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Science Spotlights

Figure 1. A post-fire ponderosa pine seedling in a high-severity burn patch of the 2000 Pumpkin Fire, Arizona.
Over the past three decades, wildfires in southwestern United States ponderosa pine forests have increased in size and severity, leaving large patches of tree mortality. Ponderosa pine evolved under fire regimes dominated by low- to moderate-severity wildfires, and they are poorly adapted to regenerating in large patches of high-severity fire. There is concern about these high-severity burn patches because the lack of seed-producing trees can...
Verde River above Horseshoe Dam in Arizona. Photo by D.M. Smith
A frequently discussed function of aridland riparian ecosystems is the contribution of woody riparian plants to breeding bird habitat. The structurally diverse, species-rich vegetation along many southwestern streams supports high densities of territories and nest sites for a variety of birds including several species of high conservation priority.A frequently discussed function of aridland riparian ecosystems is the contribution of woody...
Crossdating and digitizing an increment core using a microscope and sliding stage. Photo by Lawrence Lam.
The spruce beetle is the most significant mortality agent of spruce in western North America. Management options are limited but an effective semiochemical repellent could be economically and environmentally advantageous, compared to insecticide applications, for protection single trees and small stands.
Rocky Mountain bristlecone pines are long-lived, exhibit delayed maturation, have low genetic diversity, and inhabit cold, high-elevation environments. They are threatened by the non-native disease white pine blister rust, warming temperatures, changing precipitation patterns, and altered disturbance regimes. Sustaining bristlecone pine populations is essential to (1) maintain healthy mountain-top ecosystems and (2) ensure that the young...
Restoring abandoned mine sites with no environmental hazard or chemical contamination can be expensive because of the inhospitable (hot, dry) environment.  However, the large number of abandoned mine sites located across the west make it imperative to begin restoration activities to help shade streams, reduce erosion, provide habitat, and generally improve soil properties. 
Research Ecologist Justin DeRose measuring ring widths to crossdate and digitize tree-ring features. Photo by Lawrence Lam.
Forest fungi in the Armillaria genus comprise destructive root-disease pathogens and beneficial decomposers. It is critical to understand worldwide distributions of Armillaria species to assess invasive threats posed by Armillaria species. This collaborative work with scientists from 15 countries focused on DNA-based analyses of Armillaria species from the Northern Hemisphere.
A handful of biochar-amendment nursery substrate being tested for its potential to grow high-quality native plants for restoration.
Forest and range soils in the western United States are in need of restoration for a variety of reasons (e.g., overgrazing, fire, health). Disposing of the woody slash after restoration cuttings has been problematic for many years, and open burning has often been the easiest method for reducing wildfire risk. However, this damages the soil, limits successful regeneration on the burn sites, and encourages invasive weeds. Creating biochar is one...
A Clark’s nutcracker harvesting seed from whitebark pine cones. Photo courtesy of Diana Tomback
Whitebark pine (Pinus albicaulis) forests are declining across most of their range in North America because of the combined effects of mountain pine beetle (Dendroctonus ponderosae) outbreaks, fire exclusion policies, and the exotic pathogen Cronartium ribicola, which infects five-needle white pines and causes the disease white pine blister rust. Predicted changes in climate may exacerbate whitebark pine decline by (1) accelerating succession to...
Measuring gas exchange on an establishing seedling. Photo by Kasten Dumroese, USDA Forest Service.
Restoration and reforestation using nursery-produced seedlings can be an effective means of increasing successful establishment and rapid growth following outplanting. This, in turn, can accelerate the recovery trajectory of these ecosystems. However, in many ecosystems of the world, seasonal changes as well as changing climate can create dry conditions that are not favorable to seedling establishment.
Rangelands occupy 25 percent of America's landscape. Photo by David Valentine (used with permission).
Rangelands are ecologically diverse ecosystems in the drier parts of the United States, occupying around 25 percent of the United States land area. Rangelands provide a variety of ecosystem services, including wildlife habitat, clean water, and carbon sequestration. Rangelands also provide the opportunity for commodity products such as domestic livestock, energy (solar, and oil and gas), and small diameter wood products. Rangelands contribute to...

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