Treesearch

Native bee populations are declining worldwide, threatening both natural ecosystems and agriculture as these insects pollinate about 80 percent of all flowering plants. Research at the Starkey Experimental Forest and Range, managed by the U.S. Department of Agriculture, Forest Service, points to strategies for supporting native bees while maintaining grazing and timber production. Scientists with the Forest Service’s Pacific Northwest Research Station and Oregon State University identified more than 300 native bee species at the study site in eastern Oregon. They found that bees rely...

Asian longhorned beetle (Anoplophora glabripennis Motschulsky), a wood borer (Coleoptera: Cerambycidae) native to China, has been unintentionally and repeatedly introduced to North American and European landscapes as a stow-away in the wood packing material commonly used in international trade. Asian longhorned beetle causes extensive damage and mortality in multiple deciduous tree species and in response, countries in both North America and Europe have adopted policies of eradication. Models that integrate patterns of Asian longhorned beetle dispersal with records of infested trees are...

Historically, the prices of softwood timber and lumber have shown strong correlations within their supply chain. However, since the 2008 financial crisis, the gap between these prices has widened, a trend further exacerbated during and after the COVID-19 pandemic. This study examines the impact of various economic shocks on this expanding price gap from 1999 to 2023. Using a Markov Switching Autoregressive model and incorporating variables such as housing starts, lumber futures, mortgage rates, Canadian softwood lumber export, and standing inventory, we identify periods of divergence and...

Hybridization between exotic and native species can lead to negative ecological and economic consequences. The invasive winter moth (WM), Operophtera brumata, uses the same sex-attractant pheromone and mates and produces fertile offspring with a native congener the Bruce spanworm (BSW), O. bruceata, and a stable hybrid zone has formed where their ranges overlap in the northeastern United States. However, the fact that the two species have not merged, despite seasonal overlap of flight, suggests that one or more pre- or post-mating barriers to hybridization might therefore exist. Here, we...

As an Evaluation Monitoring project funded under the U.S. Department of Agriculture, Forest Service, Forest Health Monitoring Program, this study had an overarching goal to provide insight into which locales may be at greatest risk of losing their future black cherry component. It proposed an examination of seedling dynamics, including the extent and severity of declining abundance, over 5–20 years at multiple spatial scales. The hypothesis was that seedling abundance declines would be pronounced in the Allegheny region, where black cherry has historically been most dominant, but less...

This study was an Evaluation Monitoring project funded under the U.S. Department of Agriculture (USDA), Forest Service, Forest Health Monitoring Program with an overarching goal to yield a better understanding of regeneration dynamics during disturbance-induced canopy reductions and help triage oak forests for regeneration risks. It proposed to examine seedling and sapling dynamics through time at broad spatial scales to examine whether forest health issues in eastern upland oak forests affect oak regeneration and recruitment by addressing two specific questions: (1) Do forest health...

An Evaluation Monitoring project funded by the Forest Service’s Forest Health Monitoring Program was initiated in 2015 to delineate and map known and reported Carolina hemlock populations across the species range and assess their general health status. This article presents a project summary on the expanded map of species occurrences, stand characteristics, and overall health.

Using geospatial and statistical modeling approaches, this study evaluated how biotic interactions, abiotic conditions, and landscape factors affect the distribution of invasive plant taxa within the Southern United States. It also examined, using data from the U.S. Department of Agriculture (USDA), Forest Service, Forest Inventory and Analysis (FIA) Program, the potential impact of invasive plant taxa on desirable tree species recruitment within the region.

Five-needle pine populations are declining in many parts of the Rocky Mountains, largely due to the combined impacts of the nonnative, invasive disease known as white pine blister rust (Cronartium ribicola) and mountain pine beetle (Dendroctonus ponderosae). The purpose of this study was to gather baseline information on the distribution, abundance, and health of five-needle pines; characterize stand structure and site conditions; and determine the extent and severity of white pine blister rust in the study area.

In 2018, a severe drought caused widespread dieback of two dominant southwestern tree species, Utah juniper (Juniperus osteosperma, hereafter referred to as juniper) and twoneedle pinyon (Pinus edulis, hereafter referred to as pinyon). Drought-induced pinyon dieback has occurred several times over the past three decades. However, this dieback of juniper (generally considered one of the most drought-tolerant tree species in the United States) is likely unparalleled in severity and spatial extent. This raises significant concerns regarding the fate of woodland ecosystems in the American...