Treesearch

Water is a critical resource in the Southwestern United States. The demands for reliable regional water sources have always been present but are increasing as the human population continues to grow, especially in the Metro-Phoenix Area, which once supported Sonoran Desert ecosystems. While much of the land has been converted from farming to houses and other urban developments that use less water, the need for a reliable water supply is not diminished. The Phoenix Area's main supply of surface water is the Salt-Verde River System. These two rivers originate in the mountains to the north and...

Forest harvest scheduling has been modeled using deterministic and stochastic programming models. Past models seldom address explicit spatial forest management concerns under the influence of natural disturbances. In this research study, we employ multistage full recourse stochastic programming models to explore the challenges and advantages of building spatial optimization models that account for the influences of random stand-replacing fires. Our exploratory test models simultaneously consider timber harvest and mature forest core area objectives. Each model run reports first-period...

[1] Soil moisture is a key driver of biogeochemical processes in terrestrial ecosystems, strongly affecting carbon (C) and nutrient availability as well as trace gas production and consumption in soils. Models predict increasing drought frequency in tropical forest ecosystems, which could feed back on future climate change directly via effects on trace gasdynamics and indirectly through changes in nutrient availability. We used throughfall exclusion shelters to determine effects of short-term (3 month) drought on trace gas fluxes and nutrient availability in humid tropical forests in...

Past efforts to examine the future of wildland fire management have relied heavily on expertise from within the wildfire community. But changes in seemingly unrelated external factors - outside of the world of wildfire and fire management - can have unexpected and profound effects. This paper describes an ongoing sh1dy of the future of wildland fire management in which a broader approach is taken to explore alternative fuhrres and identify emerging trends. The goal of the project is to gain practical strategic foresight into wildland fire management. We will assemble a panel of academic...

National forest inventories report estimates of parameters related to forest area and growing stock volume for geographic areas ranging in size from municipalities to entire countries. Landsat imagery has been shown to be a source of auxiliary information that can be used with stratified estimation to increase the precision of estimates, although the increase is greater for estimates of forest area than for estimates of growing stock volume. The objective of the study was to assess the utility of lidar-based stratifications for increasing the precision of mean proportion forest area and...

Atomic Force Microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument capable of producing 100 nm spatial resolution IR spectra and images. This new capability enables the spectroscopic characterization of biomaterial domains at levels not previously possible. A tunable IR laser source generating pulses on the order of 10 ns was used for excitation of cast sample films or thin cross sections deposited on IR transparent ZnSe prisms. Short duration thermal waves, due to infrared absorption, were studied by monitoring the resulting excitation of the contact...

The Forest Service is implementing a new planning rule and starting to revise forest plans for many of the 155 National Forests. In forests that historically had frequent fire regimes, the scale of current fuels reduction treatments has often been too limited to affect fire severity and the Forest Service has predominantly focused on suppression. In addition to continued treatment of the wildland urban interface, increasing the scale of low- and moderate-severity fire would have substantial ecological and economics benefits if implemented soon. We suggest National Forests identify large...

Management efforts to promote forest resiliency as climate changes have often used historical forest conditions to provide general guidance for fuels reduction and forest restoration treatments. However, it has been difficult to identify what stand conditions might be fire and drought resilient because historical data and reconstruction studies are generally limited to accurate estimates only of large, live tree density and composition. Other stand features such as smaller tree densities, dead wood, understory conditions, regeneration and fuel loads have been difficult to quantify,...

Forests, whether public or private, provide the general public with countless goods and services. As it is the owners who ultimately decide the fate of these forests, it is important to understand forest ownership trends and patterns. As the results of political, economic, social, historic, and biophysical factors, forest ownership patterns vary considerably across the nation and across the urban–rural spectrum. For example, the eastern United States is dominated by private ownership,while the western United States is dominated by public ownerships. Across the urban–rural spectrum, federal...