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Bureau of Land Management
For Release: Wednesday, November 17, 2004
George Couch
(608) 231-9295
Peter Mali
(202) 452-5125

Bureau of Land Management and Forest Service Team Up to Fight Spread of Invasive Tree Species

The Interior Department’s Bureau of Land Management (BLM) has joined forces with the Department of Agriculture’s Forest Service to find constructive uses for an aggressive tree species plaguing the southwestern United States. The goal of the joint effort is to control the spread of saltcedar, a tree that displaces native plants and devastates wildlife habitat and ecosystems on more than a million acres of rangeland.

BLM Director Kathleen Clarke met today with researchers at the Forest Service’s Forest Products Laboratory (FPL) in Madison, Wisconsin, and toured the facility where scientists are testing saltcedar and other trees from BLM land to make a wood-plastic composite. The Director witnessed a demonstration that turned saltcedar and juniper removed from BLM land during restoration projects into boards that hold promise as house siding. “This project shows how the Federal government can turn problems into opportunities,” said Clarke. “Turning this unwanted species into building material simultaneously slows the spread of this tree on BLM land and creates a market for it,” she added.

Also known as tamarisk, saltcedars deplete surface water and groundwater and are believed to increase the salinity of soil, making the area inhospitable for native plants. Thought to have been introduced into this country from the Middle East in the 1800s, saltcedar spreads rapidly and supplants native species. A single saltcedar tree, for example, can consume up to 300 gallons of water per day and produce up to 500,000 seeds per year. These seeds establish themselves aggressively along ecologically significant stream corridors, where they crowd out native vegetation, which in turn deprives wildlife of the nutrition provided by indigenous trees.

The high cost of removing saltcedars and the lack of a market for the removed trees has hindered efforts to control the tree’s spread. In recent years, however, FPL researchers have developed techniques for combining wood with plastic to make composite materials that can be used for a variety of purposes, such as outdoor furniture, signage, and decking lumber. While the scientists’ principal purpose was to find uses for the small trees and underbrush that choke Federal forests and rangeland and increases the risk of catastrophic wildfires, researchers also looked at invasive species such as juniper and saltcedar. If markets can be created for these small trees and woody vegetation, the sale of those materials could help subsidize the cost of their removal from the public lands.

As part of the inter-agency project with BLM, FPL researchers such as Drs. Craig Clemons and Nicole Stark are expanding their work with saltcedar. This summer, BLM sent FPL a ton each of juniper and saltcedar. FPL pulverized the wood material and compounded it with polyethylene plastic and formed the wood-plastic composite into pellets. In the study that Director Clarke observed, the pellets are processed through an extruder that produces boards that might be suitable for house siding. Boards made from combinations of saltcedar, juniper, and plastic will then be exposed to the elements to study their long-term durability.

The USDA Forest Service Forest Products Laboratory was established in 1910 with the mission of conserving and extending the country’s wood resources. Today, FPL’s research scientists explore ways to promote healthy forests and clean water, and improve papermaking and recycling processes. Through FPL’s Advanced Housing Research Center, researchers also work to improve homebuilding technologies and materials. Additional information about FPL and its research activities is available at

The BLM, an agency of the U.S. Department of the Interior, manages more land—261 million surface acres—than any other Federal agency. Most of this public land is located in 12 Western States, including Alaska. The Bureau, with a budget of about $1.9 billion, also administers 700 million acres of sub-surface mineral estate throughout the nation. The BLM’s multiple-use mission is to sustain the health and productivity of the public lands for the use and enjoyment of present and future generations. The Bureau accomplishes this by managing such activities as outdoor recreation, livestock grazing, mineral development, and energy production, and by conserving natural, historical, cultural, and other resources on the public lands.