Treesearch

We are studying the ecological and evolutionary processes affecting the geographical distribution of southwestern white pine (SWWP; Pinus strobiformis), an important tree species of the Southwestern USA and Mexico. Southwestern white pine viability is threatened by changing climate and an invasive tree disease, white pine blister rust (caused by the fungal pathogen, Cronartium ribicola). Rapid climate change is negatively affecting SWWP by increasing heat and drought stress, and thus challenging its ability to adapt. White pine blister rust causes extensive tree decline and mortality,...

Mulching involves the use of heavy equipment to grind, shred, chip, or chop large woody material into smaller pieces. Mulching activities such as chipping and mastication have been relied-upon tools in forest management on the Front Range of Colorado and throughout the United States since the late 1990s (e.g. Hood and Wu 2006, Owen et al. 2009, Wolk and Rocca 2009, Battaglia et al. 2010, Gottfried and Overby 2011, Kreye et al. 2014, Jain et al. 2018). Chipping and mastication are specific types of mulching, and these techniques each have fundamental differences in operational constraints,...

The Rocky Mountain Research Station (RMRS) develops and delivers innovative science and technology to improve lives and landscapes. RMRS conducts research focused on the issues of today, applying knowledge gained from decades of prior research to contemporary problems. Scientists at RMRS also continue long-term research that provides a lens from the past into the future to inform the sustainable management of diverse ecosystems. This document showcases a selection of innovative, impactful research aligned with the 2020 Research & Development Priority Areas. These selections demonstrate how...

Wildfire is a natural component of sagebrush (Artemisia spp.) steppe rangelands that induces temporal shifts in plant community physiognomy, ground surface conditions, and erosion rates. Fire alteration of the vegetation structure and ground cover in these ecosystems commonly amplifies soil losses by wind- and water-driven erosion. Much of the fire-related erosion research for sagebrush steppe has focused on either erosion by wind over gentle terrain or water-driven erosion under high-intensity rainfall on complex topography. However, many sagebrush rangelands are geographically positioned...

Whitebark pine (Pinus albicaulis; WBP) is dramatically declining in the Crown of the Continent Ecosystem (CCE) due to a combination of mountain pine beetle (MPB, Dendroctonus ponderosae), effects of fire suppression, and the nonnative pathogen Cronartium ribicola, which causes white pine blister rust (WPBR), all of which have the potential to be exacerbated by climate change. Whitebark pine losses within the CCE are the greatest of anywhere in the species’ range with >90% mortality in some locations1. The same stressors that challenge WBP are also impacting limber pine (P. flexilis) within...

In mid-September 2020, millions of hectares in the western U.S. were on fire and the year’s second wave of seasonal hurricanes and tropical storms were queueing up to batter the states along the Gulf of Mexico. As members of a National Academies of Sciences, Engineering, and Medicine committee tasked with assessing the need for and supply of native seed in the Western United States and other regions of the country, we viewed the unfolding natural disasters as an appropriate, if troubling, backdrop for our work. The assessment of the seed supply was requested by the U.S. Bureau of Land...

Root disease pathogens, including Armillaria, are a leading cause of growth loss and tree mortality in forest ecosystems of North America. Armillaria spp. have a wide host range and can cause significant reductions in tree growth that may lead to mortality. DNA sequence comparisons and phylogenetic studies have allowed a better understanding of Armillaria spp. taxonomic diversity. Genetic sequencing has facilitated the mapping of species distributions and host associations, providing insights into Armillaria ecology. These studies can help to inform forest management and are essential in...

There are about 303 million hectares (ha) of forest lands in the U.S. (Oswalt and Smith 2014). National forests comprise 58 million ha (or roughly 145 million acres). Conducting silvicultural maintenance and restoration on these lands is important in correcting the current degraded state of overstocking or excess downed woody debris (Reinhardt et al. 2008). Overstocked trees and understory competition can induce physiological stress, and trees may become more susceptible to wildfire, insect pests, and disease (Weatherspoon and Skinner 2002). These conditions ultimately increase the...

The mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), is a major tree-killing bark beetle that attacks primarily ponderosa pine, Pinus ponderosa Lawson & C. Lawson, and lodgepole pine, Pinus contorta Douglas ex Loudon (Pinaceae), among other pines, across the western coniferous forests of North America (Negron and Fettig 2014). A continental-scale outbreak of MPB occurred from the late 1990s through the mid- to late 2010s, ranging from the southern Rockies north to British Columbia (Jarvis and Kulakowski 2015; Negron and Fettig 2014). In...

Climate change can have particularly severe consequences for high-elevation species that are well-adapted to long-lasting snow conditions within their habitats. One such species is the wolverine, Gulo gulo, with several studies showing a strong, year-round association of the species with the area defined by persistent spring snow cover. This bioclimatic niche also predicts successful dispersal paths for wolverines in the contiguous United States, where the species shows low levels of genetic exchange and low effective population size. Here, we assess the influence of additional climatic,...