Bulkley Valley Research Centre - Science in the Public Interest

Response of Ecosystems and Plants to Fire

Project Reference Number: 2020-40

Project Status: Active

Led by: Evelyn Hamilton, Sybille Haeussler, Reg Newman, Julia Chandler

Funder: Forest Enhancement Society (FESBC), BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development (MFLNRORD)

Burning Questions: Responses of Plant Species in BC to Fire

Key information needs about the effects of fire on ecosystems in BC’s interior were derived from our interviews with over 60 decision makers. The “Burning Questions” raised by resource managers encompassed the response to fire of ecosystems and plants in general, groups of plants (e.g., wildlife and livestock forage, invasives) and specific plants (e.g., culturally important medicinal berry species, and intermediate hosts for pine rusts); also considering the implications for reforestation, watershed stability and carbon balance.

We compiled data from 78 studies of responses of ecosystems in BC to fire. Some studies were long term monitoring studies where sites were sampled for up to 20 yrs post-fire and others were chronosequence or short-term treatment effects studies.

Information from 3770 plots (8378 plots x yrs) was compiled. The database includes information on over 400 plant species composition and ecosystem classification, site, soil, and regeneration data. Treatment history and fire effects (e.g. FWI, fuel loading & consumption) data is included.

We analysed this data to provide answers to questions about the long-term response of understory plant communities after clearcutting and broadcast slashburning in northern and central BC. Response of vegetation to wildfire in this area was also described. Data from monitoring of ecosystem restoration sites in the Rocky Mountain Trench was also compiled and analysed.

Post-fire plant community composition was most highly related to long-term fire history/fire climate and local site moisture and nutrient gradients. Differences in species composition between recently (past 20 years) burned and unburned sites were relatively small, suggesting that these ecosystems are broadly resilient to fire. Management decisions other than whether to burn (e.g., reforestation choices, grazing decisions) may have more impact on understory vegetation.

We have written several publications and presented a number of talks to different audiences. Plans to undertake further work to extend the results of our analysis to a wide audience are being developed. Reports, papers, and presentations are available at www.db2020.net.