Treesearch

Snowcover pattern and persistence have important implications for planetary energy balance, climate sensitivity to forcings, and vegetation structure, function, and composition. Variability in snow cover within mountainous regions of the Pacific Northwest, USA is attributable to a combination of anthropogenic climate change and climate oscillations. However, snowcovered areas can be heterogeneous and patchy, requiring more detailed mapping of snow trends to understand their potential influences on montane forests. We used standard dailyMODIS snow products (MOD10A1.5) to investigate the...

Important goals for studying dam removal are to learn how rivers respond to large and rapid introductions of sediment, and to develop predictive models to guide future dam removals. Achieving these goals requires organizing case histories systematically so that underlying physical mechanisms determining rates and styles of sediment erosion, transport, and deposition are revealed. We examine a range of dam removals predominantly in the western US over the last decade, and extract useful lessons and trends that can be used to predict the response of rivers to future removals.

This report provides a statistical analysis of the data collected from two survey regions of the United States, the Pacific Northwest and the Southeast. The survey asked about individual agricultural landowners’ characteristics, characteristics of their land, and the landowners’ willingness to enroll in a tree planting program under incentive payments for carbon sequestration. From this statistical analysis, we found both similar and contrasting features between the two survey regions. The Southeast is more responsive to incentive payment for carbon sequestration than the Pacific Northwest,...

Nine mid-latitude to high-latitude headwater catchments – part of the Northern Watershed Ecosystem Response to Climate Change (North-Watch) programme – were used to analyze threshold response to rainfall and snowmelt-driven events and link the different responses to the catchment characteristics of the nine sites. The North-Watch data include daily time-series of various lengths of multiple variables such as air temperature, precipitation and discharge. Rainfall and meltwater inputs were differentiated using a degree-day snowmelt approach. Distinct hydrological events were identified, and...

Forest disturbance and long-term succession towards old-growth are thought to increase nitrogen (N) availability and N loss, which should increase soil ä15N values. We examined soil and foliar patterns in N and ä15N, and soil N mineralization, across 800 years of forest succession in a topographically complex montane landscape influenced by human logging and wildfire. In contrast to expectations, we found that disturbance caused declines in surface mineral soil ä15N values, both in logged forests measured 40–50 years after disturbance, and in unlogged forests disturbed by severe wildfire...

Background: Nearly 40 years of research provides an extensive body of evidence about human health, well-being, and improved function benefits associated with experiences of nearby nature in cities. Objectives: We demonstrate the numerous opportunities for future research efforts that link metro nature, human health and well-being outcomes, and economic values. Methods: We reviewed the literature on urban nature-based health and well-being benefits. In this review, we provide a classification schematic and propose potential economic values associated with metro nature services. Discussion:...

Inter-annual variability (IAV) of forest Net Primary Productivity (NPP) is a function of both extrinsic (e.g., climate) and intrinsic (e.g., stand dynamics) drivers. As estimates of NPP in forests are scaled from trees to stands to the landscape, an understanding of the relative effects of these factors on spatial and temporal behavior of NPP is important. Although a high degree of spatial coherence (i.e., the degree of spatial synchrony over time) is often assumed, this inherent behavior is rarely examined. Quantifying this term may improve future predictions as site-level estimates are...

First-year tree seedlings represent a particularly vulnerable life stage and successful seedling establishment is crucial for forest regeneration. We investigated the extent to which Pinus ponderosa P. & C. Lawson populations from different climate zones exhibit differential expression of functional traits that may facilitate their establishment. Seeds from two populations from sites with contrasting precipitation and temperature regimes east (PIPOdry) and west (PIPOmesic) of the Oregon Cascade mountains were sown in a common garden experiment and grown under two water availability...

Question: Many predictions about forest succession have been based on chronosequences. Are these predictions – at the population, community and ecosystemlevel – consistent with long-termmeasurements in permanent plots? Location: Pseudotsuga menziesii (Mirb.) Franco dominated forest in western Oregon, US. Methods: Over a 100-yr period, measurements every 5–10 yrs of the growth, mortality and regeneration of individually tagged trees in three 0.4-ha forest plots dominated by P. menziesii were used to test predictions derived from chronosequence studies. Results: Population- and community-leve...

Wildlife habitat mapping has evolved at a rapid pace over the last fewdecades. Beginning with simple, often subjective, hand-drawn maps, habitat mapping now involves complex species distribution models (SDMs) using mapped predictor variables derived from remotely sensed data. For species that inhabit large geographic areas, remote sensing technology is often essential for producing range wide maps. Habitat monitoring for northern spotted owls (Strix occidentalis caurinam>