in 5-, 10-, and 20-year diameter growth predictions is estimated using Monte Carlo simulations for four Lake States tree species. Two sets of diameter growth models are used: recalibrations of the STEMS models using forest inventory and analysis data, and new growth models developed as a component of an annual forest inventory system for the North Central region of the United States. Particular attention is focused on the effects that uncertainty in the values of predictor variables has on the uncertainty of model predictions. The cumulative effects of uncertainty in model...

At the global level, a sampling scheme for tropical forest change assessment, using high resolution satellite images, has been defined using sampling units independent of any particular satellite sensor. For this purpose, a sampling frame has been chosen a hexagonal tessellation of 3,600 km².

Maximum size-density relationships were investigated for two mixed-hardwood ecological types (sugar maple-ash and beech-red maple) in New England. Plots meeting type criteria and undergoing self-thinning were selected for each habitat. Using reduced major axis regression, no differences were found between the two ecological types. Pure species plots (the species basal area greater than 70 percent of the total plot basal area) were identified for six major hardwood species, and corresponding size-density relationships were developed. Results showed that shade tolerant and intermediate...

Includes 96 papers presented at the conference Integrated Tools for Natural Resources Inventories in the 21st Century, August 16-20, 1998, in Boise, Idaho, USA. This conference drew several hundred forest inventory and related professionals from multiple organizational levels and over 30 foreign countries. Topics covered include those related to natural resource inventory design, analysis and management applications; measurement consistency issues; data management, GIS and remote sensing applications; forest growth model interfaces; and special purpose inventories and applications.

The model FIBER (Forest Increment Based on Ecological Rationale) was selected by the Technical Review Team on the Sustainability of Timber Supplies in the State of Maine to construct yield information using USDA Forest Service Forest Inventory and Analysis (FIA) field data. FIBER habitat criteria based on soil characteristics, species composition of overstory, and adjusted understory trees were used to classify FIA plots compared to the past and present records of the FIA inventory forest typing. Yield curves based on ecological classification and species compositional succession were...

Variables based on stand densities or stocking have sampling errors that depend on the relation of tree size to plot size and on the spatial structure of the population, ignoring the sampling errors of such variables, which include most measures of competition used in both distance-dependent and distance-independent growth models, can bias the predictions obtained from regression analysis.

In recent work the author used the geostatistical Monte Carlo technique of sequential Gaussian simulation (s.G.s.) to investigate uncertainty in a GIS analysis of potential old-growth forest areas. The current study compares this earlier technique to that of co-conditional simulation, wherein the spatial cross-correlations between variables are included. As in the earlier study, uncertainties were assessed across 500 independent spatial Monte Carlo realizations for each of three variables of interest (quadratic mean stand diameter; age of dominant and co-dominant trees, and percent canopy...

Intensifying interest in forests and the development of new monitoring technologies have induced major changes in forest monitoring systems in the last few years, including major revisions in the methods used for updating. This paper describes the methods available for projecting stand- and plot-level information, emphasizing advantages and disadvantages, and the subsequent use of the updated information in constructing new estimates. Research directions that might lead to improving the updating process are also discussed.

One of the most important functions of forest inventory is to facilitate management decisions towards forest sustainability based on inventory projections into the future. Therefore, most forest inventories are used for predicting future states of the forests, in modern forestry the most common methods used in inventory projections are based on implicit functions describing time and site dependent relationships derived from panel data. The essence of the implicit functions used for inventory projections is that each function is defined by its own value at one point in time - usually at the...