Decoupling the diameter‐age debate: The Boise National Forest's legacy tree guide

Abstract

As trees age, they develop discernible attributes (legacy characteristics), that provide critical wildlife habitat. An arbitrary diameter cap is often used in planning to ensure old trees remain on the landscape. Although a relation exists between tree age and diameter, several environmental factors also influence growth; consequently, not all large trees are old and not all small trees are young. Personnel on the Boise National Forest questioned the efficacy of using a diameter cap of 20 in. (51 cm) as a method for conserving old trees because it prevented the ability to meet other Forest Plan desired conditions associated with restoring ecosystems. To address this concern, Forest personnel conducted an administrative study within four project areas. Data were collected on trees ≥20 in. (51 cm) dbh - primarily ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), and grand fir (Abies grandis). Results from this study provided the data used to refine a locally relevant legacy tree field guide, built trust among stakeholders, and improved the environmental planning process.

Citation

Riling, John; Geier‐Hayes, Kathleen; Jain, Theresa. 2019. Decoupling the diameter‐age debate: The Boise National Forest's legacy tree guide. Forest Science. 65(4): 519‐527.