Document


Title

Changes in fire regime break the legacy lock on successional trajectories in Alaskan boreal forest
Document Type: Journal Article
Author(s): Jill F. Johnstone; Teresa N. Hollingsworth; F. Stuart Chapin III; Michelle C. Mack
Publication Year: 2010

Cataloging Information

Keyword(s):
  • Betula neoalaskana
  • Betula spp.
  • black spruce
  • boosted regression trees
  • boreal forest
  • CBI - composite burn index
  • coniferous forests
  • deciduous forests
  • disturbance
  • elevation
  • fire case histories
  • fire frequency
  • fire intensity
  • fire management
  • fire severity
  • forest management
  • moisture
  • organic soils
  • overstory
  • Picea mariana
  • Picea spp.
  • plant communities
  • plant growth
  • Populus spp.
  • Populus tremuloides
  • post-fire recovery
  • post-fire succession
  • regeneration
  • seedling recruitment
  • seedlings
  • succession
  • topography
  • trees
  • wildfires
Region(s):
Record Maintained By:
Record Last Modified: June 1, 2018
FRAMES Record Number: 9458
Tall Timbers Record Number: 24516
TTRS Location Status: In-file
TTRS Call Number: Fire File
TTRS Abstract Status: Okay, Fair use, Reproduced by permission

This bibliographic record was either created or modified by the Tall Timbers Research Station and Land Conservancy and is provided without charge to promote research and education in Fire Ecology. The E.V. Komarek Fire Ecology Database is the intellectual property of the Tall Timbers Research Station and Land Conservancy.

Description

Predicting plant community responses to changing environmental conditions is a key element of forecasting and mitigating the effects of global change. Disturbance can play an important role in these dynamics, by initiating cycles of secondary succession and generating opportunities for communities of long-lived organisms to reorganize in alternative configurations. This study used landscape-scale variations in environmental conditions, stand structure, and disturbance from an extreme fire year in Alaska to examine how these factors affected successional trajectories in boreal forests dominated by black spruce. Because fire intervals in interior Alaska are typically too short to allow relay succession, the initial cohorts of seedlings that recruit after fire largely determine future canopy composition. Consequently, in a dynamically stable landscape, postfire tree seedling composition should resemble that of the prefire forest stands, with little net change in tree composition after fire. Seedling recruitment data from 90 burned stands indicated that postfire establishment of black spruce was strongly linked to environmental conditions and was highest at sites that were moist and had high densities of prefire spruce. Although deciduous broadleaf trees were absent from most prefire stands, deciduous trees recruited from seed at many sites and were most abundant at sites where the fires burned severely, consuming much of the surface organic layer. Comparison of pre- and postfire tree composition in the burned stands indicated that the expected trajectory of black spruce self-replacement was typical only at moist sites that burned with low fire severity. At severely burned sites, deciduous trees dominated the postfire tree seedling community, suggesting these sites will follow alternative, deciduous-dominated trajectories of succession. Increases in the severity of boreal fires with climate warming may catalyze shifts to an increasingly deciduous-dominated landscape, substantially altering landscape dynamics and ecosystem services in this part of the boreal forest.

Online Link(s):
Citation:
Johnstone, Jill F.; Hollingsworth, Teresa N.; Chapin, F. Stuart; Mack, Michelle C. 2010. Changes in fire regime break the legacy lock on successional trajectories in Alaskan boreal forest. Global Change Biology 16(4):1281-1295.