Browsing by Subject "Forest Inventory and Analysis"

Now showing 1 - 3 of 3
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    Advancing Estimation Of Timber Products Output In The Lake States Region Of The Northern United States
    (2019-05) Young, John
    The Forest Inventory and Analysis (FIA) – Timber Products Output (TPO) program has chosen to implement a sampling design for collecting information from primary wood-using facilities across the US. Sample-based approaches are often clear alternatives to surveys, as they offer estimates with increased precision and quantifiable error at lower costs and greater speed. Coulston et al. (2018) has selected a unique stratified random sampling design, which separates mills into a “certainty” or “uncertainty” sample based on a measure of size (MOS). However, the new design is in its early stages and needs for developing the efficiency of the design have been identified. This research assesses the advancement of two key areas: the selection of an effective MOS and the identification of a threshold for allocating mills into a “certainty” sample. When sampling highly-skewed populations, a few large units may account for large portions of the mean estimated and incorrectly accounting for these units can negatively impact the precision of estimation. Systematic identification of a certainty threshold was assessed through methods inspired by the work of Glasser (1962) and Hidiroglou (1985). Estimates produced by these methods were analyzed against historic TPO data to assess for overall impact. MOS also alter the precision, and as the correlation between the variable of interest and the MOS increases the level of uncertainty tends to decrease. Sources for gathering auxiliary mill metrics were explored and relevant attributes were combined to create MOS using three separate techniques: correlation comparison, simple linear regression, and multiple regression. The implementation of different MOS and threshold identification techniques, their impact on sampling efficiency, and potential areas of further research are assessed.
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    Modeling forest growth, yield, and wildlife habitat in the Lake States
    (2013-05) Zobel, John M.
    Modeling efforts in the Lake States have produced numerous descriptive and predictive statistical models to assist forest management. However, several needs remain, including representation of (1) intensive forest management, (2) wildlife response to habitat change, and (3) projections of stand mortality for extended rotations. (1) We created a managed and intensively managed stand version of the Lake States variant of the Forest Vegetation Simulator (LS-FVS). This research concentrated on updating the large tree diameter growth model in LS-FVS using data from the Forest Inventory and Analysis (FIA) database. The final model form provides an important tool for describing individual tree level response to various management intensities in LS-FVS. (2) The Wildlife Habitat Indicator for Native Genera and Species (WHINGS) was derived from the Minnesota Generic Environmental Impact Statement and allows forest managers and policy analysts to examine the impacts of proposed management scenarios on forest wildlife habitat. This research recommended several updates to the current habitat suitability index methodology used in the model. A case study for St. Louis County, Minnesota demonstrated an application of the updated model to three 100 year harvest scheduling projections. Results illustrated that any sustainable change in forest habitat will benefit some species and diminish others.(3) This study modified and extended an existing yield curve for the red pine and aspen forest types to encompass the entire life of a forest stand (single cohort). The new model assumed that accumulated mortality eventually equals accumulated growth (i.e., stand mortality eventually reaches 100%). From among several proposed model forms, a symmetric curve based on an underlying basal area model proved superior. Forest managers and planners tasked with estimating yield (or yield loss) from diverse scenarios can now obtain realistic projections for stands beyond the age range of typical yield models.In addition, we compared several datasets from FIA for similar utility when developing empirical yield models and compared several basal area yield models and fitting methods for their applicability and stability over time. Finally, we evaluated the managed and intensively managed stand version of LS-FVS using independent growth observations from the most recently available FIA data.
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    Regional legacies of logging: Departure from presettlement forest conditions in northern Minnesota
    (2005) Friedman, Steven K; Reich, Peter B
    Forests in the Great Lakes region of Canada and the United States have been important timber producing resources for more than 100 years. Logging and fire suppression have caused major, but unquantified change in those forests, which includes both the magnitude of compositional change and its spatial patterns. Hence, a spatially explicit regional-scale change analysis was conducted using General Land Office Survey records from the late 1800s and the 1990 U.S. Forest Service Inventory and Analysis Survey, for a 3.2 million hectare study area in northeastern Minnesota, USA. These data document altered species abundance, proportional basal area, and spatial distribution patterns. Regionally, the proportionally most abundant species shifted from the presettlement period (spruce, 21%; larch, 15%; and paper birch, 15%) to aspen (30%), spruce (16%), and balsam fir (16%) in 1990. In terms of proportional basal area dominance, white pine declined from 20% to 5%, birch from 16% to 13%, spruce from 14% to 9%, and larch from 12% to 2%, while aspen increased from 8% to 35%. Based on ordination of species abundance and proportional basal area, physiographic zones varying in geology and hydrology were characterized by different species composition in the 19th century and experienced largely parallel rather than convergent shifts in community composition since that time. Maps were developed for the regional study area using a 10 × 10 km spatial resolution to document spatial patterns of species proportional basal area. White pine co-dominated (was ranked first or second in proportion of basal area) 45% of the 253 100-km2 presettlement zones, but none of the 1990 zones. Forest zones co-dominated by red pine, jack pine, and larch also largely disappeared. These forests were largely supplanted by aspen co-dominated communities, which accounted for 82% of the 1990 forest zones and represent diminished regional landscape diversity. Although the same 11 species made up the 1990 as well as the 19th century forest, change in their relative abundance and dominance was profound such that 85% of the 253 zones now contain community types (i.e., dominant species pairs) that did not dominate anywhere in the presettlement era.