Fading Forests III assesses containment practices, solutions

Scott Schlarbaum in UT Institute of Agriculture greenhouse with butternuts

Forestry professor Scott Schlarbaum inspects a butternut seedling in a UT Institute of Agriculture greenhouse. The seedling will be screened for resistance to Thousand Cankers Disease and Butternut Canker Disease, both caused by exotic pathogens. Photo by Ami Sharp, research associate. Courtesy UTIA. Download image

ARLINGTON, Virginia, and KNOXVILLE, Tennessee — A new report released by the University of Tennessee Institute of Agriculture and The Nature Conservancy compiles the latest data and analyses on the introduction, spread, and costs of non-native invasive tree pests and diseases. Fading Forests III is the third study on invasive forest pests produced by the authors over a 20-year period. 


Among the key findings:

● In the last dozen years the emerald ash borer has spread from three states to 22; the Asian longhorned beetle has been detected at four additional sites; and 28 new tree-killing pests have been detected;

● Existing government programs have failed to halt introductions or respond effectively;

● New pests are attacking tree species that have already been decimated by previous invasive species;

● Spending to control and prevent invasive species lags far behind the growth of infestation, putting valuable private and public resources at risk.

The costs of fighting non-native invasive species and associated damage were documented in a 2011 study by The Nature Conservancy and the University of California, Santa Barbara.  That study estimated local governments are spending $1.7 billion, and homeowners $777 million, a year for tree removal and replacement, and treatment of trees due to introduced non-native forest insects and diseases.

“This is a manageable problem we are allowing to become much more unmanageable, damaging, and costly as each year goes by,” said co-author Faith Campbell, Senior Policy Representative for The Nature Conservancy.  “There are clear, common-sense steps we can take now in the United States to protect trees, which provide us clean air and water, jobs, and wildlife habitat.”

“Without halting the influx of new pests and addressing established pests, the diversity and function of American forests and the values that they provide will be dramatically different in the future,” said co-author Scott Schlarbaum, a Professor of Forest Genetics and Director of the University of Tennessee Tree Improvement Program.

In the last twelve years, the attacks on various common species of American trees have intensified, including elms, ash, oaks, hemlock, and maples.  These species are the source of products as varied as lumber, baseball bats, church pews, and maple syrup.  Entire neighborhoods in several parts of the nation have lost tree cover and the associated benefits of cleaner air and shade cover.

The authors identified several actions government can take to address the invasive onslaught:

USDA’s Animal and Plant Health Inspection Service (APHIS) should finalize several regulations to minimize pests travelling on wood packaging from Canada, imports of living plants, and interstate movement of firewood. It has been more than four years since APHIS first stated they were going to install these regulations.

The Forest Service and National Park Service should adopt nationwide recommendations and regulations restricting campers from bringing in firewood to picnic areas and campgrounds, and greatly increase the availability of local or heat-treated firewood at campgrounds and concessions.

Funding to fight non-native pests has not matched the growing threat. Congress should appropriate adequate funding to support APHIS and Forest Service programs that will address these pests and take appropriate steps toward control and restoration.

Private citizens can take one simple step to avoid contributing to the spread of invasive pests and diseases: don’t move firewood.   Invasive forest pests can move long distances in contaminated firewood—creating new infestations in favorite outdoor spaces, including our backyards.  Buying local firewood near final destinations—and not bringing it back home—are the safest approach.  Visit
www.dontmovefirewood.org to learn more. 


The Nature Conservancy
is a leading conservation organization working around the world to conserve the lands and waters on which all life depends.  The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide.  www.nature.org.

The UT Tree Improvement Program works to improve and protect the forests of Tennessee and surrounding regions, including protecting the genetic resources of tree species at risk from exotic pests. The program is housed in the Department of Forestry, Wildlife and Fisheries of the UT Institute of Agriculture. In addition to UT AgResearch programs, UTIA also provides instruction, research and public service through the UT College of Agricultural Sciences and Natural Resources, the UT College of Veterinary Medicine, and UT Extension offices in every county in the state. agriculture.tennessee.edu



Additional details:


UT Tree Improvement Program