A section of Canadian Biodiversity: Ecosystem Status and Trends 2010. Full report
Focus is on fire and insects, wind not cited at national level. Regional perspectives available under Atlantic Maritime Ecozone evidence for key findings summary
Natural disturbance regimes in northeastern North America—evaluating silvicultural systems using natural scales and frequencies
Robert S. Seymour et al., 2002.Forest Ecology and Management 155 (2002) 357–367 “Many scientists and foresters have begun to embrace an ecological, natural disturbance paradigm for management, but lack specific guidance on how to design systems in ways that are in harmony with natural patterns. To provide such guidance, we conducted a comprehensive literature survey of northeastern disturbances, emphasizing papers that studied late-successional, undisturbed, or presettlement forests. Evidence demonstrates convincingly that such forests were dominated by relatively frequent, partial disturbances that produced a finely patterned, diverse mosaic dominated by late-successional species and structures. In contrast, large-scale, catastrophic stand-replacing disturbances were rare, returning at intervals of at least one order of magnitude longer than gap-producing events. Graphing the contiguous areas disturbed against their corresponding return intervals shows that these important disturbance parameters are positively related; area disturbed increases exponentially as the return interval lengthens. This graph provides a convenient metric, termed the natural disturbance comparability index, against which to evaluate both single and multi-cohort silvicultural systems based on their rotations or cutting-cycles and stand or gap sizes. We review implications of these findings for silvicultural practice in the region, and offer recommendations for emulating natural disturbance regimes.
Natural disturbance in an old-growth landscape of northern Maine, USA
Shawn Fraver*†, Alan S. White and Robert S. Seymour Journal of Ecology 2009, 97, 289–298 From the abstract: ….2. We investigated the frequency and severity of natural disturbance in a 2000-ha old-growth landscape (Big Reed Forest Reserve) in northern Maine, USA. Given its size, the Reserve provides an ideal opportunity to study, at multiple scales, natural forest processes in a region that has otherwise been dramatically altered by human activities. Using dendrochronological methods, we reconstructed disturbance histories for 37 randomly located plots stratified by five forest types (hardwood forests, mixed woods forests, red spruce forests, northern white-cedar seepage forests and northern white-cedar swamps). 3. We found no evidence of stand replacing disturbance on any plot during the last 120280 years (depending on plot). The overall mean disturbance rate was 9.6% canopy loss per decade (median 6.5%, maximum 55%, plots pooled), yet the distribution was strongly skewed toward the lower rates. 4. We found little differences in disturbance rates between forest types, save a slightly lower rate in the northern white-cedar swamps. However, if we ignore forest-type classifications, we see that disturbance rates are clearly influenced by gradients in the relative abundance of component tree species, owing to species’ relative susceptibilities to particular disturbance agents. 5. Synthesis. Relatively low rates of canopy disturbance allow the accrual of shade-tolerant saplings. The abundance of this advance regeneration…
The Presettlement Forest and Natural Disturbance Cycle of Northeastern Maine
Craig G. Lorimer Ecology Volume58, Issue1 January 1977 Pages 139-148 “Land survey records of 1793—1827 containing forest data for 1.65 x 106 ha of northern Maine were analyzed for species composition, successional status, and frequency of large—scale disturbance…If the amount of disturbed forest at this time was typical of the natural disturbance regime, then the average recurrence interval of fire and large—scale windthrow for a given site would be 800 and 1,150 years, respectively. Data on the structure of remnant virgin stands in the region likewise suggest that the time interval between severe disturbances was much longer than that needed to attain a climax, all—aged structure.
The Changing Disturbance Regime in Eastern Canadian Mixed Forests During the 20th Century
Tasneem Elzein1*, Dominique Arseneault1, Luc Sirois1 and Yan Boucher Front. Ecol. Evol., 09 June 2020
Stand-landscape integration in natural disturbance-based management of the southern boreal forest
Brian D.Harvey et al. 2002 The concept of cohorts is used to integrate stand age, composition and structure into broad successional or stand development phases. Mean forest age (MFA), because it partly incorporates historic variability of the regional fire cycle, is used as a target fire cycle. At the landscape level, forest composition and cohort objectives are derived from regional natural disturbance history, ecosystem classification, stand dynamics and a negative exponential age distribution based on a 140 year fire cycle. The resulting multi-cohort structure provides a framework for maintaining the landscape in a semi-natural age structure and composition. At the stand level, the approach relies on diversifying interventions, using both even-aged and uneven-aged silviculture to reflect natural stand dynamics, control the passage (“fluxes”) between forest types of different cohorts and maintain forest-level objectives.