What Happens after the Gap?— Size Distributions of Patches with Homogeneously Sized Trees in Natural and Managed Beech Forests in Europe

A novel but simple approach for describing stand structure in natural and managed forests driven by small-scaled disturbances is introduced. A primeval beech forest reserve in Slovakia and two beech stands in Germany with different management histories were studied, and their forest stand texture was analysed in terms of tree coordinates, stem diameter, and crown radius. Neigh-bouring trees of similar size with estimated contact of their crowns were assigned to tree groups. The study goal was to estimate the number and size of such homogeneous patches. In all cases, the number of tree groups in a particular diameter class decreased exponentially as group size increased. Single trees were predominant. Compared to simulated random tree distributions, the natural stand exhibited a more clumped distribution of small trees and more regular distribution of larger ones. The natural forest generally had smaller groups than the managed even aged stand, but the smallest group sizes were found in the uneven-aged selection forest. The simple analytical approach provided new spatial insights into neighbourhood relations of trees. The continuous scale from single trees to larger tree groups is an important achievement compared to other analytical methods applied in this field. The findings may even indicate a certain degree of self-organization in natural forests. Due to the limitations associated with each method or statistical models, a joint consideration of 1) gap dynamics, 2) forest developmental stages, and 3) size classes of homogeneous tree groups is recommended. Relevant to forest practitioners, the size class distributions enhance an understanding of the complex stand structures in natural forests and therewith support an emulation of natural forest dynamics in managed beech forests.

Close-to-nature and Value-oriented Forest Management in Harbin City, China

The paper came up with the basic principles, technology system, planning and forest governance system of close-to-nature and value-oriented forest management on the basis of discussions on its concept and theoretical foundation, and finally introduced initial effects of close-to-nature and value-oriented forest management implemented in Harbin.

Impacts of close-to-nature management on the stand states of Masson pine forests

Introduction:Research on the effect of close-to-nature management(CTNM)on stand states and dynamics of forests is crucial for the evaluation of CTNM implemented and sustainable development of forestry.Outcomes:We analyzed and compared the stand states and dynamics of Masson pine(Pinus massoniana)plantations in the young,middle-aged,and near-mature stages under CTNM eight years after selective cutting and unmanaged control.Both paired-sample T-tests and RDA ordination results demonstrated that the overall stand states with CTNM were superior to the control treatment in all three stages.The interaction of the CTNM and stand age significantly affected The Shannon-Wiener index of diameter class and regeneration density.Discussion and Conclusion:CTNM and stand age jointly affected the stand state of forests and CTNM accelerated the forest development,which promoted an increase in the heterogeneity of stand parameters and shortened the formation time of a target stand.Greater tree size differentiation and adequate regeneration are particularly important aspects for improving the quality of Masson pineforests during the management processes.

Formation mechanisms and remediation techniques for low-efficiency artificial shelter forests on the Chinese Loess Plateau

The construction of artificial shelter forests(ASFs)has resulted in substantial ecological,economic,and societal benefits to the Chinese Loess Plateau(CLP).However,the health and benefits of ASFs are being increasingly threatened by the formation of low-efficiency artificial shelter forests(LEASFs).In this study,LEASFs are systematically analyzed in terms of their status,formation mechanisms,and developmental obstacles.The key restoration techniques and schemes were summarized to improve the quality and efficiency of LEASFs.LEASFs are formed by relatively complex mechanisms,but they arise mainly due to poor habitat conditions,improper tree species selections,mismatch between stands and habitat,extensive forest management measures,and human interferences.The restoration and improvement of LEASFs are hindered by water deficits,mismatch between stands and habitat,single management purpose,and low efficiency.LEASFs are becoming more complex due to their wide range,the challenges associated with their restoration,and insufficient technological measures for their restoration.The key techniques of the quality and efficiency improvement of LEASFs include basic forest tending methods,near-natural restoration,multifunction-oriented improvement,and systematic restoration.An understanding on the formation mechanisms of LEASFs and a scientific approach toward their restoration are urgently needed and critical for the ecological protection and high-quality development of LEASFs on the CLP.Based on these analyses,we recommend strengthening the monitoring and supervision of LEASFs,considering the bearing capacity of regional water resources,implementing multiple restoration techniques,promoting multifunction-oriented ecological development,and exploring new management concepts to achieve the sustainable development of ASFs on the CLP.

Success factors for high-quality oak forest(Quercus robur, Q. petraea) regeneration

Background: Within the framework of close-to-nature forestry, oak forest(Quercus robur, Q. petraea) regeneration techniques that consider both silvicultural and nature conservation demands have become a very important issue.While there are many experimental and local studies that aim at disentangling the relationships between different environmental and silvicultural factors and the success of oak regeneration, systematic supra-regional studies at the greater landscape level are missing so far.Against this background, the first objective(a) of this study was to present an efficient and sufficiently accurate sampling scheme for supra-regional forest regrowth inventories, which we applied to young oaks stands. The second, and major, objective(b) was to identify the crucial success factors for high-quality oak forest regeneration in northwest Germany.Results: Objective(a): Factors that have been identified as potentially crucial for the success or failure of oak regeneration were either included in a field inventory procedure or extracted from forest inventory databases. We found that the collected data were suitable to be analyzed in a three-step success model, which was aimed at identifying the crucial success factors for high-quality oak forest regeneration.Objective(b): Our modeling procedure, which included a Bayesian estimation approach with spike-and-slab priors,revealed that competitive pressure from the secondary tree species was the most decisive success factor;no competition, or low competition by secondary tree species appeared to be particularly beneficial for the success of high-quality oak regeneration. Also fencing and the absence of competitive vegetation(weeds, grass, bracken)seemed to be beneficial factors for the success of oak regeneration.Conclusions: Trusting in biological automation was found to be mostly useless regarding economically viable oak forest regeneration. To efficiently organize oak regeneration planning and silvicultural decision-making within a forest enterprise, it is strongly recommended to initially evaluate the annual financial and personnel capacities for carrying out young growth tending or pre-commercial thinning and only then to decide on the extent of regenerated oak stands. Careful and adaptive regeneration planning is also indispensable to secure the long-term ecological continuity in oak forests. Oak regeneration should therefore preferably take place within the close vicinity of old oak stands or directly in them. The retention of habitat trees is urgently advised.

六盘山区辽东栎林分结构对各植物层生物量的影响

[目的]量化宁夏六盘山区辽东栎次生林各植物层(乔木层、林下植物层(草本和灌丛)、枯落物层)生物量随郁闭度及林分密度的变化,确定能使各层生物量均维持在较高水平的最佳林分结构,以充分发挥森林多种功能。[方法]基于野外调查样地数据,利用上外包线分析法确定辽东栎林各层生物量对林分密度和郁闭度的响应规律,并经综合权衡后确定最佳郁闭度范围。[结果]随郁闭度和林分密度增加,乔木层生物量先快速增加,在郁闭度0.75和密度1050株∙hm^(−2)时分别达到292.3和296.9 t∙hm^(−2),分别为其外包线最大值的80%和82%,之后增速变缓;林下植物层生物量先缓慢下降,在郁闭度0.75和密度1150株∙hm^(−2)时分别达到9.08和9.17 t∙hm^(−2),分别为其外包线最大值的89%和86%,之后快速减小;枯落物层生物量先逐渐增加,在郁闭度0.75时达到33.34 t∙hm^(−2),为外包线最大值的97%。综合分析各层生物量随郁闭度的变化表明,需维持林冠郁闭度在0.75~0.79左右,才能使林分各层生物量都保持在各自上外包线最大值的80%以上。[结论]在宁夏六盘山区,要使辽东栎林的乔木层、林下植物层、枯落物层的生物量均维持在较高水平,需维持林冠郁闭度在最佳范围0.75~0.79左右,这可用于指导该地区及类似地区的辽东栎林多功能经营。

黄土高原和六盘山区的林水协调多功能管理

【目的】面对实施黄河流域生态保护和高质量发展重大国家战略、推进“山水林田湖草”系统治理的国家要求,黄土高原等旱区的林业发展和植被恢复必须改变传统方式,增加考虑水资源的限制和对水资源的影响,关注森林的多种功能优化,探索如何克服长期存在的忽视水资源承载力、造林成活率低和生长不良、减少河川径流危及区域供水安全、整体功能低下等问题,实现森林多功能性的整体提升。【方法】针对深入理解林水关系和进行森林多功能管理的科技需求,自2000年以来在黄土高原的泾河流域和作为黄土高原区域重要水源地的六盘山土石山区,围绕“结构”、“格局”、“过程”、“耦合”、“尺度”等关键内容,在从单株到区域的多个空间尺度上,采用观测对比、统计分析、模型模拟等多种手段,长期开展旱区森林生态水文和多功能管理研究。【结果】1)林业高质量发展的本质是森林多功能优化的定量精准管理,为此需深入理解和准确量化立地环境与林分结构对多种功能形成的影响,在考虑多种功能的相互作用和供需关系基础上明确各功能的重要性差异,通过科学设计和合理调控森林的数量、质量(结构)和空间格局而权衡优化相互竞争的多种功能,在保证森林本身稳定的前提下尽可能同时满足对主导功能及其他功能的需求。2)提出了旱区林水协调多功能管理的实现途径,即在管理决策时除继续考虑可造林土地面积、立地质量、可用造林苗木等限制外,增加水资源管理及多功能管理的决策内容,并嵌入到传统的森林单功能经营决策过程中,这涉及流域森林覆盖率(造多少?)、森林空间分布(在哪造?)、植被类型和树种组成(造什么?)、林分结构(怎么管?)4个决策层。3)按决策层梳理总结了相关技术成果,在确定黄土区流域合理森林覆盖率方面,将仅考虑年降水量限制的潜在森林覆盖率提升为同时考虑降水量与产流要求限制的合理森林覆盖率,这可藉助于有关统计关系及率定过的流域水文模型模拟;在确定流域内的森林合理空间分布方面,提出相关决策需增加考虑立地类型的产流差别及其造林响应,这可借助于分布式流域水文模型模拟结果或研发的区域植被承载力计算系统;在林分尺度的森林多功能管理方面,提出了5个决策步骤,即进行立地质量分类、确定各地类的主要功能及优先性、调查现有林分结构特征、诊断现有林分的结构与功能、编制面向结构与功能的管理计划;为给森林多功能管理提供参照和目标,提出了不同详细程度的多功能水源林理想结构,包括表示为“3×0.7+X”的一般化理想结构(郁闭度0.7左右,0.6~0.8;地表覆盖度0.7以上;林木高径比0.7 m/cm以下,至少不超过0.9;X表示其他要求)、通过权衡多种功能和林分稳定的需求而确定的华北落叶松中龄林多功能合理密度、基于主要功能的变化规律和重要性排序而确定的不同海拔和林龄时的华北落叶松林多功能合理密度。【结论】本文证实了林水协调多功能管理的理论先进性和技术可行性,是旱区林业高质量发展的可行途径。通过深入认识和定量分析森林多种功能的变化规律,结合应用本文提出的管理技术,就可以科学设计和合理调节森林的数量(覆盖率)、质量(结构)和分布格局,整体提升森林的多种功能,更好地满足社会发展需求。但是,现有成果还有局限性,仍需针对各地情况开展更多理论与技术研究,助力“山水林田湖草”生命共同体治理及黄河流域生态保护和高质量发展。

中条山中段典型栎类林多功能经营效果分析

选择中条山中段典型的4种栎类林分,有针对性地采取4种多功能经营模式,通过测定3年后不同林分的平均树高、胸径、密度、蓄积量等指标,分析比较不同经营模式的效果。结果表明,栓皮栎纯林采用近自然经营模式后,林分树高、目标树胸径、优势高、枝下高、蓄积量均大于未经营样地;辽乐林混交林采取多功能经营模式后,林分胸径、目标树胸径、优势木胸径、树冠面积均大于未经营样地;油松栎类混交林采取多功能经营模式后,林分胸径、树高、目标树胸径、优势木胸径、枝下高、蓄积量均大于未经营样地;栓皮栎中龄纯林更新经营模式后,林分胸径、树高、目标树胸径、优势木高、枝下高均大于未经营样地。

天然林多目标经营研究现状及趋势

综述了天然林多目标经营关键技术研究现状,阐述存在的问题和今后研究重点,提出了林分多目标经营技术研究思路。目前多目标经营研究主要围绕木材生产、碳储量的理论模拟为主,常以多目标规划中的一少部分目标作为研究重点,缺乏实践研究。需要提出针对原始林、过伐林和次生林等不同天然林类型的多目标经营规划和与其对应的科学经营技术,才能达到多目标经营目的。因此,今后应重点解决以下问题:多目标经营的结构特点;多目标经营技术评判标准;量化各项功能的阈值、结合点或协同点;不同天然林类型的目标树经营技术;基于年龄和树种的复层、异龄、混交林碳储存计量技术以及其间伐后碳储量变化规律;基于空间结构的抚育经营技术;复层、异龄、混交林水源涵养功能等。

经营单位级的森林多功能监测体系研究

【目的】研究经营单位级的森林多功能监测体系,为森林经营单位及时掌握多功能森林的生长发育状态、内部结构特征、更新演替规律及其与所处环境间的相互关系提供有效手段,进而为其森林多功能经营提供数据支撑和理论指导。【方法】以中国林业科学研究院热带林业试验中心森林为研究对象,从抽样体系设计、样地布设方法、调查因子设置及观测指标数据采集等方面对森林多功能监测技术进行系统介绍和实践操作。【结果】基于1km×1km网格抽样框架,通过二重系统抽样,采用群状圆形样地方式,布设一重样地和二重样地,建立了经营单位级的森林多功能监测体系。实践操作结果表明,采用该监测体系调查一个样地所需费用与我国森林资源连续清查所需费用相当,但工作量仅约为后者的1/3,其中对热带林业实验中心森林蓄积量的抽样精度为94.97%,说明抽样效率较高。【结论】建立的经营单位级森林标多功能该监测体系实用性强,监测效率高,对森林经营单位开展森林多功能经营及森林多功能综合监测具有指导意义。

国外多功能林业发展经验及启示

总结和分析了美国、德国、澳大利亚的多功能林业发展和阿根廷人工林多功能经营的成功经验,概括和探讨了国外多功能森林经营的重要启示,提出了中国多功能林业发展明晰产权大力推进集体林权制度改革、政企分开加快国有林经营体制改革、依靠科技促进多功能林业可持续经营、创建专业合作推动林业可持续发展和强化全民森林教育传播生态文明理念的发展对策与建议。

云南森林及近自然森林经营关键技术应用

云南是我国的森林资源大省,由于长期忽视森林经营,导致云南省森林资源质量效益不高、局部地区生态系统退化、生态功能不强等问题突出。本文在进行云南森林资源现状质量评价以及多功能近自然森林经营的理念、理论、目标、对象和技术与传统森林经营比较分析的基础上,针对制约云南多功能近自然森林经营的关键技术瓶颈,提出开展云南省林地立地分类与质量评价、建立省级森林经营长期科研试验基地、开展森林多功能近自然经营技术集成与示范推广、加强科研基础条件平台和技术标准体系建设等技术创新重点领域的建议。

东北林区森林资源的新优势

东北森林区地域辽阔、地形复杂、气候多样,是我国最为集中的原始森林区之一,屏障着西北利亚的寒冷气流与风沙流,涵养着东北地区的水资源,影响着大气环境向降雨多的方向循环,是祖国北方的生态防线,具有森林生态服务、森林物种多样、林产工业品丰富的优势。保护好现有森林资源、恢复退化森林生态系统、建造新的森林,扩大东北森林区的区域面积,持续提高东北森林区的生产能力,用森林资源的多功能满足社会对森林的多需求,实行多目标综合经营模式,走循环经济发展之路,促使东北森林区充分发挥其生态效益、经济效益和社会效益。

森林分类经营的理论及其在黑龙江省林区的应用

指出森林分类经营的依据是：林地分工论和林木定向培育论：森工产业结构的合理化：商品林、公益林、多功能兼融林三种经营区的划分。提出分类经营的五项原则是持续发展、生态、经济、多种经济成分相适应发展和加大科教投入的原则。描述了三种经营区的性质、区划条件及在黑龙江省林区区划的结果。并对实践中存在的问题提出了建议。

不断改革探索现代林业发展之路——德国林业考察报告

德国是林业发达国家,是林学理论的发源地之一,其林业改革发展成效显著。通过对德国私有林发展、森林可持续经营、公众林业教育和国有林经营管理等方面的考察,认为：保护森林不动产产权、对林业给予公共政策扶持、重视林业合作组织发展、国有林经营体制改革、不断创新发展全民森林教育等经验值得借鉴。

间伐强度对大兴安岭天然落叶松林功能的影响

以黑龙江省大兴安岭塔河林业局盘古林场的天然落叶松林为研究对象。基于2011年所设16块天然落叶松林固定样地的调查数据,建立天然落叶松各器官(树干、树根、树枝和树叶)生物量模型,并结合碳系数预估天然落叶松林分碳储量,计算不同林分生物多样性。引入单木综合健康指数,确立间伐原则,构建综合目标值,并分析不同经营方案(间伐强度5%、10%、15%、20%)对森林的经济服务功能(木材收获)和生态服务功能(生物多样性、碳储量)的影响。结果表明:随着间伐强度的增加,林木健康指数、林分平均胸径及平均树高呈增加趋势;树木大小多样性和树种多样性呈减小趋势。在经济服务功能和生态服务功能构建的综合目标值最大条件下,结合不同间伐强度对二者的影响,提出了合理的多功能经营方案。在最优经营方案条件下,平均抚育间伐株数为375株/hm2;大小多样性平均降低0.175 8;树种多样性平均降低0.012 7;林分平均胸径增加0.81 cm;林分平均高增加0.65 m;木材收获量平均为12.3 m3/hm2;碳储量平均为47.84 t/hm2。

多功能森林经营理念在辽宁林业发展中的应用

多功能森林经营理念是一种新型的林业经营理念,也是我国林业发展的方向。多功能森林不仅对生态发展具有重要作用,而且能够创造出较高的经济效益,因此,已经在全国多地区得到发展应用。本文针对辽宁森林资源较少,生态平衡能力较弱,无法满足经济发展与生态发展实际需要的情况,结合辽宁地区多功能森林经营的现状与问题,论述了应采取的有效措施,为进一步促进多功能森林经营在辽宁林业发展和应用,具有很重要的指导意义。

多功能经营理念下森林疗养的探索与实践

近年来,随着生态环境的不断恶化,人们对林业工程建设工作越来越重视,在可持续发展理念引导下,一种新的森林生态系统建设模式应运而生,即多功能森林,并且这种森林建设模式逐渐在世界范围内发展起来,成为主流林业发展模式。多功能森林的建设,不仅可以提高森林生态系统建设的综合质量,还可以在很大程度上提高森林的经济效益。就从多功能森林概念出发,对多功能理念下森林疗养的发展现状、探索与实践有针对性的提出森林疗养提升建议,为林业工程建设提供一定参考。

多功能森林经营:理论与实践

开展森林经营是提高中国森林质量的根本举措。阐述了森林经营的定义、意义、基本原则、分类和森林作业法,介绍了近自然林业的基本理论和森林抚育的主要措施。

青岛市即墨区县级多功能森林作业法系统设计

在山东省森林经营规划的基础上,利用多功能森林经营理念,以山东省的15种主要森林类型作业法为框架,根据即墨区的特点、森林类型、森林主导作用、目标树种培育或栽培树种的组成等特点,设计了即墨区11种森林作业法,形成了一整套从建群开始(森林形成)到森林抚育、木材采收、更新造林等一系列全周期经营措施,以期能实现森林的动态平衡,确保森林生长过程的自然协调发展,真正实现多功能森林经营。