Continuous Cover Forest Management Research Articles

Resolving the trade-off between production and biodiversity conservation in integrated forest management: comparing tree selection practices of foresters and conservationists

Integrating nature conservation effectively in forests managed for timber production implies reconciling a trade-off between ecological and economic objectives. In continuous cover forest management, this culminates in decisions about tree harvesting (or retention) determining both the prevalence of tree-related microhabitats in the forest and the economic viability of timber management. Applying an innovative mixed methods approach, we compare conservationists and foresters performing a tree selection exercise. We assess the outcomes of their forest management decisions quantitatively and explore their strategies and the underlying reasoning based on qualitative data. Our findings show that particularly the habitat trees differ greatly between the two groups: while conservationists retained almost exclusively large oaks at often high opportunity costs, foresters retained a notable number of smaller-diameter hornbeams. These differences are related to a different perception of opportunity costs of retention by both groups, as well as because they do not agree about how to value current tree-related microhabitats and their projection into the future. Such diverging patterns of reasoning imply incompatible interpretations of what constitutes a habitat tree. Our results indicate that it is important to apply benchmarks for evaluating ecological goals as well as to increase foresters’ and conservationists’ understanding about the motivations and restrictions of the respective counterpart. Our study points out a significant potential for (mutual) learning, and illustrates the complementarity of quantitative and qualitative research methods to examine tree selection behaviour.

Harvester and forwarder productivity and net revenues in patch cutting

ABSTRACT Patch cutting is beneficial for many ecosystem services, but the effects of the management system on operations have not been analyzed. A two-machine system with harvester and forwarder is often used in mechanized cut-to-length operations. The aim of this study was to analyze differences in harvester and forwarder productivity in final felling and patch cutting, and estimate their effects on net revenues per harvested m3. Harvester time consumption was studied using automatic data collection from the machine computer. The data set comprised approximately 18,150 trees harvested during 48 shifts. Analyzes were based on shift level averages. In the observed interval of 0.30–0.60 m3 average tree volume, patch cutting productivity was 20–15% lower compared to final felling. Forwarding was analyzed in three steps. First, a GIS analysis of terrain transport distance found that patch cutting increased forwarding distance by 29%. Secondly, a time study found that loading and unloading times were 16% greater in patch cutting than in final felling. Thirdly, a theoretical analysis found that total forwarder time consumption was 16% higher in patch cuts than in final felling areas. Operational costs in patch cutting were 18% higher than in final felling, thereby reducing net revenues from harvesting operations by 4%. While operational costs were found to be higher in patch cutting than final felling, they are lower than the costs expected for other continuous cover forest management systems. Investigations of later stages of patch cutting are needed before full conclusions regarding the management system can be drawn.

Effects of overstory competition on canopy recruitment patterns of naturally regenerated longleaf pine on two site types

Recent interest in continuous cover forest management of longleaf pine (Pinus palustris Mill.) ecosystems raises questions of long-term sustainability because of uncertainty in rates of canopy recruitment of longleaf pine trees. We destructively sampled 130 naturally regenerated, midstory longleaf pines across an 11 300 ha, second-growth longleaf pine landscape in southwestern Georgia, United States, to reconstruct individual tree height growth patterns. We tested effects of stand density (using a competition index) and site quality (based on two site classifications: mesic and xeric) on height growth and demographics of midstory trees. We also compared height growth of paired midstory and overstory trees to infer stand regeneration and recruitment dynamics. In low-density stands, midstory trees were younger and grew at greater rates than trees within high-density stands. Midstory trees in low-density stands were mostly from a younger regeneration cohort than their paired overstory trees, whereas midstory–overstory pairs in high-density stands were mostly of the same cohort. Our results highlight the importance of releasing midstory longleaf pine trees from local competition for sustained height growth in partial-harvesting management systems. They also demonstrate patterns of long-term persistence in high-density stands, indicating flexibility in the canopy recruitment process of this shade-intolerant tree species.

Optimal Continuous Cover Forest Management with a Lower Bound Constraint on Dead Wood

AbstractWe analyze economically optimal continuous cover forestry with dead wood as a biodiversity indicator. We study mixed-species stands consisting of Norway spruce (Picea abies [L.] Karst.), birch (Betula pendula Roth.), and other broadleaves (e.g., oak [Quercus sp.], maple [Acer sp.]). The analysis is based on an economic description of continuous cover forest management using an empirically estimated size-structured transition matrix model. We use size-specific decomposition rates for dead wood, with the lower limit on total dead wood volume varying between 0 and 40 m3 ha–1. The optimization problem is solved in its general dynamic form using gradient-based interior point methods. Increasing the dead wood volume requirement affects total stand density only slightly, but increases stand heterogeneity as other broadleaves are grown in higher numbers. In addition, increasing the dead wood requirement has only a minor effect on the total felled volume, but harvests shift from timber harvests to biodiversity fellings to maintain the required dead wood volume. In the optimal steady state with a high dead wood requirement, two harvesting cohorts emerge: one for timber harvests and the other for biodiversity fellings. Increasing the dead wood requirement decreases steady-state net timber income by up to 30 percent compared to the unconstrained solution.

Market Adaptive Control Function Optimization in Continuous Cover Forest Management

Economically optimal management of a continuous cover forest is considered here. Initially, there is a large number of trees of different sizes and the forest may contain several species. We want to optimize the harvest decisions over time, using continuous cover forestry, which is denoted by CCF. We maximize our objective function, the expected present value, with consideration of stochastic prices, timber quality variations and dynamically changing spatial competition. The problem is solved using an adaptive control function. The parameters of the control function are optimized via the first order optimum conditions based on a multivariate polynomial approximation of the objective function. The second order maximum conditions are investigated and used to determine relevant parameter ranges. The procedure is described and optimal results are derived for a general function multi-species CCF forest. Concrete examples from Germany, with beech, and from Sweden, with Norwegian spruce, are used to illustrate the methodology and typical numerical results. It is important to make market adapted harvest decisions. If the stochastic price variations are not considered when the harvest decisions are taken, the expected present value is reduced by 23%.

Control function optimization for stochastic continuous cover forest management

Economically optimal management of continuous cover forests can be obtained via a new approach to adaptive control function optimization We maximize our objective function the expected present value with consideration of stochastic prices timber quality variations and dynamically changing spatial competition The parameters of the control function are optimized via the first order optimum conditions based on a multivariate polynomial approximation of the objective function The second order maximum conditions are investigated and used to determine relevant parameter ranges The procedure is described and optimal results are derived for general function multi species CCF forests A numerically specified model with empirical data showed that if the stochastic price variations are not considered when the harvest decisions are taken the expected present value is reduced by

Dynamic growth models for continuous cover multi-species forestry in Iranian Caspian forests

This study concerns some of the relevant topics of the Iranian Caspian forestry planning problem, in particular the first central components in this modelling process, such as forest modelling, forest statistics and growth function estimations. The required data was collected from Iranian Caspian forests. To do so, 201 sample plots were determined and the parameters such as number of trees, tree diameter at breast height and tree height were measured at each sample plot. Three sample plots at different 3 elevations were chosen to measure the tree increment. Data has been used to estimate a modified logistic growth model and a model that describes the growth of the basal area of individual trees as a function of basal area. General function analysis has been applied in combination with regression analysis. The results are interpreted from ecological perspectives. Furthermore, a dynamic multi-species growth model theory is developed and analysed with respect to dynamic behaviour, equilibria, convergence and stability. Logistic growth models have been found applicable for continuous cover forest management optimization. Optimization of management decisions in a changing and not perfectly predictable world should always be based on adaptive optimization.

Economic Assessment of European Beech and Turkey Oak Stands with Close-to-Nature Forest Management

AbstractThe paper analyses the complex economic models of continuous cover forestry based on the ‘Dauerwald’ principles in the early transformation period and in the traditional rotation system both in European beech (Fagus sylvaticaL.) and Turkey oak (Quercus cerrisL.) stands in central Hungarian study sites. The analysis was carried out on both the stand and estate-levels, and the performances were compared as well. We found that continuous cover forest management (CCF) can achieve at least the same economic efficiency as traditional rotation forest management (RF) in both beech and in Turkey oak stands. The regeneration problems occurring in poor quality sites in Turkey oak stands made visible the economic differences between the two management systems investigated.

Light Conditions, Soil Moisture, and Vegetation Cover in Artificial Forest Gaps in Western Hungary

AbstractOne of the greatest challenges of continuous cover forest management is to find a suitable gap size in a given forest stand that will help the regeneration of economically significant tree species, and possibly control competitor species. This paper summarizes the results of a two-year intensive mapping of various bearing artificial gaps at two sites in western Hungary: a sessile-oak-hornbeam and a Turkey oak forest. Light conditions and soil moisture were measured in the gaps as abiotic variables. Hemispherical photography and a Field Scout TDR 300 Soil Moisture Meter were used. Vegetation cover as well as quantity and height of the regeneration were measured as biotic variables. There are significant differences between the middle of a gap and the closed canopy forest stands. The maximum light intensity below the canopy shows a slight northward dislocation. Correlation analysis results showed that a gap’s slight, northward irradiation surplus effected soil moisture, regeneration heights, and total vegetation cover less than a gap’s real shape and size, ergo, its openness did.

Habitat network assessment of forest bioenergy options using the landscape simulator LandSim – A case study of Kronoberg, southern Sweden

Forest biomass is a renewable resource that is increasingly utilised for bioenergy purposes in Sweden, which along with the extraction of industrial wood may conflict with biodiversity conservation. The aim of this paper is to present a method for integrated sustainability assessment of forest biomass extraction, particularly from bioenergy and biodiversity perspectives. The landscape simulator LandSim was developed and linked with models for the assessment of biomass yields and habitat networks representing prioritised biodiversity components. It was applied in a case study in Kronoberg County in southern Sweden. Forest growth and management were simulated for the period 2010–2110, following two land zoning scenarios, one applying even-aged forest management on all forest land except for protected areas (EAF-tot), and one applying continuous cover forest management on parts of the forest land, combined with protected areas and an intensified even-aged management on the other parts (CCF-int). The EAF-tot scenario implied higher yields of biomass feedstock for bioenergy, the CCF-int scenario only giving 66% of that yield, while the CCF-int scenario performed substantially better when it came to the habitat network indicators, if habitat suitability was ensured. Conclusively, the case study confirmed that the modelling framework of the LEcA tool, linking the landscape simulator LandSim with the biomass yield assessment and the habitat network model can be used for integrating main policy concerns when assessing renewable energy options.

Plenterwald, Dauerwald, or clearcut?

Forest landowners are interested in management alternatives which do not involve clearfelling and planting. Also many citizens that do not own forest are against clear-felling do to its harmful effects on amenity values and ecosystem services. Most studies on continuous cover forest management (CCF) deal with regular, steady state uneven-aged forests (Plenterwald), or with the conversion of stands into steady-state structure. However, people who want CCF management seldom want Plenterwald in particular; continuous tree cover would in most cases be sufficient. This type of management corresponds to the German Dauerwald concept. This study compared the profitability of Plenterwald, Dauerwald and clear-cutting schedules in Finnish spruce forests. As expected, Dauerwald was more profitable than cutting schedules that converted the stand into steady-state Plenterwald structure. The difference in net present value decreased with increasing number of conversion cuttings. Clear-cutting and planting was more profitable than optimal CCF only in a mature initial stand when the planted spruces were assumed to grow 20% faster in dbh and height, compared to naturally regenerated spruces. In young, medium-aged and uneven-aged initial stands, CCF was more profitable even when 20% tree breeding benefit was assumed in the plantation that was established in the clear-felling site.

Forest Typification to Characterize the Structure and Composition of Old-growth Evergreen Forests on Chiloe Island, North Patagonia (Chile)

The Evergreen forest type develops along the Valdivian and North-Patagonian phytogeographical regions of the south-central part of Chile (38° S–46° S). These evergreen forests have been scarcely studied south of 43° S, where there is still a large area made up of old-growth forests. Silvicultural proposals for the Evergreen forest type have been based on northern Evergreen forests, so that the characterization of the structure and composition of southern Evergreen forests, e.g., their typification, would aid in the development of appropriate silvicultural proposals for these forests. Based on the tree composition of 46 sampled plots in old-growth forests in an area of >1000 ha in southern Chiloé Island (43° S), we used multivariate analyses to define forest groups and to compare these forests with other evergreen forests throughout the Archipelago of North-Patagonia. We determined that evergreen forests of southern Chiloé correspond to the North-Patagonian temperate rainforests that are characterized by few tree species of different shade tolerance growing on fragile soils. We discuss the convenience of developing continuous cover forest management for these forests, rather than selective cuts or even-aged management that is proposed in the current legislation. This study is a contribution to forest classification for both ecologically- and forestry-oriented purposes.

The bivariate distribution characteristics of spatial structure in natural Korean pine broad‐leaved forest

AbstractAimsSpatial structure is important in describing forest stand structure and change. We present a new method for the quantitative analysis of forest spatial structure based on the relationship of nearest neighbour tree groups.LocationSix hundred m a.s.l., Dongdapo Natural Reserve, Jiaohe, Jilin Province, ChinaMethodsSix plots in three common stand types of natural Korean pine broad‐leaved forest in northeast China were used to validate the method. Each plot measured 100 × 100 m, and all trees with DBH ≥5 cm were marked and located using a Total Station. We calculated bivariate distribution of the structural parameters, uniform angle index, mingling and dominance using Winkelmass and Excel software.ResultsMost trees in the forest were highly mixed by species and randomly distributed. Individuals with high DBH values were typically surrounded by other species; trees within stochastic distribution patterns were usually surrounded by different species; and medium‐sized trees were randomly distributed.ConclusionsThe bivariate distribution of structural parameters can provide more direct and useful information about the heterogeneity of spatial structure than can univariate distributions or other conventional stand descriptors. This could be helpful for selective thinning in continuous cover forest management and in modelling and restoring forests.

Relationships between economic profitability and habitat quality of Siberian jay in uneven-aged Norway spruce forest

In the southern and central parts of Finland, Siberian jay (Perisoreus infaustus) lives in large non-fragmented spruce-dominated forests. Due to the reduction of such forests, Siberian jay has disappeared from the southern parts of Finland. This study analyzed continuous-cover uneven-aged forest management as a way to maintain Siberian jay habitats simultaneously with timber production. Continuous cover management is able to provide the necessary spatial and temporal continuity of forest features important to the viability of Siberian jay populations. The study analyzed the relationship between habitat quality of Siberian jay and profitability of uneven-aged management of Norway spruce (Picea abies) stands. Profitability was evaluated by the net present value of timber sales, calculated with 2% discount rate. The results showed that uneven-aged management that maximizes economic profitability is not seriously in conflict with the maintenance of feeding habitats; there was a temporary decline in habitat quality after the cutting treatment but the decline was not drastic and the habitat recovered during the 15-year cutting cycle. Maintenance of nesting habitat reduced the profitability of timber production by 50–60% and wood production was decreased by 23%. Since nesting habitats cover only some tens of hectares within a home range of 200–500ha, the impact of habitat maintenance on timber production would be rather small in continuous cover forest management.

Optimal Continuous Cover Forest Management in an Uneven-Aged Forest in the North of Iran

Optimal Continuous Cover Forest Management in an Uneven-Aged Forest in the North of Iran

The behaviour of the measure of surround in relation to the diameter and spatial structure of a forest stand

Forestry inventory practices have, in the past, concentrated on obtaining information primarily required for timber management. To assess the ecological impact of exploitation, particularly under continuous cover forest management, diversity measures are required that consider the structural diversity in a forest stand. The measure of surround that was initially developed in Germany may be used to quantify the spatial interspersion of different tree size classes as a measure of spatial diversity. While the measure of surround has been applied to practical problems in the past, little is known about its actual performance in relation to stand compositions. This study investigate the behaviour of the index using a number of simulated age class distributions under various degrees of interspersion to provide a norm against which it may be compared. The measure of surround applied to diameter distributions is closely related to the diameter structure of a stand. When diameter classes are interspersed completely randomly within a stand the relative cumulative frequency of the diameter class provides an estimator of the size specific measure of surround. This provides a baseline from which the index may be interpreted.