Efficiently mapping an appropriate thinning schedule for optimum carbon sequestration: An application of multi-segment goal programming

Thinning is an important strategy for carbon sequestration in forest management. Linear programming (LP) and goal programming (GP) can only set fixed parameters for the left hand side constraints, which are incapable of simulating different thinning intensities at thinned stands to map an appropriate thinning schedule for optimum carbon sequestration efficiently. However, multi-segment goal programming (MSGP) with the flexibility to set multi-level parameters can be applied by forest managers to quickly choose an appropriate level from different thinning intensities.The purpose of this study was to combine MSGP with LP to efficiently adopt thinned area and thinning intensity together as decision variables. In a demonstrated case, an appropriate thinning schedule for three age-classes was chosen from 768 combinations of thinning intensity in just one step. Each age-class was allocated well such as practicing medium thinning intensity on young age-class and strong thinning intensity on the old age-class. Totally 1379643.03 tons of carbon sequestration was obtained after two planning horizons, which was 34.75% higher than no thinning. Besides, a stable supply of wood form thinning is made for carbon sequestration in each period and the stocking of each age-class is also improved.     

Evaluation of carbon sequestration and thinning regimes within the optimization framework for forest stand management

Due to the urgent demand for thinning in planted forests and the tend towards sustainable forest resource management, the forest stand age class eligible for the thinning subsidy in Japan was expanded during the period from 2000 to 2004. Currently, further expansion is under consideration in line with meeting the Kyoto Protocol target of carbon sequestration. In this paper, we conducted evaluation analyses of carbon sequestration and subsidy effects within the optimization framework for the forest stand management. The optimal forest stand management model called Dynamic Programming model for Kyushu Stand Simulator (DP-KYSS) was utilized for the analysis of the target sugi (Cryptomeria japonia) forest stand in the Kyushu region, Japan. Our results showed that the thinning subsidy was effective to stimulate thinning activities at the eligible age class for the subsidy, and that 20% of the current or proposed payment was appropriate to give an incentive to forest owners for conducting the same optimal thinning regime. The amount of carbon sequestered in remaining trees at final harvest was not always shown to increase over time. Depending upon the subsidy condition, it could decrease. The average annual amount of carbon sequestered under no subsidy showed its maximum at age 35, while under the other subsidy conditions, it was shortened to age 25. The net present value of cost per unit carbon loss associated with subsidy became the highest for the rotation age of 35 years for all subsidy policies considered here.     

低碳经济与森林碳汇

1全球变暖与低碳经济 1．1两个基本概念 温室效应（Green house effect） 现代工业化社会过多燃烧煤炭、石油和天然气等化石燃料,放出大量的二氧化碳等气体进入大气。二氧化碳气体具有吸热和隔热的功能,它在大气中增多的结果是形成一种无形的“玻璃罩”,使太阳辐射到地球上的热量无法向外层空间发散,其结果是地球表面变热,因此,二氧化碳也被称为温室气体。     

基于碳汇管理的苏北沿海防护林林分结构优化

为了优化沿海防护林林分结构,提高其碳储量,以苏北海堤12年生基干林带刺槐纯林、刺槐杨树混交防护林为对象,分析不同密度配置下的生物量碳储量差异,探讨群落竞争与群落生物量碳储量的关系.结果表明,1 m×1 m刺槐纯林、1 m×2m刺槐纯林、2m×3m刺槐纯林、3m×3m刺槐纯林、杨树高优势度混交林、杨树中优势度混交林、杨树低优势度混交林生物量碳储量分别为:29.38、28.32、26.70、24.43、64.09、59.16、47.02 t/hm2.平均单木竞争指数分别为:7.16、4.82、2.94、1.99、5.52、3.05、2.70.刺槐与杨树混交后单位面积碳汇能力较刺槐纯林大大提高.林分结构优化结果显示,当刺槐平均单木竞争指数为3.47,杨树平均单木竞争指数为1.29时,12年生刺槐杨树混交群落最大生物量碳储量为63.18 t/hm2,此时刺槐胸径达9.4 cm,杨树胸径达22.0 cm.     

Strategy for implementing silvicultural practices in Japanese plantation forests to meet a carbon sequestration goal

The strategy for implementing silvicultural practices in Japanese plantation forests was examined to achieve a carbon uptake of 13.0 Mt-C year^–1, which was capped by the Marrakesh Accords, during the first commitment period, 2008–2012. The plantation forests that implemented silvicultural practices in the period 1990–2012 (FM plantation forests) were identified in compliance with the hypothesized identification rules, and carbon uptake in the forests was estimated using a simple model composed of simulation and optimization components on the assumption that whole plantation forest is classified into only two groups. Furthermore, parametric analysis was conducted to investigate the relationships among three factors: (1) the average annual harvesting volume (including thinning) in plantation forests during the first commitment period, (2) the total area of FM plantation forests in 2012, and (3) the average annual amount of carbon to be sequestered in FM plantation forests during the first commitment period. The results imply that young stands have to be prioritized in implementing silvicultural practices under any harvesting plan and carbon sequestration goal, and that FM plantation forests sequestered 8.0–10.5 (Mt-C year^–1) carbon in inverse proportion to the harvesting volume of 21.0–14.0 million m³ year^–1 (log volume), assuming that most of the plantation forests were incorporated into them.     

Reconciliation of research on forest carbon sequestration and water conservation

Carbon sequestration and water conservation are two of the key ecosystem services that forests provide for societal need to address environmental issues.Optimization of the dual services is the ultimate goal in forest management for mitigating global climate change and safeguarding terrestrial water balance.However,there are some tradeoffs between gain in forest productivity and ecosystem water balance.We conducted literature review based on published articles for learned knowledge on forest carbon fixation and hydrological regulations.Some knowledge gaps and research needs are identified by examining the inter-connections between forest carbon sequestration and water conservation.Past researches have helped gain basic understanding of the mechanisms and controls of forest carbon fixation and hydrological regulations as two separate issues.Tools and approaches are well established for quantifying and monitoring forest carbon and hydrological issues,operating at different spatial and temporal scales.There are knowledge gaps on how to design afforestation schemes facilitating enhanced ecosystem services in forest carbon sequestration and water conservation.For the top-down planning of afforestation in regions where water availability is anticipated to be problematic,the questions of how much and where to plant for given land availability,known environmental implications,and sustained regional development and livelihood need to be addressed.For local management considerations,the questions of what and how to plant prevail.Efforts are needed in joint studies of forest carbon sequestration and water conservation functionalities,specifically in relation to establishment and management of planted forests aiming for delivering regulatory ecosystem services in carbon sequestration,water conservation and other social values.We propose an integrated framework with dual consideration of carbon sequestration and water conservation in forest management for future research pursue.     

Post-fire salvage logging reduces carbon sequestration in Mediterranean coniferous forest

Post-fire salvage logging is a common silvicultural practice around the world, with the potential to alter the regenerative capacity of an ecosystem and thus its role as a source or a sink of carbon. However, there is no information on the effect of burnt wood management on the net ecosystem carbon balance. Here, we examine for the first time the effect of post-fire burnt wood management on the net ecosystem carbon balance by comparing the carbon exchange of two treatments in a burnt Mediterranean coniferous forest treated by salvage logging (SL, felling and removing the logs and masticating the woody debris) and Non-Intervention (NI, all trees left standing) using eddy covariance measurements. Using different partitioning approaches, we analyze the evolution of photosynthesis and respiration processes together with measurements of vegetation cover and soil respiration and humidity to interpret the differences in the measured fluxes and underlying processes. Results show that SL enhanced CO₂ emissions of this burnt pine forest by more than 120 g C m⁻² compared to the NI treatment for the period June-December 2009. Although soil respiration was around 30% higher in NI during growing season, this was more than offset by photosynthesis, as corroborated by increases in vegetation cover and evapotranspiration. Since SL is counterproductive to climate-change and Kyoto protocol objectives of optimal C sequestration by terrestrial ecosystems, less aggressive burnt wood management policies should be considered.     

森林固碳能力估测方法及其研究进展

综述了全球范围内森林生态系统碳平衡估测的2种主要方法,即测定表面通量的微气象学方法(涡旋相关法)和生物量清单统计方法。指出了每种方法的优缺点及综合运用各种方法的重要性。简要介绍了应用上述方法对森林生态系统碳平衡研究的进展情况,并对今后森林生态系统碳平衡研究的发展趋势进行了探讨。     

Long-term nitrogen addition further increased carbon sequestration in a boreal forest

In recent decades, global warming and nitrogen (N) deposition have been increasing obviously, which have led to some strong responses in terrestrial ecosystems, especially the carbon (C) cycle. The boreal forest occupies an important position in the global C cycle with its huge C storage. However, the impact of global change such as N deposition on boreal forest ecosystem C cycle has been not very clear. In order to solve this problem, the field experiment of N addition in a boreal forest has been built in the Greater Khingan Mountains of Northeast China since 2011. Four N addition gradients (0, 25, 50, 75 kg N ha^?1 year^?1) were set up to study the response of above- and belowground C pool to N addition. The results showed that the total forest C sequestration of low-, medium- and high-N treatments was 104.4?±?5.9, 20.2?±?2.7 and 5.3?±?0.4 g C/g N, respectively. Aboveground trees were the largest C pool, followed by soil, roots and floor C pool. Low-N increased the input of C by promoting photosynthesis. Trees of Larix gmelini increased the investment in the belowground root system and increased the belowground C pool. High-N reduced the inter-annual litter biomass and decreased litter C:N that accelerated the decomposition of litter, resulting in a reduction in the floor C pool. Low-N increased total soil respiration, while medium- and high-N inhibited heterotrophic respiration and then increased soil C sequestration. The estimation of forest C pool provides valuable data for improving the C dynamic characteristics of boreal forest ecosystem and is of great significance for us to understand the impact of climate change on the global C cycle.

     

湖南省森林生态系统碳汇经济价值初探

通过利用立木蓄积量及森林面积等基本监测数据,对湖南省森林生态系统的碳汇能力及其经济价值进行了初步估算。结果表明:湖南省森林生态系统总贮碳量为2164.95Mt,年固碳量为12.73Mt,其经济价值分别为6603.10亿元和38.84亿元;湖南省森林生态系统平均碳密度为215.42t·hm-2。预计我省森林生态系统固碳增长潜力415.51Mt碳或1524.93MtCO2,由此产生的经济效益平均每年可达60.35亿元。同时还对湖南14个市州的森林碳汇及其经济价值分别进行了估算,并进一步对通过林业建设实现CO2减排进行了探讨。     

岛东林场森林碳汇能力分析与评价

为了探讨森林碳汇能力、森林碳汇贮存量,该研究利用IPCC(政府间气候变化专门委员会)制定计算方法,通过对岛东林场2009年森林资源二类清查数据进行分析,得出目前岛东林场碳汇蓄积量约31.4万t。数据分析结果表明,当前岛东林场森林经营方式不能满足国家层面上以应对全球气候变化为目的的多功能森林经营要求,也不能满足海南国际旅游岛建设中对森林游憩资源开发需求,在这基础上提出对岛东林场人工林科学合理的近自然化改造模式。     

Comparison of uncertainties in carbon sequestration estimates for a tropical and a temperate forest

We compare uncertainty through sensitivity and uncertainty analyses of the modelling framework CO2FIX V.2. We apply the analyses to a Central European managed Norway spruce stand and a secondary tropical forest in Central America. Based on literature and experience we use three standard groups to express uncertainty in the input parameters: 5%, 10% and 20%. Sensitivity analyses show that parameters exhibiting highest influence on carbon sequestration are carbon content, wood density and current annual increment of stems. Three main conclusions arise from this investigation: (1) parameters that largely determine model output are stem parameters, (2) depending on initial state of the model, perturbation can lead to multiple equilibrium, and (3) the standard deviation of total carbon stock is double in the tropical secondary forest for the wood density, and current annual increment. The standard deviation caused by uncertainty in mortality rate is more than 10-fold in the tropical forest case than in the temperate managed forest. Even in a case with good access to data, the uncertainty remains very high, much higher than what can reasonably be achieved in carbon sequestration through changes in forest management.     

华北落叶松天然林目标树间伐释压与胸径生长关系研究

为探究华北落叶松所受竞争压力与胸径生长之间的关系,利用目标树中心样圆法对关帝山林区华北落叶松天然林间伐迹地进行调查研究。结果表明:受到不同竞争压力的目标树在1998年间伐后胸径生长量差异显著,且随着竞争强度的升高而减少;华北落叶松胸径连年生长量的变化由间伐释压前的下降趋势逐渐转变为缓释压力后的上升趋势;其中,间伐后受不同竞争压力的目标树胸径增长速率仍趋异化,弱度竞争目标树上升速率大于中度竞争目标树,而强度竞争目标树年平均胸径生长量上升最缓且趋势较不明显;竞争压力指数与伐后15 a胸径生长量呈幂函数关系,拐点出现在竞争压力指数为1处并在大于2后趋于平缓;以目标树为核心构建的经营体系能更加具有针对性,通过适度干扰及抚育间伐手段改良一定条件下的林木生长模式,进而精准提升森林质量。     

Carbon sequestration of naturally regenerated Aleppo pine stands in response to early thinning

Sustainable forest management ought to include the production of non-use value, mainly in forests with low value of direct production. Predictions on climate change points out increase in aridity and changes in fire regime (increasing fire risk, recurrence and severity), particularly in the Mediterranean Basin. However, we have to question whether this implies a decrease in forest resilience and productivity. In summer 1994, large forest fires burned a huge surface of Aleppo pine stands in Spain. In areas naturally regenerated, we carried out early thinning and sampled 18 plots. In winter 2008 and 2009, we inventoried all pine trees in sampling plots, recording total height, diameter and canopy cover for scaling-up results to stand-level estimation. In addition, we destructively sampled 54 individual pine trees, selecting various thinning and dating treatments, to measure and estimate biomass and partitioning. The date of thinning influenced allometric relationships, earlier thinning stimulated the productivity of individual pine saplings, increasing the three components of carbon intake. Although, the total net carbon value was lower in almost all thinned plots (at least for short periods after thinning), differences were actually found depending on the cutting age and thinning severity. Control and thinned plots (mainly those thinned earlier and heavier) showed similar amounts of carbon but comprised in a low number of living trees with high productivity. Thus, productivity and carbon storage assessment should be monitored, in the long-term, to check prediction of proposed models for evaluation on early treatments.     

吉林市森林固碳释氧生态效益评价

以吉林市现有森林资源面积和各林龄组面积、蓄积为基础数据,按国家林业行业标准规定的方法,测算森林年净生产力、固碳量与释氧量和货币价值量.结果表明:森林净生产力为1 822 783.3 t·a-1,固碳量为2 835 277.2 t·a-1,释氧量为2 168 711.2 t·a-1;固碳价值为34.02亿元·a-1,释氧...     

塞罕坝人工公益林生态疏伐浅析

该文阐述了塞罕坝人工公益林生态疏伐的目的和原则、调查设计和疏伐作业中的技术要求。     

森工企业森林抚育采伐现状分析及对策建议

本文分析了我省森工企业森林经营中存在的问题,提出了现行森林抚育规程和缴库政策的调整建议。     

Cost-effectiveness analysis of subsidy schemes for industrial timber development and carbon sequestration in Japanese forest plantations

This study uses simulations to investigate the effects of implementing two different Japanese forestry subsidy systems on timber production and carbon stock, and examines the consequences for harvesting strategies. An existing Local Yield Table Construction System (LYCS), a wood conversion algorithm, and a harvesting cost model were used in the simulations to test the applicability of different subsidies to the thinning of stands. Using forest inventory data collected by local government staff, simulation output was used to calculate forestry profits, carbon stocks, subsidies, the amount of labor required, and the cost effectiveness of investing in subsidies. By comparing the output of simulations based on two scenarios, we found that both the clear-cutting area and the amount of harvested timber were larger under Scenario 2, in which the rules governing subsidy allocations are more relaxed, than under Scenario 1, in which the rules are more restrictive. Because the harvested timber under Scenario 1 was mainly produced by clear-cutting, the forestry profits and the subsidy predicted in the early period of the simulation, were larger under Scenario 1 than under Scenario 2. In contrast, the carbon stock was larger under Scenario 2 than under Scenario 1. The simulation model is likely to be useful for improving Plan-Do-Check-Act cyclesimplemented in Japanese forest management systems.     

The combined effects of thinning and prescribed fire on carbon and nutrient budgets in a Jeffrey pine forest

? Both burning and harvesting cause carbon and nutrient removals from forest ecosystems, but few studies have addressed the combination of these effects. For a Pinus jeffreyii forest in the Sierra Nevada Mountains of California, we posed the question: what are the relative impacts of thinning and subsequent burning on carbon and nutrient removals?

? The thinning methods included whole-tree thinning (WT, where all aboveground biomass was removed) cut to length (CTL, where branches and foliage were left on site in a slash mat on top of skid trails) and no harvest (CONT). Total C and nutrient exports with thinning and burning were greater in the WT and CTL than in the CONT treatments. Total C and N removals were approximately equal for the WT and CTL treatments, although harvesting dominated exports in the WT treatment and burning dominated exports in the CTL treatment. Total removals of P, K, Ca, Mg and S were greatest in the WT treatments, where harvesting dominated removals.

? Comparisons of nutrient removals with ecosystem capital and calculations of potential replenishment by atmospheric deposition suggested that N is the nutrient likely to be most depleted by harvesting and burning treatments.

     

Modelling soil carbon sequestration of intensively monitored forest plots in Europe by three different approaches

Information on soil carbon sequestration and its interaction with nitrogen availability is rather limited, since soil processes account for the most significant unknowns in the C and N cycles. In this paper we compare three completely different approaches to calculate carbon sequestration in forest soils. The first approach is the limit-value concept, in which the soil carbon accumulation is estimated by multiplying the annual litter fall with the recalcitrant fraction of the decomposing plant litter, which depends on the nitrogen and calcium content in the litter. The second approach is the N-balance method, where carbon sequestration is calculated from the nitrogen retention in the soil multiplied with the present soil C/N ratio in organic layer and mineral topsoil. The third approach is the dynamic SMART2 model in combination with an empirical approach to assess litter fall inputs. The comparison is done by first validating the methods at three chronosequences with measured C pools, two in Denmark and one in Sweden, and then application on 192 intensive monitoring plots located in the Northern and Western part of Europe. Considering all three chronosequences, the N-balance method was generally most in accordance with the C pool measurements, although the SMART2 model was also quite consistent with the measurements at two chronosequences. The limit-value approach generally overestimated the soil carbon sequestration. At the intensive monitoring plots, the limit-value concept calculated the highest carbon sequestration, ranging from 160 to 978 kg ha⁻¹ year⁻¹, followed by the N-balance method which ranged from 0 to 535 kg ha⁻¹ year⁻¹. With SMART2 we calculated the lowest carbon sequestration from −30 to 254 kg ha⁻¹ year⁻¹. All the three approaches found lower carbon sequestration at a latitude from 60 to 70° compared to latitudes from 40 to 50 and from 50 to 60. Considering the validation of the three approaches, the range in results from both the N-balance method and SMART2 model seems most appropriate.