A tree-ring reconstruction of western spruce budworm history in the southern Rocky Mountains

T. W. Swetnam, A. M. Lynch

Research output: Contribution to journalArticle

85 Scopus citations


Tree-ring width chronologies from 10 mixed-conifer stands in the Colorado Front Range and New Mexico Sangre de Cristo Mountains were used to reconstruct the timing, duration, and radial growth impacts of past outbreaks of Choristoneura occidentalis. At least 9 outbreaks were identified from 1700-1983. Severity and timing of outbreaks was high variable. Average duration of reduced growth periods caused by budworms was 12.9 yr and ranged from 5-26 yr. Average interval between initial years of successive outbreaks was 34.9 yr and ranged from 14-58 years. Average maximum and periodic radial growth reductions were 50% and 21.7%, respectively. There was a relatively long period of reduced budworm activity in the first few decades of the 20th century, and since that time outbreaks have been markedly more synchronous among the sampled stands, possibly due to changes in age structure and species composition following harvesting and fire suppression in the late 19th and early 20th centuries. -from Authors

Original languageEnglish (US)
Pages (from-to)962-986
Number of pages25
JournalForest Science
Issue number4
StatePublished - Jan 1 1989


ASJC Scopus subject areas

  • Forestry
  • Ecology
  • Ecological Modeling

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