Disturbances of Plant Communities : Spruce Bark Beetle Infestation

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The spruce bark beetle (Dendroctonus rufipennis) is not new to the area, nor is it the only insect to affect the region's forests. Epidemic scale outbreaks are known to have occurred on the lower Kenai Peninsula as far back as the mid-1800s. The recent epidemic, however, has certainly been the most significant terrestrial ecological disturbance to the area in recorded history (Wittwer et al. 1998). Notable outbreaks were not noted in the Kachemak Bay Watershed until the 1950s and early 1960s when the first outbreak was observed near Anchor Point. At approximately the same time, beetle outbreaks were growing outside of the Watershed. An extended period of drought is thought to have contributed to the surge in outbreaks by reducing trees' ability to resist and recover from beetle attack. Increased rainfall in the late 1960s, however, dampened the drought conditions, curtailing a more widespread epidemic. By the late 1970s, beetle outbreaks had skyrocketed again on the Kenai Peninsula. Despite this outbreak, the Kachemak Bay Watershed remained healthy until 1984 when an outbreak in the Fox River drainage began to expand, and beetles commenced consuming forests along East Road on the northern side of the Bay. Meanwhile, a small infestation in Mallard Bay, on the southern side of the Watershed, expanded to 12,000 acres by 1988. In addition, more outbreaks were developing to the north of Homer, near Ninilchik and Crooked Creek. There was some thought that the maritime climate of the Bay area would keep the outbreaks from expanding throughout the area, but this was not to be the case.


This is an electronic [digital] resource produced by the Kachemak Bay Research Reserve and NOAA Coastal Services Center report #NOAA/CSC/20017-CD. This public document may be viewed for personal or informational use without owing an obligation to the publisher as long as the documents are not modified in any respect.
Report can be accessed online here.