Loblolly Pine Decline

Background

More than one million acres of southern yellow pine stands across the south are estimated to be declining. Loblolly pine stands in 3 southern states (with a predominance of sites in central and southern Alabama) are reported to be declining based on data from Forest Health Monitoring plots established in the 1990's. Current studies of affected stands show a strong correlation with (upland) site, deterioration of fine roots, presence of a fairly constant set of insect associates, and infection by Leptographium spp. affecting the primary roots. The influence of fire, previous agriculture, and landform are other factors that may have a role in the loblolly decline complex. The symptoms of the decline are sparse crowns, short chlorotic needles, and reduced radial growth primarily above 40 years of age and first apparent in trees in the 40-50 year age class. Mortality can occur beginning as little as two to three years after first symptom expression. Although the symptoms of the decline complex are similar to those of littleleaf disease, the site conditions on stands are found expressing this decline are different. On upland sites on federal lands, loblolly pine is the major forest type since it was used for watershed restoration and is easily regenerated. Many of these sites are now managed for red-cockaded woodpecker (RCW) habitat and decline of the pine stands is impacting the long-term habitat needs of this endangered species. One of mitigations recommended for decline sites is to convert them to longleaf pine where site conditions are suitable to fulfill the habitat requirements for RCW.

Project Highlights

• Two major pine decline studies have been implemented since FY 2000
  
  • Assessment of Loblolly Pine Decline in Central Alabama; FY 2000-FY 2002
    • Forest Health Monitoring (FHM) protocols, two root sampling/pitfall insect trapping, fire impact assessment/histology of fine roots
    • Funding: FHM, FHP, LSU Ag. Center and SRS Cost Share
    • Products:
      • Defined loblolly pine decline
      • Developed risk mapping system
      • Produced brochure, "Role of Histology in Defining Fine Root Mortality of Loblolly Decline Stands"
      • PhD dissertation, "Biology and Ecology of Leptographium Species and Their Vectors as Components of Loblolly Pine Decline"
      • Masters Degree thesis completed, "The Association of Phytophthora cinnamomi and Pythium spp. with Loblolly Decline in Alabama"
      • Implementation of a Longleaf Ecosystem Restoration Project utilizing Loblolly Decline Risk Maps (NF in AL)
  • Survey and Biological Evaluation of Current Conditions of Loblolly Pine Stands and Delineation of Potential Sustainable Stands for RCW Colony and Foraging Habitat, Fort Benning, GA. FY 2003-FY 2005
    
    
    • Plot designs and data collection are similar to the AL study
    • Root sampling/insects traps/fire assessment/age classes
    • Funding: FHP, LSU Ag. Center Participating Agreement, and Ft. Benning Military Interdepartmental Purchase Request
    • Products/findings:
      • Validation of Pine Decline Risk Mapping System - Masters Degree thesis
      • Confirmed association of root-feeding beetles with Leptographium spp. in roots of declining pines
      • Increased populations of root-feeding insects and their vectored Leptographium spp. are more prevalent after silvicultural disturbances, i.e. fire and thinning
• Partnerships include; Louisiana Agricultural Center (Plant Pathology Dept., Baton Rouge, LA), Southern Research Station (Tree Root Biology unit, Athens, GA), Forest Operations (Auburn, AL) and Emeritus Scientist from Forest Management Research, Pineville, LA.

Conclusions/Future direction

Current Status:

• Pest Trend-Impact Plot System (PTIPS) - FY 2004-FY 2006

• To establish baseline loblolly decline database using Forest Health Monitoring protocols for the assessment in the western zone (Alabama to Texas) of the Southern Region

• Funding: PTIPS

Projected:

• Proposed
  
  

  • 2 years (FY 2006-FY 2008), proof of concept study at Ft. Benning, "The influence of historical disturbance on pine decline risk model"

  • Funding/Partnerships: Strategic Environmental Research and Development Program (SERDP), FHP and Participating Agreement with Auburn University Forestry Department

• Further Emphasis
  
  

  • Regional scale assessment/validation of pine decline risk sites/risk mapping

  • Analysis and reports of FHM plot data of loblolly component

FHP Contacts:

• Nolan Hess, Plant Pathologist, Pineville Field Office
• Roger Menard, Biological Science Technician, Pineville Field Office

Forest Service-USDA
2500 Shreveport Hwy.
Pineville LA 71360
Phone: 318-473-7287
Email: nhess@fs.fed.us

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USDA Forest Service - Forest Health Protection, Southern Region
Last Modified: Thursday, 08 May 2008 at 10:52:06 EDT