湖南省油茶林生态经济效益研究(续)

在全省油菜林典型县中，共抽样标准地80块，测单株3610株，调查样地立地条件，林内外环境，测定油茶测树因子计算油茶表象因子与产量关系，首次编制了油茶产量表，测定油茶林，涵养水源，保持水土等生态功能值和经济社会效益等。     

湖南油茶产量影响因子分析

在湖南省油茶产区，用二阶抽样抽取样地80块，实测单株4360株。筛选出冠幅、年龄为产量的最相关因子，并据此编制了油茶林产量表。     

湖南省油茶林分生态功能效益评估

近年对木材林群落生态功能和效益的评估层出不穷，但对经济林油茶的生态功能及生态效益，却未见，本研究用抽样方法在湖南油茶林产区抽取样地80块，实测单木1960株，测定油茶立地因子和生态因素、土壤非毛管孔隙度、侵蚀模数等，计量油茶林、涵养水源、保持水土迳流能力，并进行效益评估。     

湖南省油茶林产量调查研究

通过连续7年对湖南省25个油茶林样地的产量状况进行调查测定,结果表明:油茶自然低产林平均产果量只有2 382 kg/hm~2,油茶低产林经改造后产量提高2.01倍,4年平均产果量达到了4 788 kg/hm~2。油茶林采用良种+良法,造林第四年产果量1 249.5 kg/hm~2,第五年产果量3 075 kg/hm~2,第六年产果量5 497.5kg/hm~2,盛产期产果量9 757.5 kg/hm~2。油茶花期,油茶花芽分化与油脂转换高峰期的气候条件对油茶产量有较大的影响,尤其是油茶盛产期良种林,由于其产量高,对水、养分等需求量大,更容易受花期低温阴雨、高温干旱等灾害性气候的影响。     

浙江省油茶良种造林效益分析

2013-2015年连续对浙江省21个油茶(Camellia oleifera)重点县(市、区)的低产改造林和良种新造林的油茶产量进行测定。结果表明,浙江省油茶种植总面积16.6万hm~2,其中新造良种面积4.3万hm~2;低产林主要分布在丽水和衢州,约占总面积的80%。新造良种油茶林优势明显,6~8年生每公顷产量已超过低产改造林,经济效益也更加可观;不同地区油茶产量不同,青田县油茶产量最高。对油茶产量与立地条件各因子进行相关性分析,结果表明,油茶产量与坡度呈明显的负相关性(r=-0.271,Sig=0.009),进一步通过一元线性回归分析,自变量坡度与因变量产量的线性关系的非标准化回归方程为:Y(产量)=340.61-5.299X(坡度)。提出加大良种推广力度、扩大油茶良种栽培面积,增加油茶经济效益。     

肇庆市油茶产业发展分析思考

肇庆市宜林地资源充足,气候条件适宜种植油茶,油茶栽培历史悠久,具有发展油茶产业的有利条件,但目前全市油茶林面积小、产量少、多为散生、不成规模,应促进油茶产业化发展.为此,提出了肇庆市发展油茶产业要重视栽培区域与立地、油茶品种与苗木、茶油产量与品质等3大关键科技问题.油茶基地规划与建设务必考虑海拔、坡度、坡向等地形因子及...     

油茶低产林改造效应的研究：II.低产林改造相关分析

采用相关分析和典型相关分析方法，对油茶低产林改造中效应因子间及其与产量间的相关关系进行分析，表明：叶绿素含量，叶片中磷含量，单株果数，地面相对光强和土壤容重与产量关系密切；生态效应因子是通过影响生长效应因子，生长效应因子又是通过影响结实效应因子，进而影响油茶产量的，还采用灰色局势决策方法，对低改措施组合进行决策，结果是综合改造效应最显著，增产最明显。     

油茶林套种效益分析

油茶林地经过合理套种和间种后，可明显提高土壤肥力，改善油茶林生长环境，实现以耕代抚，促进油茶生产良性循环，使油茶达到高产稳产，同时，提高了油茶林地单位面积产量，经济效益十分显著。     

用灰色系统理论分析油茶产量形成

本文应用灰色关联分析方法,研究分析经济性状、树体结构及气象因子对油茶产量形成的影响。结果表明,干籽率、林产果量及上一年11月日照量和上一年7～8月蒸发量等因子,分别对果含油率、每平方米冠幅产果量及年产果量的影响最大。为油茶良种选育和低产林改造提供理论依据,为油茶产量形成的研究提出新思路。     

油茶林地和树体内营养元素变化研究

为了探索油茶林地和油茶树体内营养元素变化规律，掌握有效的施肥量，提高油茶产量，我们在油茶产区永兴县选定了１２块不同立地类型的油茶林标准地，通过一年的连续采样，测定土壤和树体内Ｐ，Ｋ，Ｃｕ，Ｍｎ，Ｚｎ，Ｆｅ，Ｍｇ等元素的含量，分析了它们的变化规律，对林地施肥有一定的指导作用。     

四川主要农用土壤中丛枝菌根真菌数量和种类的初步研究

用形态学分类法测土壤样品中丛枝菌根真菌的数量和种类分布特点,结果表明,丛枝菌根真菌广泛分布于四川农业土壤中,但其数量和种类较少,种群结构单一。共计分离鉴定出3个属18种丛枝菌根真菌,球囊霉属(Glomus)13种,无梗囊霉属(Acaulospora)2种,盾巨孢囊霉属(Scutellospora)3种,其中只有Gl.mosseae,Gl.cale-donium,Gl.constrictum的出现频率大于10%,是主要四川省农用土壤中的优势种。研究还发现,地域因素、土壤类型和土壤的理化性质以及人为因素对丛枝菌根真菌的数量和种类有显著影响(P<0.05)。     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

四川省草地生态系统碳储量估算

草地生态系统在全球碳循环中起着极为重要的作用。但是实测数据十分匮乏。利用2008年四川省草原地面调查数据,以及卫星遥感数据,对2008年四川省草地的碳储量进行了估算。主要结论如下:四川省草地总面积约为20.38×104km2,2008年四川省草地总有机碳为2 302.97 Tg,其中地上生物量有机碳为15.54 Tg,地下生物量碳为104.45 Tg,地下根系储存的碳是地上碳储量的6倍多,四川省草地土壤有机碳为2 182.98 Tg。土壤储存的碳是植被的19倍多。     

民勤沙区沙丘的基本特征及其移动规律研究

民勤沙区的沙丘包括新月型沙丘、新月型沙丘链、沙垄、沙堆和复合型沙丘及沙丘链5 种类型;沙丘高度一般为4~10 m;沙丘走向有横向(NE-SW)和纵向(NW-SE)以及多风向形成的不规则形。沙丘移动的基本特征是:(1)风是沙丘移动的动力,风向单一时沙丘移动速度快。(2)沙丘越高移动速度越缓慢。(3)沙丘自西北向东南方向移动为主。(4)沙丘移动的方式有前进式、摆动式和摆动前进式3 种。(5)植被盖度越大移动就越缓慢。(6)一年中5月份移动速度最快,9月份最为缓慢。     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.     

The Picking of Wild Berries in Finland in 1997 and 1998

Nation-wide figures related to berry-picking in Finland were based on postal questionnaire surveys carried out in 1997 and 1998. The sample in 1997 consisted of 6849 households and the response rate was 60%. The questionnaire was concerned with the utilization of all non-wood forest products. In 1998, a subsample of 1858 households was taken and the new questionnaire focused solely on berries and mushrooms. The response rate was 69%. In 1997, Finnish households picked 56.5 million kg of wild berries (95% confidence limits were 52.3 and 60.4 million kg). In 1998, a total of 49.7 million kg (44.0, 55.3) was picked. In 1997 the proportion of products sold was 27%, harvested by 5% of households. It is possible that the quantity of wild berries picked in 1997 was higher than in any year previously, but because of a lack of reliable earlier data this cannot be verified.     

Seedling emergence in uneven-aged Norway spruce stands in Finland

The emergence of Norway spruce seedlings on different types of germination sites in uneven-aged Norway spruce dominated stands four years after selection harvesting was studied. The data were collected from 20 stands in southern Finland. In each stand, ground cover was measured from a set of 64 one square metre subplots on a permanent experimental plot of 1600?m². Correlation analysis, direct comparison of subplots with and without seedlings and mixed-effects models were used to estimate the influence of ground and tree cover on seedling occurrence. Grass cover, dwarf shrub cover, cover of certain moss species and close vicinity of trees decreased the occurrence probability and number of seedlings, while greater stand and local basal area around the subplots increased the seedling number. The cover of vegetation free surfaces, usually considered as good germination sites, was rather low. Variation in seedling emergence between plots was high. We concluded that spruce regeneration was slightly more abundant in stands with greater overall stand density and local density within a stand in postharvest conditions.     

Joint ventures in private forestry in Ireland

A study was conducted with the objective of obtaining a profile of farmers who have participated in the Farm Partnership Scheme in Ireland. This scheme is a joint venture between Coillte (The Irish Forestry Board) and farmers. Under the terms of the scheme, Coillte is responsible for the establishment, management and harvesting of the forest plantation on the farmer’s land. The farmer retains ownership of the land, receives premium payments and shares in the harvesting profits. Fifty farmers who joined the Farm Partnership Scheme between 1993–1997 were interviewed in 1999 and a detailed questionnaire was completed. Survey results indicate that the typical farm partner was male, married and aged 50 years or older. Over half of those surveyed had an off-farm job. The most popular reason for farmers opting to participate in the Farm Partnership Scheme was that they did not have sufficient time to undertake the establishment and management of a forest plantation themselves. The average size of forest established under the scheme was 23.7 ha, with Sitka spruce the most popular species planted. The average annual payment under the scheme was €8077. For 46% of those surveyed, the returns from the Farm Partnership Scheme comprised all of their farm income.     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Polysaccharides in cones of eleven coniferous species growing in Turkey

Composition of polysaccharides in the cones of conifer species growing in Turkey was studied. The content of polysaccharides was between 39 and 57% (w/w). The total amount of polysaccharides was generally higher in pine species. Polyoses were the predominant polysaccharides. The percentage of polyoses was between 23.3 and 33.9% (w/w). The main units of polyoses were mannose and galactose, while in some species xylose was the other important sugar unit. Between 1 and 6.7% of the polyoses were soluble in hot water. Polyoses were more readily dissolved from fir species than from other species. Galactoglucomannan was dissolved from all cones. Contrary to wood, the content of cellulose was only between 13 and 27.5% (w/w) in cones.