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Identifying old trees to inform ecological restoration in montane forests of the central Rocky Mountains, USA

Posted date: April 05, 2019
Publication Year: 
2019
Authors: Brown, Peter M.; Gannon, Benjamin; Battaglia, Mike A.Fornwalt, Paula J.Huckaby, Laurie Kay Stroh; Cheng, Antony S.; Baggett, Scott
Publication Series: 
Scientific Journal (JRNL)
Source: Tree-Ring Research. 75(1): 34-48.

Abstract

Old trees (defined here as ≥150 years old) can be rare in many forests because of past timber harvest, uncharacteristically severe wildfires, and - increasingly - climate change. Old trees provide unique structural, ecological, scientific, and aesthetic values missing in forests containing only younger trees. Here we compile crossdated ages from over 10,000 living and dead trees sampled in montane forests of the central Rocky Mountains in Colorado and southern Wyoming, USA, to examine changes in age structure of the oldest trees since Euro-American settlement and to provide guidelines to aid in identification of old trees for retention during ecological restoration treatments. Eroded stumps (containing only heartwood) were found in over 93% of 179 randomly sampled plots. Number of stumps found in each plot was proportional to reconstructed historical (1860 C.E.) stand basal area. The regional median date of maximum plot tree recruitment was over 150 years older when including stumps versus only living trees, suggesting that if all those harvested trees had survived to the present, the ages of oldest trees would be substantially greater than it is today. However, the regional median age of oldest trees in 1860 before harvesting was not different from the median age of oldest living trees in the current forest (246 vs. 248 years), which alternatively suggests that the regional population of oldest trees has recovered to near historical levels in the time since early Euro-American harvests. Each living tree at the time of sampling was assigned to one of three potential age classes based on a subjective assessment of tree morphology: old (likely ≥150 years old), young (likely

Citation

Brown, Peter M.; Gannon, Benjamin; Battaglia, Mike A.; Fornwalt, Paula J.; Huckaby, Laurie S.; Cheng, Antony S.; Baggett, L. Scott. 2019. Identifying old trees to inform ecological restoration in montane forests of the central Rocky Mountains, USA. Tree-Ring Research. 75(1): 34-48.