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Keyword: tree mortality

Alpine treeline ecotones are potential refugia for a montane pine species threatened by bark beetle outbreaks

Publications Posted on: April 02, 2021
Warming‐induced mountain pine beetle (Dendroctonus ponderosae; MPB) outbreaks have caused extensive mortality of whitebark pine (Pinus albicaulis; WBP) throughout the species’ range. In the highest mountains where WBP occur, they cross alpine treeline ecotones (ATEs) where growth forms transition from trees to shrub‐like krummholz, some of which survived recent MPB outbreaks.

Twenty years of drought‐mediated change in snag populations in mixed‐conifer and ponderosa pine forests in Northern Arizona

Publications Posted on: March 27, 2021
Background: Snags (standing dead trees) are important biological legacies in forest systems, providing numerous resources as well as a record of recent tree mortality. From 1997 to 2017, we monitored snag populations in drought-influenced mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona. Results: Snag density increased significantly in both forest types.

Tree mortality in western U.S. forests forecasted using forest inventory and Random Forest classification

Publications Posted on: March 27, 2021
Climate change is projected to significantly affect the vulnerability of forests across the western United States to wildfires, insects, disease, and droughts. Here, we provide recent mortality estimates for large trees for 53 species across 48 ecological sections using an analysis of 23,215 Forest Inventory plots and a Random Forest classification model.

Droughty times in mesic places: Factors associated with forest mortality vary by scale in a temperate subalpine region

Publications Posted on: March 19, 2021
Understanding how drivers of ecological disturbance operate across scales is important in an era of increasing disturbance activity. Severe and extensive Dendroctonus bark beetle outbreaks across western North America have left in their wake dominance by shade-tolerant and commonly late-seral trees such as subalpine fir (Abies lasiocarpa), which can foster resilience of forest cover.

Physiological responses to fire that drive tree mortality

Publications Posted on: March 09, 2021
A summer storm passes, flashing lightning but little rain and a fire starts to grow. Flames lick the bases of trees, charring stems and strong winds fan the fire at times, causing the flames to scorch foliage, as it burns through a forest. The fate of these burned trees after the flames are doused is one of intense interest. Will the forest become a carbon source? Will there be suitable wildlife habitat?

Dynamics of beetle-killed snags following mountain pine beetle outbreaks in lodgepole pine forests

Publications Posted on: January 05, 2021
Snags (standing dead trees) are important components of forest ecosystems that, among other benefits, provide critical habitat for many species of wildlife, but also represent important safety concerns to firefighters, forest workers, and the public. We identified factors that influence the fall rates of lodgepole pines, Pinus contorta Dougl.

Tree-ring growth and stable-carbon isotope response data to forest restoration treatments in ponderosa pine forests of the Lick Creek Demonstration-Research Forest, Bitterroot National Forest, Montana, USA

Datasets Posted on: December 30, 2020
This data publication includes the data used in "Forest restoration treatments in a ponderosa pine forest enhance physiological activity and growth under climatic stress" by Tepley et al. (2020).

Warning signals of tree mortality masked by extreme drought and bark beetles

Science Spotlights Posted on: November 09, 2020
Determining why some trees die while others survive both drought and insect outbreaks is valuable for forecasting tree mortality events, which are expected to become more frequent with further climate change. We collected stand and tree-level data on the Sierra and Los Padres National Forests in Central and Southern California, where tree mortality from the combination of drought and bark beetles was widespread. 

Within-stand distribution of tree mortality caused by mountain pine beetle, Dendroctonus ponderosae Hopkins

Publications Posted on: October 02, 2020
The mountain pine beetle (MPB) (Dendroctonus ponderosae) is a bark beetle that attacks and kills ponderosa pine (Pinus ponderosa), among other pine species throughout the western conifer forests of the United States and Canada, particularly in dense stands comprising large trees. There is information on the stand conditions that the insect prefers.

Few generalizable patterns of tree-level mortality during extreme drought and concurrent bark beetle outbreaks

Publications Posted on: September 29, 2020
Tree mortality associated with drought and concurrent bark beetle outbreaks is expected to increase with further climate change.When these two types of disturbance occur in concert it complicates our ability to accurately predict future forest mortality.