Summary
Southeastern forests form the backbone of an industry that supplies 5.5 percent of the jobs, 7.5 percent of the region's industrial economic activity, and 16 percent of global industrial wood. Forest Service scientists from the Southern Research Station’s Eastern Forest Environmental Threat Assessment Center, along with their university partners, investigated the impacts of fertilization and simulated drought on stand productivity and tree physiology in a 9-year old loblolly pine plantation in Virginia. The study is part of the Pine Integrated Network: Education, Mitigation, and Adaptation Project to improve the resilience and sustainability of pine forests under variable climates.
Researchers simulated drought by removing 30 percent of precipitation before it reached the ground using extensive exclusion structures and then continuously monitored environmental conditions and tree water use with a network of more than 100 automated sensors. Their results show that fertilization reduces water use and increases wood production. Fertilized trees had 21 percent larger stems, meaning that fertilization led to greater harvestable wood production with less water used. Since reduced water use is also a sign of stress, fertilized trees may suffer more under a more severe drought. Results varied by site, so researchers are studying why fertilization might have a greater impact on drought stress at some sites to help practicing foresters develop site-specific management plans.
