Patterns of Spread of Hemlock Woolly Adelgid in Carolina Hemlock Populations
Levy F, Baker J, Chen K, Cooke G, Lieu YC, Walker ES, McDowell T. 2008. Patterns of Spread of Hemlock Woolly Adelgid in Carolina Hemlock Populations. Pages 168-176. In Onken B (ed): Fourth Symposium on Hemlock Woolly Adelgid in the Eastern United States. Hartford, CT. February 12-14, 2008. US Forest Service. FHTET-2008-01
Census and mapping of individuals was carried out in four populations of Carolina hemlock to uncover patterns of spread of hemlock woolly adelgid. Spatial cluster analysis was used to distinguish among three patterns of adelgid transmission: random spread, spread in a wavelike pattern, and spread from multiple foci. The finding of clusters in all populations refuted the random spread hypothesis. In the two recently infested populations, trees in all size classes were in good condition, but infestation clusters were evident. In the population with a more advanced infestation but under chemical treatment, tree condition was poorer but infestations were light and seedlings were abundant and in excellent condition. Close monitoring of adelgid infestations and treatment of tree clusters with high densities of adelgids is recommended.
- Type
- Conference Proceeding Paper
- Authors
- Levy, Foster; Baker, Jordan; Chen, Ke; Cooke, Graham; Lieu, Yu-Sheng; Walker, Elaine; McDowell, Tim
- Units
- BLRI
- Keywords
- Carolina hemlock, cluster analysis, Hemlock Woolly Adelgid, Infestation, Transmission