Insects are important forest disturbance agents, and mapping their effects on tree mortality and surface fuels represents a critical research challenge. Although various remote sensing approaches have been developed to monitor insect impacts, most studies have focused on single insect agents or single locations and have not related observed changes...
Diagnostic carbon cycle models produce estimates of net ecosystem production (NEP, the balance of net primary production
and heterotrophic respiration) by integrating information from (i) satellite-based observations of land surface
vegetation characteristics; (ii) distributed meteorological data; and (iii) eddy covariance flux tower observations of
net ecosystem exchange (NEE) (used in...
Climate change affects public land ecosystems and services throughout the American West and these effects
are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands
are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species
and ecosystems survive...
This report assesses how current management actions are adhering to the original mandate set by the Wilderness Act of 1964 by monitoring the five qualities of Wilderness character (untrammeled, natural, undeveloped, opportunities for solitude/unconfined recreation, and other features of value) as they pertain to this specific Wilderness area.
Eddy covariance flux research has relied on open- or closed-path gas analyzers for producing estimates of net ecosystem exchange of carbon dioxide (CO₂) and water vapor (H₂O). The two instruments have had different challenges that have led to development of an enclosed design that is intended to maximize strengths and...
The degree to which carbon concentration (CC) of woody detritus varies by tree taxa, stage of decay, tissue
type (i.e., bark versus wood), and vertical orientation was examined in samples of 60 tree species
from the Northern Hemisphere. The mean CC of 257 study samples was 49.3% with a range...
In the Pacific north-west, the Cascade Mountain Range blocks much of the precipitation and maritime influence of the Pacific Ocean, resulting in distinct climates east and west of the mountains. The current study aimed to investigate relationships between water storage and transport properties in populations of Douglas-fir (Pseudotsuga menziesii) and...
Assessing the ecological importance of clouds has substantial implications for our basic understanding of ecosystems
and for predicting how they will respond to a changing climate. This study was conducted in a coastal Bishop pine
forest ecosystem that experiences regular cycles of stratus cloud cover and inundation in summer. Our...
Information on land cover at global and continental scales is critical for addressing a range of ecological, socioeconomic and policy questions. Global land cover maps have evolved rapidly in the last decade, but efforts to evaluate map uncertainties have been limited, especially in remote areas like Northern Eurasia. Northern Eurasia...
• Premise of the Study: Tropical liana abundance has been increasing over the past 40 yr, which has been associated with reduced
rainfall. The proposed mechanism allowing lianas to thrive in dry conditions is deeper root systems than co-occurring trees,
although we know very little about the fundamental hydraulic physiology...
Comparative analysis of multiple angiosperm genomes has implicated gene duplication in the expansion and diversification of many gene families. However, empirical data and theory suggest that whole-genome and small-scale duplication events differ with respect to the types of genes preserved as duplicate pairs. We compared gene duplicates resulting from a...
Carbon sequestration is increasingly recognized as an ecosystem service, and forest management has a large potential to alter regional carbon fluxes − notably by way of harvest removals and related impacts on net ecosystem production (NEP). In the Pacific Northwest region of the U.S.,
the implementation of the Northwest Forest...
Soil organic matter is a complex mixture of material with heterogeneous biological, physical, and chemical properties. Decomposition models represent this heterogeneity either as a set of discrete pools with different residence times or as a continuum of qualities. It is unclear though, whether these two different approaches yield comparable predictions...
We combine a scenario-based, standard-response optimization model with stochastic simulation to improve the efficiency of resource deployment for initial attack on wildland fires in three planning units in California. The optimization model minimizes the expected number of fires that do not receive a standard response-defined as the number of resources...
• Premise of the study: The pathway of radial water movement in tree stems presents an unknown with respect to whole-tree
hydraulics. Radial profi les have shown substantial axial sap fl ow in deeper layers of sapwood (that may lack direct connection
to transpiring leaves), which suggests the existence of...
Background: DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood.
Results: We surveyed DNA methylation from...
Measurements on growth traits up to 41 years of age
from 68 progeny sites in eight first-generation breeding
zones of coastal Douglas-fir (Pseudotsuga menziesii
[MIRB.] FRANCO var. menziesii) in the US Pacific Northwest
were used to investigate age trends of genetic parameters
and to determine optimum age of selection. Heritabilities...
The 12-site National Fire and Fire Surrogate study (FFS) was a multivariate experiment that evaluated ecological consequences of alternative fuel-reduction treatments in seasonally dry forests of the US. Each site was a replicated experiment with a common design that compared an un-manipulated control, prescribed fire, mechanical and mechanical + fire...
A new class of enclosed path gas analyzers suitable for eddy covariance applications combines the advantages
of traditional closed-path systems (small density corrections, good performance in poor weather)
and open-path systems (good spectral response, low power requirements), and permits estimates of
instantaneous gas mixing ratio. Here, the extent to which...
Terrestrial ecosystem-atmosphere exchange of carbon, water vapor, and energy has been measured for over a decade at many sites globally. To minimize measurement and analysis errors, quality assurance data have been collected over short periods along-side tower instruments at AmeriFlux research sites. Theoretical and empirical error and uncertainty values have...