Decadal soil and stand response to fire, harvest, and salvage-logging disturbances in the western boreal mixedwood forest of Alberta, Canada

Abstract

Empirical knowledge of long-term ecosystem response to single and compound disturbances is essential for predicting disturbance effects and identifying management practices to maintain productive capacity of managed and restored landscapes. We report on soil, foliar nutrition, and regeneration growth response to wildfire, clearcut harvesting, and postfire salvage logging, as well as undisturbed control stands within the first year following disturbance and 10-11 years after disturbance in trembling aspen -white spruce mixedwood forests near Lesser Slave Lake, north-central Alberta, Canada. The compound disturbance of salvage logging resulted in greater long-term impacts on forest floor properties than either wildfire or harvesting alone. Changes in forest floor properties such as carbon and nitrogen pools and cation exchange capacity under salvage logging have persisted for 10 years and exhibit a different recovery trajectory than fire or harvesting. Forest floor properties under harvesting, including depth, carbon content, pH, extractable ammonium, and extractable sulphur, were not different from the control condition 10 years after harvest. Effects on soil and foliar nutrition were not reflected in productivity (height and diameter) of regenerating vegetation. Our results show differences between short-and long-term responses to disturbance, among single natural and anthropogenic disturbances, and among single and compound disturbances.Résumé : La connaissance empirique de la réponse des écosystèmes à des perturbations simples ou combinées est essentielle pour prédire les effets et identifier les pratiques d'aménagement pour maintenir la capacité productive des paysages aménagés et restaurés. Nous rapportons les effets du feu, de la coupe totale et de la coupe de récupération après feu, ainsi que leur comparaison avec des sites non perturbés, sur les sols, la nutrition foliaire et la croissance de la régénération, un an et 10-11 ans après perturbation dans des forêts mixtes de peuplier faux-tremble et d'épinette blanche près de Lesser Slave Lake (centre-nord de l'Alberta, Canada). Par rapport au feu ou à la coupe, la coupe de récupération après feu, qu'on peut qualifier de perturbation combinée, a causé des impacts plus importants à long terme sur les horizons organiques de surface. Les changements dans les propriétés des horizons organiques, tels que les réservoirs de carbone et d'azote et la capacité d'échange cationique, ont persisté après 10 ans, et montrent une trajectoire dans le temps différente de celles observées après feu ou coupe. Dix ans après perturbation, les propriétés des horizons organiques incluant l'épaisseur, le contenu en carbone, le pH et les concentrations en ammonium et soufre extractibles n'étaient pas différentes dans les sites coupés par rapport aux sites non perturbés. Les effets sur la nutrition des sols et des arbres ne se sont pas traduits par une plus grande productivité (hauteur et diamètre) de la régénération à ce stade précoce de la révolution du peuplement. Nos résultats mont...

Twenty‐four years after the Yellowstone Fires: Are postfire lodgepole pine stands converging in structure and function?

“…Stand-replacing fires dominate the disturbance regime of many northern coniferous forests (Johnson 1992, Schoennagel et al 2004, and fire frequency and size are expected to increase in coming decades (Westerling et al 2011, Barbero et al 2015. Knowledge of postfire stand development is essential for anticipating the future of these forest landscapes and their role in regional carbon budgets (Stephens et al 2013, Kishchuk et al 2015, Trumbore et al 2015.…”

Reclamation of boreal forest after oil sands mining: anticipating novel challenges in novel environments

“…), and tamarack (Larix laricina (Du Roi) K. Koch) (Beckingham and Archibald 1996). Biodiversity patterns and biogeochemical cycles are shaped by the region's subhumid and subarctic climate, its predominant brunisol and luvisol soils, and the occurrence and distribution of natural (i.e., wildfire) and anthropogenic disturbances (i.e., logging) (Bergeron et al 2002;Brandt et al 2012;Kishchuk et al 2015;Maynard et al 2013).…”

“…Determining where sites may require additional management inputs and deriving appropriate intervention approaches based on these trajectories can be equally ambiguous and possibly lead to protracted costs of reclamation (Jackson and Hobbs 2009). The general approach of looking to the past has been widely criticized for both its narrow and static assessment of recovering ecosystems (Harris et al 2006;Choi 2007;Hobbs and Cramer 2008;Hobbs and Suding 2009), particularly in those ecosystems with complex natural disturbance and succession regimes (e.g., wildfire, insect epidemics, or drought) (Bergeron et al 2002;Kishchuk et al 2015;Maynard et al 2013). Given the inevitability of a rapidly growing industry, a central question for the sustain- Note: The geology factor includes both the geology and the biochemistry of the parent material (including, for example, tailings and spoils).…”

Post-Fire Salvage Logging Imposes a New Disturbance that Retards Succession: The Case of Bryophyte Communities in a Macaronesian Laurel Forest

“…This is probably because it is a human-conducted action, often planned with the idea of restoring forests, and hence is perceived free of the negative connotations that typical disturbances often have for forest management. Knowledge of the effect of multiple interacting disturbances is in fact a critical gap in the development of ecological theory [17,24,25,28,29], and the study of the impact of (post-fire) salvage logging on ecological succession may greatly contribute to the understanding of the effect of compound perturbations on ecosystem functioning and structure [30].…”

“…This reference ecosystem is often based on climax communities that are usually well known for a specific site [34]. However, most studies addressing the effect of salvage logging on ecosystem regeneration have focused on the comparison between salvaged and non-salvaged areas, but without exploring the results with respect to a non-disturbed reference ecosystem (see [30,35,36]). Although this approach provides crucial and invaluable information concerning the effect of SL on ecosystem regeneration and functioning, the use of a reference ecosystem may place the effect of SL within the context of succession, helping to evaluate with more accuracy its long-term effect and the difference with respect to the mature communities.…”