冀北地区华北落叶松林与樟子松人工林最大生物量及碳贮量比较

为了探究冀北地区华北落叶松与樟子松人工林生物碳汇能力的差异,对其人工林的最大生物碳贮量进行了比较。结果表明:在胸径相同的情况下,单株华北落叶松的干、枝及地上生物量均高于樟子松,而叶生物则相反;在林分平均胸径小于19cm时,华北落叶松人工林地上部分生物量高于樟子松人工林,大于19cm时,樟子松林生物量高于华北落叶松林。在胸径相同时,华北落叶松单株林木的碳贮量高于樟子松;在林分平均胸径小于19cm时,华北落叶松人工林的碳贮量高于樟子松林,大于19cm时,樟子松林高于华北落叶松林。     

人工樟子松林生物量预估模型的研究

根据标准地、解析木及生物量调查资料,建立了人工樟子松林叶、枝、干及全树生物量预估模型,并对模型参数进行了小样本t检验。结果表明,地上生物量与胸径密切相关,樟子松生物量随着树龄的增长而增加,y=aDb Hc为该地区人工樟子松林叶量、枝量、干量和全树生物量的最优模型。     

黑龙江东部地区樟子松人工林单木生物量研究

文章研究以黑龙江东部地区不同年龄、不同密度及不同立地条件的樟子松(Pinus sylvestris var. mongolica )人工林作为研究对象,基于 26块标准地中139株标准木的树干解析和生物量数据,以树木各测树因子为自变量建立樟子松人工林单木的树干、树枝、树叶及全树重的生物量预测模型;并研究了不同年龄樟子松林分的生物量结构.研究结果表明:樟子松人工林单木各分量生物量的最优模型形式均为CAR模型,各最优模型的变量主要为胸径(D)和树高(H)因子,D2H能够很好地反映树干的干重,胸径和树高能够很好地反映树枝、树叶及全树重的变化;樟子松单株生物量随着年龄的增大而增加,树干的生物量占全树重的比例随年龄的增大而增大,枝和叶的生物量变化趋势与树干相反,都随着年龄的增大而减小.文中研究的不同年龄阶段樟子松人工林的生物量结构变化规律及相应的预测模型,可为进一步了解樟子松人工林生物量的积累提供依据.     

杉木人工林生物量变化规律的研究

基于大岗山林区相似立地条件前后3次生物量调查研究资料,结合杉木人工林固定样地长期观测材料对杉木人工林生物量的变化规律作了较为详尽的研究,得到了如下主要研究结果：(1)对于同一林分,除叶生物量和某些枝生物量存在一个减小的时期外(5a至8a时),单株和林分各组分生物量均随林龄的增加而增大。在12a前的林分速生期间,叶、枝、干所占比重微弱增加,致使地上部分比重增加,而根比重减小;在干材期(12～16a),单株各组分所占比例趋于稳定。(2)立地指数对单株和林分各组分的生物量、总生物量以及生物量分配比率均存在显著影响,且这种影响随着林龄的变化而变化,并受初植密度的制约。(3)随着初植密度的增大,单株各组分生物量明显减小,干生物量分配比率在任一林龄时刻均呈下降趋势;由密度所形成的不同林分生物量间的差距随林龄呈减弱的趋势。     

大熊猫主食竹—冷箭竹生物学特性的研究

冷箭竹(Bashania fangiana(A. Camus) Keng f. et Wen)是大熊猫周年喜食的竹种。本文研究了冷箭竹的发笋期、成竹率、竹笋—幼竹的高生长节律、高与径生长的数学相关式、枝叶生长规律、冠幅与基径的生长关系和生物量等。生物量与高、径增长呈正相关,配以幂函数方程,建立了估算二年生以上单株竹各器官生物量的经验公式: W_(地上重)=1.09122(D~2H)~(0.5678) R=0.7332 P=-0.0357 W_秆=0.36396(D~2H)~(0.7757) R=0.9054 P=-0.0179 W_枝=0.22848(D~2H)~(0.6014) R=0.6944 P=-0.0479 W_叶=0.25986(D~2H)~(0.6227) R=0.7336 P=-0.0355 式中R为相关系数,P为系统误差。中等密度冷箭竹生物量1m~2为548.21g,地上部份生物量占总生物量的68.7％,地下部份占31.7％。1m~2有竹株98—128株。为采取措施,抢救和保护大熊猫提供了科学依据。     

密度对大叶相思林生物量分配的影响

以密度为10 000、4 444和1 667株/hm2的4年生大叶相思林为研究对象,对各种不同密度林分中大叶相思各器官生物量分配、生物量径级结构和群落生物量进行了研究。结果表明:各密度大叶相思干的生物量占林分生物量的55%以上,根占14.11%~15.50%,叶占8.34%~10.76%,而在枝和皮的分配比例上差异较大;三种密度大叶相思林的总生物量径阶分配呈正态分布;群落总生物量随林分密度的增加而增加,但林下植物生物量随林分密度的增加而减小。     

沙地樟子松林分密度对林木生长的影响研究

以红花尔基地区沙地樟子松人工林为研究对象,研究林分密度与胸径、树高、生物量等林分因子之间的关系。结果表明,沙地樟子松林分密度对其林木生长因子的影响有显著相关性和规律性,随林分密度的递增,林分平均胸径、平均冠幅、单株材积、林木各器官生物量等各项指标呈减小趋势,二者呈幂指函数相关关系,y=ax~b,对树高影响不显著,但树木的高径比随密度增加呈增大趋势;林分密度对单株和不同器官生物量均有显著影响,随林分密度的增加而减小;林下植被生物量和多样性与林分密度呈极显著负相关。     

不同林分密度楠木人工林生物量初步研究

对福建省顺昌埔上国有林场不同林分密度的37年生楠木人工纯林的生物量及分配进行调查和分析,结果表明:低密度林分(1 500~1 650株.hm-2)楠木单株标准木的平均生物量为56.52 kg.株-1,是高密度林分(2200~2400株.hm-2)的1.39倍。单株标准木各器官的平均生物量均随林分密度的增加而减小;楠木人工林乔木层生物量随林分密度的增加而增大,乔木层总平均生物量在干材中的分配基本不受林分密度的影响(低密度的为53.59%,高密度的为53.72%),在根、皮中的分配比例随林分密度的增大略有增大,而在枝与叶中的分配比例则随密度的增加而下降。各器官生物量均存在干材>根>皮>枝>叶这一规律,其中干材生物量占总物量的比例最大,均超过了50%,最大达到61.11%。     

兴安落叶松天然林树冠生长特性分析

分析兴安落叶松天然林分级木和林分冠生长特性,建立冠幅生长及单株冠、枝、叶生物量模型。结果表明:1)年龄36～39年、密度983～3263株·hm-2林分和年龄54～61年、密度1101～2241株·hm-2林分,随林分密度增加,分级木冠幅差距趋于减小;冠长占树高比例及冠长与冠幅比值增加;优势木、平均木和被压木平均冠积分别达22.479,15.296,6.179和26.864,11.154,8.192m3。2)年龄36～39年和54～61年林分优势木、平均木和被压木平均单株冠生物量分别为0.0082,0.0049,0.0009和0.0079,0.0038,0.0014t;占单株地上生物量平均比例分别达18.5%,24.2%,17.3%和15.9%,12.0%,20.5%。3)单株冠生物量分配中,枝比例高于叶比例,并因分级木不同而不同。年龄36～39年和54～61年林分,优势木、平均木、被压木枝生物量比例分别为76.6%,74.7%,66.6%和76.8%,73.3%,71.4%;叶生物量比例分别为23.4%,25.3%,33.4%和23.2%,26.7%,28.6%。4)年龄36～39年和54～61年林分,林分...     

嫩江沙地樟子松人工林各测树因子数量关系的研究

在对嫩江沙地樟子松人工林生物量调查的基础上,采用回归分析的方法模拟了林龄与胸径、树高和生物量之间以及胸径、生物量与树高之间的数量关系,建立了樟子松林分各器官生物量回归方程,结果表明:林龄与胸径、树高和生物量相关紧密;采用W=aebD模型,地上生物量、树干、树枝、树根的回归方程的相关系数都达到了极显著水平,平均拟合率都大于70%。     

北京地区栓皮栎地上部分生物量的研究

以北京地区栓皮栎人工林为研究对象,应用典型样地调查法和相对生长法对乔木生物量展开研究,结果显示：各器官中生物量大小顺序为树干〉枝条〉叶片,其中树干约占65%,树冠约占35%。通过回归分析探讨了各变量的相关性,并对其各器官的生物量与胸径和树高进行模型拟合。其中树干和树冠的生物量与胸径、树高的拟合方程分别是：W=0.018（D2H）1.09、W=0.9（D）2.128。     

Effects of afforestation on microbial biomass C and respiration in eroded soils of Turkey

ABSTRACT

Soil erosion is a major socioeconomic and environmental problem in Turkey. Almost 86% of the land in Turkey has suffered various degrees of soil erosion. The objective of this study was to determine whether differences in tree species affect soil characteristics and microbial activity in degraded soils. Results from this study showed that organic C (C_org) was highest in the black locust soil at 0–20 cm depth and lowest in the bare land. Microbial biomass C (C_mic) increased in the order black locust > Scotch pine > bare land at two soil depths. One-way ANOVA demonstrated that afforested soils contain significantly higher microbial biomass C than those in the bare land soils. Microbial quotient (C_mic/C_org) of soils are positively influenced by afforestation as the bare land soils exhibited lower microbial quotient than the associated Scotch pine and black locust soils. Microbial communities in black locust soils were energetically more efficient—had a lower metabolic quotient (qCO₂)—with a higher C_mic/C_org compared to those in Scotch pine soils. However, the microbial quotient in our study was still below range and cannot reach equilibrium again 15 yr after afforestation. Restoration of degraded lands could be a long-term process from microbial activity in the observed regions.     

Biomass and carbon sequestration of ponderosa pine plantations and native cypress forests in northwest Patagonia

Fast growth tree plantations and secondary forests are considered highly efficient carbon sinks. In northwest Patagonia, more than 2 million ha of rangelands are suitable for forestry, and tree plantation or native forest restoration could largely contribute to climate change mitigation. The commonest baseline is the heavily grazed gramineous steppe of Festuca pallescens (St. Yves) Parodi. To assess the carbon sequestration potential of ponderosa pine (Pinus ponderosa (Dougl.) Laws) plantations and native cypress (Austrocedrus chilensis (Don) Flor. et Boutl.), individual above and below ground biomass models were developed, and scaled to stand level in forests between 600 and 1500 annual rainfall. To calculate the carbon sequestration baseline, the pasture biomass was simulated. Also, soil carbon at two depths was assessed in paired pine-cypress-pasture sample plots, the same as the litter carbon content of both forest types. Individual stem, foliage, branch and root log linear equations adjusted for pine and cypress trees presented similar slopes (P>0.05), although some differed in the elevations. Biomass carbon was 52.3 Mg ha⁻¹ (S.D.=30.6) for pine stands and 73.2 Mg ha⁻¹ (S.D.=95.4) for cypress forests, given stand volumes of 148.1 and 168.4 m³ ha⁻¹, respectively. Soil carbon (litter included) was 86.3 Mg ha⁻¹ (S.D.=46.5) for pine stands and 116.5 Mg ha⁻¹ (S.D.=38.5) for cypress. Root/shoot ratio was 19.5 and 11.4%, respectively. The low r/s value for cypress may account for differences in nutrient cycling and water uptake potential. At stand level, differences in foliage, taproot and soil carbon compartments were highly significative (P<0.01) between both forest types. In pine stands, both biomass and soil carbon were highly explained by the rainfall gradient (r²=0.94). Nevertheless, such a relationship was not found for cypress, possibly due to stand and soil disturbances in sample plots. The carbon baseline estimated in pasture biomass, including litter, was 2.6 Mg ha⁻¹ (S.D.=0.8). Since no differences in soil carbon were found between pasture and both forest types, additionality should be accounted only by biomass. However, the replacement of pasture by pine plantations may decrease the soil carbon storage, at least during the first years. On the other hand, the soil may be a more relevant compartment of sequestered carbon in cypress forests, and if pine plantation replaces cypress forests, soil carbon losses could cause a negative balance.     

南岭小坑木荷群落地上生物量

森林生物量是评价森林生态系统生产力、研究森林生态系统结构与功能的重要指标,也是深入了解森林生态系统变化规律的重要途径和评估森林碳收支的重要参数(吴仲民等,1998)。亚热带常绿阔叶林是我国面积最大的森林类型,它在世界森林植     

Impact of local slope and aspect assessed from LiDAR records on tree diameter in radiata pine (Pinus radiata D. Don) plantations

Context

Reliable information on tree stem diameter variation at local spatial scales and on the factors controlling it could potentially lead to improved biomass estimation over pine plantations.

Aims

This study addressed the relationship between local topography and tree diameter at breast height (DBH) within two even-aged radiata pine plantation sites in New South Wales, Australia.

Methods

A total of 85 plots were established, and 1,302 trees were sampled from the two sites. Airborne light detection and ranging (LiDAR) was used to derive slope and aspect and to link them to each individual tree.

Results

The results showed a significant relationship between DBH and local topography factors. At both sites, trees on slopes below 20° and on southerly aspects displayed significantly larger DBHs than trees on steeper slopes and northerly aspects. Older trees with similar heights also exhibited a significant relationship between DBH and aspect factor, where greater DBHs were found on southerly aspects.

Conclusions

The observed correlation between tree DBH and LiDAR-derived slope and aspect could contribute to the development of improved biomass estimation approaches in pine plantations. These topographical variables are easily attained with airborne LiDAR, and they could potentially improve DBH predictions in resource inventories (e.g. stand volume or biomass) and support field sampling design.     

泡桐生物量的研究*

本文通过对1－8年生兰考泡桐生物量的研究，揭示了各器官之间的内在联系以及变化规律；泡桐各器官生物量与（－／D1.3^2H)有密切相关关系；树干生物量向上呈递减趋势；在中、幼龄阶段、细枝所占的比例较大，其次为中枝、大枝，6－7年以后大枝最重，其次为中枝、小枝；在树根生物量中，根桩所占的比例最大（40％－60％），各级根系生物量随树龄而异，树龄增加，较粗的根占的比例增大，而直长4cm以下的根呈减小趋势，全株各器官生物量3年生前顺序为：根＞干＞叶＞枝；3年生后为：干＞枝＞根＞叶＞花＞果。     

不同地理种源马尾松造林试验

马尾松不同种源、不同密度、不同整地规格造林试验表明,马尾松不同种源生长差异显著,容县松、上思松、尤溪松三者之间幼林生长表现最好的是容县松,其次是上思松,造林3年后容县松树高、胸径分别达到3．07m、3．51cm,比尤溪松树高、胸径生长分别增加了15．0％、25．8％,单株总生物量、地上部生物量、地下部生物量分别增加了32．5％、31．1％、40．4％;造林2年的宁明松和尤溪松相比,宁明松生长明显优于尤溪松,树高生长增加了16．4％,胸径生长增加了10．1％,单株总生物量、地上部生物量、地下部生物量分别增加了43．4％、40．2％、60．7％;马尾松虽然耐瘠薄,但立地条件的好坏对林分生长影响比较明显,高标准、高质量的马尾松林分需要立地条件的保证;造林密度和整地规格对马尾松幼林生长无显著影响,考虑到生产实际,马尾松造林株行距可采用2．0m×2．0m,马尾松容器苗造林整地规格可以适当降低,穴的规格可以采用25cn×20cn×20cn中穴造林或15cn×15cn×10cm的小穴造林。     

米老排林分生长规律及生物量分布格局研究

通过选定同乐林场米老排林分作为研究对象,采用样地调查与解析木对该树种进行生长特性研究。结果表明:0~6年是米老排幼林生长的阶段,树高、胸径生长均较为旺盛,6~12年材积与胸径生长迅速,而树高生长速度呈现下降趋势,12~16年是米老排生长树高、胸径、材积这三个指标的速生时期,28年以后树高生长速度逐渐下降,材积与胸径生长还呈现上升趋势。米老排的单株和林分生物量排序为干枝根皮叶。     

人工林采伐系统的生物质流分析

针对伐区作业系统层面的人工林采伐作业,确定生物质流的分析方法和分析模型。分别研究南方常见的3种人工林即马尾松林、桉树林和杉木林的采伐系统,利用跟踪观察法进行试验分析,建立相应的生物质材料流动图和跟踪模型。分析结果表明:每公顷获得原木的干物质量以桉树林最大,占立木干物质量的59.16%,达到68 927.05 kg/hm2。在杉木林和马尾松林伐区,原木干物质量分别占立木干物质量的53.35%和53.14%,原木干物质量分别为53 685.05 kg/hm2和50 916.44 kg/hm2。