Commercial thinning to provide harvest stability to forests with an unbalanced age class distribution

1994 ◽  
Vol 70 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Mark Jamnick ◽  
Ted Needham ◽  
Marshall Bateman
Keyword(s):  
Stages Of Development ◽  
Wood Supply ◽  
Habitat Protection ◽  
Class Distribution ◽  
Age Class ◽  
Commercial Thinning ◽  
Supply Analysis ◽  
Mature Stands

Maintaining harvest stability while minimizing volume losses to mortality is a challenge in forests characterized by an unbalanced age-class distribution with an overabundance of "over-mature" and too few 'mature' stands. In many areas with this situation, emphasis is on harvesting over-mature stands and regenerating them quickly at defined density and stocking levels to minimize the eventual wood supply downfall. However, silvicultural activities in stands at other stages of development are often neglected. Wood supply analysis of a spruce-fir forest with the above characteristics indicated that both harvest stability and maintenance of the total volume harvested could be obtained by commercial thinning in mature stands. In addition, the treatment may have other benefits such as habitat protection. Defining the specifics of the treatment is required to move from consideration at the strategic level to operational implementation.

scholarly journals Economic impacts of partial harvesting: Mitigating mid-term timber supply shortages as a result of pest outbreaks

2021 ◽  
Vol 97 (3) ◽  
pp. 271-276
Author(s):  
Torben Jensen ◽  
Jean-Martin Lussier
Keyword(s):  
Class Structure ◽  
Forest Sector ◽  
Timber Supply ◽  
Age Class ◽  
Eastern Spruce Budworm ◽  
Partial Harvesting ◽  
Pest Outbreaks ◽  
Supply Analysis ◽  
Regional Forest ◽  
Mature Stands

Natural disturbances such as pest outbreaks have a significant impact on forest dynamics and services, including the loss of mature stands. From a wood production perspective, these disturbances can lead to long-lasting imbalances in the overall age-class structure of the forest, potentially resulting in a shortage of mature harvestable stands. Researchers from Natural Resources Canada’s (NRCan) Canadian Forest Service (CFS) have made a timber supply analysis of the Dunière forest located in the centre of the Gaspé Peninsula (Québec). This region suffers from an age-class structure imbalance caused by an eastern spruce budworm (ESB) outbreak that ended in 1984, and is consequently facing a reduced annual allowable cut, leading to long- term implications for the regional forest sector. The authors suggest that partial harvesting – the removal of a proportion of timber in a mature stand several years before a final cut is carried out – is a promising opportunity in the ESB-affected area for mitigating mid-term timber supply shortages by smoothing the fibre supply over time.

scholarly journals Discussion: Road network designs in wood supply analysis

1991 ◽  
Vol 67 (2) ◽  
pp. 145-146
Author(s):  
Robert A. Douglas
Keyword(s):  
Road Network ◽  
Wood Supply ◽  
Supply Analysis

Timber production versus old-growth preservation with endogenous prices and forest age-classes

2004 ◽  
Vol 34 (6) ◽  
pp. 1296-1310 ◽  
Author(s):  
Olli Tahvonen
Keyword(s):  
Environmental Values ◽  
Timber Harvesting ◽  
Timber Production ◽  
Forest Age ◽  
Forest Land ◽  
Age Classes ◽  
Old Growth ◽  
Class Distribution ◽  
Age Class ◽  
Long Run

This study combines timber production and environmental values, applying a dynamic forest-level economic model with any number of forest age-classes. The model includes endogenous timber price or nonlinear harvesting costs and various possibilities to specify the dependence of environmental values (related e.g. to species persistence) on the forest age-class structure. The nonlinearities in the net benefits from timber production have the consequence that fluctuations in optimal timber harvesting may totally vanish or at least become smaller than in forest scheduling models without ad hoc even flow constraints. If environmental values are specified to depend on the fraction of forest land preserved as old growth, the optimal long run allocation between timber production and old growth is represented by an equilibrium continuum. Thus the optimal long run allocation depends on the initial age-class distribution. The continuum and the dependence of initial age-class distribution vanish when the rate of discount approaches zero. If the environmental values of age-classes increase smoothly with age, the long run equilibrium may simultaneously include multiple rotation periods. The model determines the optimality of producing timber and environmental values separately at different parts of the forest or at the same piece of forest land. Numerical computation suggests that the optimal solution always converges toward some optimal long run stationary age-class distribution.

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.

scholarly journals Road Network Designs in Wood Supply Analysis

1989 ◽  
Vol 65 (6) ◽  
pp. 431-440 ◽  
Author(s):  
H. D. Walker ◽  
W. H. Lougheed
Keyword(s):  
Information System ◽  
Linear Programming ◽  
Geographic Information System ◽  
Road Network ◽  
Management Strategies ◽  
Road Networks ◽  
Geographic Information ◽  
Timber Management ◽  
Wood Supply ◽  
Supply Analysis

A system for designing timber management strategies which considers the location, construction timing, and standards of road networks is presented. The system allows the effects of alternative road networks on economic wood supplies and timber management strategies to be assessed. A geographic information system is used to update stand attributes in response to alternative road networks, prior to analysis using a linear-programming-based forest planning model. A case study illustrating the planning system is briefly reviewed and instructions for obtaining system software are provided. Key Words: timber management planning, geographic information system, spatial analysis, road network design, linear programming, wood supply analysis.

Estimating the time since fire of long-unburnt Eucalyptus salubris (Myrtaceae) stands in the Great Western Woodlands

2013 ◽  
Vol 61 (1) ◽  
pp. 11 ◽  
Author(s):  
Carl R. Gosper ◽  
Suzanne M. Prober ◽  
Colin J. Yates ◽  
Georg Wiehl
Keyword(s):  
Plant Height ◽  
Growth Ring ◽  
Plant Size ◽  
Current Approach ◽  
Significant Advance ◽  
Growth Rings ◽  
Trunk Diameter ◽  
Class Distribution ◽  
Age Class ◽  
Time Since Fire

Establishing the time since fire in infrequently burnt, yet fire-prone, communities is a significant challenge. Until this can be resolved for >50-year timeframes, our capacity to understand important ecological processes, such as the periods required for development of habitat features, will remain limited. We characterised the relationship between observable tree growth rings, plant age and plant size in Eucalyptus salubris F.Muell. in the globally significant Great Western Woodlands in south-western Australia. In the context of recent concerns regarding high woodland fire occurrence, we then used this approach to estimate the age of long-unburnt E. salubris stands, and the age-class distribution of Eucalyptus woodlands across the region. Time since fire was strongly predicted by trunk growth rings and plant size predicted growth rings with reasonable accuracy. The best model estimating growth rings contained parameters for trunk diameter, plant height and plot location, although simple models including either trunk diameter or plant height were nearly as good. Using growth ring–size relationships to date long-unburnt stands represents a significant advance over the current approach based on satellite imagery, which substantially truncates post-fire age. However, there was significant uncertainty over the best model form for estimating the time since fire of stands last burnt over 200 years ago. The management implications of predicted age-class distributions were highly dependent on both the choice of what, if any, transformation was applied to growth rings, and the theoretical age-class distribution to which the actual age-class distribution was compared.

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