Treesearch

Current mortality in lodgepole pine caused by mountain pine beetle (MPB) throughout much of western North America has resulted in concern about future forest structure. To better understand the long-term effects of the current mortality, and how it might differ depending on forest species composition, we measured forest vegetation and woody fuel accumulations in forest affected by a MPB outbreak in the late 1970s and early 1980s and compared conditions to 1980s USDA Forest Service data to quantify changes in the approximately 30 years following tree mortality. Stands were classified into...

We compared soil properties beneath naturally-occurring patches of Lycium ruthenicum Murray (fam. Solanaceae) to evaluate the shrub’s potential to improve the fertility of saline soils. Soil pH, total nitrogen and carbon and extractable potassium, magnesium and phosphorus were respectively significantly higher in the A and B horizons of Lycium shrub patches compared to adjacent unvegetated soils. The influence of Lycium on these soil properties increased with shrub density. Total soil N and extractable Mg and K concentrations were 1.8, 2.6- and 6.6-fold higher under dense Lycium shrub...

Snowshoe hares (Lepus americanus) are a primary prey species for Canada lynx (Lynx canadensis) in western North America. Lynx management plans require knowledge of potential prey distribution and abundance in the western United States. Whether even-aged regenerating forests or multi-storied forests contain more snowshoe hares is currently unknown. During 2006-2008, we estimated snowshoe hare density in 3 classes of 30-70-year-old lodgepole pine (Pinus contorta) and 4 classes of late seral multi-storied forest with a spruce (Picea engelmannii)-fir (Abies lasiocarpa) component in the...

We have developed a robust meteorological tower for deployment in locations with extreme conditions and for applications that require relatively maintenance-free structures. The basic design consists of a triangular base with two horizontal rails on each side, and uprights at the triangle vertices for various instrument configurations. The fabrication materials include 6061-T6 aluminum pipe (schedule 40 or 80), and cast aluminum connectors. The design is self-supporting, but may be guyed. Advantages of the design compared to conventional towers include easy assembly, readily available...

Whether accomplished above the water surface or performed underwater by snorkel, scuba, or hookah divers or remotely operated vehicles (ROVs); direct observation techniques are among the most effective means for obtaining accurate and often unique information on aquatic organisms in their natural surroundings. Many types of studies incorporate direct observation methods, including broad-scale inventories of aquatic organism distribution and abundance (Hankin and Reeves 1988), highly specialized observations of behavior (Drew et al. 1976), evaluations of habitat use (Fausch and White 1981),...

The Manitou Experimental Forest (MEF) is part of the USDA Forest Service Rocky Mountain Research Station. Established in 1936, its early research focused on range and watershed management. Currently, the site is home to several meteorological, ecological and biological research initiatives. Our collaborators include the University of Colorado, Colorado State University, Colorado College, Colorado School of Mines, Denver Museum of Nature and Science, University of California, the National Center for Atmospheric Research, and the US Geological Survey. Currently, the site is home to several...

Recovering populations often must meet specific growth rate or abundance targets before their legal status can be changed from endangered or threatened. While the efficacy, power, and performance of population metrics to infer trends in declining populations has received considerable attention, how these same metrics perform when populations are increasing is less clear. We examined the ability of a one-sample effective population size (Ne) estimator (LDNe) to discriminate between stable and increasing population trends across varying sample and initial population sizes. The performance of...

Changing climatic conditions and an abundance of dense, mature pine forests have helped to spur an epidemic of mountain pine beetles larger than any in recorded history. Millions of forested acres have been heavily impacted and have experienced extreme rates of tree mortality. This has raised concerns among many people that the death, desiccation, and decomposition of the overstory could have dramatic and negative consequences for affected ecosystems. Compromised water quality, increased fire danger, and losses in timber production are among the primary concerns of what could lie ahead for...

Evaluating the risks of wildfire relative to the valuable resources found in any managed landscape requires an interdisciplinary approach. Researchers at the Rocky Mountain Research Station and Western Wildland Threat Assessment Center developed such a process, using a combination of techniques rooted in fire modeling and ecology, economics, decision sciences, and the human dimensions of managing natural resources. The method combines predictive mapping of the distribution and intensity of wildfire with locations of highly valued resources. By soliciting input from experts, the response of...

Limber pines are one of the most picturesque trees in Rocky Mountain National Park (RMNP). Growing in some of the park's most exposed rocky sites, the trees' gnarled trunks give testimony to fierce winds that buffet them in winter. Limber pines live to great ages, with some in the park exceeding 1,000 years. An especially photogenic stand of ancient trees defies the wind at Knife's Edge along Trail Ridge Road, and a remarkable old giant stands sentinel on the shore of Lake Haiyaha. Although the species occurs in small stands dominating only about 2,700 acres of the park, limber pine is an...