title: Latent resilience in ponderosa pine forest: effects of resumed frequent fire.
abstract: Ecological systems often exhibit resilient states that are maintained through negative feedbacks. In ponderosa pine forests, fire historically represented the negative feedback mechanism that maintained ecosystem resilience; fire exclusion reduced that resilience, predisposing the transition to an alternative ecosystem state upon reintroduction of fire. We evaluated the effects of reintroduced frequent wildfire in unlogged, fire-excluded, ponderosa pine forest in the Bob Marshall Wilderness, Montana, USA. Initial reintroduction of fire in 2003 reduced tree density and consumed surface fuels, but also stimulated establishment of a dense cohort of lodgepole pine, maintaining a trajectory toward an alternative state. Resumption of a frequent fire regime by a second fire in 2011 restored a low-density forest dominated by large-diameter ponderosa pine by eliminating many regenerating lodgepole pines and by continuing to remove surface fuels and small-diameter lodgepole pine and Douglas-fir that established during the fire suppression era. Our data demonstrate that some unlogged, fire-excluded, ponderosa pine forests possess latent resilience to reintroduced fire. A passive model of simply allowing lightning-ignited fires to burn appears to be a viable approach to restoration of such forests.
authors.affiliation: Department of Forest Management, University of Montana, 32 Campus Drive, Missoula, Montana 59812, USA. a.larson@umontana.edu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Larson
authors.forename: R Travis
authors.initials: RT
authors.lastname: Belote
authors.forename: C Alina
authors.initials: CA
authors.lastname: Cansler
authors.forename: Sean A
authors.initials: SA
authors.lastname: Parks
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Dietz
mesh_terms: D017753:Ecosystem; D005390:Fires; D028223:Pinus / Q000502:physiology*; D011157:Population Dynamics; D014197:Trees