USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.
[image:] TreeSearch, links to

Giving you access to more than 45,000 online USDA Forest Service Research publications.

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What's new
PSW researcher Frank Lake sitting on a log in the forest.

The benefits of combining modern science and traditional ecological knowledge can be seen through the research of PSW's Frank Lake. Visit the USDA Blog for the full story.

A temperate rain forest in Washington state.

PNW and PSW have developed the draft Northwest Forest Plan science synthesis, to help provide a scientific foundation for Forest Service land management plans in the northwest.

Trees with green leaves in summer line both sides of a city street with parked cars and no traffic.

PSW recently published a technical manual and launched the most extensive database available cataloging urban trees with their projected growth tailored to specific geographic regions.

Downed trees and woody debris among green vegetation. A small stream is in view.

Since 2010, an estimated 40 million trees have died in California. Visit the California Tree Mortality website to learn about the Forest Service's response and National Forest visitor safety.

A YouTube screenshot on how to detect a tree infected with Ohia wilt.

Our researchers are working with the University of Hawaii and other partners to spread awareness on Rapid Ohia Death. Visit the Hawaii Forestry Extension website to learn about the disease.

Science that makes a difference.

The Pacific Southwest Research Station is a world leader in natural resources research through our scientific excellence and responsiveness to the needs of current and future generations.

We represent the research and development branch of the USDA Forest Service in the states of California and Hawaii and the U.S. affiliated Pacific Islands. Our primary work occurs in California (the most populous state with the eighth-largest economy in the world) and Hawaii (a strategic location in the Pacific Rim economies and tourism).

Our mission is to develop and communicate science needed to sustain forest ecosystems and their benefits to society.

[image-text]: Featured Science
citizen science
Approximately half of the trees remain in one of the units for the "variable retention salvage" study on the Black Mountain Experimental Forest, Lassen National Forest, CA, in June 2006, four years after the Cone Fire and three years after salvage harvest. (U.S. Forest Service/Carl Skinner)
Response of understory vegetation to salvage logging following a high-severity wildfire

PSW scientists recently published a paper in the journal Ecosphere comparing understory vegetation after salvage logging treatments. Overall, the amount and composition of understory vegetation differed little compared to areas not logged.

Following the 2002 Cone Fire on the Lassen National Forest, units were logged at five different intensities, from complete removal to complete retention of all fire-killed trees. Researchers compared vegetation regrowth in two-year intervals starting four years post-fire.

Non-native weed populations didn't differ among treatments. Most native species, which tend to sprout from deeply buried plant parts, also displayed resilience to logging. Factors other than salvage logging appeared to drive differences observed in vegetation growth.

[image-text]: Recent Publications
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Urban tree database and allometric equations

Information on urban tree growth underpins models used to calculate the effects of trees on the environment and human well-being. Maximum tree size and other growth data are used by urban forest managers, landscape architects, and planners to select trees most suitable to the amount of growing space, thereby reducing costly future conflicts between trees and infrastructure.

Cover image psw-rp-267
Defoliation effects on growth and mortality of three young southern pine species

Foliage from loblolly (Pinus taeda L.), slash (P. elliottii Engelm.), and longleaf (P. palustris Mill.) pines was hand plucked to isolate the effects of level and timing of foliage removal on growth and mortality. Slash and loblolly pine received one of five defoliation treatments during one of four months: January, April, July, or October.

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Water Temperature, Dissolved Oxygen, Flow, and Shade Measurements in the Three Stream Sections of the Golden Trout Wilderness

To determine the current range of water temperatures in the streams inhabited by California golden trout, Oncorhynchus mykiss aguabonita, water temperature recording probes were deployed and monitored from 2008 through 2013 in three meadows in the Golden Trout Wilderness.

Last Modified: Dec 30, 2016 11:40:43 AM