Optimal management of Korean pine plantations in multifunctional forestry

Korean pine is one of the most important plantation species in northeast China.Besides timber,it produces edible nuts and plantations sequester carbon dioxide from the atmosphere.This study optimized the management of Korean pine plantations for timber production,seed production,carbon sequestration and for the joint production of multiple benefits.As the first step,models were developed for stand dynamics and seed production.These models were used in a simulation–optimization system to find optimal timing and type of thinning treatments and optimal rotation lengths.It was found that three thinnings during the rotation period were optimal.When the amount or profitability of timber production is maximized,suitable rotation lengths are 65–70 years and wood production is 5.5–6.0 m~3 ha~(-1) a~(-1).The optimal thinning regime is thinning from above.In seed production,optimal rotation lengths are over 100 years.When carbon sequestration in living biomass is maximized,stands should not be clear-cut until trees start to die due to senescence.In the joint production of multiple benefits,the optimal rotation length is 86 years if all benefits(wood,economic profits,seed,carbon sequestration) are equally important.In this management schedule,mean annual wood production is 5.5 m~2 ha~(-1) and mean annual seed yield 141 kg ha~(-1).It was concluded that it is better to produce timber and seeds in the same stands rather than assign stands to either timber production or seed production.     

Multiple-use forest management in consideration of climate change and the interests of stakeholder groups

In this study, the overall utility of forest management alternatives at the forest management unit level is evaluated with regard to multi-purpose and multi-user settings by a multi-criteria analysis (MCA) method. The MCA is based on an additive utility model. The relative importance of partial objectives of forest management (carbon sequestration, ground water recharge, biodiversity, and timber production) is defined in cooperation with stakeholders. The forest growth model 4C (Forest Ecosystems in a Changing Environment) is used to simulate the impact of six forest management strategies and climate on forest functions. Two climate change scenarios represent uncertainties with regard to future climatic conditions. The study is based on actual forest conditions in the Kleinsee management unit in east Germany, which is dominated by Scots pine (Pinus sylvestris L.) and oak (Quercus robur L. and Quercus petraea Liebl.) stands. First, there is an analysis of the impact of climate and forest management on forest functions. Climate change increases carbon sequestration and income from timber production due to increased stand productivity. Secondly, the overall utility of the management strategies is compared under the priority settings of different stakeholder groups. From an ecological perspective, a conservation strategy would be preferable under all climate scenarios, but the business as usual management would also fit the expectations under the current climate due to high biodiversity and carbon sequestration in the forest ecosystem. In contrast, a forest manager in public-owned forests or a private forest owner would prefer a management strategy with an intermediate thinning intensity and a high share of pine stands to enhance income from timber production while maintaining the other forest functions.     

不同森林经营措施对木材产量和碳储量的影响

在应对全球气候变化中, 林业具有特殊地位和重要功能, 以社会、经济和环境可持续发展为目标的森林可持续经营是全球趋势。文中阐述了森林在减缓和适应气候变化中的独特作用; 重点分析了不同营林措施对木材产量和碳储量的影响, 并结合可持续林业的发展趋势评价了不同经营模式框架下木材产量与碳储量之间的平衡; 针对全球气候变化对森林生态系统带来的挑战, 探讨了今后森林经营措施的研究重点和难点, 旨在为制定合理的经营方案提供理论依据。     

Enhancing the value of multiple use plantations: a case study from southeast Queensland, Australia

In the 1990s, an expansion of small-scale (farm) forestry in medium to low rainfall areas was considered to be an important part of increasing the national forest estate but it remains a very minor source of timber, largely confined to the higher rainfall areas. In most areas, returns from timber are much less than for alternative land uses, even with low discount rates. If however, there are additional returns from plantation grazing and carbon sequestration and there are other potential management gains, multiple use plantations may be more attractive. The goal of this study is to estimate the net present values of multiple use spotted gum plantations in a medium rainfall area of southeast Queensland. For the case study, production, carbon sequestration and emissions data were supplemented by formal and informal interviews with landholders, sawmill staff and government extension personnel. Forest inventory, biomass and soil sampling, and stakeholder interviews were used as sources of primary data. The costs and benefits data were converted into monetary terms and discounted to produce net present values. Evaluations in this study identify the optimal rotation age of plantations to be 33–34?years. This is the case if including carbon and stock values, and using either farm- or factory-gate timber prices. The net present value increases significantly however if farmers harvest the trees themselves. In addition, at harvesting age, it was found that carbon and stock had the potential to account for 19.2 and 11.4?% respectively of the total returns from spotted gum plantations. Policy initiatives to support the farm forestry sub-sector should include pricing greenhouse gas emissions and developing and strengthening farmers co-operatives and marketing institutions to enhance farmers’ bargaining power.     

Optimal rotation age for carbon sequestration and biodiversity conservation in Vietnam

Biodiversity loss is a major problem in terms of loss of genetic and ecosystem services and more specifically via impacts on the livelihoods, food security and health of the poor. This study modeled forest management strategies that balance economic gains and biodiversity conservation benefits in planted tropical forests. A forest-level model was developed that maximized the net present value (NPV) from selling timber and carbon sequestration while maintaining a given level of biodiversity (as per the population density of birds). The model was applied to Eucalyptus urophylla planted forests in Yen Bai Province, Vietnam. It was found that the inclusion of biodiversity conservation in the model induces a longer optimal rotation age compared to the period that maximizes the joint value from timber and carbon sequestration (from 8 to 10.9 years). The average NPV when considering timber values plus carbon sequestration was 13 million Vietnamese Dong (VND) ha^− 1 (765 USD ha^− 1), and timber, carbon sequestration and biodiversity values were 11 million VND (676 USD) ha^− 1. Given this differential, governments in such tropical countries may need to consider additional incentives to forest owners if they are to encourage maximizing biodiversity and its associated benefits. The results also have some implications for implementing the climate control measure of “Reducing Emissions from Deforestation and Forest Degradation-plus (REDD +)” in developing countries, i.e., payment for carbon sequestration and biodiversity benefits in planted forests.     

Impact of bark beetle (Ips typographus L.) disturbance on timber production and carbon sequestration in different management strategies under climate change

The likely environmental changes throughout the next century have the potential to strongly alter forest disturbance regimes which may heavily affect forest functions as well as forest management. Forest stands already poorly adapted to current environmental conditions, such as secondary Norway spruce (Picea abies (L.) Karst.) forests outside their natural range, are expected to be particularly prone to such risks. By means of a simulation study, a secondary Norway spruce forest management unit in Austria was studied under conditions of climatic change with regard to effects of bark beetle disturbance on timber production and carbon sequestration over a time period of 100 years. The modified patch model PICUS v1.41, including a submodule of bark beetle-induced tree mortality, was employed to assess four alternative management strategies: (a) Norway spruce age-class forestry, (b) Norway spruce continuous cover forestry, (c) conversion to mixed species stands, and (d) no management. Two sets of simulations were investigated, one without the consideration of biotic disturbances, the other including possible bark beetle damages. Simulations were conducted for a de-trended baseline climate (1961–1990) as well as for two transient climate change scenarios featuring a distinct increase in temperature. The main objectives were to: (i) estimate the effects of bark beetle damage on timber production and carbon (C) sequestration under climate change; (ii) assess the effects of disregarding bark beetle disturbance in the analysis.Results indicated a strong increase in bark beetle damage under climate change scenarios (up to +219% in terms of timber volume losses) compared to the baseline climate scenario. Furthermore, distinct differences were revealed between the studied management strategies, pointing at considerably lower amounts of salvage in the conversion strategy. In terms of C storage, increased biotic disturbances under climate change reduced C storage in the actively managed strategies (up to −41.0 tC ha⁻¹) over the 100-year simulation period, whereas in the unmanaged control variant some scenarios even resulted in increased C sequestration due to a stand density effect.Comparing the simulation series with and without bark beetle disturbances the main findings were: (i) forest C storage was higher in all actively managed strategies under climate change, when biotic disturbances were disregarded (up to +31.6 tC ha⁻¹ over 100 years); and (ii) in the undisturbed, unmanaged variant C sequestration was lower compared to the simulations with bark beetle disturbance (up to −69.9 tC ha⁻¹ over 100 years). The study highlights the importance of including the full range of ecosystem-specific disturbances by isolating the effect of one important agent on timber production and C sequestration.     

The impact of carbon trade on the management of short-rotation forest plantations

We extended the Hartman model to examine the optimal rotation, taking into consideration the economic benefits of wood and the dynamics of three carbon pools (aboveground biomass, dead organic matter, and harvested forest products). Chinese fir (Cunninghamia lanceolata) stands in Southern China were taken for a numerical example to analyze the effects of carbon price on the optimal management of short-rotation plantations. The results show that, with the current price of carbon, introducing the effects of harvesting on different carbon pools into the decision model would increase the optimal rotation age on poor (SI = 10) and medium (SI = 17) sites by one year, while it does not have any impact on the optimal rotation for good sites (SI = 21). Irrespective of site condition, the optimal rotation age is not sensitive to carbon price and interest rate. An increase in interest rate by 1% would reduce the optimal rotation age by one year. In conclusion, forest carbon trade could effectively enhance land owners' income from short-rotation forest plantations. However, it does not lead to any significant increase in forest carbon sink.     

全球人工林环境管理策略研究

全球人工林为木材生产和缓解贫困做出了重要贡献, 在减缓和适应气候变化中起到了非常重要的作用。文中在介绍全球人工林资源的基础上, 分析了人工林对生物多样性、水分循环、养分循环和碳循环的影响和相互作用机制, 提出了人工林环境管理策略, 即建立人工林多功能经营制度、通过森林认证助推人工林可持续经营、充分利用REDD+机制提高人工林固碳效应的政策推动策略, 加强生物多样性保护、降低人工林对水循环负面影响、提高人工林的养分循环、促进人工林生态系统碳循环的生态系统完整性策略, 以及保育高保护价值区域策略和鼓励利益相关者参与人工林规划与管理策略。     

广西桉树人工林延长轮伐期效益分析及可行性策略

延长桉树人工林轮伐期,培育中大径材林,不仅契合国家储备林的培育理念,也能提升桉树经济、社会和生态效益,促进桉树人工林健康可持续发展。文中阐述广西桉树人工林的培育现状,分析了延长桉树人工林轮伐期的经济、生态和社会效益。在此基础上,提出延长轮伐期的可行性策略:1)金融机构强化桉树人工林认知,适当延长涉林贷款期限;2)林业主管部门澄清桉树种植诸多误解,加大延长轮伐期宣传工作;3)相关国企、国有林场率先延长轮伐期,作好桉树科学经营示范。研究可为推动广西桉树人工林延长轮伐期、加大中大径材林培育力度提供参考。     

Typology of Nonindustrial Private Forest Landowners and Forestry Behavior: Implications for Forest Carbon Sequestration in the Southern US

To implement effective climate change mitigation and carbon sequestration activities in the southern US, nonindustrial private forest landowner (NIPF) participation is necessary because of the significant area of forest land under their ownership. For policy implementation to involve this major ownership group in climate change mitigation activities in this region, it is important to understand their forest management motivations and understanding toward carbon sequestration. This study develops a regional typology of NIPF landowners based on reasons for owning forest land in the southern US. The specific goals were to: (1) segment NIPF landowners into smaller homogeneous groups based on reasons for owning forest land; (2) identify landownership characteristics and forest management behavior by ownership groups; and (3) assess their climate change beliefs and understanding of forest carbon sequestration by ownership groups. A principal component-cluster analysis of 735 responses to a mail questionnaire distributed to NIPF landowners in the southern US revealed three groups, which were named amenity, multi-objective, and timber-oriented landowners. The amenity group included 21% of the landowners, while the timber and multi-objective groups included 40% and 39% of the landowners, respectively. These landowner groups varied in terms of owner characteristics, forest species type and management behavior, climate change beliefs and understanding of carbon sequestration. The amenity and multi-objective owners tend to have more positive belief toward climate change than the timber group, but more landowners in each group indicated having poor understanding of forest carbon sequestration. The study fills a knowledge gap in research efforts by developing a regional typology of NIPF landowners and linking it with their forestry resources and management strategies along with their climate change beliefs and understanding of forest carbon sequestration.     

Making Forest Projects Sustainable

Abstract

At present Nepal's demand for forest products exceeds its production. The Sagarnath Forest Development Project with its 10,000 hectares in sissoo and eucalyptus plantations may fulfill part of the country's requirement of firewood and timber products. To ensure the sustainable management of these plantations, a harvesting plan was developed. Linear programming was applied to obtain optimal harvesting levels. Models for both sissoo and eucalyptus were run with and without nondeclining, and even flow constraints separately. Linear Interactive and Discrete Optimizer (LINDO) was used to run these models. The plan with even flow constraints was found to be the best fulfilling the demands of both timber and fuelwood to some extent and making the harvest financially sustainable.     

Experience with patterns of change in soil carbon resulting from forest plantation establishment in eastern Australia

Forest plantations are extensively established in eastern Australia for production of timber products and more recently, potentially for sequestration of carbon. Intensive management of these plantations involves clearing of existing vegetation, often using fire, ripping and/or mounding of the soil and weed control, followed by planting, use of fertilizers, and subsequent tending. The plantations are managed on a 10–30-year rotation and often have high growth rates and accumulation of carbon. However, after establishment, there are reduced inputs of carbon into the soil from prior vegetation or rapidly growing weeds, together with accelerated decomposition of soil organic matter as a result of disturbance, and this leads to a net loss of soil organic carbon. In some systems this loss of soil organic carbon is not balanced by carbon biomass sequestration until 5–10 years after establishment and on some sites, a reduction in soil organic carbon may remain until the end of the rotation. The patterns of accumulation and loss of carbon vary according to location, soil type and plantation management system. The effects of intensive forest establishment on soil organic carbon were evaluated in a number of studies in eastern Australia using time sequence and chronosequence studies and comparisons of plantation soils with those from adjacent undisturbed sites. There was a general pattern of reduced carbon in surface soil immediately after plantation establishment and with time this extended deeper into the soil profile. The actual quantities varied greatly depending on the soil type. The decline was primarily a result of losses of labile carbon and was greater when the previous land use had essentially been native vegetation or highly improved pastures as opposed to regrowth woodland, or native pasture, or degraded land. In the absence of further disturbance, soil organic carbon can accumulate to pre-establishment levels but many short rotation plantations are terminated prior to this being attained. The potential upper level of accumulation of soil carbon can be increased by alteration of the soil nutritional status using fertilizer application.     

The development of reforestation options for dryland farmland in south-western Australia: a review§

Current forest industries in south-western Australia are based on regrowth natural eucalypt forests and Pinus and Eucalyptus spp. plantations, and restricted to areas with >600 mm y^?1 annual rainfall. Dryland farming systems have been developed across 20 million ha in a zone with 300–600 mm y^?1 annual rainfall and a Mediterranean climate. This zone is beset with land degradation problems, such as salinity and wind erosion, and there has been considerable effort in the last three decades to develop reforestation options to stabilise the landscapes. Traditional forestry approaches using pulp wood or sawlog production in this zone have been limited by unfavourable economics driven by modest tree growth rates, large transport costs to processing and export facilities, and high labour costs. Given that salinity results from a disruption of the landscape water balance, reforestation has represented a major component in attempts to tackle the problem. Issues with reforestation include (1) obtaining sufficient scale of activity to impact watershed water balances, (2) obtaining a hydrological response without displacing farm production and rural communities and (3) gaining payment for non-forest benefits. This paper reviews the approaches that have been used to integrate trees into the dryland farming (300–600 mm y^?1 annual rainfall) systems of south-western Australia, and have resulted in at least 113 286 ha of reforestation. These included both traditional (pine and eucalypt sawlogs) and new (sandalwood, biodiversity restoration and carbon mitigation through bioenergy and carbon sequestration) projects. Ongoing investment has centred on carbon sequestration as this represents one of the few profitable options for the management of dryland salinity in this region. Approaches developed in this region to encourage farmland reforestation will be applicable in other dryland regions, particularly with the interest in using the land-sector to meet climate mitigation targets.     

论中国桉树发展的贡献和可持续经营策略

我国最早于1890年引进桉树,刚开始主要作为庭院和四旁绿化树种,20世纪50年代在粤西和桂南大面积试种成功后,逐步推广作为南方主要造林树种.20世纪80年代,我国开始大规模种植桉树,1986年,全国桉树人工林面积达46.6万hm2,进入21世纪后,桉树发展迅猛,2015年达450万hm2,年产木材3000万m3,占全国商品林木材产量的26.9％,为保障我国木材安全做出了重要贡献.桉树产业已形成包括种苗、肥料、制材、制浆造纸、人造板、生物质能源和林副产品等完整的产业链,年总产值达3000亿元.发展桉树人工林具有非常重要的意义:一是缓解我国木材供应紧张局面,减少对外依存度,以保障国家木材安全;二是桉树产业已形成完整的产业链,构成国民经济不可或缺的一部分;三是对提高森林碳汇、发挥气候调节、完善森林的生态和防护功能具有重要意义;四是重要的民生林业,促进林农增收和农村致富.桉树科学发展的关键在于可持续经营.首先必须更新观念:由木材生产为主向木材生产与环境保护并重转化,由封闭式经营向开放式经营转化,由传统的永续利用向森林可持续经营转化.同时,必须推行以下可持续经营的技术措施:(1)立地与树种、品种相匹配;(2)适当的人工混交林措施;(3)进行科学的植被管理;(4)改进造林技术;(5)控制病虫害.     

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.     

Increasing rotation periods during a time of decreasing profitability of forestry — a paradox?

The profitability of forestry in Germany decreased during recent decades because of more or less constant prices for forest products, increasing input prices and limited success in rationalisation. However, the volume of growing stock increased significantly during this period since forest enterprises have chosen longer rotation periods. This is especially true for state owned and community owned forests but also at least partly for private forests. It is normally not an alternative for the owners of forest enterprises in Germany to sell the forests completely, but on a first glance increasing investments in standing timber during a time of decreasing profitability of forestry seems to be inconsistent with economic theory. On the one hand this observation could be explained as the result of non-timber values. However, this paper is focused on another approach, which is an expanded Faustmann model in line with soil rent theory and focused on timber production. Profitable rotations in the future have the effect of shortening the optimal rotation period because an investment in standing timber causes opportunity costs by delaying the establishment of the next generation of the forest. Unprofitable future rotations have the opposite effect, if the landowner is forced to reforest. In case investments in reforestations are not profitable decision-makers have good reasons not to cut the mature stands, in spite of the fact that the internal rates of return of investments in standing timber are low in comparison with investments on the financial market. Empirical data for the period 1954–1998 mostly from guidelines for forest valuation are used together with inflation corrected interest rates to show that optimal rotation length increased over time. Nevertheless we have to recognise that the observed rotation periods are distinctly longer than the calculated optimal rotation lengths. Other factors which may also explain the investments in forestry are discussed later.     

Do the Risk Attitudes of Smallholder Forest Managers Drive Their Forest Carbon Supply: A Risk Experiment in China

It is widely recognized that enhancing forest carbon sequestration (FCS) can be an effective approach for mitigating climate change. Given the uncertainty about carbon pricing and the outcomes of FCS management, household perceptions of FCS management will be heavily dependent upon their risk attitudes, especially in developing countries with rich forest resources. Using a survey of 200 smallholder forest managers in Zhejiang Province in China and a risk experiment, this paper analyzes how the risk attitudes of households drive their FCS supply. We simulated the carbon supply with different risk attitudes of households based on a revised Faustmann model and a sensitivity analysis. A key finding is that compared with a timber benefit only, FCS management will generate more investment value. However, households have little incentive to change their harvest decision-making when the carbon price is low. Among the three identified risk attitude groups, although they have the same optimal rotation age when the carbon value is considered, their carbon supply per hectare is different due to difference in their planting densities. Also, the rotation age with FCS management and the FCS supply per hectare do not change significantly unless there is a substantial change in the carbon price, the management costs and the discount rate for all three risk attitude groups completely.     

干旱和涝渍胁迫对入侵物种喜旱莲子草生长的影响

苦郎树是一种沿海防沙固堤的半红树植物，不仅在红树林群落中具有重要的生态价值，叶片提取物还有一定的医药价值。本研究通过4种光响应模型对苦郎树光响应曲线拟合，计算光合参数进行对比分析，评估最适拟合模型，并研究其光合特性。结果表明：不同模型对苦郎树光响应拟合存在差异，四种模型拟合优度均在0.996以上，苦郎树气孔导度随光合辐射增加而增加，在1800 μmol·m-2·s-1有效光合辐射下达到最大；在500 μmol·m-2·s-1有效光合辐射下水分利用效率最高，胞间二氧化碳维持在一个不变的浓度，与大部分植物的光合特性相似。非直角双曲线模型对苦郎树拟合效果最佳，如何精确拟合光饱和点还需进一步研究，应需要根据实际情况选用最适宜的光响应拟合模型，为海岸生态、防风固堤和园林绿化等工作提供理论依据。     

鄂西南鹅掌楸天然林林分结构特征

以鄂西南鹤峰县鹅掌楸天然林为研究对象,通过对林分空间结构(角尺度、大小比、混交度)和林分非空间结构 (径级结构、树高结构、重要值)的研究与分析,直观地反映其林分结构的特征,查清该区鹅掌楸种群的发展现状,为鹅掌楸 天然林的合理保护与科学经营提供依据 。在鹅掌楸天然林集中生长的代表性地段建立 17个 20mx20m调查样地,进行 每木定位与检尺调查,应用 Excel2019、Winkelmas2.0软件对样地调查数据进行处理与分析 。结果表明:研究区鹅掌楸 天然林中共 73个树种,鹅掌楸为该群落的优势种,生长处优势地位( =0.17),种群整体呈轻微聚集分布(为 0.56),同 时该种群在林分中呈现极强度混交状态( =0.85):种群整体径级、树高分布都呈右偏正态分布,小径级林木株数很少, 种群整体呈现稳定型一衰退型 。FSI均值为 0.82,FSD 均值为 0.30,林分空间结构为接近于理想状态(41.18%)或达 到理想状态(58.82%)。鹅掌楸天然林处于演替后期,林分结构整体上较为理想,可对处于聚集分布的林木进行适当调整, 辅以 一定人为促进更新的措施,促使鹅掌楸林分结构更加合理。     

美国森林及草原碳管理措施及启示

增加陆地生态系统碳汇是应对气候变化的主要策略之一。鉴于森林和草原是陆地生态系统的主体,美国林务部门已将提高其固碳水平作为推行低碳经济和实现可持续发展的一项目标。文中在简述美国森林及草地资源整体现状及其碳储量的基础上,介绍美国林业管理体制并进一步说明其关于森林及草地碳计量及监测数据库,进而说明在上述林业管理体制下美国各部门为应对气候变化指定的一系列关于森林及草地碳汇管理的措施及战略框架,最后总结对我国森林和草原碳管理的启示。