Treesearch

Conversion of forest, range, and agricultural resource lands to residential and commercial uses affects the available land base, management practices on remaining resource lands, habitat quality, and ecosystem services. The Forest Inventory and Analysis program (FIA) mandate includes monitoring changes in the land area in forest use, and this has proved valuable for policy-makers interested in the effectiveness of laws regulating changes in local land-use. A variety of semi-automated approaches have been used to identify land-use change with imagery, but distinguishing changes in land...

Models of forest succession provide an appealing conceptual framework for understanding forest dynamics, but uncertainty in the degree to which patterns are regionally consistent might limit the application of successional theory in forest management. Remeasurements of forest inventory networks provide an opportunity to assess this consistency, improving our understanding of forest dynamics through succession at regional scales. In this study, we examined the responses of proportional Pseudotsuga menziesii biomass change to successional status, relative abundance, resource availability,...

The air in California’s forests spans a broad range of purity, from virtually no locally generated pollutants to highly elevated levels of pollutants in forests downwind of urban and agricultural source areas. Ten-year remeasurement data from Forest Inventory and Analysis (FIA) plots in California were used in combination with modelled atmospheric nitrogen (N) deposition to evaluate tree diameter growth and mortality responses across the state. After controlling for tree size, site productivity, climate attributes, stand density, and competition experienced by each tallied tree, we found...

How vulnerable are US forest to a changing climate? We answer this question using Landsat time series data and a unique interpretation approach, TimeSync, a plot-based Landsat visualization and data collection tool. Original analyses were based on a stratified two-stage cluster sample design that included interpretation of 3858 forested plots. From these data, we derived annual plot-based estimates (with uncertainties) of rates of forest decline from 1985-2012. Noted was a dramatic national-level increase in rates from the mid-90s (<1% of total forest per year) to 2000 (nearly 3% per...

The area burned by Southern California wildfires has increased in recent decades, with implications for human health, infrastructure, and ecosystem management. Meteorology and fuel structure are universally recognized controllers of wildfire, but their relative importance, and hence the efficacy of abatement and suppression efforts, remains controversial. Southern California’s wildfires can be partitioned by meteorology: fires typically occur either during Santa Ana winds (SA fires) in October through April, or warm and dry periods in June through September (non-SA fires). Previous work...

Estimates of forest soil organic carbon stocks across the US are currently developed from expert opinion in STATSGO/SSURGO and linked to forest type. The results are reported to the US EPA as the official United States submission to the UN Framework Convention on Climate Change. Beginning in 2015, however, estimates of soil organic carbon (SOC) stocks will be based on SOC data from soil cores collected in the field (0-10 and 10-20 cm depth). In addition, the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidance suggests these estimates extend to at least 30 cm for all...

Traditional growth, removals, and mortality (GRM) estimates produced from Forest Inventory and Analysis (FIA) periodic inventories were limited to changes in volume on timberland. Estimates on forestland were added in the east as the first installment of annual inventory plots was remeasured. The western FIA units have begun annual remeasurement, precipitating the need to produce GRM estimates on the macroplot and for woodland species. In addition, FIA faces increased demand to produce biomass and carbon GRM estimates. Recent accomplishments that meet the need for expanded GRM estimation...

The Pacific Northwest Research Station’s Forest Inventory and Analysis Unit began remeasurement of permanently located FIA plots under the annualized design in 2011. With remeasurement has come the need to implement the national FIA system for compiling estimates of forest growth, removals, and mortality. The national system requires regional diameter-growth models to estimate diameters on trees in situations where the initial or terminal diameter is not known at the beginning or end of a measurement interval. Examples of such trees are those classified as alive at the beginning of the...

The Interior West Forest Inventory and Analysis Unit (IWFIA) will soon transition from a regional system to a national FIA system for compiling estimates of forest growth, removals, and mortality. The national system requires regional diameter-growth models to estimate diameters on trees in situations where the initial or terminal diameter is not known at the beginning or end of a measurement interval. Examples of such trees are those classified as alive at the beginning of the measurement interval and subsequently died (mortality) or have been harvested (removal). Only single-stem growth...

Changes in the national Forest Inventory and Analysis (FIA) processing system required the Southern Research Station’s FIA unit to create a diameter growth model to estimate the growth of trees that could not be measured at both ends of a measurement interval. Examples of such trees are trees that have died or been harvested, and trees that grow over the minimum diameter threshold. I used a form of the Chapman-Richards function to model the growth. A function containing crown ratio, condition basal area, amount of basal area in larger trees, latitude, longitude, elevation, site class, tree...