Volume 8, Issue 3 - July/August 2015
Eastern Threat Center Highlights Cont'd
Genetic Studies Reveal a Tree’s History to Ensure its Future
It can reach heights of 200 feet and live 500 years, and occupies landscapes across the western United States. It grows in a variety of soils and climates and survives fires that consume other species. It is also an ecologically and economically valuable tree that provides food, habitat, and ponderous (heavy) lumber. It is the iconic ponderosa pine. But the world is changing, and ponderosa pine is vulnerable to climate shifts, high-intensity wildfires, and bark beetles — as well as development that replaces trees. Kevin Potter, a North Carolina State University scientist cooperating with the Eastern Threat Center, has led a study of the genetic diversity between and within what researchers have believed to be two varieties of ponderosa pine. Results, which were recently published in the journal Tree Genetics & Genomes, can help managers plan for conservation of existing trees and restoration of lost populations. Read more in CompassLive...
Ponderosa pines stand tall in front of Yosemite Falls in California. Photo by Kevin Potter.
For Loblolly Pines, A Fertilization and Water Scarcity Paradox
As in natural forests, the growth of loblolly pines in plantations is limited by essential resources: sunlight, nutrients, and water. Fertilization — an increasingly common practice for adding nutrients to boost wood production — allows trees to shift their growth away from roots to leaves and stems. Since a tree is dependent on its roots to provide water, how does a fertilized tree respond when water supplies are limited in times of drought? University and Eastern Threat Center researchers experimented with fertilization treatments and simulated drought during a two-year study in a loblolly pine plantation located in central Virginia. Their findings, recently published in the journal Forest Ecology and Management, indicate that fertilized trees use water more efficiently, but may suffer the most in drought. Read more in CompassLive...
An exclusion structure allowed researchers to simulate a 30 percent rainfall reduction in loblolly plots. Photo by Andy Laviner, Virginia Tech.
Study Finds No Evidence for Widespread Southern Pine Decline
Millions of acres of southern pine forests form the foundation of forest industry in the South, so the presence of widespread southern pine decline would have important and costly implications. A study by University of Georgia and U.S. Forest Service scientists, including Eastern Threat Center research ecologist Frank Koch, found no evidence for the widespread occurrence of southern pine decline. Researchers believe that if this phenomenon--tree weakness and death involving multiple factors--is occurring, it is not apparent at the landscape level. Read more in CompassLive...
Loblolly (pictured), longleaf, shortleaf, and slash pines stretch across millions of acres in the South. Photo by USDA Forest Service.