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新栽培区尾叶桉人工林的生物量和生产力 总被引:1,自引:0,他引:1
采用收获法和相对生长法对田林县不同年龄尾叶桉人工林的生物量和生产力进行了研究.结果表明:尾叶桉林分生物量随着年龄的增长而增加,0.4年生林分生物量为6.18 t/hm2,2.4年生林分为32.09 t/hm2,4.4年生林分为80.59 t/hm2;不同年龄林分的净生产量分别是14.82 t/(hm2.a)(0.4年)、13.02 t/(hm2.a)(2.4年)和19.90 t/(hm2.a)(4.4年);不同林分尾叶桉各器官生物量分配存在较大差异,在林分生长初期,以枝条和叶所占比例较高,干材比例较小,随着林分年龄的增长,干材和根的比例明显增大,叶的比例有所下降;不同年龄林分各器官生物量分配的大小顺序为:0.4年生林分为枝(37.54%)>叶(31.38%)>干材(14.77%)>根系(11.69%)>皮(4.62%),2.4年生林分为干材(50.83%)>根(18.43%)>枝(12.32%)>皮(10.22%)>叶(8.20%),4.4年生林分为干材(47.29%)>枝(18.42%)>根(14.73%)>叶(10.80%)>皮(8.75%);造林后第2年林分的平均枯梢率为84.62%,第3年为63.46%,枯长率分别为21.64%和27.15%.田林县尾叶桉具有较高的生物生产力,但林木干材比例偏低、枝和叶比例偏高以及枯梢严重等影响着林分的生长量和经济产量. 相似文献
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《林业资源管理》2013,(6):76-80
采用树干解析法分析了闽北高海拔地区湿地松人工林的生物量和生长量。结果表明:湿地松各器官的生物量大小排序为干>枝>根>叶>果,水分分配为根>干>叶>枝,单株平均含水率为56.19%;33a生湿地松种群总生物量为396 735kg/hm2,净生产力为12 022.27 kg/(hm2·a);33a生湿地松人工林的树高、胸径、单株材积分别达到了21m,24.6cm,0.380 5m3;胸径和树高分别出现3次和4次生长高峰,且高生长期与低生长期年份基本一致。树高连年生长曲线与平均生长曲线出现多次相交,材积的变化幅度相对较小。运用SPSS 13.0拟合了胸径、树高、材积总生长量与树龄之间的回归方程,拟合模型精度较高。 相似文献
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采用相对生长法研究了中幼龄毛白杨优良无性系生物量增长及其各器官相对生物量的积累和分配规律.结果表明:毛白杨生物量以干才占主导;6a生以前,各器官生物量分配不稳定,6~8a生以后,其分配趋势为干材>根>枝>干皮>叶;3个优良无性系每年单位面积的生物量和固定的太阳能均为对照的2~4倍;净光合效率比对照高24.41%~27.81%.并建立了各器官生物量增长的数学模型. 相似文献
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《林业实用技术》2015,(4)
选用4种不同密度马尖相思幼林,采用单因素、随机区组设计进行造林试验。对4种不同密度3年生马尖相思幼林的胸径、树高、冠幅、枝下高生长进行了观测分析,用标准木的各器官干质量估测林分的生物量。结果表明:不同密度对3年生马尖相思幼林的胸径、树高、冠幅生长无显著性影响,对枝下高生长的影响到第3年时已趋明显,差异显著。3年生幼林生物量以密度为2 505株/hm2最高,鲜质量达59.24t/hm2,气干质量达24.33t/hm2;3 330株/hm2最低,鲜质量为42.97t/hm2,气干质量为17.33t/hm2。不同密度3年生幼林各器官生物量气干质量所占比率均为干>叶>枝>根>皮。 相似文献
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对不同高度等级2年生红豆树Ormosia hosiei容器苗各器官的生物量和水分分配规律进行研究。结果表明,处于不同高度时期各器官生物量和水分分配规律不同:(1)红豆树容器苗单株生物量及各器官生物量都随着高度的增加而增加,各器官生物量分配顺序从大到小依次为叶生物量根生物量干生物量枝生物量;根、干、枝、叶生物量分配随着高度的增加呈现一致增加的趋势;苗高与地径,苗高、地径与根、干、枝、叶生物量以及地上、地下和单株生物量都具有极显著相关关系(P0.01);(2)苗高在40~45 cm的红豆树根、干、叶和单株含水率均达到最大值,其中枝含水率在各器官含水率中最大,达到67.04%,而苗高在65~70 cm的根、干、叶及单株含水率均为最低值,但枝含水率却是在此高度的时候达到最大值;(3)根、干和单株含水率与各器官生物量呈极显著负相关(P0.01),枝含水率与各器官生物量呈不显著相关,叶含水率与根、干生物量呈现显著负相关(P0.05),与叶、单株生物量呈现极显著负相关(P0.01)。 相似文献
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毛竹人工林生物量结构变化研究 总被引:1,自引:0,他引:1
对会同县经营10年的毛竹人工林林分生物量结构变化进行研究,结果表明:人工竹林不同龄级、径级、枝下高级和不同密度的生物量分配,81.2%生物量分配于1~7年生幼龄、壮龄、中龄竹;83.4%生物量分配于胸径11~15 cm之内;90.7%的生物量分配于枝下高7~11 m之内;86.2%生物量分配于立竹4 500~9 000株/hm2的林分之内,其中立竹4 500~6 750株/hm2的中密度林分,群体和个体生物量都表现出较高的水平。试验竹林垂直总生物量和地上、地下生物量比对照竹林分别增多1.81倍和1.97倍、1.56倍,地上与地下生物量之比为1.774∶1,经济系数为0.501,生物量从大到小的排序,地上部分为秆﹥枝﹥叶﹥凋落物﹥竹箨﹥退笋,地下部分为鞕根﹥竹鞕﹥竹蔸﹥竹根﹥死鞕。 相似文献
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Annika Kangas Mikko Nurmi Jussi Rasinmäki 《Scandinavian Journal of Forest Research》2014,29(7):154-165
The Finnish state forest enterprise, Metsähallitus, defines the regional harvest levels for a 10-year period in a strategic-level natural resources plan. Although this plan defines stand-level harvest schedules for all stands, in practice, it cannot be used, as the harvests need to be clustered in time and in space. It is applied by giving each subregion goals they need to fulfill in a tactical level planning process, and the harvests are manually clustered into predefined groups of adjacent stands (departments). In this study, we developed a hierarchical optimization process making use of departments for clustering the harvests. For each of the departments, 91 different stand-level harvest schedules (plans) were determined using incomes from one period and the forest value at the end as objectives. The department-level plans were then used as alternatives in a region-level goal optimization problem. The resulting hierarchic plan was compared to the stand-level solution of the strategic-level plan which served as a benchmark plan. The hierarchical plan clustered the harvests and achieved the goals set better than the benchmark plan, but the net present income was 3.3% lower. The approach turned out usable, but further developing of the approach is needed to reduce the costs of clustering. 相似文献
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Soil changes after traffic with a tracked and a wheeled forest machine: a case study on a silt loam in Sweden 总被引:2,自引:0,他引:2
Alterations to some soil physical parameters were evaluatedafter passes by a tracked forest machine and a wheeled one ofequal mass (about 20 000 kg). Measurements were made after arange of machine passes, with a maximum of eight. The measuredsoil physical parameters were dry bulk density, penetrationresistance, intrinsic air permeability, saturated hydraulicconductivity, porosity and pore-size distribution. Rut depthwas also measured. Although the wheeled machine caused deeper ruts than the trackedone, alterations caused by the two machines to the measuredsoil parameters were similar, except in the uppermost 510cm. The wheeled machine caused a decrease in bulk density at5 cm depth, whereas the tracked machine caused an increase,despite its lower ground pressure. 相似文献
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The Silvopastoral Project is being implemented by CATIE in the Atlantic humid lowland of Costa Rica, in order to develop alternatives
to the current destructive mode of livestock production. The overall approach is briefly described and two superimposed on-farm
experiments are discussed in more detail. The main constraints for on-farm research within the project are analysed: the limited
previous knowledge of the area and of the local species, the difficulty of achieving a common understanding about research
with collaborating farmers, the need for additional staff supervision and the complexity of the statistical analyses. An attempt
is made to draw lessons from the ongoing project regarding how to resolve the apparent contradiction between rigorous scientific
requirements and questions of immediate value to extension, the compromises to be achieved between different types of evaluation
(statistical, risk, etc.) and the potentials and limitations of farmers' participation in research. 相似文献
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Kebin Zhang Rui Li Yunfang Liu Baitian Wang Xiaohui Yang Ruiping Hou 《Frontiers of Forestry in China》2008,3(3):326-333
The spatial distribution characteristics of plant communities in a wetland-dry grassland ecosystem in arid and semi-arid regions
in northwestern China and the main factors affecting the distribution pattern were studied. The Siertan wetland in the Haba
Lake Nature Reserve was the study area. Four transect lines, each about 1 km long, were set up in the growing season along
the biotope gradient in four directions: east, northeast, west and northwest. Attributes measured include frequency of occurrence,
height, density, coverage, biomass and environmental soil factors. The data were analyzed using a two-way indicative species
analysis (TWINSPAN), detrended correspondence analysis (DCA) and Spearman correlation coefficients. On this basis, the vegetation
in the Siertan wetland was classified into three types and 14 associations. The first vegetation type was halophytic marsh
vegetation, mainly distributed in the wetland zone. This type largely contains halophyte and hygric plants and its representative
association is Phragmites communis + Kalidium foliatum. The second type was meadow vegetation, distributed in the ecotone. The meadow vegetation species are mainly mesophytic and
their representative association is Nitraria tangutorum + Pennisetum flaccidum. The third vegetation type is grassland vegetation, which mainly consists of mesophytic and xerophytes, distributed in the
arid grassland zone. The representative association of the third vegetation type is the association of Anaeurolepidium secalium + Saussurea runcinata. Correlation analysis between the axes of DCA and environmental soil factors shows that soil moisture content, organic matter,
soil salt content and total nitrogen are the main environmental factors affecting the pattern of vegetation distribution along
the biotope gradients from wetland to arid grassland. Other factors affecting the vegetation are microtopography and grazing
pressure. Additionally, we have reported modifications and improvements to the importance value methodology.
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Translated from Journal of Beijing Forestry University, 2008, 30(1): 6–13 [译自: 北京林业大学学报] 相似文献
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利用RSM模型模拟计算三维水力旋流器模型,分析了计算结果,并且与相关文献比较后认为:三维模型模拟水力旋流器具有一定的可行性,而二维轴对称模型与实际有一定的差距。 相似文献
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为适应我国山地丘陵多、坡度陡和绞盘机作业强度大、维护不便等特点,提升绞盘机的操作性和转运能力,设计了一种无卷筒离合器的轻型绞盘机,阐述了绞盘机总体布置方案和工作原理,设计了采用齿轮传动的新型选筒机构,取代传统绞盘机的卷筒离合器,传动可靠,制造工艺简单,对选筒机构的花键轴和齿轮进行了强度校核,并对绞盘机传动系统的主要零部件进行了选型与设计,利用Matlab对绞盘机卷筒进行了轻量化优化设计,利用Solidworks进行了卷筒三维建模和有限元分析。结果表明,优化后的卷筒强度满足要求。该绞盘机采用新型的选筒机构,结构紧凑,安全可靠,整机轻量化程度高,便于运输,操作简便,可以有效提升绞盘机的工作效率。 相似文献
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Tomohito Sano Takashi Hirano Naishen Liang Ryuichi Hirata Yasumi Fujinuma 《Forest Ecology and Management》2010
A typhoon event catastrophically destroyed a 45-year-old Japanese larch plantation in southern Hokkaido, northern Japan in September 2004, and about 90% of trees were blown down. Vegetation was measured to investigate its regeneration process and CO2 flux, or net ecosystem production (NEP), was measured in 2006–2008 using an automated chamber system to investigate the effects of typhoon disturbance on the ecosystem carbon balance. Annual maximum aboveground biomass (AGB) increased from 2.7 Mg ha−1 in 2006 to 4.0 Mg ha−1 in 2007, whereas no change occurred in annual maximum leaf area index (LAI), which was 3.7 m2 m−2 in 2006 and 3.9 m2 m−2 in 2007. Red raspberry (Rubus idaeus) had become dominant within 2 years after the typhoon disturbance, and came to account for about 60% and 50% of AGB and LAI, respectively. In comparison with CO2 fluxes measured by the eddy covariance technique in 2001–2003, for 4.5 months during the growing season, the sum of gross primary production (GPP) decreased on average by 739 gC m−2 (64%) after the disturbance, whereas ecosystem respiration (RE) decreased by 501 gC m−2 (51%). As a result, NEP decreased from 159 ± 57 gC m−2 to −80 ± 30 gC m−2, which shows that the ecosystem shifted from a carbon sink to a source. Seasonal variation in RE was strongly correlated to soil temperature. The interannual variation in the seasonal trend of RE was small. Light-saturated GPP (Pmax) decreased from 30–45 μmol m−2 s−1 to 8–12 μmol m−2 s−1 during the summer season through the disturbance because of large reduction in LAI. 相似文献
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Shinji Kaneko Noriko Akieda Fumiya Naito Koji Tamai Yasuhiro Hirano 《Journal of Forest Research》2007,12(1):38-44
Rehabilitated forests established about 100 years ago on denuded lands in a hilly granitic area are widespread in the Kyoto–Osaka
area, the second largest megalopolis in Japan. From 2001 to 2003, we monitored the annual nitrogen (N) budget of a rehabilitated
forest watershed dominated by Quercus serrata and Ilex pedunculosa. The ion concentrations of bulk rain in the watershed were similar to those of other watersheds in Japan. The annual bulk
rain input of N ranged from 5.1 to 6.3 kg N ha−1 year−1, and the N deposition from throughfall and stem-flow ranged from 7.5 to 8.2 kg N ha−1 year−1. Estimated annual outputs of N from the stream ranged from 3.3 to 10.6 kg N ha−1 year−1. These results indicate that the amount of N deposition in this area is less than that in urban Tokyo (>10 kg N ha−1 year−1), but the N output of the watershed is comparable with that of the Tokyo area. We discuss the characteristics of N dynamics
in rehabilitated forests, focusing on the biogeochemical processes of this watershed. 相似文献
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英犁 《绿色中国(A版)》2011,(6)
今天,你秒杀了吗?时下,许多网购爱好者都在津津乐道于秒杀话题:马尔代夫度假秒杀价1999元;iPhone手机秒杀价399元……果真有这样的好事?秒杀,就是以压倒性优势一招致命;在极短时 相似文献
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