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At what carbon price forest cutting should stop

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Journal of Forestry Research 2020年第3期31卷 713-727页

作者： timo pukkala University of Eastern Finland Yliopistokatu 780100 JoensuuFinland

T he carbon sink of boreal forests can be increased by paying forest landowners for carbon sequestration and taxing carbon releases. The aim of the study was to analyze the eff ect of carbon pricing on optimal forest management when forests are managed for maximal discounted benefi ts from timber production and carbon payments. A0.5% random sample of all private forest stands of Finland was used in the analyses(48,842 stands). Calculations were performed for a 100-year time horizon. It was assumed that the carbon balance(diff erence between sequestrated carbon and released carbon) in the forest(trees and soil) or the carbon balance of forestry(trees, soil and wood-based products)was subsidized(positive balance) or taxed(negative balance)by 0, 50, 100 or 150 € t-1, corresponding to CO2 prices of 0,13.6, 27.3 or 40.9 € t-1, respectively. The results showed that paying forest landowners 150 € t-1 of carbon sequestrated in forests would lead to the cessation of all cuttings everywhere in Finland for at least 100 years. In the northern part of the country, a carbon price of 100 € t-1 would be enough to make the no-cutting management economically optimal.A low carbon price had the highest relative impact(value ofincreased sequestration divided by the cost of carbon payments). The benefi t/cost ratio of carbon subsidies was higher in the northern part of boreal zone than in the southern parts. Subsidizing within-forest carbon sequestration by 50 € t-1 would increase the carbon sequestration of Finnish forestry by 50%, ranging from 36%(south Finland) to 116%(north Finland). A payment of 100 € t-1 or more would increase carbon sequestration by 70%, which is nearly the maximum possible increase that can be obtained by carbon subsidies.

关键词： Boreal forest Carbon balance Carbon sequestration Carbon subsidies Optimal forest management

Delineating forest stands from grid data

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Forest Ecosystems 2020年第3期7卷 301-314页

作者： timo pukkala University of Eastern Finland PO Box 11180101 JoensuuFinland

Background: Forest inventories are increasingly based on airborne laser scanning(ALS). In Finland, the results of these inventories are calculated for small grid cells, 16 m by 16 m in size. Use of grid data in forest planning results in the additional requirement of aggregating management prescriptions into large enough continuous treatment units. This can be done before the planning calculations, using various segmentation techniques, or during the planning calculations, using spatial optimization. Forestry practice usually prefers reasonably permanent segments created before planning. These segments are expected to be homogeneous in terms of site properties, growing stock characteristics and treatments. Recent research has developed methods for partitioning grids of ALS inventory results into segments that are homogeneous in terms of site and growing stock characteristics. The current study extended previous methods so that also the similarity of treatments was considered in the segmentation *** study also proposed methods to deal with biases that are likely to appear in the results when grid data are aggregated into large ***: The analyses were conducted for two datasets, one from southern and the other from northern *** automaton(CA) was used to aggregate the grid cells into segments using site characteristics with(1)growing stock attributes interpreted from ALS data,(2) predicted cutting prescriptions and(3) both stand attributes cutting prescriptions. The CA was optimized for each segmentation task. A method based on virtual stands was used to correct systematic errors in variable estimates calculated for ***: The segmentation was rather similar in all cases. The result is not surprising since treatment prescriptions depend on stand attributes. The use of virtual stands decreased biases in growth prediction and in the areas of different fertility ***: Automated stand delineation was not sensitive

关键词： Cellular automata Segmentation Stand demarcation Particle swarm optimization

Measuring the social performance of forest management

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Journal of Forestry Research 2021年第5期32卷 1803-1818页

作者： timo pukkala University of Eastern Finland P.O.Box 11180101 JoensuuFinland

Forests produce several types of benefits to both forest landowners and *** social benefit of private forestry is equal to private benefit plus positive externalities minus negative *** study developed alternative metrics for the evaluation of the social benefit of forest *** management was assessed in terms of five criteria:economic,socio-cultural,environmental and ecological performance and the resilience of the forest *** criterion was described with three numerical *** performance indices were calculated from the indicator values using methods developed for multi-criteria decision *** was concluded that indices based on the multiplicative Cobb-Douglas utility function might be the most recommendable when forestry should produce a balanced combination of different ecosystem *** the indices were used to compare alternative silvicultural systems in terms of their social performance,continuous cover management was ranked better than even-aged *** performance of even-aged management improved when it aimed at increasing the share of mixed stands and broadleaf *** net present value(NPV) with a 1 % discount rate led to better social performance than maximizing NPV with a 4% discount rate.

关键词： Efficiency analysis Acceptability Sustainable forestry Performance index Utility function Multi-criteria analysis Continuous cover forestry Evenaged forestry Resilience

Optimal nitrogen fertilization of boreal conifer forest

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Forest Ecosystems 2017年第2期4卷 123-132页

作者： timo pukkala University of Eastern Finland PO Box 11180101 Joensuu Finland

Background： Forest fertilization offers a means to increase the production of renewable *** is the most common fertilizer in boreal upland *** is plenty of research on the effect of nitrogen fertilization on volume growth, but less research on the optimal timing of fertilization and optimal management of fertilized ***： This study used simulation and optimization to analyze the profitability of fertilization, optimal management of fertilized stands and the effects of fertilization on cash flows and timber *** management of 100 stands representing the most common growing sites of Scots pine and Norway spruce was ***： Fertilization improved profitability in most of the analyzed *** improved most in spruce stands growing on mesic *** stem quality increased the economic benefit of *** timber yields of medium-aged conifer stands can be increased by almost 1 m^3·ha^（-1）·a^（-1）（15%） in sub-xeric pine and mesic spruce sites and about 0.5 m^3·ha^（-1）·a^（-1）（5%） in mesic pine and herb-rich spruce sites when the recommended nitrogen dose（150kg·ha^（-1）） is applied once in 30 ***： Nitrogen fertilization of boreal conifer forest should be used mainly in spruce-dominated stands growing on medium *** gains are the highest in stands where the mean tree diameter is 16–20 cm and stand basal area is 14–20 m^2·ha^（-1）.

关键词： Forest fertilization Optimal management Response model

Effect of species composition on ecosystem services in European boreal forest

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Journal of Forestry Research 2018年第2期29卷 261-272页

作者： timo pukkala University of Eastern Finland P.O.Box 11180101 JoensuuFinland

Forest management in several boreal countries is strongly focused on conifers because they are more productive,the technical quality of their stems is better,and their wood fibers are longer as compared to *** conifers in forest management leads to simple forest structures with low resilience and *** forests are risky in the face of climate change and fluctuating timber *** change increases the vitality of many forest pests and pathogens such as Heterobasidion *** Ips typographus *** attack mainly *** damages are also increasing because of a shorter period of frozen soil to provide a firm anchorage against ***-thrown trees serve as starting points for bark beetle *** the proportion of broadleaved species might alleviate some of these *** study predicts the long-term(150 years) consequences of current conifer-oriented forest management in two forest areas,and compared this management with silvicultural strategies that promote mixed forests and broadleaved *** results show that,in the absence of damages,conifer-oriented forestry would lead to 5–10% higher timber yields and carbon *** somewhat lower carbon sequestration of broadleaved forests was counteracted by their higher albedo(reflectance).Mixed and broadleafforests were better providers of recreational *** diversity was much higher in mixed stand and broadleaf-oriented silviculture at stand and forest *** analysis indicates that conifer-oriented forest management produces rather small and uncertain economic benefits at a high cost in resilience and diversity.

关键词： Albedo Boreal forest Carbon sequestration Diversity Mixed forest Resilience Scenario analysis

Carbon forestry is surprising

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Forest Ecosystems 2018年第2期5卷 140-150页

作者： timo pukkala University of Eastern Finland PO Box 111 80101 Joensuu Finland

Background： Forestry offers possibilities to sequestrate carbon in living biomass, deadwood and forest soil, as we as in products prepared of wood. In addition, the use of wood may reduce carbon emissions from fossil fuels. However, harvesting decreases the carbon stocks of forests and increases emissions from decomposing harvest residues. Methods： This study used simulation and optimization to maximize carbon sequestration in a boreal forest estate consisting of nearly 600 stands. A reference management plan maximized net present value and the other plans maximized the total carbon balance of a 100-, 200- or 300-year planning horizon, taking into account the carbon balances of living forest biomass, dead organic matter, and wood-based products Results： Maximizing carbon balance led to low cutting level with all three planning horizons. Depending on the time span, the carbon balance of these schedules was 2 to 3.5 times higher than in the plan that maximized net present value. It was not optimal to commence cuttings when the carbon pool of living biomass and dead organic matter stopped increasing after 150-200 years. Conclusions： Letting many mature trees to die was a better strategy than harvesting them when the aim was to maximize the long-term carbon balance of boreal Fennoscandian forest. The reason for this conclusion was that large dead trees are better carbon stores than harvested trees. To alter this outcome, a higher proportion of harvested trees should be used for products in which carbon is stored for long time.

关键词： Carbon balance Carbon sequestration Decomposition model Wood product model Boreal forest

Which type of forest management provides most ecosystem services？

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Forest Ecosystems 2016年第3期3卷 190-205页

作者： timo pukkala University of Eastern Finland PO Box 11180101 Joensuu Finland

Background： Forest ecosystems are increasingly seen as multi-functional production systems, which should provide, besides timber and economic benefits, also other ecosystem services related to biological diversity, recreational uses and environmental functions of forests. This study analyzed the performance of even-aged rotation forest management （RFM）, continuous cover forestry （CCF） and any-aged forestry （AAF） in the production of ecosystem services. AAF allows both even-aged and uneven-aged management schedules. The ecosystem services included in the analyses were net present value, volume of harvested timber, cowberry and bilberry yields, scenic value of the forest, carbon balance and suitability of the forest to Siberian jay. Methods： Data envelopment analysis was used to derive numerical efficiency ratios for the three management systems. Efficiency ratio is the sum of weighted outputs （ecosystem services） divided by the sum of weighted inputs. The linear programing model proposed by Charnes, Cooper and Rhodes was used to derive the weights for calculating efficiency scores for the silvicultural systems. Results and conclusions： CCF provided more ecosystem services than RFM, and CCF was more efficient than RFM and AAF in the production of ecosystem services. Multi-objective management provided more ecosystem services （except harvested timber） than single-objective management that maximized economic profitability. The use of low discount rate （resulting in low cutting level and high growing stock volume） led to better supply of most ecosystems services than the use of high discount rate. RFM where NPV was maximized with high discount rate led to particularly poor provision of most ecosystem services. In CCF the provision of ecosystem services was less sensitive to changes in discount rate and management objective than in RFM.

关键词： Data envelopment analysis Production efficiency Multi-objective management Multi-functional forestry Continuous cover forestry Rotation forest management Any-aged forestry

Optimizing continuous cover management of boreal forest when timber prices and tree growth are stochastic

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Forest Ecosystems 2015年第2期2卷 91-103页

作者： timo pukkala University of Eastern Finland

Background： Decisions on forest management are made under risk and uncertainty because the stand development cannot be predicted exactly and future timber prices are unknown. Deterministic calculations may lead to biased advice on optimal forest management. The study optimized continuous cover management of boreal forest in a situation where tree growth, regeneration, and timber prices include uncertainty. Methods： Both anticipatory and adaptive optimization approaches were used. The adaptive approach optimized the reservation price function instead of fixed cutting years. The future prices of different timber assortments were described by cross-correlated auto-regressive models. The high variation around ingrowth model was simulated using a model that describes the cross- and autocorrelations of the regeneration results of different species and years. Tree growth was predicted with individual tree models, the predictions of which were adjusted on the basis of a climate-induced growth trend, which was stochastic. Residuals of the deterministic diameter growth model were also simulated. They consisted of random tree factors and cross- and autocorrelated temporal terms. Results： Of the analyzed factors, timber price caused most uncertainty in the calculation of the net present value of a certain management schedule. Ingrowth and climate trend were less significant sources of risk and uncertainty than tree growth. Stochastic anticipatory optimization led to more diverse post-cutting stand structures than obtained in deterministic optimization. Cutting interval was shorter when risk and uncertainty were included in the analyses. Conclusions： Adaptive optimization and management led to 6%-14% higher net present values than obtained in management that was based on anticipatory optimization. Increasing risk aversion of the forest landowner led to earlier cuttings in a mature stand. The effect of risk attitude on optimization results was small.

关键词： Adaptive optimization Anticipatory optimization Stochastic optimization Risk preferences Risk Uncertainty Reservation price

Optimized cellular automaton for stand delineation

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Journal of Forestry Research 2019年第1期30卷 107-119页

作者： timo pukkala University of Eastern Finland

Forest inventories based on remote sensing often interpret stand characteristics for small raster cells instead of traditional stand compartments. This is the case for instance in the Lidar-based and multi-source forest inventories of Finland where the interpretation units are 16 m 9 16 m grid cells. Using these cells as simulation units in forest planning would lead to very large planning problems. This difficulty could be alleviated by aggregating the grid cells into larger homogeneous segments before planning calculations. This study developed a cellular automaton(CA) for aggregating grid cells into larger calculation units, which in this study were called stands. The criteria used in stand delineation were the shape and size of the stands, and homogeneity of stand attributes within the stand. The stand attributes were: main site type(upland or peatland forest), site fertility, mean tree diameter, mean tree height and stand basal area. In the CA, each cell was joined to one of its adjacent stands for several iterations,until the cells formed a compact layout of homogeneous stands. The CA had several parameters. Due to high number possible parameter combinations, particle swarm optimization was used to find the optimal set of parameter values. Parameter optimization aimed at minimizing within-stand variation and maximizing between-stand variation in stand attributes. When the CA was optimized without any restrictions for its parameters, the resulting stand delineation consisted of small and irregular stands. A clean layout of larger and compact stands was obtained when the CA parameters were optimized with constrained parameter values and so that the layout was penalized as a function of the number of small stands(<0.1 ha). However, there was within-stand variation in fertility class due to small-scale variation in the data. The stands delineated by the CA explained 66–87% of variation in stand basal area, mean tree height and mean diameter, and 41–92% of variatio

关键词： Forest planning Particle swarm optimization Raster data Segmentation Spatial optimization