Pacific Southwest Research Station

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In The News

• The Fungus-Fighting Secrets in the Sugar Pine's Genome - UConn Today (Jan. 10, 2017)
• Forest Health And Fire, A Dangerous Balance: Studies show fire managers caught between too much and too little - Payson Roundup (Jan. 9, 2017)
• In California's forests, removing small trees leaves water for bigger ones and for dwindling reservoirs - The Economist (Dec. 17, 2016)
• Pines imperiled: Bark beetles are decimating California's parched forests - Chico News & Review (Dec. 8, 2016)

Recent News Releases

• Database captures urban tree sizes, growth rates across United States (Nov. 1, 2016)
• Caught 'napping': First direct evidence of migratory hoary bats hibernating (Oct. 25, 2016)

More About Us

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• Research Programs & Projects

Research Topics

• Air Quality
• Biological Control
• Climate Change
• Ecosystem Processes
• Fire Science
• Forest Genetics
• Forest Management
• Insect and Disease
• Invasive Species
• Recreation
• Urban Forestry
• Water and Watersheds
• Wildlife and Fish

• Video: Habitat restoration for the American Pika
• Blog: Database captures urban tree sizes, growth rates across US
• The draft Northwest Forest Plan (NWFP) science synthesis is online
• Responding to tree mortality on national forests in California
• Learn about Rapid Ohia Death affecting ohia trees on Hawaii Island

See our latest video focusing on the habitat of the American pika. Researchers are attempting to determine their historic range and how rising temperatures will affect their habitats.

A recent USDA Blog focuses on PSW's latest technical manual and database cataloging urban trees and their projected growth tailored to specific geographic regions.

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.

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.

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.

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.

Urban tree database and allometric equations

(GTR-PSW-253)

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.

Defoliation effects on growth and mortality of three young southern pine species
(RP-PSW-267)

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.

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

(RN-PSW-427)

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.