The fire history of a 416-year-old western larch tree in southeastern British Columbia

Abstract

The fire history obtained from pre-settlement fire-scarred trees provides useful benchmarks for the restoration of dry interior, fire-dependent forest ecosystems. In the Rocky Mountain Trench of southeast British Columbia, historical benchmarks obtained from periods prior to significant European influence (i.e., pre-1850) are common reference points for forest ecosystem restoration. This extension note discusses the fire history of a 416-year-old western larch (Larix occidentalis) whose growth rings recorded 268 years of fire history before 1850. The study tree's estimated mean fire interval (MFI) is 34.1 years, and its fire intervals ranged from 19 years to 51 years. The tree did not record a fire during the last 130 years of its life. This extension note also discusses the development of a network of cross-dated benchmark sites across the landscape that would create a master fire chronology for the region. Such a chronology would reflect the natural variability of historical fire patterns, helping policy-makers, managers, recovery teams, and restoration practitioners understand the spatial and temporal distribution of landscape-scale disturbances that historically have created fire-dependent ecological communities (many of which include wildlife and plant species now at risk). The creation of a benchmark network would also refine dry interior forest restoration/conservation programs and improve their efficacy.