Treesearch

Forest ecosystems are the largest terrestrial carbon sink on earth with more than half of their net primary production moving to the soil via the decomposition of litter biomass. Therefore, changes in the litter carbon pool have important implications for global carbon budgets and carbon emissions reduction targets and negotiations. Litter accounts for an estimated 5 percent of all forest ecosystem carbon stocks worldwide. Given the cost and time required to measure litter attributes, many nations that are signatories to the United Nations Framework Convention on Climate Change (UNFCCC)...

Federal forests in the Pacific Northwest region have undergone exceptional changes in management over the past 20 years, and these changes have led to a reduction in regional timber production and significant changes in the management and current age structure of forests. Public lands include large areas of older forests with relatively little younger early-seral forests. In contrast, private lands include large areas of younger forests and little land in older forests. The lack of early-seral forests on federal lands is an important and distinguishing characteristic of these forests and...

Small area estimation (SAE) techniques have been successfully applied in forest inventories to provide reliable estimates for domains where the sample size is small (i.e. small areas). Previous studies have explored the use of either Area Level or Unit Level Empirical Best Linear Unbiased Predictors (EBLUPs) in a univariate framework, modeling each variable of interest at a time, and not considering their potential correlation. Yet most forest inventory variables such as basal area (G) and volume (V) are strongly correlated. In this situation, EBLUPs for multivariate responses can improve...

This study will investigate how global and local predictors differ with varying spatial scale in relation to species evenness and richness in the gulf coastal plain. Particularly, all-live trees >= one-inch d.b.h. Forest Inventory and Analysis (FIA) data was used as the basis for the study. Watersheds are defined by the USGS 12 digit hydrologic units. The dataset includes various environmental data such as temperature, rainfall, frost free days, soil productivity, stand age, latitude, longitude, average elevation, and land use fragmentation or disturbance indicators. Multivariate analysis...

Plot mapping is one of the innovations that were implemented when FIA moved to the annual forest inventory system. Mapped plots can improve the precision of estimates if the mapped conditions are carefully chosen and used judiciously. However, after plots are remeasured multiple times, it can be difficult to properly track changes in conditions and incorporate this into the analysis. Early discussions about plot mapping considered 2 mapping options: 1) full mapping and 2) fuzzed mapping. Full mapping is what FIA adopted. Fuzzed mapping (fuzzing) was felt to provide less precision, since it...

Understanding forest ecosystems is paramount for their sustainable management and for the livelihoods and ecosystem services which depend on them. However, the complexity and diversity of these systems poses a challenge to interpreting data patterns. The availability and accessibility of data and tools often determine the method selected for forest assessment. Capacity building is fundamental to ensure that sampling methods, data analysis and use of tools are efficiently and sustainably appropriated. FAO has trained people from over 30 countries to develop tools and databases to improve...

Imputation models were developed and tested to estimate tree regeneration on Forest Service land in Oregon and Washington. The models were based on Forest Inventory and Analysis and Pacific Northwest Regional NFS Monitoring data. The data was processed into sets of tables containing estimates of regeneration by broad plant associations and spanning a large variety in forest cover conditions. The output tables were organized to facilitate their use within variants of FVS commonly used in the Pacific Northwest region. The methods were implemented in a highly reproducible fashion to ensure...

The effects of subsample design and imputation of total height (ht) and live crown ratio (cr) on the accuracy of stand-level estimates of component and total aboveground biomass are not well investigated in the current body of literature. To assess this gap in research, this study uses a data set of 3,454 Douglas-fir trees obtained from 102 stands in southwestern Oregon to simulate different combinations of subsample designs and imputation methods. The predictive ability of the regional ht and cr imputation methods on estimates of component and total aboveground biomass for a range of...

In the summer of 2014 the US Forest Service’s Forest Inventory and Analysis (FIA) Program of the Pacific Northwest (PNW) Research Station in conjunction with NASA Goddard carried out a pilot inventory of the forests of interior Alaska. This inventory was conducted on the State of Alaska’s Tanana Valley State Forest and on the Tetlin National Wildlife Refuge. As part of the field protocols that were implemented, field crews measured Down Woody Material (DWM), sampled soils and collected tree cores. The DWM protocols were based on standard FIA protocols. The soil sampling included a modified...

Vegetation profile data were collected as part of a forest inventory project in the Tanana Valley in interior Alaska, providing a means of characterizing the forest vegetation. The black spruce forest type was most common, followed by Alaska paper birch, and white spruce, quaking aspen, and balsam poplar. For individual tree species, black spruce was recorded on 68 percent of all plots, birch was recorded on 67 percent and white spruce on 58 percent. The distribution of growth habits in horizontal layers varied by forest type. There was a higher percentage tree cover in hardwood forest...