Treesearch

Forest understory communities are important components in forest ecosystems providing wildlife habitat and influencing nutrient cycling, fuel loadings, fire behavior and tree species composition over time. One of the most widely utilized understory component metrics is understory vegetation cover, often used as a measure of vegetation abundance. To date, understory vegetation cover estimation and prediction has proven to be inherently difficult using traditional explanatory variables such as: leaf area index, basal area, slope, and aspect. We introduce airborne lidar-derived metrics into...

We collected data to estimate depth of the remaining (residual) organic layer as well as data to estimate total pre-fire organic layer depth in 99 plots located in mature black spruce (Picea mariana (Mill.) BSP) forests in interior Alaska that burned during the large fire seasons of 2004 and 2005. These data were collected immediately adjacent to trees as well as from throughout the plot along with tree stand characteristics (density and basal diameter), and used to assess if trees influenced depth of burning. While other studies have found residual organic layer depths to be shallower...

We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000-2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1),...

We used simulation modeling to analyze wildfire exposure to social and ecological values on a 0.6 million ha national forest in central Oregon, USA. We simulated 50,000 wildfires that replicated recent fire events in the area and generated detailed maps of burn probability (BP) and fire intensity distributions. We also recorded the ignition locations and size of each simulated fire and used these outputs to construct a fire source–sink ratio as the ratio of fire size to burn probability. Fire behavior was summarized for federal land management designations, including biological conservation...

Epiphytic lichen communities are highly sensitive to excess nitrogen (N), which causes the replacement of native floras by N-tolerant, ‘‘weedy’’ eutrophic species. This shift is commonly used as the indicator of ecosystem ‘‘harm’’ in studies developing empirical critical levels (CLE) for ammonia (NH3) and critical loads (CLO) for N. To be most effective, empirical CLE and/or CLO must firmly link lichen response to causal pollutant(s), which is difficult to accomplish in field studies in part because the high cost of N measurements limits their use. For this case study we synthesized an...

This report traces the flow of California’s 2006 timber harvest through the primary wood products industry (i.e., firms that process timber into manufactured products such as lumber, as well as facilities such as pulp mills and particleboard plants, which use the wood fiber or mill residue directly from timber processors) and provides a description of the structure, condition, and economic impacts of California’s forest products industry. Historical wood products industry changes are discussed, as well as trends in harvest, production, mill residue, and sales. Also examined are employment...

Nationally, there is growing public interest in and policy pressure for developing alternative and renewable sources of energy. Wind energy facilities in the Pacific Northwest expanded rapidly over the past decade, as a result of state policies that encourage wind energy development. While much of the development thus far has occurred on private lands, there is interest in expanding onto federal land. However, there are concerns about the impacts of wind energy on wildlife. Wind energy facilities have the potential to harm wildlife both directly through collisions with turbines and...

Disturbance processes of various types substantially modify ecosystem carbon dynamics both temporally and spatially, and constitute a fundamental part of larger landscape-level dynamics. Forests typically lose carbon for several years to several decades following severe disturbance, but our understanding of the duration and dynamics of post-disturbance forest carbon fluxes remains limited. Here we capitalize on a recent North American Carbon Program disturbance synthesis to discuss techniques and future work needed to better understand carbon dynamics after forest disturbance. Specifically,...

In spring and summer of 2010 and 2011, sawmill production capacity and wood utilization information was collected from major wood manufacturers in southeast Alaska. The estimated mill capacity in southeast Alaska for calendar year (CY) 2009 was 249,350 thousand board feet (mbf) (log scale), and for CY 2010 was 155,850 mbf (log scale), including idle sawmills. Mill consumption in CY 2009 was estimated at 13,422 mbf (log scale), and for CY 2010 was 15,807 mbf (log scale). Wood products manufacturing employment in southeast Alaska increased from 57.5 full-time equivalent positions in 2009 to...

Agencies and organizations deploy various strategies in response to environmental challenges, including the formulation of policy, programs, and regulations. Citizen-based environmental stewardship is increasingly seen as an innovative and important approach to improving and conserving landscape health. A new research focus on the stewardship of urban natural resources is being launched by the U.S. Forest Service in the Pacific Northwest region. Early scoping efforts are addressing various scales of human systems ranging from individuals to organizations to the entire positive "footprint"...