马尾松林生物量及其结构的研究

采用分层切割法对不同年龄马尾松人工林的生物量进行研究。根据各径级标准木生物量建立回归方程,估算不同年龄马尾松林分各器官生物量。同时还比较了不同年龄林分生物量结构和生产力。马尾松林的生物量随着年龄的增大而增大,净生产力随着年龄增大而呈抛物线状态     

木麻黄林生产力动态变化的研究

对木麻黄林生物产量随立地条件、林分密度和林龄的动态变化的研究表明,木麻黄林生物量大小在不同立地表现为潮积沙土>风积沙土>残积沙土,立地愈好干材生物量所占比例愈高;15年生木麻黄林生物量随林分密度增大而增加,但干材生物量百分率的变化趋势相反;林分净生产量随林龄而增大,至成熟阶段达到最大,到过熟阶段又趋下降,林俞生产力与叶面积指数呈线性相关。     

冀北山地油松林净生产力与相关立地因子关系模型的研究

为推测林分生产力,提高森林经营水平,在对冀北山地油松林标准地进行调查的基础上,建立树高随林龄的增长而变化的导向曲线模型,通过模型给出各标准地的立地指数;建立油松单株生物量与单株胸径树高关系模型,导出各标准地林分生物量;建立林分生物量与林分密度、林龄及立地指数关系模型,进而建立林分净生产力与林分密度、林龄及立地指数关系模型。     

林分密度对巨尾桉生物产量及生产力的影响

对湘南低山丘岗区林分密度为900,1 125和1 500株.hm-2的6年生巨尾桉Eucalyptus grandis×urophglla丰产示范林进行了生物量及生产力的测定分析.结果表明:单株生物量随密度的增加而明显减小,低密度林分是高密度林分的1.48倍;林分生物量随密度的增加而增加,高密度林分比低密度林分高出16.82 t.hm-2.年均净生物量高于杉木中心产区杉木人工林的水平,分别达到22.57,24.85和25.37 t.hm-2a-1.林分各组分的生物量随密度的增大而增大,并出现W干> W根> W枝>W皮>W叶>W果的规律.林分结构以中密度林分合理,叶面积指数最高,干材生物量达63%以上.在湘南低山丘岗区发展潜力大,可作为短周期工业用材林培育首选树种.     

华北落叶松人工林生物生产力研究

以华北落叶松人工林为研究对象,选择18a、22a、38a等3个不同林龄的林分,每个林龄林分设置15块样地。通过样地调查,对华北落叶松人工林的林分生物量、林下植被层生物量、林分净生产力进行研究,以揭示其生物生产力。结果表明：华北落叶松人工林林分生物量随着林龄的增加而增加,18a、22a、38a的林分生物量分别为94．58t／hm2、101．19t／hm2、216．25t／hm2。各器官的生物量分配,以干材所占的比例最大,达到51．36％以上;华北落叶松人工林林下植被层中凋落物层与灌木、草本层的生物量也随着林龄的增加而不断积累;华北落叶松森林净生产力表现为乔木层的净第一生产力、不同林龄阶段的华北落叶松人工林植被净生产力均较高,达到4．60t／（hm2·a）以上,其中干材的净生产力积累最快,为2．36～3．20t／（hm2·a）。     

木麻黄人工林生物量的密度效应研究

以福建省惠安县１５年生木麻黄为试材,对５种不同密度木麻黄人工林的生物量进行研究,结果表明：随密度增大单株生物量减少,林分生物量和净生产力增加,但枝与小枝的生物产量趋于平稳;各器官生物量分配规律为干＞根＞枝＞小枝,净生产力表现为干＞小枝＞根＞枝。     

林分密度对木麻黄生物产量影响的研究

以福建惠安15年生木麻黄为试材,对5种不同密度木麻黄林的生物量进行研究。结果表明:随密度增大单株生物量减少,林分生物量和净生产力增加,但树枝与小枝的生物产量趋于平稳;各器官生物量分配规律为干>根>树枝>小枝,净生产力表现为干>小枝>根>树枝。     

林分密度对邓恩桉生物产量及生产力的影响

对湘南低山丘岗区密度为1 110、1 667和2 500株.hm-2的8年生邓恩桉Eucalyptus dunnii丰产示范林生物量进行了测定.结果表明:单株生物量随林分密度的增加而明显减小,低密度林分林木平均木的生物量是高密度林分的1.22倍;林分生物量随林分密度的增加而增加,高密度林分比低密度林分高出271.26 t.hm-2;各密度林分的年均净生物量分别为32.35、43.97和59.51 t.hm-2a-1,高于杉木中心产区杉木人工林的水平,林分各组分的生物量随林分密度的增大而增大,并出现干>根>枝>皮>叶的规律;林分结构以中密度林分合理,叶面积指数高,干材生物量达61%以上.邓恩桉在湘南低山丘岗区发展潜力大,可作为该地区短周期工业用材林培育造林树种.     

云杉天然林分生物量和生产力的研究

本文对四川西部高山林区云杉天然林分的生物量和生产力进行了测定与研究。按平均标准木法和样方收获法分别调查了乔木层、幼树下木层、草本地被物层和枯枝落叶层的生物量。据调查数据,按“相对生长法则”建立了估测乔木层单株木各器官生物量的回归方程,方程均具较高的精度。文中还研究了不同自然分布区和不同林型对于云杉林分生产力的影响,以及不同密度的林分中产量结构的变化。结果表明:云杉天然林分平均总生物量为285.906吨/公顷;净生产量为6284公斤/公顷·年林分中乔木层、幼树下木层、草本地被物层和枯枝落叶层生物量的平均比例是:74.4％∶4％∶11.6％和10％。乔木层生物量为212.773吨/公顷、净生产量是4676公斤/公顷·年。乔木层各器官(干、皮、技、叶、根)生物量的比例是:54.9％∶5.2％∶12.5％∶7.1％∶20.3％。发现云杉林分的生产力在针叶树种中是比较高的。另外云杉在高山峡谷区比在丘状高原区其生产力要高出77.1％,可达6536公斤/公顷·年。调查的云杉四种林型中,生产力最高的是灌木—云杉和箭竹—云杉林型,其净生产量可达6422和9246公斤/公顷·年,其次是禾草—云杉林型,为5975公斤/公顷·年,最差的是苔藓—云杉林型,只有3095公斤/公顷·年。林分密度对林木的产量结构有显著影响。林分内各     

能源树种晚松生物量及其能源利用研究

采用标准木法对江西省泰和困难立地和江西农大苗圃地晚松生物量进行实测,采用恒温氧弹量热计对晚松各组分热值进行测定,研究晚松作为能源树种的最佳采伐期。结果表明:(1)晚松实生林在不同立地条件下,苗圃地单株净生产力比困难立地单株净生产力大。各组分生物量组成中,干材生物量比例最大。(2)立地条件对萌生林单株生物量影响不显著。萌芽林各组分生物量组成中,干材生物量比例最大。(3)23年生晚松1m×1m密度时,干的热量值最大,为203.57×108kJ/hm2。枝、叶、干3部分能源值中干的热值最大,并且热值随密度的增大而增大。     

不同密度南方型杨树人工林的主伐年龄研究

根据湖北省10个县、市31块标准地的11种主要密度类型林分的调查资料,从技术经济学的角度,以林分数量成熟与经济成熟为依据,对各密度类型林分的主伐年龄进行了研究,结果表明:①南方型杨树各种密度类型人工林的年均收益最大值出现在材积连年生长量最大值与数量成熟龄之间,一般早于数量成熟龄1～2a。②林分的主伐年龄与数量成熟龄表现出随着林分密度的减少而逐渐变大的总趋势,而主伐年龄时的最大年均净收益则随林分密度增大而增加,与林分单位面积蓄积量的变化趋势基本一致。③培育造纸、刨花板等小径材林分的轮伐期为5～6a,木芯板、火柴、家具等中径材的轮伐期为6～9a,培育胶合板等大径材的年限则需要10～12a。     

洞庭湖滩地开沟抬垄造杨树林效益分析

对季节性淹水的洞庭湖滩地进行开沟抬垄造杨树林试验。结果表明：滩地开沟抬垄造林降低了杨树林地的相对淹水时间和高度,提高了杨树造林保存率,促进树高和单株材积的生长,提高单位面积蓄积,提高径阶≥12cm的林木的比例和林分木材的价值;开沟抬垄造林能显著提高杨树林分生物量和生产力,开沟抬垄营造的7年生杨树单株生物量、保存林分生物量、林分平均净生产量分别为32.32kg／hm^2、32.34t／hm^和4.62t／（hm^2·年）,分别是未开沟抬垄的1.43、3.16和3.2倍;滩地开沟抬垄与未开沟抬垄营造的杨树林各器官生物量大小均遵循干〉根〉皮〉枝〉叶的规律;开沟抬垄造杨树林增加的木材效益比开沟抬垄工程总投入多,经济效益较好,第1个轮伐期年均利润为166.3元／（hm^2·年）,投入产出比是0.95。     

安徽淮河堤防杨树防护林生长与土壤养分的关系

对安徽淮河堤防Ⅰ-69杨防护林生长与土壤养分关系进行了调查分析,结果表明,不同立地条件下杨树防护林生长差异显著,10~12年生林分年平均蓄积生长量为10.45~23.27 m3.hm-2.a-1,林分生产力水平的高低主要受控于土壤有机质含量及氮、磷有效性。     

Fine root biomass of Scots pine stands differing in age and soil fertility in southern Finland

The biomass of small and large fine roots (相似文献   

Two-decadal trends in aboveground litterfall and net primary production in self-thinning Pinus banksiana stands in Wood Buffalo National Park,NWT, Canada

We estimated the aboveground net primary production (ANPP) in five self-thinning jack pine (Pinus banksiana) stands in Wood Buffalo National Park, NWT, Canada. The stands (11 to ca.175 years old) were selected to examine the relationship between stand density and tree size and its effect on carbon dynamics. Aboveground litterfall was collected from each stand from 1997 to 2012. Stand biomass was estimated by measuring tree size every 5 years and estimating the individual mass using allometric relationships. ANPP was then estimated by summing the litterfall mass, dead stem mass increment and stand biomass increment. We determined the proportional contribution of each organ to the total litter and the seasonal pattern of needle litterfall. There was a lower turnover rate of aboveground biomass in older stands than younger stands. The ANPP increased in the youngest stand (<30 years old) showed a decreasing trend in stands >50 years old. The maximum ANPP was estimated to be ca. 500?g m^?2 year^?1 in dry matter, which was found in 30–50 year-old stands.     

Aboveground biomass and net primary production of semi-evergreen tropical forest of Manipur, north-eastern India

The aboveground biomass dynamics and net primary productivity were investigated to assess the productive potential of Dipterocarpus forest in Manipur, Northeast India. Two forest stands (stand I and II) were earmarked randomly in the study site for the evaluation of biomass in the different girth classes of tree species by harvest method. The total biomass was 22.50 t·ha-1 and 18.27 t·ha-1 in forest stand I and II respectively. Annual aboveground net primary production varied from 8.86 to 10.43 t·ha-1 respectively in two forest stands (stand I and II). In the present study, the values of production efficiency and the biomass accumulation ratio indicate that the forest is at succession stage with high productive potential.     

Effects of thinning level and site productivity on age-related changes in stand volume growth can be explained by a single rescaled growth curve

In this study, I developed a nonlinear mixed-effects model based on the Richards curve that describes the effects of thinning and site productivity on stand volume growth. I fitted the model to data from 29 long-term experimental monitoring plots in Japanese cedar (Cryptomeria japonica D. Don) plantations in northeastern Japan. Simulations using the model on high-productivity sites and at moderate thinning intensities indicated that net yields after ca. 80 years were lower in unthinned stands than in thinned stands; in other cases, such as at younger ages and at sites with low and average productivities, net yields were similar for each thinning intensity (including no thinning). These results could be attributed to the fact that the net current annual increment in stand volume (CAI_net) in the thinned stands exceeded that of the unthinned stands after a certain age (the “inversion” age) and to the negative correlation between site productivity and the inversion age. In addition, I found that a single rescaled growth curve was capable of describing the growth in stand volume at sites with different thinning histories and site productivities. This rescaled curve simply and clearly explained the effects of thinning and site productivity on stand volume growth. The existence of a single curve suggests that the positive effect of thinning on stand volume growth does not depend on site productivity, but it will require patient measurements over longer periods to reveal a positive effect at sites with low productivity.     

杨树速生林适宜采伐期的测定研究

确定杨树速生林适宜采伐期,与树种结构、林龄、林分密度和林木连年生长量有直接关系,当林分密度进入极限时,林木连年生长量开始从高峰下降,说明林分已进入适宜采伐期,实行适宜采伐期采伐作业,可获最佳经济效益。     

Thinning alters crown dynamics and biomass increment within aboveground tissues in young stands of Chamaecyparis obtusa

The stand density of a forest affects the vertical distribution of foliage. Understanding the dynamics of this response is important for the study of crown structure and function, carbon-budget estimation, and forest management. We investigated the effect of tree density on the vertical distribution of foliage, branch, and stem growth, and ratio of biomass increment in aboveground tissues; by monitoring all first-order branches of five trees each from thinned and unthinned control stands of 10-year-old Chamaecyparis obtusa for four consecutive years. In the control stand, the foliage crown shifted upward with height growth but the foliage quantity of the whole crown did not increase. In addition, the vertical distribution of leaf mass shifted from lower-crown skewed to upper-crown skewed. In the thinned stand in contrast, the foliage quantity of individual crowns increased two-fold within 4 years, while the vertical distribution of leaf mass remained lower-crown skewed. The two stands had similar production rates, numbers of first-order branches per unit of tree height, and total lengths of first-order branches. However, the mortality rate of first-order branches and self-pruning within a first-order branch were significantly higher in the control stand than in the thinned stand, which resulted in a higher ratio of biomass increment in branch. Thinning induced a higher ratio of biomass increment in foliage and lower in branch. The increased foliage quantity and variation in ratio of biomass increment after thinning stimulated stem growth of residual trees. These results provide information that will be useful when considering thinning regimes and stand management.     

南埂长江滩地杨树人工林生物量及生长量规律研究

本文利用在安徽省安庆市大观区海口镇南埂长江滩地不同时期所做的杨树解析木资料,较为系统地研究了滩地杨树人工林的生物量及生长量,并建立了其材积生长方程和生物量方程。结果表明：长江滩地杨树林分具有较高的生长量和森林生产力,并且能够维持较长时间的快生长,这有利于长期维持滩地森林生态系统的稳定性,持续有效地发挥“抑螺防病林”的功能,同时也具有较高的经济效益;长江滩地杨树的数量成熟迟于一般杨树林分,约在22年左右;长江滩地杨树树干生物量的分配比例在60％以上,树枝17％左右,树叶3％左右,树根大致在13％-19％之间,树干生物量分配比例随年龄增加而增加,枝叶则略有下降,而树根下降较多。