A stochastic characterisation of the natural disturbance regime of the boreal mixedwood forest with implications for sustainable forest management

1999 ◽  
Vol 29 (4) ◽  
pp. 424-433 ◽  
Author(s):  
Glen W Armstrong
Keyword(s):  
Monte Carlo ◽  
Sustainable Forest Management ◽  
Natural Disturbance ◽  
Class Structure ◽  
Distribution Models ◽  
Age Class ◽  
Boreal Mixedwood Forest ◽  
Random Draw ◽  
Negative Exponential ◽  
Burn Rate

The annual area burned on an 8.6 × 106 ha study area in the boreal mixedwood forest of northeastern Alberta, Canada, was characterised as a serially independent random draw from a lognormal distribution. This characterisation was applied in Monte Carlo simulations, which showed that estimates of the mean annual burn rates, even with long sample periods, are highly imprecise. Monte Carlo simulation was also used to simulate the development of a forest subject to lognormally distributed annual burn rate in an attempt to characterise the equilibrium age-class structure. No equilibrium age-class structure could be identified from the simulation results. The validity of equilibrium age-class distribution models (e.g., the negative exponential and Weibull) and analysis that relies on these models is questioned for forests where the annual burn rate is highly variable.

Past, current, and future fire frequencies in Quebec's commercial forests: implications for the cumulative effects of harvesting and fire on age-class structure and natural disturbance-based management

2006 ◽  
Vol 36 (11) ◽  
pp. 2737-2744 ◽  
Author(s):  
Yves Bergeron ◽  
Dominic Cyr ◽  
C Ronnie Drever ◽  
Mike Flannigan ◽  
Sylvie Gauthier ◽  
...  
Keyword(s):  
Forest Management ◽  
Sustainable Forest Management ◽  
Natural Disturbance ◽  
Fire Frequency ◽  
Ecological Functions ◽  
The Past ◽  
Class Distribution ◽  
Age Class ◽  
If Current ◽  
In Fire

The past decade has seen an increasing interest in forest management based on historical or natural disturbance dynamics. The rationale is that management that favours landscape compositions and stand structures similar to those found historically should also maintain biodiversity and essential ecological functions. In fire-dominated landscapes, this approach is feasible only if current and future fire frequencies are sufficiently low compared with the preindustrial fire frequency, so a substitution of fire by forest management can occur without elevating the overall frequency of disturbance. We address this question by comparing current and simulated future fire frequency based on 2 × CO2 and 3 × CO2 scenarios to historical reconstructions of fire frequency in the commercial forests of Quebec. For most regions, current and simulated future fire frequencies are lower than the historical fire frequency, suggesting that forest management could potentially be used to maintain or recreate the age-class distribution of fire-dominated preindustrial landscapes. Current even-aged management, however, tends to reduce forest variability by, for example, truncating the natural age-class distribution and eliminating mature and old-growth forests from the landscape. Therefore, in the context of sustainable forest management, silvicultural techniques that retain a spectrum of forest compositions and structures at different scales are necessary to maintain this variability and thereby allow a substitution of fire by harvesting.

Using salvage logging and tolerance to risk to reduce the impact of forest fires on timber supply calculations

2015 ◽  
Vol 45 (4) ◽  
pp. 480-486 ◽  
Author(s):  
A. Leduc ◽  
P.Y. Bernier ◽  
N. Mansuy ◽  
F. Raulier ◽  
S. Gauthier ◽  
...  
Keyword(s):  
Forest Fires ◽  
Timber Harvest ◽  
Mitigation Measures ◽  
Class Structure ◽  
Forest Age ◽  
Timber Supply ◽  
Salvage Logging ◽  
Age Class ◽  
Burn Rate ◽  
The Impact

It is acknowledged that natural forest fires cannot and even should not be eliminated from the North American boreal forest. Forest fires produce immediate losses of wood volume, disrupt the conversion of the actual forest age structure into a target structure, and prevent planned timber supply (PTS) levels from being achieved. In this paper, we explore the extent to which periodic shortfalls in available timber under various burn rates can be mitigated through salvage logging and the tolerance of forest managers to a given level of shortfall, both as a function of forest age class structure. Simulations are done using both a deterministic and a stochastic representation of burn rate over time. Results show that the frequency of shortfall events can be reduced by salvage logging and by the introduction of measures that generate a tolerance to shortfall and that this mitigation potential is influenced by initial forest age class structure and burn rate. Results also show that even a 100% rate of salvage logging cannot fully compensate for timber losses to fire and eliminate fire-induced timber shortfalls. Furthermore, interannual burn rate variability reduces the efficiency of both mitigation measures. As the PTS is never realized under fire risk, the real cost of opting for different PTS scenarios should be estimated not from the difference in PTS but rather from the more realistic difference in realized timber harvest.

Age-class distribution and the forest fire cycle

1978 ◽  
Vol 8 (2) ◽  
pp. 220-227 ◽  
Author(s):  
C. E. Van Wagner
Keyword(s):  
Computer Simulation ◽  
Exponential Distribution ◽  
Forest Fire ◽  
Fire History ◽  
Class Structure ◽  
Fire Cycle ◽  
Class Distribution ◽  
Age Class ◽  
Negative Exponential Distribution ◽  
Negative Exponential

The expected age-class structure of a forest dependent on random periodic fire for disturbance and renewal is derived and presented. It is simply the negative exponential distribution, well known in probability mathematics. An important feature of this concept is that the present age-class structure of such a forest is the key to its past fire history. Its limitations are discussed, and the computer simulation of variations, including the interaction of fire and logging, is described. Three examples of its use in interpreting fire history are given.

scholarly journals Predictive Ecosystem Mapping of South-Eastern Australian Temperate Forests Using Lidar-Derived Structural Profiles and Species Distribution Models

2019 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
Melissa Fedrigo ◽  
Stephen B. Stewart ◽  
Stephen H. Roxburgh ◽  
Sabine Kasel ◽  
Lauren T. Bennett ◽  
...  
Keyword(s):  
Species Distribution ◽  
Vegetation Structure ◽  
Species Distribution Models ◽  
Sustainable Forest Management ◽  
Continuous Distribution ◽  
Forest Monitoring ◽  
Distribution Models ◽  
Study Region ◽  
South Eastern ◽  
Eastern Australia

Modern approaches to predictive ecosystem mapping (PEM) have not thoroughly explored the use of ‘characteristic’ gradients, which describe vegetation structure (e.g., light detection and ranging (lidar)-derived structural profiles). In this study, we apply a PEM approach by classifying the dominant stand types within the Central Highlands region of south-eastern Australia using both lidar and species distribution models (SDMs). Similarity percentages analysis (SIMPER) was applied to comprehensive floristic surveys to identify five species which best separated stand types. The predicted distributions of these species, modelled using random forests with environmental (i.e., climate, topography) and optical characteristic gradients (Landsat-derived seasonal fractional cover), provided an ecological basis for refining stand type classifications based only on lidar-derived structural profiles. The resulting PEM model represents the first continuous distribution map of stand types across the study region that delineates ecotone stands, which are seral communities comprised of species typical of both rainforest and eucalypt forests. The spatial variability of vegetation structure incorporated into the PEM model suggests that many stand types are not as continuous in cover as represented by current ecological vegetation class distributions that describe the region. Improved PEM models can facilitate sustainable forest management, enhanced forest monitoring, and informed decision making at landscape scales.

scholarly journals Synthesizing knowledge of the Claybelt to promote sustainable forest management

2002 ◽  
Vol 78 (5) ◽  
pp. 665-671 ◽  
Author(s):  
P Lefort ◽  
B Harvey ◽  
J Parton ◽  
G KM Smith
Keyword(s):  
Forest Management ◽  
Biological Diversity ◽  
Sustainable Forest Management ◽  
Scientific Literature ◽  
Large Body ◽  
Natural Disturbance ◽  
Engineering Research ◽  
Forestry Practices ◽  
Body Of Knowledge ◽  
Forest Practices

A review of the scientific literature relevant to the Claybelt region was undertaken under the initiative of Lake Abitibi Model Forest (LAMF) and in collaboration with the Canadian Forest Service, the Ontario and Quebec Ministries of Natural Resources and the NSERC-UQAT-UQAM (Natural Sciences and Engineering Research Council – Université du Québec en Abitibi-Témiscamingue – Université du Québec à Montréal) Industrial Chair in Sustainable forest Management. The objective was to synthesize this information in order to develop better forestry practices and identify knowledge and research gaps. Forestry-related knowledge was gathered on six broad topics: i) natural disturbances, ii) forest ecosystems, iii) past and present forest practices, iv) biological diversity, v) forest management and vi) examples of current applications of natural disturbance-based forest management. The work allowed us to synthesize a large body of knowledge into one publication that will be a useful reference for foresters in both provinces. Key words: biodiversity, Claybelt, even-aged/uneven-aged forests, fire, silvicultural practices

Influence of Swiss needle cast on foliage age-class structure and vertical foliage distribution in Douglas-fir plantations in north coastal Oregon

2006 ◽  
Vol 36 (6) ◽  
pp. 1497-1508 ◽  
Author(s):  
Aaron R Weiskittel ◽  
Douglas A Maguire ◽  
Sean M Garber ◽  
Alan Kanaskie
Keyword(s):  
Vertical Distribution ◽  
Douglas Fir ◽  
Parameter Estimates ◽  
Class Structure ◽  
Needle Cast ◽  
Age Class ◽  
Relative Contribution ◽  
Crown Structure ◽  
Growth Decline ◽  
Swiss Needle Cast

Swiss needle cast (SNC) causes premature loss of foliage and subsequent growth decline in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Although the mechanisms leading to this growth decline include loss of photosynthetic surface area and physiological disruption of surviving foliage, estimating the relative contribution of these two primary sources requires precise quantification of SNC effects on total foliage mass, foliage age-class structure, and vertical foliage distribution. The effect of SNC severity on these crown structural attributes was tested across a range of stand densities and site qualities in 10- to 60-year-old plantations in north coastal Oregon. Foliage mass in each age-class was sampled at the branch level, and the resulting equations were applied to all live branches on intensively measured sample trees. Vertical distribution of each foliage age-class was described by a beta distribution fitted to each sample tree, and sources of variation in vertical distribution were tested by regressing beta parameter estimates on SNC intensity and other covariates representing tree, stand, and site attributes. Distribution of foliage mass by age-class and by relative height in the crown was significantly affected by SNC severity, in addition to other covariates such as crown size and tree social position. SNC caused a reduction in the amount of foliage in each age-class and greater relative representation of younger needles. SNC also shifted the mode of relative vertical distribution toward the top of the tree for the three youngest foliage age-classes, but toward the base of the crown for 4- and 5-year-old foliage. Quantification of foliage age-class structure and vertical distribution across a range of SNC severity has helped to establish diagnostic criteria for assessing changes in crown structure that precede declines in growth and vigor. The induced changes in crown structure will also help to identify the relative contribution of several mechanisms causing growth losses in diseased trees.

How do forest harvesting methods compare with wildfire? A case study of soil chemistry and tree nutrition in the boreal forest

2007 ◽  
Vol 37 (9) ◽  
pp. 1658-1668 ◽  
Author(s):  
Evelyne Thiffault ◽  
Nicolas Bélanger ◽  
David Paré ◽  
Alison D. Munson
Keyword(s):  
Pinus Banksiana ◽  
Sustainable Forest Management ◽  
Black Spruce ◽  
Base Cations ◽  
Natural Disturbance ◽  
Forest Harvesting ◽  
Exchange Capacity ◽  
Molar Ratio ◽  
Organic C ◽  
Tree Nutrition

An important tenet of the natural disturbance paradigm as a basis for sustainable forest management is that impacts of interventions fall within the range of natural variation observed for the disturbance in question. We evaluated differences in soil nutrients, soil acid–base status, and tree nutrition between two harvesting methods (whole-tree (WTH) and stem-only (SOH)) and wildfire, 15–20 years after disturbance, to assess whether these harvesting methods have biogeochemical impacts that are within the natural range of variation caused by wildfires in boreal coniferous stands of Haute-Mauricie (Quebec). Both SOH and WTH created conditions of forest floor effective cation-exchange capacity, exchangeable Ca and K concentrations, base saturation, Ca:Al molar ratio, and organic C concentrations that were lower than the range of values for wildfires. We hypothesize that the immediate deposition of soluble base cations and the incorporation of recalcitrant organic matter that characterize wildfires generate biogeochemical conditions that are not emulated by either harvesting method. The improved soil nutritional environment after wildfire compared with SOH and WTH was reflected in jack pine ( Pinus banksiana Lamb.) foliar nutrient composition but not in black spruce ( Picea mariana (Mill.) BSP) foliage. The results raise uncertainties about the long-term base nutrient availability of the harvested sites on Boreal Shield soils.

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