广东省生态公益林生态环境价值计量及评估

2001年至2003年,在湛江、江门、东莞、广州、汕头、韶关等地设点对广东省生态公益林的森林涵养水源效益、森林水土保持效益、森林改善小气候效益、森林吸收二氧化碳效益、森林净化大气效益、森林游憩资源效益和森林野生生物保护效益等7种效益进行计量与评价.结果表明:7种生态效益价值的总值为736.843 6×108(元·a-1),占2003年全省生产总值的5.47%;生态效益价值依大小顺序为:净化大气效益472.590 7×108(元·hm-2a-1),占64.14%;涵养水源效益127.450 6×108(元·hm-2a-1),占 17.30%;水土保持效益72.830 0×108(元·hm-2a-1),占9.88%;改善小气候效益33.077 8×108(元·hm-2a-1),占4.49%;森林游憩资源效益16.559 2×108(元·hm-2a-1),占2.25%;吸收二氧化碳效益10.526 7×108(元·hm-2a-1),占1.43%;保护野生生物效益 3.808 6×108(元·hm-2a-1),占0.52%.平均生态效益价值为21 358.82(元·hm-2a-1),表现出较高的效益.     

湖北森林生态资源基础价值研究

笔者指出了森林生态价值计量及补偿研究方面的主要误区,提出了森林生态资源价值计量的重要观点,对湖北森林生态资源基础价值进行了计算,主要结果如下:湖北森林生态资源价值总量为1 568.37亿元,年增长量为72.94亿元,其中有形资源年增长量为43.62亿元,无形资源的年增长量为29.32亿元,有形资源与无形资源的价值及增量比约为1.5∶1.0。湖北不同类型森林生态资源价值存在着明显差别,由高到低依次为:四旁林>针阔混交林>阔叶林>针叶林>竹林等,森林有形生态资源是森林生态资源的物质基础。针阔混交林、阔叶林、针叶林是湖北森林生态资源的主体。社会自然经济环境对森林生态资源价值有直接影响,不同年度、不同地区森林生态资源价值会发生相应的变化。     

北碚中梁山生态修复带森林生态系统服务功能评估

以北碚区中梁山生态修复带森林生态系统为研究对象,采用林业行业标准《森林生态系统服务功能评估规范》(LY/T 1721-2008),对北碚区中梁山生态修复带森林生态服务功能进行了评价。结果表明:北碚区中梁山生态修复带森林生态服务功能总价值9.09亿元·a-1,相当于2014年北碚区GDP(375.58亿元)的2.45%;森林提供的单位面积价值平均为7.70万元·hm-2·a-1,比重庆市2008年森林生态系统服务功能单位面积价值6.88元·hm-2·a-1高出11.92%。     

基于水源涵养服务视角的汀江（韩江）流域森林横向生态补偿标准

【目的】森林生态效益补偿是应对环境恶化、平衡区域发展的重要举措,厘清生态补偿标准是实施森林横向生态补偿的基础。结合森林生态系统服务流转理论,基于森林生态受益方向,从水源涵养生态服务视角开展森林横向生态补偿标准研究,为完善跨省流域森林生态补偿机制提供科学依据。【方法】以汀江（韩江）流域为例,综合运用当量因子法、水足迹法和引力模型,研究案例流域森林水源涵养服务溢出价值及其空间转移,确定受益主体与受偿主体相匹配的森林水源涵养效益补偿标准。【结果】1）汀江（韩江）流域上游地区龙岩市、漳州市和三明市的森林水源涵养服务外溢价值分别为80 448.89万元、5 857.33万元和13 038.28万元,广东省拟应向福建省合计支付水源涵养生态补偿资金99 344.50万元;2）三明市、漳州市和龙岩市提供的森林水源涵养服务价值辐射面积最广的地区均是梅州市,梅州市应承担主要的生态补偿资金;3）龙岩市可获得的水源涵养横向生态补偿资金最多,占补偿资金总额的80.98%,梅州市拟应支付的森林水源涵养生态补偿金额最多,占生态补偿总额的88.89%。【结论】流域上游存在森林水源涵养服务价值外溢,对下游具有不同的辐射...     

呼和浩特市森林生态补偿标准研究

文章以呼和浩特市2015年森林资源现状为研究对象,从森林经济价值和生态价值两方面,对呼和浩特市地区森林生态效益补偿标准进行了研究,提出森林生态补偿标准应包括经济价值和生态服务功能价值两部分,经测算呼和浩特市森林生态补偿参考值为3 390元/hm2。     

森林生态补偿标准体系研究

构建科学的生态补偿标准体系,能够实现以生态补偿带动精准扶贫,将生态环境退化与经济贫困恶化的困局兼而治之。目前,对森林补偿标准的研究主要集中在局地层面,国家尺度补偿标准体系研究尚不多见。将经济水平、营林成本、生态区位和林分质量等因素引入补偿标准模型,应用森林长期定位观测数据和31省森林经营成本等基础数据,构建效益法和成本法的补偿标准区间体系,结合皮尔(R.Pearl)生长曲线模型和经济发展阶段设计我国适度补偿标准体系。结果表明:效益法补偿标准均值是1 605.90元/(hm~2·a),成本法补偿标准均值是615.15元/(hm~2·a),各地适度补偿标准的均值为783.60元/(hm~2·a);效益法和成本法分别能够解释实际补偿标准变异的38.5%和41.4%;补偿标准区间和适度补偿标准体系的构建能够响应多种异质性要素,有利于实现森林生态补偿制度的激励相容。     

云南森林生态系统服务功能价值评估

利用云南省森林资源连续清查第5次复查数据,按照森林生态系统服务功能价值的评估方法,对云南省森林生态系统的服务功能价值进行了估算。云南省森林生态系统服务功能总价值为12 353.81×108元.a-1,其中提供非直接产品的生态产值为12 224.36×108元,占服务功能总价值的98.95%;生态服务功能价值为12 220.33×108元,占总价值的98.92%;产品提供价值为129.44×108元,占1.05%。森林的生态服务功能价值是其直接产品提供价值的94.41倍,表明生态服务功能价值远远高于其直接利用价值。云南省森林总面积占全国森林总面积的10.02%,而森林生态系统生态服务功能价值占全国森林生态系统生态服务功能价值的12.21%。单位面积林分的年生态服务功能价值为6.77×104元.hm-2,高于全国5.52×104元.hm-2的水平。     

森林生态资源价值补偿机制的探讨

笔者在相关研究成果的基础上,对建立森林生态资源价值补偿机制所涉及到的有关问题进行了讨论,提出了价值补偿的4种途径,即自我补偿、行业补偿、社会补偿以及国家和地方补偿等;指出了森林生态资源价值补偿的具体办法和措施,这些办法和措施带有明显的过渡性质,并呈现多样化趋势;针对湖北森林生态资源价值补偿工作的现状,提出了建立补偿机制的应对策略,“局部补偿带动全面补偿”,“先易后难,分步实施”等是应对策略的核心;强调全社会广泛的参与和积极配合,是补偿机制能否顺利建立及有效运行的关键,只有调动全社会的力量,资源价值补偿的目的才能最终实现。     

不同林龄杉木人工林生态功能比较研究

从涵养水源、保持肥力、固碳释氧和提供负离子等方面比较分析5年生、15年生、25年生及30年生杉木人工林生态功能服务价值的差异,结果表明,不同林龄杉木林生态功能综合服务价值大小差异不显著,综合服务价值变化范围为19 844. 0～22 282. 1元·hm-2·a-1,最高的是15年生的,最低的是30年生的;各林龄杉木林保持土壤肥力的价值为14 537. 6～16 337. 1元·hm-2·a-1,占综合服务价值的72. 6%～79. 9%,大大高于其他生态功能服务价值;杉木速生阶段和干材阶段生态功能综合服务价值呈增加趋势,成过熟林时呈降低趋势。     

基于Shannon-Wiener指数的三明市森林生物多样性评价

参考LY/T 1721—2008森林生态系统服务功能评估规范,以2006年三明市森林资源二类调查数据为基础,采用Shannon-Wiener指数计算三明市森林生物多样性保护价值。结果表明:三明市森林生物多样性保护价值为396.80亿元,单位森林面积生物多样性保护价值为2.28万元·hm-2,森林生物多样性保护价值占到福建省的20.58%,单位森林面积生物多样性保护价值略高于福建省平均水平(2.11万元·hm-2),高于全国平均水平(1.40万元·hm-2)。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.