Harvested Timber Volume Research Articles

Financial Revenues from Timber Harvesting in Secondary Cloud Forests: A Case Study from Mexico

Secondary forests, i.e., those arising after the clearance and abandonment of previously forested land, dominate tropical forest landscapes, rapidly sequester carbon, provide essential ecosystem services and are prone to re-clearance. Secondary cloud forests (SCF) play a particularly critical role for biodiversity and hydrological regulation. To promote their persistence, sustainable management is necessary; however, there is limited information regarding SCF potential for sustainable timber production. We estimated the revenue from selective timber harvesting in a pilot study in a 20-year-old SCF in Mexico. We explored the effect of the harvested timber volume, harvesting costs and price of forest products on the Net Present Value (NPV). Small landowners could only extract 17% of the harvestable standing volume due to a high number of small trees, a high (34%) volume of non-timber species, and their limited capacity to process timber. A third of the income derived from fuelwood, and overall financial returns were negative. A positive NPV may result from a 20% harvesting intensity, a 10% reduction in harvesting costs, or a 20% increase in stumpage price. Our results warrant the development of forest policy instruments and economic incentives for small-scale SCF landowners to alleviate poverty and meet national and global restoration and climate mitigation goals.

Prediction of butt rot volume in Norway spruce forest stands using harvester, remotely sensed and environmental data

Butt rot (BR) damage of a tree results from a decay caused by a pathogenic fungus. BR damages associated with Norway spruce (Picea abies [L.] Karst.) account for considerable economic losses in timber production across the northern hemisphere. While information on BR damages is critical for optimal decision-making in forest management, maps of BR damages are typically lacking in forest information systems. Timber volume damaged by BR was predicted at the stand-level in Norway using harvester information of 186,026 stems (clear-cuts), remotely sensed, and environmental data (e.g. climate and terrain characteristics). This study utilized Random Forests models with two sets of predictor variables: (1) predictor variables available after harvest (theoretical case) and (2) predictor variables available prior to harvest (mapping case). Our findings showed that forest attributes characterizing the maturity of forest, such as remote sensing-based height, harvested timber volume and quadratic mean diameter at breast height, were among the most important predictor variables. Remotely sensed predictor variables obtained from airborne laser scanning data and Sentinel-2 imagery were more important than the environmental variables. The theoretical case with a leave-stand-out cross-validation resulted in an RMSE of 11.4 m3 · ha−1 (pseudo-R2: 0.66) whereas the mapping case resulted in a pseudo-R2 of 0.60. When spatially distinct clusters of harvested forest stands were used as units in the cross-validation, the RMSE value and pseudo-R2 associated with the mapping case were 15.6 m3 · ha−1 and 0.37, respectively. The findings associated with the different cross-validation schemes indicated that the knowledge about the BR status of spatially close stands is of high importance for obtaining satisfactory error rates in the mapping of BR damages.

Forest Management of Pinus pinaster Ait. in Unbalanced Forest Structures Arising from Disturbances—A Framework Proposal of Decision Support Systems (DSS)

Forests assume a great socioeconomic and environmental importance, requiring good management decisions to value and care for these natural resources. In Portugal, forest land use accounts for 34.5% of the continental area. The softwood species with the highest representation is maritime pine (Pinus pinaster Ait.). Traditionally, the species is managed as pure and even-aged stands for timber production, with a rotation age of 45 to 50 years. Depending on the initial stand density, the stands are thinned 2 to 4 times during the rotation period. Disturbances associated with forest fires have a negative impact on the age structure of stands over time, as they result in a narrow range of stand ages. This age homogenization over large forest areas increases with the recurrence and size of forest fires, bringing new challenges to forest management, namely the difficulty in ensuring the long-term sustainability of the wood supply. The problem aggravates with the increasing demand pressure on pine wood. This article aims to suggest a framework of DSS for Pinus pinaster that can effectively support the management of forest areas under these circumstances, i.e., narrow age ranges and high demand of harvested timber volume. A communal woodland area in the Northern region of Portugal affected by forest fires was selected as a study case. The Modispinaster model was used as the basis of the DSS, to simulate growth scenarios and interventions along the optional rotation period. Two clear-cut ages were considered: 25 and 40 years. The results obtained were the input data for an integer linear programming (ILP) model to obtain the plan that maximizes the volume of timber harvested in the study area, during the planning horizon. The ILP model has constraints bounding the area of clearings, and sustainability, operational and forestry restrictions. The computational results are a powerful tool for guidance in the decision-making of scheduling and forecasting the execution of interventions determining the set of stands that are exploited according to the different scenarios and the period in which the clear-cut is made throughout the planning horizon. Considering all constraints, the solution allows a balanced extraction of a total of 685 m3·ha−1, over the 50-year horizon, as well as the representation of all age classes at the end of the planning period.

Multi-objective forestry increases the production of ecosystem services

Abstract Boreal forests produce multiple ecosystem services for the society. Their trade-offs determine whether they should be produced simultaneously or whether it is preferable to assign separate areas to different ecosystem services. We use simulation and optimization to analyse the correlations, trade-offs and production levels of several ecosystem services in single- and multi-objective forestry over 100 years in a boreal forest landscape. The case study area covers 3600 ha of boreal forest, consisting of 3365 stands. The ecosystem services and their indicators (in parentheses) considered are carbon sequestration (forestry carbon balance), biodiversity (amount of deadwood and broadleaf volume), economic profitability of forestry (net present value of timber production) and timber supply to forest industry (volume of harvested timber). The treatment alternatives simulated for each of the stands include both even-aged rotation forestry (thinning from above with clear cut) and continuous cover forestry regimes (thinning from above with no clear cut). First, we develop 200 Pareto optimal plans by maximizing multi-attribute utility functions using random weights for the ecosystem service indicators. Second, we compare the average level of ecosystem services in single- and multi-objective forestry. Based on our findings, forestry carbon balance and the amount of deadwood correlate positively with each other, and both of them correlate negatively with harvested timber volume and economic profitability of forestry. Despite this, the simultaneous maximization of multiple objectives increased the overall production levels of several ecosystem services, which suggests that the management of boreal forests should be multi-objective to sustain the simultaneous provision of timber and other ecosystem services.

Reducing rotation age to address increasing disturbances in Central Europe: Potential and limitations

Forest disturbance regimes are intensifying in many parts of the globe. In order to mitigate disturbance impacts a number of management responses have been proposed, yet their effectiveness in addressing changing disturbance regimes remains largely unknown. The strong positive relationship between forest age and the vulnerability to disturbances such as windthrows and bark beetle infestations suggests that a reduced rotation length can be a potent means for mitigating the impacts of natural disturbances. However, disturbance mitigation measures such as shortened rotation lengths (SRL) can also have undesired consequences on ecosystem services and biodiversity, which need to be considered in their application.Here, we used the process-based landscape and disturbance model iLand to investigate the effects of SRL on the vulnerability of a 16,000 ha forest landscape in Central Europe to wind and bark beetle disturbances. We experimentally reduced the current rotation length (between 100 and 115 years) by up to −40% in 10% increments, and studied effects on disturbance dynamics under current and future climate conditions over a 200-year simulation period. Simultaneously, we quantified the collateral effects of SRL on forest carbon stocks and indicators of biodiversity. Shortening the rotation length by 40% decreased disturbances by 14%. This effect was strongly diminished under future climate change, reducing the mitigating effect of shortened rotation to <6%. Collateral effects were severe in the initial decades after implementation: Reducing the rotation length by 40% caused a spike in harvested timber volume (+92%), decreased total forest carbon storage by 6% and reduced the number of large trees on the landscape by 20%. The long-term effects of SRL were less pronounced. At the same time, SRL caused an increase in tree species diversity. Shortening rotation length can reduce the impact of wind and bark beetle disturbances, but the overall efficiency of the measure is limited and decreases under climate change. Given the potential for undesired collateral effects we conclude that a reduction of the rotation length is no panacea for managing increasing disturbances, and should be applied in combination with other management measures reducing risks and fostering resilience.

A value-added forest management policy reduces the impact of fire on timber production in Canadian boreal forests

When fire rates are sufficiently high, fire disturbances can have negative impacts on industrial timber supplies. One can mitigate such problems at the strategic level by accounting for potential fire losses in the timber supply planning process by reducing harvest levels to maintain a buffer stock of timber. With a forest planning model based on a timber volume maximizing policy, reducing the harvest level will lead to a reduction in the harvested timber volume and likely, of revenues. One possible solution is to change the policy to increase the value of the wood that is harvested so as to minimize such reductions with less risk. We have evaluated alternative policies for three commercially-managed forests that have different burn rates in northeastern Canada. When compared with a volume-maximization policy, a revenue-maximization policy that considers sustained production and the sale of sawmilling wood products (lumber, chips and sawdust) increased mean revenues by 130% (36–770%) with >0.90 probability and substantially decreased the area and volume harvested by 27% (11–38%) and 28% (14–36%), respectively. By reducing the harvest volume, the total number of jobs associated with forest operations decreased by 20% (10–27%) but the number of jobs per unit area harvested and volume increased. The policy also increased the harvest age and thereby enhanced the retention of a greater proportion of old-growth stands. Our study indicated that a tighter link between strategic planning and wood product processing helped identify better compromises between harvesting activities and revenues, despite the occurrence of natural disturbances.

Dynamics of ecosystem services in Pinus sylvestris stands under different managements and site quality classes

Timber and biodiversity are considered two antagonistic ecosystem services (ES), largely influenced by silviculture and site ecological conditions. In order to address the trade-offs between these two ES over time, we performed a retrospective study at compartment level in the Pinus sylvestris forests of the Spanish Central Mountain System. Archival data from Management Plans for eight forests with contrasting silvicultural systems (uniform shelterwood system, group shelterwood system, irregular shelterwood system,) and three different site quality classes were analysed. Timber production was assessed through stand volume, harvested timber volume and a stand volume index. Biodiversity was examined through structural diversity (Gini index, Shannon tree size diversity index, Simpson’s reciprocal index and evenness index, all applied to diameter classes) and the abundance of large living trees. For all silvicultural systems investigated, stand volume and harvested timber volume have grown since the beginning of the management plans (beginning of the twentieth century in some forests). The largest yields of timber corresponded to the best quality sites with more intensive silvicultural treatments (uniform and group shelterwood systems). The uniform shelterwood system showed lower figures for structural diversity, though not always significant. The best site qualities maintained notable structural diversity values, even under the most intensive management system. The application of the different management systems over decades has revealed a synergy between timber production and structural diversity, particularly in those systems maintaining more than one age class, although results are conditioned by forest harvesting history. The interaction between historical silvicultural treatment and site quality has been identified as an important source of information to understand forest dynamics and functioning of ES provision.

Quantifying differences between ecosystems with particular reference to selection forests in Durango/Mexico

Continuous cover forestry (CCF), which is characterized by selective tree removals in uneven-aged forests, is often believed to be superior to single-species planted forests in addressing a wide range of requirements. Sustainability, which is an important component of CCF, implies limiting the harvested timber volume and often also the structural disturbance by harvest events. Structure is central to CCF silviculture because it determines the current output of products and services as well as the resilience and future dynamics of the managed ecosystem. Therefore, measuring deviations from a desired target structure is a fundamental requirement of CCF. Quantitative description of the differences between ecosystems is necessary for classification of forest types and silvicultural targets, as well as for harvest event analysis and nature conservation. The objective of this study is to present such an approach in the context of exploring new methods of measuring structural differences between forest communities. We investigate the dependence of such differences on the scale of resolution. The general approach is based on measuring discrepancies between relative frequencies involving tree species, tree sizes and spatial patterns. Data from selectively managed mixed and uneven-aged pine-oak forests in Mexico provide the empirical basis for the study. The approaches presented in this study can be used to quantify structural differences between forests and between a given structure and some theoretical target structure. A quantitative measure of the difference between two ecosystems can provide foresters with information about the consequences of particular silvicultural activities. The approach presented in this study therefore offers great potential for analysing the impact of human disturbance on forest ecosystems.

Estimating the long-run impact of forest fires on the eucalyptus timber supply in Galicia, Spain

Abstract Using annual data, we have estimated the timber harvest of eucalyptus in the region of Galicia (Spain). The explanatory variables considered were price, pulp exports, and salvage timber. The latter variable was used as a proxy for forest fires. The problems related to spurious regression were addressed by applying the bounds testing approach to cointegration, and confidence intervals were constructed using the bootstrap technique. The results indicate that pulp exports have a positive effect on the harvested timber volume. Moreover, we find that salvage timber positively affects the timber supply. This result indicates that there is no substitution between salvage timber and non-damaged timber. It also suggests that the natural expansion of the eucalyptus in Galicia compensates for the destruction caused by forest fires, avoiding supply shortages. On the other hand, and according to the economic law of supply, the timber price shows a positive effect.

Trading off Species Protection and Timber Production in Forests Managed for Multiple Objectives

We address a multiobjective forest-management problem that maximizes harvested timber volume and maximizes the protection of species through the selection of protected habitat reserves. As opposed to reserving parcels of the forest for general habitat purposes, as most published works do, the model we present, and its several variants, concentrate on the preservation status of each one of the species living in the forest under study. Thus, all of the formulations we propose trade off harvested timber volume against the weighted number of preserved species. Each formulation represents a different management policy. Casting the models in a static setting allows us to analyze the effect of several management policies through computational experience with different forest-stucture — species relationships.

Reconstructing 100-150 years of logging history in coastal spruce forest (Picea abies) with special conservation values in central Norway

Coastal spruce forests of central Norway harbour a unique assemblage of epiphytic lichens and are given high priority with respect to conservation of biodiversity. To assess the historical impact of logging during the last 100-150 yrs, 31 remnant stands were studied by means of tree-ring analysis of 2199 trees and the decay stage of 1605 stumps. No stands had been clear-cut, but all had been selectively logged at least twice during the last 150 yrs. Total harvested timber volume ranged from 65 to 409 m3ha-1 (31-124% of present-day standing volume) and the selective logging kept standing volume low (40-200 m3ha-1) during 1890-1930. Present-day stand characteristics were strongly correlated with site productivity and topographic position within the ravine valleys. Low amounts of dead wood at sites with high historical logging activity was the only consistent relationship found after covariance of site productivity, topographic position and deciduous trees were taken into account. The results indicate that old-growth stand characteristics, such as reversed J-shaped age distributions and dead wood in advanced decay classes, can be obtained 100-150 yrs after intensive selective logging.

Temporal and spatial harvesting of irregular systems of parcels

Spatial management issues have assumed a central position in planning for forest ecosystems in the United States on both public and private lands. The arrangement of management activities, especially harvesting activities, can often have adverse impacts on other neighboring areas of the forest. Thus, spatially explicit programming models, which can account for or prevent certain arrangements of activities or land allocations through the use of harvest adjacency constraints, have received considerable attention in the literature. The need for spatial specificity in programming models has led to the development of integer programming or mixed integer programming models. Given that integer programming problems are often viewed as a difficult class of problems to solve, heuristic solution methods have most often been used to solve spatially constrained forest management models. In this paper, a discrete (0–1) integer programming model that maximizes harvested timber volume over a multiperiod time horizon subject to harvest adjacency constraints is developed and tested for irregular, realistic systems of parcels. This model performed well computationally for many example configurations and was solved exactly using the simplex algorithm and limited branching and bounding. Certain spatial configurations with long time horizons did, however, require a nontrivial amount of branching and bounding. The model was tested using both contrived and real spatial data sets.