Comparative Assessment of Mortality of Eastern Hemlock in Biologically-Treated Areas Using Spatial Analyses
Hakeem A, Grant JF, Wiggins GJ, Rhea R, Lambdin PL, Buckley DS, Hale FA, Colson T. 2013. Comparative Assessment of Mortality of Eastern Hemlock in Biologically-Treated Areas Using Spatial Analyses. Pages 90. In McManus K and Gottschalk KW (ed): Proceedings 23rd U.S. Department of Agriculture Interagency Research Forum on Invasive Species 2012. Annapolis, Maryland. January 10-13, 2012. Newton Square, PA. General Technical Report NRS-P-114
Geographic Information Systems (GIS) have been used to model the spread of pest species in various systems. Hemlock woolly adelgid, Adelges tsugae, was first reported on eastern hemlock, Tsuga canadensis (L.) Carr., in the Great Smoky Mountains National Park in 2002. This minute insect pest has caused mortality of tens of thousands of hemlock trees in the Park. To assess tree mortality, remotely-sensed digital orthoimages from recovery, non-recovery, and control (no release) sites were evaluated, and percent tree mortality was compared using spatial analyses. Remotelysensed digital ortho images (four-band color infrared, 1m-pixel resolution) were used in this study. Dead hemlocks identified by spatial analysis were supported by on-site examinations as part of another ongoing study. Additionally, on-site evaluation of tree health characteristics found that hemlock trees in recovery sites were healthier and had denser canopies than trees in non-recovery sites. This study provided useful information on how spatial analysis, coupled with onsite evaluations, can characterize hemlock mortality on a landscape scale, which may ultimately help to assess effectiveness of introduced natural enemies in forest systems. The spatial analyst tool could be used to detect outbreaks of pests and assess effectiveness of other natural enemies in forest systems. If properly developed, this spatial model will help land managers to detect dead and/or declining trees in landscapes at an early stage and to determine the extent of pest and disease outbreaks. This type of model also can assist land managers in devising appropriate management strategies, which may provide a means to maintain hemlock in natural areas.
- Type
- Conference Proceeding Paper
- Authors
- Hakeem, Abdul; Grant, Jerome; Wiggins, Greggory; Rhea, Rusty; Lambdin, Paris; Buckley, David; Hale, Frank; Colson, Thomas
- Units
- GRSM
- Keywords
- Adelges tsugae, GIS, GRSM-00820, Hemlock, Hemlock Wooly Adelgid, Mortality, spatial analysis, Tsuga canadensis
- Subjects
- Ecological Framework: Biological Integrity | Infestations and Disease | Insect Pests