Open Collections

Liu, Mingrui

University of British Columbia

Climate change has significantly impacted wildfire regimes in lodgepole pine forests, resulting in prolonged fire seasons and altered fire behavior. In North America, fire patterns have shifted towards more frequent and severe wildfires after a century of suppression. In response, silviculture practices in fire-prone areas aim to restore diverse forest structures that are resilient to wildfires. In Western Canada, interest in silvicultural solutions for promoting forest resilience to wildfires has increased following the devastating wildfire seasons between 2017 and 2023. Irregular shelterwood, a silvicultural system with a relatively short history in British Columbia, has been deployed in ecologically sensitive areas to promote structural heterogeneity and meet management goals for aesthetics, biodiversity, and wildlife. Although the impacts of irregular shelterwood on wildlife habitat and abundance have been well studied, the interaction between wildfire and the stand structure created by irregular shelterwood remains poorly understood. The effectiveness of irregular shelterwood in building wildfire resilience remains unclear. This thesis presents a study of a lodgepole pine stand treated with irregular shelterwood that partially burned in a wildfire in 2017. This study collected ground fuel, canopy fuel, and timber cruising data from four stand types (irregular shelterwood treated-burnt, treated-unburnt, untreated-burnt, and untreated-unburnt) and analyzed the difference in char height and fire-induced mortality between burnt and unburnt stands with irregular shelterwood treatment as a variable. The results demonstrated reduced wildfire effects in the irregular shelterwood stand. Additionally, the fuel data was used to generate an irregular shelterwood stand in US and Canadian fire models, and the model predictions of fire intensity and fire type were compared to field observations. The results agreed with field observations that irregular shelterwood resulted in moderated fire behavior. Moreover, fire models showed uncertainty in modeling fire behavior in stands with discontinuous canopy structure. The study provides valuable initial insights into the effectiveness of irregular shelterwood in mitigating wildfire risk and proposes a potential silvicultural solution to promote forest resilience to wildfire. The findings from fire modeling will also inform the applicability and accuracy of contemporary wildfire models in the lodgepole pine forests of interior British Columbia.

Text

2024-06-13

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88462

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/