Author(s):
Jaclyn Guz, Nathan S. Gill, Dominik Kulakowski
Year Published:

Cataloging Information

Topic(s):
Fire Ecology
Fire Effects
Fire & Climate

NRFSN number: 23987
FRAMES RCS Number: 64318
Record updated: January 4, 2022

Increased wildfire activity and climate change have intensified disturbance regimes globally and have raised concern among scientists and land managers about the resilience of disturbed landscapes. Here we test the effects of climate, topographic variation, and pre-fire stand structure on regeneration in lodgepole pine (Pinus contorta var. latifolia) forests following high severity fire over the past decades.

We surveyed lodgepole pine regeneration 8-72 years after eight high-severity fires in western Colorado and southern Wyoming. We used dendroecological methods and machine learning to (1) identify temporal trends in post-fire regeneration and (2) examine influences of climate on post-fire regeneration, with focus on post-fire establishment, initial post-fire density, and radial growth.

All burned sites reached a median stocking density of ≥ 150/seedlings ha, but there was a large range of spatial heterogeneity, with many plots having an absence or scarcity of regeneration, implying a trend of increasing patchiness, with likely cascading effects on subsequent patterns and processes. Our analysis indicated that (1) post-fire regeneration is influenced by pre-fire stand structure (stand age and density), elevation, and post-fire minimum temperature; (2) pre-fire densities of > 14,000 stem/ha promoted successful stocking (≥150 seedlings/ha) and reduced lag between the disturbance and initial regeneration; (3) minimum post-fire temperatures > -1.6 °C reduced lag of initial regeneration and promoted initial radial growth.

Synthesis: Our study demonstrates lodgepole pine in high-elevation forests are regenerating following fires under recent climactic trends, but that regeneration is affected by post-fire climatic conditions. Importantly, forest patchiness may be increasing in a way that may affect future ecological dynamics and may compromise resilience of these systems.

Citation

Guz, Jaclyn; Gill, Nathan S.; Kulakowski, Dominik. 2021. Long-term empirical evidence shows post-disturbance climate controls post-fire regeneration. Journal of Ecology 109(12):4007-4024. https://doi.org/10.1111/1365-2745.13771

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