森林收获调整的灰色线性规划模型

森林收获调查模型应该是一个动态模型。本文应用灰色系统理论,提出了森林收获调整的灰色线性规划模型,举例说明了模型的建立,求解过程,并就模型的结构,适应性作了讨论。     

CAS理论对森林收获调整的启示

基于CAS理论从7个基本点出发分析森林生态系统的复杂适应性,从中得到启示并对森林收获调整进行展望。应用多目标决策方法,分别经营单位进行森林收获调整的思想体现了森林收获调整方法的多样性特征,这是森林生态系统的复杂适应性决定的。运用遗传算法求解模型,利用SWARM软件进行仿真研究对做好森林收获调整工作有重大意义。     

应用林龄空间理论和线性规划方法建立森林收获调整模型

应用林龄空间理论和线性规划方法,以福建沙县现实森林为对象,分别按优势树种杉木、松木和杂阔组织三个经营单位(下称作业级)建立森林收获调整模型。     

森林生长收获模型发展中存在的问题及相关建议

森林生长收获模型能比较准确地预估森林的生长速度并反映林木各个器官(枝、叶、根、干等)之间生物量的关系, 是掌握林分结构及生长动态变化规律的有效途径, 在林分生长量和收获量预估、生物量与碳储量计算、森林生态系统内部结构分析、森林多功能监测与评价等方面均具有广泛应用。文中简述森林生长收获模型的发展现状, 分析其发展中存在的主要问题, 并针对这些问题提出了发展森林生长收获模型的有关建议, 以期为相关研究提供借鉴与参考。     

线性规划在森林收获调整中的应用

本文以南平地区建瓯水西林场的现实森林为研究对象,重点以杉木中径材作为主要材料,根据该场对树种结构的要求和适地适树原则,运用线性规划方法建立该经营类型的森林收获调整模型,并分析了调整期内各分期的面积变化情况。     

基于遥感信息的森林生物量、碳储量估测技术研究

利用遥感数据结合地面调查建立模型是定量评价森林生物量、碳储量的重要手段、以遥感数据及GIS易于获取的地学因子为主要信息源,应用逐步回归方法选取与森林生物量相关的7个遥感及地学因子为自变量,利用地面样地每木胸径调查数据结合生物量相对生长式获取样地生物量作为因变量,建立多元回归模型用于估测森林生物量．森林碳储量通过森林生物量结合碳转换系数获取、经方差分析检验,模型达到极显著相关水平．研究结果袁明,这一方法是获取较大尺度森林生物量、碳储量及其动态变化监测的有效方法．     

关于建立石首市森林资源收获调整模型的探讨

本文结合编制石首市森林经营方案的实践,为探讨建立县级森林资源收获调整模型方法的科学性和实用性,运用林龄空间转移理论和运筹学的原理和技术,对该市意杨、杉木、马尾松、水杉(池杉)和其它阔叶树(枫杨、香椿等)等用材林建立了经营级收获调整模型。     

马尾松生长和收获模型的研究

利用马尾松人工林标准地材料，选择林分年龄、地位指数和断面积为辅助变量，采用逐步回归技术建立林分材积收获模型。从生长和收获的一致性出发，由材积收获方程对年龄取微分导出材积生长模型，并建立断面积生长模型。从而为预估森林生长量和收获量提供科学依据。     

森林动态计算机模拟模型研究

综述了国内外目前广泛应用的6种森林动态计算机模型:森林收获模型、生态林窗模型、生态分室模型、过程模型、植被分布模型和混合模型。在介绍每种森林动态模型时, 分别选取几个典型的计算机模拟模型, 来评述每种森林动态模型的优缺点, 并在此基础上探讨今后森林动态模型的发展趋势。     

分层序列法在林分收获调整中的应用(英文)

分层序列法是一种多目标决策方法，本文将其用于山西省管涔山森林经营局千秋沟林场落叶松经营类型的森林收获调整．结果表明：使用该法，决策者可将对不同目标的要求落实到合理的水平上；该法求解简单，是进行森林收获调整有力的数学工具     

The impact of the introduction of sustainable forest management objectives on the optimisation of PC-based forest-level harvest schedules

Previous to the introduction of sustainable forest management principles, PC-based modelling techniques had been developed for the financial optimisation of forest-level harvest scheduling under Irish conditions. These financial models were further developed to produce a Mixed Integer Programming-Sustainable Forest Management (MIP-SFM) model, in which principles of sustainable forest management were incorporated into the harvest scheduling process. The effectiveness and practicality of the harvest schedules produced by the financial model and the MIP-SFM model were compared to the harvest schedules produced by the process currently employed by Coillte (The Irish Forestry Board). Evaluation of the models was carried out in Clonbrock forest (294.8 ha), a typical Irish plantation forest, owned and managed by Coillte. The MIP-SFM model produced effective and practical harvest schedules that enhanced the sustainability of Clonbrock forest by incorporating environmental, ecological and social management parameters. The application of the developed MIP-SFM model resulted in an increase in NPV of 5.7% compared to the NPV produced by the scheduling process currently employed by Coillte. The application of the financial model had resulted in a comparable increase in NPV of 14.2%. The smaller increase in NPV produced by the MIP-SFM model provided an indication of the cost associated with the introduction of environmental, ecological and social SFM principles in the management of Clonbrock forest.     

Potential use of a spatially constrained harvest scheduling model for biodiversity concerns: Exclusion periods to create heterogeneity in forest structure

The objective of this paper is to investigate potential use of a spatially constrained harvest scheduling model for biodiversity concerns. Change in the degree of biodiversity is represented only by spatial characteristics of harvesting patterns of forest stands with different exclusion periods applied to adjacent forest stands. A spatially constrained harvest scheduling model called SSMART (Scheduling System of Management Alternatives foR Timber-harvest) is used for the analysis. It is one of the heuristics to solve a spatially constrained harvest scheduling problem by using the partitioning heuristic. The algorithm incorporated into SSMART is designed to seek a solution for a multicriteria problem with present net value maximum, meeting spatial feasibility and minimizing period-to-period harvest flow fluctuation, approximating even-flow constraints within the 0–1 integer programming framework. Our experimental analysis shows that the longer exclusion period, the less the harvest flow level and the total present net value are derived and the more heterogeneous the forest structure becomes in terms of the forest stand age distribution. It is also shown that the three exclusion period results in a stable forest stand age distribution over the time horizon for our experimental forest. This research supported by the Grants-in-Aid for Scientific Research (No. 09041071) from the Ministry of Education, Science, Sports, and Culture of Japan.     

林木生长和收获预估模型的研究动态

从近年来林木生长和收获模型的研究中,可以看出有如下的发展动向:（1）由林分水平模型向径级水平模型、单木水平模型转变;（2）从林木的自然生长模型发展来考虑人为育林措施的经营模型;（3）由简单的人工同龄纯林模型深化到复杂的天然异龄混交林;（4）关注点从测树学调查因子的经验性模型转向生理生态的机理性模型。还就今后我国的林木生长模型研究提出了几点建议。     

Ideal Point Method Applied in Forest Harvest Regulation

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林木生物量模型研究概述

林木生物量模型回归估计法是林分生物量测定的常用方法之一,林木生物量模型的研究对森林生物量的研究及其估测有重要价值。随着森林碳储量的研究,森林生物量再次被重视,其精度要求也随之提高。介绍了林木生物量模型历史和现状,对生物量模型类型、参数估计方法、模型评介指标,模型中的异方差、不兼容等问题及其解决方法作了简介,概括了当前国内的一些新进展,并对未来的发展趋势作了预测。     

德国北部挪威云杉林可持续经营中期计划的实例分析

可持续森林经营理论为中期林业计划和收获调整提供了丰富的模型选择,其不同的方法可应用于各种特定的场合和不同经营类型.本文简要回顾了传统的森林计划方法,一种称为"多林分发展"的概念可以用于任意的经营系统,这个概念把森林看作由一系列林分组成,在每一个林分中可以预先制定多种经营措施的选项,每种选项都可以通过木材或其它产品以及消耗的资源计算出一个目标值.这种简单的概念可以应用到大量的不同森林经营场合,它为森林经营者制定切实可行的森林措施和评价森林经营计划提供方法.在本研究中,以德国北部一片包括21个小班的挪威云杉林班的一个中期计划为例,说明"多林分发展"这一经营系统在实际生产中的应用.每个小班具有不同的初始状态,每个小班预设了若干经营选项,根据小班的初始状态、生长模型为各种选项计算各时期的木材产出.在林班的水平上,经营目标方程包括两个组成部分:净现值和均衡木材收获值.用模拟退火的方法来优化总体目标方程值.优化的总体解决方案在为每个小班选定合适的经营选项的同时,在全林的水平上获得最优的经济和均衡产出组合.     

Optimal harvest scheduling in Eucalyptus plantations: A case study in Galicia (Spain)

This paper focuses on strategic management planning of Eucalyptus globulus Labill. plantations in Galicia (northwestern Spain). Several problems associated with the management of these plantations were identified first. Current management plans for plantations of this species consist of the systematic and somewhat arbitrary application of the area control method. Thus, these plans do not take into consideration the optimum length for one full plantation cycle that maximizes the land expectation value, neither do they formulate the area control method through any mathematical programming model for scheduling regeneration harvests. In this paper, we present a modelling approach based on linear and goal programming. The models consider area and volume control regulation strategies, and take into account variations in land productivity among site classes and successive rotation intervals. To illustrate this approach, we applied the models to a neighbourhood community-owned forest currently managed by the Regional Forest Service with a recent management plan. The results showed that the models provided more flexible harvest schedules, and the profitability of eucalypt stands was 64% higher than that under the current management plan. Finally, extensions to this study were identified.     

采伐对森林土壤碳库影响的不确定性

森林土壤有机碳(SOC)是全球碳循环的重要组成部分,然而,多样的森林类型和不同森林经营措施的干扰,使得森林土壤碳库维持机制以及碳固存过程的研究和森林土壤碳库的估算存在较大的变异。作为主要的森林经营措施之一,采伐对森林土壤碳储量以及碳过程均产生直接或间接地影响。为深刻理解森林土壤碳库对于采伐干扰的响应,本文综述了近十几年来不同采伐方式下森林土壤碳储量及其主要碳排放过程——土壤呼吸的研究现状,综合分析了采伐方式、森林类型、采伐剩余物管理以及微生物因子等对土壤碳库的影响及其不确定性,并在此基础上阐述了研究中尚未解决的主要问题:1)生物因子作为CO₂产生的主体,在应对干扰时结构、功能的变化直接影响着土壤碳排放以及碳固定,但它们具体作用机制以及过程并不清楚,需展开进一步的调查;2)不同森林采伐方式对不同地区和不同类型森林土壤的影响的复杂性,亟须在进一步加强实验研究的基础上,发展森林土壤碳循环的过程或机理模型,为森林生态系统完整的碳循环过程表达及碳计量提供技术支撑,以期为我国森林经营以及碳汇等方面研究提供参考。     

Modeling the effects of alternative management strategies on forest carbon in the Nothofagus forests of Tierra del Fuego,Chile

The impact of forest management activities on the ability of forest ecosystems to sequester and store atmospheric carbon is of increasing scientific and social concern. The nature of these impacts varies among forest ecosystems, and spatially and temporally explicit ecosystem models are useful for quantifying the impacts of a number of alternative management regimes for the same forest landscape. The LANDIS-II forest dynamics simulation model is used to quantify changes to the live overstory and coarse woody debris pools under several forest management scenarios in a high-latitude South American forest landscape dominated by two species of southern beech, Nothofagus betuloides and N. pumilio. Both harvest type (clearcutting vs. partial overstory retention) and rotation length (100 years vs. 200 years) were significant predictors of carbon storage in the simulation models. The prompt regeneration of harvest units greatly enhanced carbon storage in clearcutting scenarios. The woody debris pool was particularly sensitive to both harvest type and rotation length, with large decreases noted under short rotation clearcutting. The roles of extended rotations and partial overstory retention are noted for enhancing net carbon storage on the forest landscape.