Treesearch

Forest harvesting and management techniques were hypothesized to result in significant differences in stream water N (NO3–N), P (total P [TP]), and total suspended sediment (TSS) responses among regions of United States. The objectives were (i) to determine the mean response periods after harvesting for each water quality variable, (ii) to compare the regional response yields, and (iii) to determine relationships among water quality, rainfall, and flow. Watershed-scale studies where best management practices were implemented provided a basis for water quality analyses. A mixed model was...

Southern pine beetle, Dendroctonus frontalis Zimmermann, is a major native pest of pine trees in the southeastern United States, Mexico, and Central America. The species' range has recently expanded north for the first time in recorded history. Accordingly, information about the timing of population divergence and past geographic range occupancy may provide an important yardstick for understanding rapid range expansions. Using 16 new and eight existing microsatellite loci, together with mitochondrial (COI) and nuclear (EF-1α and 28S) DNA sequence data, we characterized broad-scale patterns...

Anthropogenic disturbances fragmenting wildlife habitat greatly contribute to extinction risk for many species. In western Canada, four decades of oil and gas exploration have created a network of seismic lines, which are linear disturbances where seismic equipment operates. Seismic lines cause habitat fragmentation and increase predator access to intact forest, leading to declines of some wildlife populations, particularly the threatened woodland caribou, Rangifer tarandus caribou. Restoration of forests within seismic lines is an important activity to reduce habitat fragmentation and...

In addition to their unusually long life cycle, periodical cicadas, Magicicada spp., provide an exceptional example of spatially synchronized life stage phenology in nature.Within regions ("broods") spanning 50,000–500,000 km2, adults emerge synchronously every 13 or 17 years. While satiation of avian predators is believed to be a key component of the ability of these populations to reach high densities, it is not clear why populations at a single location remain entirely synchronized. We develop nonlinear Leslie matrix-type models of periodical cicadas that include predation-driven Allee...

Statistically downscaled climate change scenarios from four General Circulation Models for two Representative Concentration Pathways (RCP)were applied as inputs to a biogeochemical model, PnET-BGC, to examine potential future dynamics of water, carbon, and nitrogen in an old-growth Douglas-fir forest in the western Cascade Range. Projections show 56% to 77% increases in stomatal conductance throughout the year from 1986–2010 to 2076–2100, and 65% to 104% increases in leaf carbon assimilation between October and June over the same period. However, future dynamics of water and carbon under...

Forest ecosystem nutrient cycling is controlled to a large extent by environmental conditions, including soil and air temperature and patterns and forms of precipitation (i.e., rain, snow, and fog). Climate changes around the globe have led to increases in mean land surface temperatures (Hansen et al., 2010; Lawrimore et al., 2011; Jones et al., 2012; Rohde et al., 2013), altered patterns of precipitation (Smith et al., 2012), and an increased occurrence of extreme temperature and precipitation events (Hartmann et al., 2013) over the last several decades. Temperatures are expected to...

In Elko County, Nevada, grazing practices on federal and private lands began to change in the early 1990s to restore proper functioning condition to degraded riparian areas that provide habitat for Lahontan cutthroat trout (Oncorhynchus clarkii henshawi), which is listed as threatened under the Endangered Species Act. Changes in grazing management focused on changing the frequency and duration of hot-season grazing in riparian areas. These changes led to the recovery of riparian vegetation accompanied by the natural colonization of streams by beavers. Beavers and their dams, in turn, have...

The FireFlux II experiment was conducted in a tall grass prairie located in south-east Texas on 30 January 2013 under a regional burn ban and high fire danger conditions. The goal of the experiment was to better understand micrometeorological aspects of fire spread. The experimental design was guided by the use of a coupled fire–atmosphere model that predicted the fire spread in advance. Preliminary results show that after ignition, a surface pressure perturbation formed and strengthened as the fire front and plume developed, causing an increase in wind velocity at the fire front. The...

Growing indigenous empowerment and recognition of rights with respect to natural resources was identified as an emerging trend in the USDA Forest Service-University of Houston Forest Futures Horizon Scanning system. An exploratory Implications Wheel® exercise was conducted to uncover possible future implications of this trend. The exercise was carried out with a group of University of Houston Foresight graduate students, faculty, and alumni. The exercise did not include American Indian or Alaska Native participants, and due to this limitation it should be viewed as an illustration of the...

A scenario backcasting project, an offshoot of the Forest Futures Horizon Scanning system, was carried out for the USDA Forest Service, Northern Research Station’s Strategic Foresight Group. The horizon scanning team, from the University of Houston Foresight program, sought to provide context for the scanning hits and emerging issues identified through scanning by linking them to a set of scenarios. Scanning hits and emerging issues could then be analyzed and understood in relation to the scenarios; the ways that emerging issues might develop under different scenarios could be explored. A...