不同林农复合经营模式的生物量比较研究

研究了安徽省具有代表性的不同林粮和林茶复合模式的生物量。结果表明,各林粮复合模式生物量存在极显著差异,农作物的生物量大于林木的生物量,枫香-花生模式有利于花生的生长,马褂木-花生模式有利于后期总生物量的累积;各林茶复合模式生物量也存在极显著差异,总生物量大小顺序为香樟>栾树>枫香;林木生物量在各器官中分配树种间存有差异,幼树表现为树根或枝叶大于树干,树干的比例随着树龄的增大而增加,根系和枝叶相对减少。     

红锥天然林生长规律与生物量的调查研究

华安金山林场红锥天然林调查表明,红锥生长快,３４～３８年生树高可达２１．９～２３．７ｍ、胸径可达２０～３０ｃｍ。全林保存密度５７２株／ｈｍ２,蓄积量３６６ｍ３／ｈｍ２;Ⅱ级立地级保存红锥６００株／ｈｍ２,蓄积量高达４８３ｍ３／ｈｍ２,生物量５００．８７ｔ／ｈｍ２,材积年生长量可达１３．４ｍ３／ｈｍ２;Ⅲ级立地红锥蓄积量３４２ｍ３／ｈｍ２,生物量３５４．６５ｔ／ｈｍ２。林分生产力很高,树高速生期为４～１８年生。胸径速生期为６～１４年生,材积速生期为１０～２７年生,３４～３８年生的红锥尚未达到数量成熟。表明红锥适应性强,不苛求立地,生长潜力大,极有发展前途。     

Productivity and growth efficiency in sugar maple forests

Sugar maple (Acer saccharum Marsh.)-dominated northern hardwood forests were examined at four locations along an acid deposition and climatic gradient in the Great Lakes region of the USA. The study sites were matched in terms of physiography, soils, stand history, and vegetative characteristics. Measurements of basal area and biomass growth were made for the 1988–1991 growing seasons. There were no significant differences in either basal area of biomass increment among the four sites over the 4 year period. There was a great deal of year-to-year variability with relative basal area growth rates ranging from as low as 0.2% to as high as 2.4% on a single site in successive years. Growth efficiency measures reflected this variability with as much as an 800% difference between successive years on a single site. When coupled with year-to-year variability of up to 34% in leaf area related to heavy seed years and defoliation, this indicates that growth efficiency and leaf area measures are not consistent indicators of aboveground productivity for tolerant deciduous species, especially if derived from short-term measurements or temporary plots.     

Biomass harvesting from buffer strips in Italy: three options compared

There is an urgent need for new, mechanized systems that may restitute some profitability to buffer strip harvesting and motivate regular maintenance. An opportunity for innovation is offered by the growing success of chip-fed boilers, since the production of chips is simpler than that of logs and has a higher potential for cost reduction. Within this context, a study was conducted in Italy with the goals of: (a) designing three alternative chip harvesting methods for buffer strips, (b) field-testing the performance of each alternative, and (c) developing a model for estimating the cost of these methods under varying operational and economic conditions. The three harvesting methods reflected different mechanization levels, with escalating investment requirements. Overall, the study demonstrated that frequent maintenance of young, single row buffer strips generates profits only when thoroughly mechanized. Using a dedicated feller-buncher, a front-end loader for extraction and an industrial truck-mounted chipper brought the delivered cost below the 14 €/m³ loose chips (approximately 4 €/GJ) presently paid by the district heating stations. However, the intermediate-mechanization system showed the highest potential for improvements. The␣study generated a spreadsheet-based model for predicting the effects of varying work conditions and cost hypotheses.     

青钩栲人工林生态系统生产力的研究

青钩栲(Castanopsis kawakamii Hayata)是福建中亚热带区域性代表种。在我国除三明市莘口格氏栲天然林保护区有成片的青钩栲优势种群以外,其区域性分布仅呈零星少量。为了繁衍珍贵树种资源,推广多树种造林,莘口教学林场自60年代以来,人工成片驯化栽培珍贵树种达45个,计400ha之多。其中青钩栲人工林23年生蓄积量高达163m~3/ha,最大单株材积为0.922m~3(胸径42cm,树高18m)。是一个很成功的造林树种。研究青钩栲人工林生态系统的生产力,可对制定合理的营林技术措施提供一定的依据。     

复合农林业系统碳贮量研究进展

CO2作为一种主要温室气体,其固存与排放对全球气候变化有重要影响。本文以复合农林业系统为研究对象,介绍了农林复合类型中林木、农作物、凋落物、土壤碳贮量的估算方法,并指出目前碳贮量研究方面的问题和发展方向,为碳循环研究提供部分基础研究数据和理论支持。     

闽南福建柏人工林生物量结构的研究

在福建柏人工林生物量中 ,乔木层占主要部分 (90 %以上 ) ,其次是枯枝落叶层 ,下木活地被物层最小 ;林分总生物量、乔木层、凋落物层生物量随年龄的增大而增大 ,下木活地被物层随郁闭度的增加而减少。不同龄级的福建柏林分生产力差异明显 ,以Ⅵ龄级的林分生产力最大 ,生产力的总趋势随龄级的增加而增大 ,至Ⅵ龄级后又减少。福建柏人工林胸径与枝叶重、干重、枝重、叶重呈极显著相关 ,结合树高因子 ,可建立相关方程W =aDbHc。     

Simplified inference about dominance in forest stands

In a series of papers, Binkley and coauthors suggested dominance curves as a framework for understanding growth dominance and resource use efficiency in forest stands. Constructing a dominance curve requires three major supporting components: an appropriate allometric equation for biomass, sufficient data to characterize the size distribution of trees in the stand, and data on growth from a sufficient number of trees to characterize the relationship between tree size and growth across the entire size distribution. These components are not always available. Here, I propose a simplified approach to inference that can be used to diagnoze positive, neutral, and reverse dominance when the conditions for constructing a full dominance curve cannot be met. I illustrate the approach with published data from an old-growth kauri (Agathis australis) stand, which shows clear evidence of reverse dominance.     

Biomass production and root distribution of Gmelina arborea under an agrisilviculture system in subhumid tropics of Central India

A study of an agrisilviculture system comprising Gmelina arborea and soybean (Glycine max) was conducted in the subhumid region of Central India. Above- and below-ground biomass production and distribution of coarse and fine roots were studied in 4-year-old G. arborea, planted at a spacing of 2 × 2 m, 2 × 3 m, 2 × 4 m and 2 × 5 m. The total biomass varied from 10.89 Mg ha^–1 to 3.65 Mg ha^–1 depending on the tree density. Among the different tree components, stemwood contributed maximum biomass (54.3–79.4%), followed by branches and leaves. Root distribution pattern showed that most of the coarse roots were distributed in the top 40 cm of soil, whereas fine roots were concentrated in the top 20 cm. Coarse root biomass decreased with an increase in spacing. The spread of roots was asymmetrical in trees planted at 2 × 2 m and 2 × 3 m spacings, while it was symmetrical in trees planted at wide spacings. No significant difference was observed in the fine root biomass in different stands. The root:shoot ratio increased with an increase in spacing. Crop (soybean) growth and productivity varied significantly and it increased with a decrease in tree density. Soybean yield varied between 1.5 Mg ha^–1 to 2.1 Mg ha^–1. The role of root architecture of G. arborea trees on productivity of crops under agri-silviculture system is discussed.     

灌木状白蜡——农作物间作系统的生物量及养分分配的初步研究

灌木状白蜡 (Ｆｒａｘｉｎｕｓｃｈｉｎｅｎｓｉｓ,又称白蜡条 )—农作物间作系统是豫东沙区重要的农林复合经营形式 ,有数百年的经营历史 ,仅宁陵县就有 1 50 0ｈｍ2 。它把多年生的灌木状白蜡和 1年生的作物结合起来 ,不但可以充分利用自然资源 ,生产大量的条子、白蜡杆等小型用材 ,而且还可以改善农田生态系统的结构 ,提高其多样性与稳定性 (王广钦等 ,1 987ａ;1 987ｂ ;1 990 ;ＷａｎｇＧｕａｎｇｑｉｎｅｔａｌ.,1 991 )。因此 ,把条农间作当作一个完整的人工生态系统 ,研究其物质的固定、消耗、分配、循环规律 ,对于进一步研究条农复…     

竹林生产力因子的评价

生产力因子的分析是衡量与评价林分生产潜力与管理水平的重要方法。我国对这个领域的综合研究与应用还不多。深度与广度也不平衡。本文试图对竹子林分的经济指数、立竹度、叶面积指数、生境质量与生长级等方面作进一步探讨、以供各地参考。     

苏北海堤防护林主要造林树种林分生物量与生产力的研究

对海堤防护林水杉、刺槐和柳杉林分生物量进行测定,建立了林木干、皮、枝、叶、根及全树生物量相对生长模型。据此模型和每木检尺数据估算,柳杉、刺槐和水杉林分乔木层的现存生物量分别为１１０．８７、８９．５１和７２．１８ｔ／ｈｍ＾２,年均净生长量分别烽４．８１ｔ／ｈｍ＾２。刺槐、水杉干材最大,占林分总生物量６６￣６２％,柳杉干材仅占４７．６％,而枝叶约占３０％。     

第二代杉木幼林生物量的定位研究

在湖南会同杉木人工林生态系统定位站试验区内;研究了第二代7年生杉木幼林的生物量和生产力;并与第一代同龄杉木幼林作了比较。结果表明;第二代杉木林比第一代杉木林生物量减少14.18t/hm²;净生产力减少2.04t／hm²·a,减少幅度达31.47％。应引起林业工作者的高度重视。     

森林生物量与生产力研究综述

森林生态系统在维护全球碳平衡中有着重要作用，其生物量和生产力是研究生态系统碳平衡的基础数据，进一步推动了森林生物量和生产力的研究。阐述了森林生物量和生产力形成的生理生态学基础，不同森林类型的生物产量、区域分布格局，森林经营对生物产量的影响、研究方法和模型等。在多尺度上，采用先进的研究手段，围绕资源环境等热点问题来研究森林生物量和生产力，实现数据共享和网络化是森林生物量和生产力研究的发展趋势。     

杉木人工林连作生物生产力的研究

在全国杉木中心产区,选择不同栽植代数（1、2、3代）,不同生长发育阶段（5、10、15、20a)及不同立地（14、16、18地位指数）的杉木人工林,进行不同栽植代数杉木人工林生物生产力的比较研究。结果表明：连栽导致了不同生长发育阶段杉木人工林生产力的明显下降,随栽植代数增加,不同生长发育阶段杉木林林分生物量逐代递减,林下植被生物量呈递增趋势,其中2、3代20a生杉木林林分生物量分别比1代下降20.24%和38.09%,3代比2代下降22.38%。同时林分树干生物量所占比例下降,根系生物量所占比例增加,连栽刺激了杉木根系生长发育,并有利于林下植被恢复。     

农林复合系统研究概述

文章从农林复合系统的结构选择、对生态环境的影响和系统内部作物与环境相互作用三个方面对农林复合系统研究现状进行分析,并指出要在把握农林系统整体性的基础上,采用多种方式开展复合结构模式研究,重点开展农林复合系统种间相互作用机理的研究。     

花椒杂草系统地下生物量的空间分配格局

农林复合系统中,地下生物量的分配格局是目的物种和间作作物竞争的结果,因而可以看作是模式物种选择及系统设计的依据。在花椒杂草系统模式更新改造中,为了达到间作作物选择和行间配置的合理性,采用壕沟法研究了系统地下生物量的空间分配现状。结果表明：（1）花椒杂草系统地下生物量总量248．57g·m^-2,杂草生物量占82％,花椒仅占18％;（2）该系统地下生物量总量和杂草生物量在水平空间上呈均匀分配,而在垂直空间上随土层加深呈负指数分配,其表达式分别是Y=1024．6exp^-0.5254x（R^2=0．9688,x为土层深度,cm）和Y=1187．2exp^-0.6889（R^2=0．9989,x为土层深度,cm）;花椒根量均匀分配于垂直空间,而在水平空间上呈负指数式分配,其表达式为Y=118．3exp^-0.3817x（R^2=0．8215,x为距树干距离）;（3）花椒吸水根生物量均匀分配于地下空间,杂草吸水根生物量的分配呈现出明显的分层现象,其吸水根总量的81．11％分配于0～15cm土层,而15cm以下土层仅占18．89％;（4）所研究的256个500cm^3的取样单元中,花椒和杂草吸水根的重合率50．4％,非重合率49．6％;然而在127个吸水根非重合单元中,花椒吸水根仅占29．1％,杂草吸水根却占了70．9％。文中根据花椒和杂草地下空间生物量的分配现状,讨论了四川盆地丘陵区退耕还林地花椒模式更新中间作物选择、行间配置和水肥管理应注意的问题．     

农林复合系统的林网对冬小麦水分利用效率影响的研究

本文研究了林网式农林复合系统对冬小麦水分利用效率(WUE)的影响。结果表明,农林复合系统可以提高冬小麦的水分利用效率,其日平均水分利用效率较对照提高了6.33%。小麦水分利用效率也存在着“午休”现象,林网可以有效地缓减这一现象。应用主成份分析证明林网提高小麦水分利用效率的主要原因是影响了空气温度、叶温、饱和差和光合强度。     

森林生态系统碳蓄积研究方法进展

作为陆地生态系统的主体,森林生态系统的碳循环与碳蓄积对研究陆地生态系统碳循环起着重要作用.生物量、生产力、土壤有机质以及凋落物量及其分解等相互关系决定了森林生态系统的碳库量和碳交换量.本文简单地介绍了在碳蓄积研究中森林生物量和生产力的几种研究方法,并对研究过程中的问题(大尺度生物量的精确估算,地下生物量的研究,森林生态系统土壤碳库估算)进行了探讨.