WildEarth Guardians

Thursday, August 20, 2009
Report Finds Public Lands Grazing a Threat to Public Forests

Livestock Jeopardize Forest Health and Wildlife on 15 Million Acres
Contact: Mark Salvo (503) 757-4221

PHOENIX - Livestock are grazing nearly everywhere on publicly owned ponderosa pine forests, wreaking havoc on forest ecology and natural fire regimes, according to a new report by WildEarth Guardians. "Ponderosa Pine in Peril," documents, for the first time, the extent of livestock grazing in ponderosa pine ecosystems on public lands. More than 15 million acres-or 80 percent-of ponderosa pine forests managed by the Forest Service and Bureau of Land Management are currently open to grazing by domestic cattle and sheep, according to the mapping analysis presented in the report.

A suite of wildlife species are also imperiled by the transformation and loss of open-canopied, old-growth ponderosa pine forests. "Ponderosa Pine in Peril" features several species, including the Northern Goshawk, which has virtually disappeared from forests where grazing and fire suppression have created dense thickets of small-diameter ponderosa pine.

“Livestock have long avoided blame for creating unhealthy forests,” said Mark Salvo, a public lands advocate for WildEarth Guardians and a primary author of the report. “Now that we’ve confirmed the overwhelming presence of livestock in publicly owned ponderosa pine forests, it may be more difficult for managers to ignore their affect on forest ecology.”

The ponderosa pine (Pinus ponderosa) forest type covers nearly 34 million acres in the western United States and is believed to be in significantly degraded condition across much of this extent.Most ponderosa pine forests were historically maintained by low-intensity, high-frequency fire as open-canopied forests of diverse age structure. However, many of these forests today have been transformed into dense, even-aged thickets of young trees that are prone to high-intensity fire.

Although federal agencies are loathe to admit it, the long history of grazing in these forests has contributed to altered forest structure, particularly in the Southwest. Livestock reduce ground vegetation that would naturally carry frequent, low-intensity wildfire that kills ponderosa pine seedlings and maintains open, old-growth forests. Seedlings grow quickly in the absence of fire, filling in the understory and acting as tinder for high-intensity, forest-clearing fires. Federal agencies have responded by suppressing fire wherever it occurs-which has the adverse consequence of allowing even more seedlings to crowd onto the landscape.

Arizona and Oregon are the two western states that have the most publicly owned ponderosa pine forests that are open to grazing according to the report, which relied on a west-wide map of federal grazing allotments and a west-wide map of where ponderosa pine is the dominant forest type. Oregon has nearly five million acres and Arizona nearly three million acres of publicly owned ponderosa pine forests that are grazed, including much of the Coconino and Kaibab national forests where restoration projects have often ignored the threat of cattle grazing to this delicate ecosystem.

“Any fire management or forest restoration plan for ponderosa pine should begin by removing livestock from the landscape,” said Salvo. “These beautiful and uniquely western forests need grasses and other vegetation to carry ‘good,’ low-intensity fire that is essential to maintaining forest health.”

"Ponderosa Pine in Peril," which includes numerous maps of federal grazing allotments and ponderosa pine forests, is the third in an ongoing series of reports about the threats to and values of western public lands. The report is available at ../support_docs/report-ponderosa-pine-08-09.pdf.