Silvicultural Investments Research Articles

Modeling Advance Oak Reproduction at Landscape Scale: The Relative Importance of Abiotic and Biotic Factors

Abstract Establishing advance oak reproduction in the understory of mature oak forests before an overstory removal is critical to regenerate mixed-oak forests (Quercus spp.). Many studies have been conducted at the stand scale; however, studies at landscape scale can be particularly useful to guide silvicultural management investments. We developed a model of advance reproduction abundance at landscape scale using inventory, climate, topography, and soils data from ninety-seven mixed-oak forests located in Pennsylvania, USA. A negative binomial model was used to predict the abundance of oak seedlings between 15.2 and 91.4 cm in height and with a root collar diameter of 0.64 to 1.9 cm (established oak seedlings). This model had a Nagelkerke’s pseudo R2 of 58%. Deviance partitioning methods indicate that climate and overstory influence explain similar proportions of total deviance, but climate contributes a higher proportion of nonoverlapping information (22% versus 18%). Overstory basal area of two common oak species were positively associated with seedling abundance, whereas biotic stressors were negatively correlated. Biotic stressors showed considerable overlap with information provided by climate and overstory influences. The results of this study provide a reference to guide silvicultural management at a landscape scale.

Balsam fir stands of northeastern North America are resilient to spruce plantation

Globally, there is an increasing demand for wood products. Because of their productivity, forest plantations will increasingly serve to meet this demand. A cumulative anthropogenic disturbance, such as a plantation scenario, could alter resilience of natural forests, thereby triggering alternative successional pathways towards a state that is predominated by planted species. These alternative ecosystems could represent a threat to biodiversity and ecosystem services that are provided by natural forests. Our objective in this study was to evaluate whether a spruce plantation scenario alters the resilience of natural balsam fir stands in the balsam fir ecological region of Quebec (Canada). We studied successional pathways in 897 spruce plantations covering a 40-year period. The spruce plantation scenario does not seem to have altered resilience of natural balsam fir stands. The main tree species naturally regenerating on balsam fir ecological site types had indeed recovered from the plantation scenario to the detriment of planted spruce species. Balsam fir stands are resilient to the spruce plantation scenario, largely because of the effective regeneration processes of balsam fir and birch species, compared to spruce species. Maintaining functional regeneration processes is a way to maintain resilience and insure that biodiversity and ecosystem services will be gradually restored after anthropogenic disturbances. Regeneration processes should enable a resilient forest to follow natural successional pathways back to its pre-disturbance composition, structure and functions. Hence, planting a tree species in a resilient forest that is not in accordance with the successional pathway of the natural forest could put silvicultural investments at risk. With increasing use of plantations to meet wood demand, some sites inevitably will undergo consecutive cycles of the plantation scenario. Cumulative effects of consecutive plantation scenarios may then be detrimental to the resilience of balsam fir stands. We propose initiatives to mitigate these potential threats.

Policy instruments for developing planted forests: Theory and practices in China, the U.S., Brazil, and France

Abstract Planted forests are seen as a means to meet increasing demand for timber and environmental services and thus to achieve sustainable forest development. In this paper, we use the Faustmann–Hartman silvicultural investment model to demonstrate how policy instruments influence planted forest development and review such a development in China, the U.S., Brazil, and France. We find that planted forests emerge because of scarcity in timber and environmental services and develop in response to economic and policy and institutional instruments, including secure property rights, stumpage price policy, and efficient forestry governance and administration.

Large-Scale Variations in Lumber Value Recovery of Yellow Birch and Sugar Maple in Quebec, Canada.

Silvicultural restoration measures have been implemented in the northern hardwoods forests of southern Quebec, Canada, but their financial applicability is often hampered by the depleted state of the resource. To help identify sites most suited for the production of high quality timber, where the potential return on silvicultural investments should be the highest, this study assessed the impact of stand and site characteristics on timber quality in sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.). For this purpose, lumber value recovery (LVR), an estimate of the summed value of boards contained in a unit volume of round wood, was used as an indicator of timber quality. Predictions of LVR were made for yellow birch and sugar maple trees contained in a network of more than 22000 temporary sample plots across the Province. Next, stand-level variables were selected and models to predict LVR were built using the boosted regression trees method. Finally, the occurrence of spatial clusters was verified by a hotspot analysis. Results showed that in both species LVR was positively correlated with the stand age and structural diversity index, and negatively correlated with the number of merchantable stems. Yellow birch had higher LVR in areas with shallower soils, whereas sugar maple had higher LVR in regions with deeper soils. The hotspot analysis indicated that clusters of high and low LVR exist across the province for both species. Although it remains uncertain to what extent the variability of LVR may result from variations in past management practices or in inherent site quality, we argue that efforts to produce high quality timber should be prioritized in sites where LVR is predicted to be the highest.

Should climate change make us think more about the economics of forest management?

Forest management agencies have budget constraints and continually face difficult questions regarding how much to invest in silviculture and when to harvest forests. Economic thought suggests these decisions should be guided by the pursuit of economic efficiency and tools like net present value (NPV) analysis. In forestry this would make use of the so-called Faustmann model and generally result in shorter rotation ages than the Maximum Sustained Yield (MSY) criterion, which is often used as a policy objective in forest management. The two approaches have caused tension and controversy between foresters and economists. Climate change is adding yet another uncertainty dimension to the forest management challenge. Global climate models suggest massive changes in climate this coming century that will surely affect forests. Here we use climate change as a backdrop to compare the MSY and Faustmann results for black spruce (Picea mariana) and white pine (Pinus strobus) in Ontario. Climate change is adding new risks to silvicultural investments. Our intent is not to “resolve” the management problem but highlight some issues and differences between the two approaches. We suggest that climate change could, or should, cause a resurgence of the debate over pursuit of intertemporal efficiency in forest management.

Forest carbon stocks change and silvicultural investment in China – the case of coniferous forests

This paper reports change in forest carbon stocks and their relationship to investment in forestry fixed assets in silviculture in China employing the forest stock volume conversion method for carbon stocks and annual sinks. The paper establishes carbon stock estimates, and then analyses recent carbon stock trends of main coniferous species based on the latest inventory of China’s forest resources. The inventory data cover the seven dominant coniferous species from 1989 to 2008. The paper shows that investment in forestry fixed assets in silviculture and forest carbon stocks of some species have a significant effect with a lag of 3–7 years; and there is discussion of various problems regarding forest carbon stocks and sinks.

Interactive effects of simultaneously applied thinning, pruning and fertiliser application treatments on growth, biomass production and crown architecture in a young Eucalyptus nitens plantation

Thinning, pruning and fertiliser are often applied simultaneously but interactions between these treatments are rarely examined. This may inhibit managers from making the most of these silvicultural investments. This study examined whether thinning, pruning and nitrogen fertiliser application at age 3.2years, interact with each other to influence the growth and crown architecture of Eucalyptus nitens trees to age 8.1years. Two levels of each treatment were applied in a factorial design replicated three times in a plantation near Carrajung, Victoria, Australia. Treatments included: unthinned, or thinned from ca. 900 to 300treesha−1; unpruned, or 50% of the live crown length pruned of the largest 300potential sawlog crop treesha−1; and nil, or 300kgha−1 N fertiliser. All treatments interacted, such that by age 6years the relative pruning effects were greater in thinned and fertiliser application treatments. The treatment interactions observed were consistent with ecological theory relating to the influence of resource availability on defoliation. Increases in crown size after thinning and fertiliser application were associated with increases in branch sizes and longevities. Leaf area density (m2 leaf area per m3 volume of a given crown section) increased with height in the crown and treatments had only a minor influence on this trend. Thinning and fertiliser also increased the ratio of leaf to wood mass, while pruning had the opposite effect, and all were independent of differences in tree size. Due to these treatment effects on biomass partitioning, treatment interactions in terms of stand above-ground biomass of the largest 200potential sawlog crop treesha−1 were not significant. Despite significant variability across treatments, stand level biomass growth across all treatments was closely related to leaf area index, with deviations occurring for about one year after thinning and pruning due to increases in the growth efficiency expressed as volume growth per unit leaf area. This study illustrates the crown plasticity with which foresters can work to achieve specific management goals relating to growth rates and log quality. It also shows that responses to thinning, pruning and fertiliser application may not be independent of each other, with both thinning and fertiliser application increasing the effects of pruning.

Standardized Occupancy Maps for Selected Wildlife in Central British Columbia

Habitat occupancy models were developed for 10 vertebrate species that we expected would demonstrate a gradient of response to extensive losses of lodgepole pine (Pinus contorta) and other linked habitat alterations resulting from the mountain pine beetle (Dendroctonus ponderosae) infestation and gradual changes in regional climate. A process-based Bayesian Belief Network approach was used to develop interlinked species models focussed at two levels of land management: (1) the forest stand level including changes in forest overstorey and understorey species composition, within-stand structures, canopy closure, and amounts of standing and fallen deadwood; and (2) the landscape level including changes in size of habitat patches, seral stage composition, and proximity to roads. We also considered indirect influences of broad ecological changes including alteration of some key species interactions (e.g., displacementfrom preferred habitat and [or] increased risk of mortality). We used results of this modelling to provide preliminary predictions of species occupancy in a large area of British Columbia designated by the Nature Conservancy of Canada as their Central Interior ecoregion. This work demonstrates an approach to building species occupancy models capable of representing the effects of large-scale disturbances on habitat supply at both the stand and landscape levels of habitat management. The resultant occupancy maps are also useful when integrated into various strategic planning initiatives including species recovery, silvicultural investments, and long-term conservation planning.

The costs and profitability of using granulated wood ash as a forest fertilizer in drained peatland forests

Abstract Increasing and more intensive energy wood harvesting from forests necessitate efforts to ensure that adequate amounts of nutrients are recycled back onto the site. Recycling nutrients back to the forest in the form of wood ash is a natural means to correct the nutrient imbalance and acidity of forest soils that can occur from intensive management, as well as to solve the problem of disposing of wood combustion wastes. Methods of refining and spreading have been developed to improve the logistics and cost competitiveness of recycling wood ash back into the forest as fertilizer. In this study, the costs of spreading granulated wood ash in the forest were calculated under Finnish conditions. The profitability of recycling wood ash to drained peatland forests as a fertilizer was also analyzed, from the forest owner’s point of view. For this analysis, wood ash was compared with chemical fertilizer in terms of effect, cost and profitability. Wood ash fertilization using the ground-based forwarder system was two to three times cheaper than using the aerial helicopter-loader system. From the forest owner’s point of view, the fertilization of peatland forest with wood ash proved to be a very profitable silvicultural investment (IRR 3–12 percent). To improve the economics of wood ash recycling to forests, ground-based spreading of granulated ash should be emphasized. Furthermore, in order to create large enough operational units for the cost-efficient spreading of ash, there needs to be comprehensive planning of spreading sites.

Carbon rentals and silvicultural subsidies for private forests as climate policy instruments

A forest model with an endogenous growth description and age-class structure is applied to study the impacts of potential climate policy instruments on the carbon services of privately owned and managed forests. The model describes the behaviour of a utility-maximizing private nonindustrial landowner who optimizes consumption flow, harvest timing, and the intertemporal allocation of silvicultural investments. Two policy options, one in which the landowner is granted periodic carbon rental payments and one in which the government subsidizes the costs of silvicultural investments, are studied. The rules for when the policy measures have both intended and unintended effects are derived. Using numerical examples, we demonstrate that the effectiveness of both policy options depends on the age-class structure of forests when future carbon benefits are discounted. In that case, carbon rental payments are more effective for forests with old age-class structures, while silvicultural subsidies are more effective for forests with young age-class structures.

Forest and economic impacts of alternative management strategies on Crown land in New Brunswick

This study evaluated the long-run economic impacts of four alternative forest management strategies on New Brunswick’s Crown land forests: two volume-based strategies focused on business as usual (BAU) and intensive (INT) timber volume production and two value-based strategies focused on forest manufacturing sector contribution to gross domestic product (GDP) and government surplus (GOV). These were defined within an extended wood supply model that incorporated both economic indicators (logging sector profit, government surplus, forest manufacturing sector shipments, and forest manufacturing sector GDP) and timber supply indicators (harvest levels, operable growing stock, and products). Results showed that a number of indicator trade-offs emerge under each strategy. For instance, the GOV strategy produced the highest present value government surplus value (at $1.2 billion, exceeding INT, BAU, and GDP strategies by $352 million, $302 million, and $169 million, respectively) and logging sector profit (at $2.4 billion, exceeding BAU, INT, and GDP strategies by $4 million, $11 million, and $8 million, respectively) over an 80 year planning horizon. However, this strategy also produced the lowest forest manufacturing sector contribution to GDP (at $12.8 billion, below the GDP, INT, and BAU strategies by $4.3 billion, $1.6 billion, and $1.4 billion, respectively) and the lowest annual softwood volume harvest, operable growing stock, and silvicultural investment of all strategies. Thus, although these findings emphasize that value-based strategies can produce some favourable economic outcomes, a number of trade-offs emerge that need to be further investigated before such strategies can be supported.

Potential impacts of carbon taxes on carbon flux in western Oregon private forests

This study considers a carbon tax system as a policy tool for encouraging carbon sequestration through modification of management in existing forests and examines its welfare impacts and costs of the carbon sequestered. The simulated carbon tax leads to reduced harvest and increased carbon stock in the standing trees and understory biomass. Changes in the level of silvicultural investments vary by owner, depending on the nature of their initial inventory. In general investment under the tax is concentrated in regimes that establish faster growing plantations. Average rotation age increases, varying in extent across ownerships and site qualities. The carbon tax reduces both consumer and producer surpluses in regional timber markets. Producers are compensated by the carbon subsidies, except at low carbon tax levels. Not all rates of carbon tax will attract interest from private owners if participation is voluntary. Estimates of the marginal cost of sequestering carbon in western Oregon private forests are shown to be within the range of costs for projects considering afforestation alone in some eastern regions of the United States.

Land tenure, market, and the establishment of forest plantations in Ghana

This paper presents an empirical study on the relationship among land tenure, market incentives, and forest plantation establishment in Ghana based on a two stage selectivity model. Our results show that the total amount of land owned and/or cultivated by farmers, amount of land owned by farmers outright, and use of government extension services by the farmers have a significant positive influence on plantation establishment. In addition, lands owned outright by farmers and the prices of plantation products have a significant positive effect on silvicultural investment in plantation. These results demonstrate the potential for land market reforms and market incentives in enhancing forest plantation establishment.

Market prospects for Acadian forest products in the context of future energy availability

As the peak of non-renewable energy production passes during the next forest rotation it is expected that markets, which have recently been driven by pulp and paper and dimension lumber exports, will shrink due to a general decrease in the affluence of the customer base and attrition in its numbers. An expected increase in demand for forest biomass fuels should begin to influence present silvicultural investment decisions now. Emphasis on the production of softwood fibre for commodity markets should yield to emphasis on the restoration of diverse Acadian temperate forest species assemblages. Means of encouraging a shift in harvesting practices in advance of changes in market demand are discussed. Key words: energy scarcity, market alteration, silvicultural investments

Evaluation of growth response, stand value and financial return for pre-commercially thinned jack pine stands in Northwestern Ontario

This study examined the impact of pre-commercial thinning (PCT) on tree growth, product recovery, stand value and financial return in jack pine stands in Northwestern Ontario. Ten sites composed of both control and PCT stands representing various stand densities (2000–6000 trees/ha) and stand ages (26–36 years old) were selected for this study. Three thousand and eighty-two trees were measured for DBH and total height, and were reconstructed in 3-D using a taper equation for jack pine. The reconstructed virtual trees were then “sawn” using the software package Optitek to obtain optimal lumber value recovery, which was then used to determine total product value per tree and financial return. The quadratic mean DBHs of trees from the PCT stands were significantly larger than those from the control stands for all 10 sites. Six of ten PCT stands had significantly taller trees than did the controls of the same sites. With increasing stand density, tree DBH decreased in the control stands while no consistent pattern could be recognized for the DBH of the PCT stands. The increment in average DBH due to PCT increased with increasing thinning intensity. PCT reduced total tree volume per hectare, benefited merchantable stem volume per hectare, and improved the total lumber volume and value recovery per hectare. On average, the PCT stands produced approximately $2760 and $1770/ha (or 19.6 and 16.1%) more product value per hectare for the dimension mill and stud mill, respectively. PCT also significantly reduced logging and lumber conversion costs. Higher total product values and lower total costs resulted in higher benefit/cost (B/C) ratios in the PCT stands than did in the control stands. The increased financial return due to PCT is associated with the magnitude of difference in quadratic mean DBH resulting from PCT. The B/C ratio difference between control and PCT stands increased with increasing thinning intensity. Overall, this study indicates that PCT appears to be an economically viable silvicultural investment for jack pine stands in Northwestern Ontario.

Economic Returns Model for Silvicultural Investments in Young Hardwood Stands

Abstract Despite covering the majority of forestland in the southern United States, hardwoods continue to be grown primarily in natural, extensively managed stands. One reason has been that hardwood growth increases resulting from active management have been small in comparison with unmanaged stands. Recent studies indicate, however, that the productivity responses of very young (ages 1–15 years) natural even-aged hardwood stands to silvicultural treatments such as fertilization, herbicide release, or stocking control can yield large productivity increases, demonstrating the potential for faster timber growth of higher quality in shorter rotations. In determining the extent to which these productivity increases may justify investment in various silvicultural treatments, we have developed hardwood management scenarios representing productivity increases of up to 33%. Timber revenues have been estimated and rates of return compared across various management intensities. Results indicate that the assumed productivity increases would readily pay for treatments such as fertilization, herbaceous release, and stocking control while yielding rates of returns equal to or greater than those generated by untreated stands. South. J. Appl. For. 28(4):179–184.

Faustmann in an uncertain policy environment

This paper deals with optimal forest rotation age and silvicultural investment under policy or regulatory uncertainty to which wasteful deforestation and lack of reforestation and afforestation efforts in the developing countries and loss of old growth forests and biodiversity in the developed countries are attributed. Incorporating a stochastic uncertainty factor into the familiar deterministic Faustmann formula yields a result that confirms with casual observations — when policy uncertainty is present, forest stands are harvested earlier and silvicultural investment is smaller than otherwise. The policy implication is that, in order to promote forest resource conservation, encourage afforestation and reforestation, and attack other forest-related problems effectively, the pervasive nature of policy uncertainty needs to be curbed.

An economic assessment of using the allowable cut effect for enhanced forest management policies: an Alberta case study

In Canada, forest policymakers are considering the allowable cut effect (ACE) as a potential mechanism to provide tenure holders with incentives to practice enhanced forest management. To investigate the incentives created by the ACE, this paper estimates returns to ACE investments for a trembling aspen (Populus tremuloides Michx.) - white spruce (Picea glauca (Moench) Voss) mixedwood forest in Alberta. A timber supply model is used to optimize harvesting schedules to maximize net present values over a 200-year planning horizon. A number of scenarios are investigated with variations in intensity of silvicultural investments, beginning age-class distributions, levels of flexibility around the allowable annual cut (AAC), calculations of AACs based on coniferous and mixedwood volumes, and green-up constraints. In our simulations, it was difficult to find positive returns to the ACE. Positive returns only occurred when operating under harvesting constraints with a mature starting forest and AAC calculations that ignored deciduous volumes. In those limited cases where there were positive returns to the ACE, returns were higher for extensive, rather than intensive investments. Combining these results with other potential impediments to the ACE, previously identified in the literature, the probability of tenure holders having incentives to undertake ACE investments is low.

An economic assessment of using the allowable cut effect for enhanced forest management policies: an Alberta case study

In Canada, forest policymakers are considering the allowable cut effect (ACE) as a potential mechanism to provide tenure holders with incentives to practice enhanced forest management. To investigate the incentives created by the ACE, this paper estimates returns to ACE investments for a trembling aspen (Populus tremuloides Michx.) - white spruce (Picea glauca (Moench) Voss) mixedwood forest in Alberta. A timber supply model is used to optimize harvesting schedules to maximize net present values over a 200-year planning horizon. A number of scenarios are investigated with variations in intensity of silvicultural investments, beginning age-class distributions, levels of flexibility around the allowable annual cut (AAC), calculations of AACs based on coniferous and mixedwood volumes, and green-up constraints. In our simulations, it was difficult to find positive returns to the ACE. Positive returns only occurred when operating under harvesting constraints with a mature starting forest and AAC calculations t...

AVVIRK-2000: A Large-scale Forestry Scenario Model for Long-term Investment, Income and Harvest Analyses

A computer model for long-term forest management analysis is described. It is a deterministic simulation model, and provides means for a range of possible analyses, different management strategies, i.e. harvest and silvicultural investment strategies, along with the corresponding cash flow, development of forest state and profitability. The description is accompanied by a case study, employing some features of the model, based on data covering Hedmark county in Norway, with the objective of mapping consequences for potential harvest level and net present value related to varying treatments for different border zone types.