Tree-ring Reconstruction of Insect Outbreaks in Lake Clark and Katmai National Park and Preserve

  • Sherriff, Rosemary (PI)

Grants and Contracts Details


The Southwest Alaska Network (SWAN) was established for the study and protection of five National Park units (Alagnak Wild River (ALAG), Aniakchak National Monument & Preserve (ANIA), Katmai National Park & Preserve (KATM), Kenai Fjords National Park (KEFJ), and Lake Clark National Park & Preserve (LACL». The SWAN Monitoring Plan identifies insect and disease outbreaks as an important indicator, or 'vital sign,' of ecosystem health (Bennett et al. 2006). Currently, southern Alaska is experiencing a regional outbreak of spruce bark beetle (Dendroctonus rufipennis) that has killed 0.8-1.2 million ha of spruce forest on the western Kenai Peninsula (Berg 1998; Fastie et al. 2000), and nearly 14,000 ha on the northern Alaska Peninsula (Wittwer 2004). Tree-ring studies from the Kenai indicate that regional episodes of thinning occurred several times during the l800s and 1900s (Berg 1998, 2000). However, these previous outbreaks were not as severe as the 1990s outbreak that has killed most of the mature white spruce in the region (Berg 2000). In contrast to our understanding of beetle disturbance on the Kenai, we know little about the history of such disturbance on the Alaska Peninsula, particularly in the forests ofLACL and KATM, where mortality has been greatest. In addition, we have little understanding of the relationship, if any, between long-term climate trends and short-term extremes (i.e., drought and wet periods) on beetle activity. Given current climate change scenarios, it is possible that areas that have sustained little damage from the bark beetle in the past may become susceptible to widespread outbreaks in the future, also increasing their susceptibility to fire. The degree to which new outbreaks could disrupt ecological processes in the SWAN is unknown and will likely be the subject of future monitoring efforts. This two-year project will examine historic spruce bark beetle disturbance (100-400 year chronologies) within LACL and KATM using standard dendrochronological techniques. The project was initiated in 2005 under a separate agreement with the Hawaii-Pacific Islands CESU. Tree-ring reconstructions will provide information regarding the frequency and extent of past outbreaks and the effect that increasing temperatures could have on the severity of future outbreaks. Results of this work will enable us to address the following questions of relevance to monitoring: • Is there evidence of previous spruce bark beetle outbreaks in LACL and KATM? • When, and at what frequency? • Where in the landscape? How old are the stands? • Are the outbreaks localized or synchronized across the landscape? • Is there a relationship between climate and insect disturbance? A research permit issued to the cooperator will be required for field collection of tree cores in 2007. National Park Service and u.S. Fish & Wildlife Service personnel will be responsible for the field collections, while the cooperator will be responsible for the processing and analysis of tree-ring data. No training will be required of the cooperator for the completion of this project.
Effective start/end date8/16/0710/31/10


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