不同林龄尾巨桉林木碳贮量研究

以雷州半岛6个林龄尾巨桉林分为研究对象,分析了不同林龄尾巨桉林分的单株生物量和林分碳贮量变化特征。结果表明：随着林龄的增长,尾巨桉林分的平均树高、平均胸径和单木生物量均有所增加,但各个器官所占比例的变化趋势不同：树干和树叶所占比例增加,树枝、树皮和树根所占比例降低。1—7年生尾巨桉林分碳贮量在1822．56—33925．75kg·hm2,随着林龄增长,尾巨桉林分的碳贮量呈逐渐增多的趋势。树干有机碳贮量所占比例迅速增大,树枝、树皮和树根的逐渐减小,树叶所占比例先增大后减小。     

桂西北马尾松人工林生物量生长规律及其分配模式

对桂西北马尾松人工林的单木生物量相对生长模型、林分生物量及其分配规律的研究结果表明:(1)马尾松树干、树皮、地上生物量、地下生物量以及总生物量以方程W=a×(D2H)b的拟合效果为好,树枝和树叶以方程W=a×Db的拟合效果为好。(2)不同林龄马尾松林分标准木各器官的生物量所占总生物量的百分比出现明显的变化。在不同的马尾松林龄中,各器官的生物量均以树干为最高,同时随着林龄的增加,其所占百分比例出现明显的升高,随着林龄的继续增大,其所占百分比逐渐趋于稳定。与树干的变化趋势相反,树皮、树枝、树叶和树根的所占总生物量百分比随着林龄的增加而呈现下降。(3)林分生物量随着林龄的增大而出现明显的增加。林分树干和树枝的总生物量和所占百分比均出现明显的上升;树皮和树叶的总生物量随林龄的增加而增加,但其所占乔木层总生物量的百分比则随着林龄的增加而下降;地下生物量随林龄的增大而无显著变化。     

不同年龄阶段侧柏林生物量结构分析

采用样木法对清西陵侧柏人工林林分不同林龄生物量进行了调查,结果显示:单株侧柏因林龄不同,其各器官生物量分布规律也有差异(树干大于树枝大于树叶),且随年龄增大而增大,侧柏的树干、树枝及树叶占地上总生物量的比例因林龄的增加而产生变化,其中,树干生物量占全株地上总生物量的比例会随林龄增加而增加,由11a生的50.6%增加到20a生的54.8%,32a生侧柏林以后的增长趋于平稳;侧柏单株树枝生物量占地上总生物量的比例随林龄增加变化不明显;侧柏单株树叶生物量占地上总生物量的比例随林龄增加而逐渐减少,由11a生的23.5%降至45a生的13.5%。单株树干所占总生物量比例随年龄增加而增大,枝所占总生物量比例有所增大,而叶所占总生物量比例有所减少;林分乔木层各器官生物量及地上部分总生物量随林龄的增加而增加。     

马尾松人工幼林营养元素积累及其分配特征

通过野外调查和实验室分析,对马尾松各器官生物量及营养元素含量、积累量和分配进行了研究。结果表明:1)2.5a生和8.5a生马尾松不同器官营养元素总含量大小顺序分别为树叶树根树枝树干、树叶树枝树根树干,各器官营养元素含量大小顺序分别为NKCaPMgMnFeBZnCu和NCaKMgPFeMnZnBCu;2)2.5a生和8.5a生马尾松树体营养元素总积累量分别为180.69,617.46g/株。2.5a生和8.5a生各器官营养元素积累量大小次序分别为树叶树枝树干树根、树干树枝树叶树根。2.5a生和8.5a生马尾松树体各种营养元素积累量大小次序分别为NCaKPMgMnFeZnBCu和NCaKMgPFeMnZnBCu。马尾松幼林不同器官营养元素积累量随林龄增长而增加。树体各营养元素的分配与各器官生物量不成正比例关系。     

林龄和立地条件对杉木林乔木层生物量分配的影响

于2010—2019年，采用样地调查法对福建省三明市将乐县国有林场杉木人工林的地况因子、林况因子及乔木层的生物量进行调查；通过构建引入林龄和地位指数的相容性生物量模型，估算杉木林乔木层各组分生物量，研究各组分生物量分配规律与立地条件和林龄之间的关系。结果表明：引入林龄和地位指数的相容性生物量模型，能够更好地反映林龄和立地条件对生物量异速生长规律和分配的影响；杉木各组分生物量的分配比例受林分林龄的影响显著，其中干材、树皮生物量占比随林龄的增大而增大，树叶、树根则相反，树枝生物量占比先增加后减小；除树枝外，立地条件不会改变各组分生物量占比随林龄的变化趋势，但会影响各组分生物量占比大小。在立地条件较好的林分中，树干生物量占比较大，树叶、树根的分配则相反。研究结果可为杉木人工林碳汇经营提供参考。     

不同林龄两代杉木人工林生物量积累特征研究

通过定位观测取得的数据,对不同林龄两代杉木人工林生物量积累特征进行研究,并对第1代、第2代杉木林进行了比较.结果表明:7、14、20年生两代杉木单株生物量和林分生物量均随林龄增大而增加.树叶、树枝生物量随着林龄增长所占比例逐渐减小,但树干生物量比例逐年增大,树根生物量变化不明显.7、14、20年生第2代杉木林的单株生物...     

福建省火炬松造林密度试验

在火炬松世行造林试验中,设计了4种密度,结果表明,不同密度对火炬松6年生林分的树高无显著影响,对6年生火炬松的胸径、材积、蓄积的影响达显著水平,对14年生火炬松的树高、胸径、材积、蓄积的影响均达极显著水平；不同密度、林龄火炬松各器官生物量的分配规律为：树干＞树根＞树枝＞树叶,各器官生物量的分配比例相对稳定。     

辽宁省不同林龄油松林分生物量分析

文章对辽宁省不同林龄的油松林分总生物量及各分项生物量的分配进行了分析,随着林龄的增长,树干生物量所占比例呈现增加趋势,树枝、树叶和树根生物量的占比都呈不同程度的降低。在各个生长阶段,各分项所占平均比例排序均为树干树根树枝树叶。同时以较易调查的林分因子为自变量建立了总生物量和各分项生物量模型,模型拟合精度较高,可以为当地油松林分生物量调查提供参考。     

塞罕坝机械林场华北落叶松生物量研究

为了给塞罕坝人工华北落叶松生物量建模提供依据,采用样木调查法,对不同径阶和树高华北落叶松的树根、树枝、树皮、树叶、树干木质部的含水率进行测定,计算各器官的生物量、总生物量及各器官在单株总生物量中所占的比例,结果表明:华北落叶松单株器官生物量的分配,在胸径达到20cm以前,树干木质部分的生物量所占比例呈逐渐增大的趋势;当胸径在20cm以上,树干木质部分的生物量所占比例相对有所降低,树冠(包括树枝与树叶)生物量与树干(包括树干木质与树皮)的生物量在单株生物量中所占的比例呈现此消彼长的趋势,而树根所占的生物量比例基本趋于稳定,大约占20%左右;此外,应用2种生物量模型W=a(D2 H)b和W=aDb进行拟合,经比较分析发现,W=aDb模型不仅方便而且精度更高,应为首选模型。     

不同林龄桉树固碳放氧量的研究

对广东省丰顺县不同林龄桉树人工纯林开展研究,旨在阐明桉树林龄的变化对其固碳放氧量的影响。结果表明:桉树人工林平均树高、胸径和公顷蓄积随着林龄增长均有所增加。1～6 a桉树人工林的保存率由95%逐步降低至90%;桉树各器官生物量随着年龄增长均增加,但各器官生物量所占比例却有不同的变化趋势。1～6年生桉树各器官生物量按大小排序均为:树干树根树皮树枝树叶;随着林龄的增长,桉树吸收CO_2量、放氧量以及碳储量均逐年增加,在前5 a碳储量平均增量为5.7 kg,生长较快,第6 a碳储量仅增加1.9 kg,增长速度出现变缓趋势。     

Biomass and carbon pools of disturbed riparian forests

Quantification of carbon pools as affected by forest age/development can facilitate riparian restoration and increase awareness of the potential for forests to sequester global carbon. Riparian forest biomass and carbon pools were quantified for four riparian forests representing different seral stages in the South Carolina Upper Coastal Plain. Three of the riparian forests were recovering from disturbance (thermal pollution), whereas the fourth represents a mature, relatively undisturbed riparian forest. Above and belowground carbon pools were determined from linear transects established perpendicular to the main stream channels and spanning the width of the riparian area. The objective of this study was to quantify the biomass and carbon pools in severely disturbed, early successional bottomland hardwood riparian forests and to compare these values to those of a less disturbed, mature riparian forest.

Aboveground biomass in all four riparian forests increased during the 2.5-year investigation period. The total carbon pool in these South Carolina Coastal Plain riparian forests increased with forest age/development due to greater tree and soil carbon pools. The mature riparian forest stored approximately four times more carbon than the younger stands. The importance of the herbaceous biomass layer and carbon pool declined relative to total aboveground biomass with increasing forest age. As stands grew older fine root biomass increased, but an inverse relationship existed between percentages of fine root biomass to total biomass. The root carbon pool increased with forest age/development due to a combination of greater fine root biomass and higher root percent carbon.

Aboveground net primary production (NPP) in young riparian forests rapidly approached and exceeded NPP of the more mature riparian forest. As a woody overstory became established (after 8–10 years) annual litterfall rate as a function of NPP was independent of forest age and litterfall amount in the young riparian forests was comparable to mature riparian forests. Biomass in the riparian forest floor and carbon pool declined with increasing riparian forest development. Woody debris in these riparian forests comprised a relatively small carbon pool. An understanding of bottomland hardwood riparian forest carbon pools at different stages of succession allows us to assess how time since disturbance influences these pools, leading to a better understanding of the recovery processes.     

Analysis of spatio-temporal changes in forest biomass in China

Forests play a central role in the global carbon cycle.China's forests have a high carbon sequestration potential owing to their wide distribution,young age and relatively low carbon density.Forest biomass is an essential variable for assessing carbon sequestration capacity,thus determining the spatio-temporal changes of forest biomass is critical to the national carbon budget and to contribute to sustainable forest management.Based on Chinese for-est inventory data (1999-2013),this study explored spatial patterns of forest biomass at a grid resolution of 1 km by applying a downscaling method and further analyzed spatio-temporal changes of biomass at different spatial scales.The main findings are:(1) the regression relationship between forest biomass and the associated influencing factors at a provincial scale can be applied to estimate biomass at a pixel scale by employing a downscaling method;(2) for-est biomass had a distinct spatial pattern with the greatest biomass occurring in the major mountain ranges;(3) forest biomass changes had a notable spatial distribution pattern;increase (i.e.,carbon sinks) occurred in east and southeast China,decreases (i.e.,carbon sources) were observed in the northeast to southwest,with the largest biomass losses in the Hengduan Mountains,Southern Hainan and Northern Da Hinggan Mountains;and,(4) forest vegetation functioned as a carbon sink during 1999-2013 with a net increase in biomass of 3.71 Pg.     

毛乌素沙地樟子松壮苗深栽造林效果分析

为提高毛乌素沙地樟子松的造林效果,开展了壮苗深栽试验。在总结壮苗深栽技术要点的基础上,分析了壮苗深栽的造林效果及其生物量分配格局调节规律。结果表明,壮苗深栽可以提高根系分布层的土壤含水量,从而提高造林保存率和林木生长量。且随着林分年龄的增大,壮苗深栽与常规栽植林分的生长量差异越来越大。究其原因,壮苗深栽提高了各个构件的生物量投资,同时将更多的生物量分配于地上部分的生长发育。     

Forest biomass and root–shoot allocation in northeast China

Temperate and boreal forests act as major sinks for atmospheric CO₂. To assess the magnitude and distribution of the sinks more precisely, an accurate estimation of forest biomass is required. However, the determinants of large-scale biomass pattern (especially root biomass) are still poorly understood for these forests in China. In this study, we used 515 field measurements of biomass across the northeast part of China, to examine factors affecting large-scale biomass pattern and root–shoot biomass allocation. Our results showed that, Picea & Abies forest and coniferous & broadleaf mixed forest had the highest mean biomass (178–202 Mg/ha), while Pinus sylvestris forest the lowest (78 Mg/ha). The root:shoot (R/S) biomass ratio ranged between 0.09 and 0.67 in northeast China, with an average of 0.27. Forest origin (primary/secondary/planted forest) explained 31–37% of variation in biomass (total, shoot and root), while climate explained only 8–15%, reflecting the strong effect of disturbance on forest biomass. Compared with shoot biomass, root biomass was less limited by precipitation as a result of biomass allocation change. R/S ratio was negatively related to water availability, shoot biomass, stand age, height and volume, suggesting significant effects of climate and ontogeny on biomass allocation. Root–shoot biomass relationships also differed significantly between natural and planted forests, and between broadleaf and coniferous forests. Shoot biomass, climate and forest origin were the most important predictors for root biomass, and together explained 83% of the variation. This model provided a better way for estimating root biomass than the R/S ratio method, which predicted root biomass with a R² of 0.71.     

马尾松人工林生物量及生产力变化规律研究Ⅱ.不同林龄生物量及生产力

采用以空间代时间的径级标准木收获法,研究了从幼林到成熟林的5种不同林龄的林分生物量.结果表明:树木干物质是按一定比例分配到各器官,其比例与径阶大小无关,而与发育阶段有关.林分平均木及林分各器官生物量均随林龄增加而增加,平均木在18 22a生物量年增加速率最大,而林分是在12 18年生.树干生物量所占百分比(占48%以上)随林龄增加而增加,而枝、叶、皮刚好相反,18年生以前,根所占百分比随林龄增加而下降,此后趋于稳定.各器官所占百分比由大到小依次为:干、枝、根、皮、叶.8、12、18、22、30年生的林分乔木层生物量分别为:33.94、89.94、204.51、223.71、234.14t.hm-2,净生产力为:6.24、11.14、15.63、14.07、11.93t.hm-2.a-1.中龄前,生物量按径阶分布的规律与株数按径阶分配规律相似,多呈左偏态,此后呈右偏态,峰值比株数按径阶分布向右移动1 2个径阶.培育纸浆材林,在18年生前利用最佳.     

不同经营模式杉木林的生物量研究

为揭示不同营林模式对杉木林生物量分配格局的影响,作者以不同林龄的杉木纯林、杉木×马尾松混交林和杉木×枫香混交林为对象,研究了其乔木层生物量分配格局,结果表明：在22年生杉木林下套种马尾松和枫香,经18年培育之后,与40年生杉木纯林相比,林分总生物量无显著差异,但林分净生产力得到一定程度的提高,尤其以林下套种阔叶树种枫香的样地提高更为明显,不同营林模式乔木层生物量的空间分配皆表现为千〉根〉枝〉叶,干器官的生物量在总生物量中占较大比重,并随着林龄的增加而逐渐增加,混交林可有效提高林分地上和地下部分生物量和生产力,改善其生物量分配格局,提高森林对空间的利用率。     

湖北省太子山森林植被碳密度及碳储量研究

以湖北省太子山林场管理局2009年森林二类清查数据资料为基础,运用生物量转换因子连续函数法,从森林类型、林龄和林分起源角度,对该区域森林植被碳储量和碳密度进行估测.研究表明：湖北省太子山林管局森林植被碳储量为233855.66 t,平均植被碳密度为39.31 t·hm^－2.人工林碳储量高于天然林4．02倍,该区域森林植被碳储量主要由人工林提供.按森林类型划分,不同森林类型碳储量和碳密度均表现为针叶林＞阔叶林＞针阔混交林;按林龄划分森林碳储量,幼龄林＞成熟林＞中龄林＞近熟林＞过熟林,各林龄碳密度随林龄的增加表现为先增加后降低的趋势,中幼林森林面积和碳储量所占比例较大,该区域森林植被碳储量潜力巨大.     

Simulation of the biomass dynamics of Masson pine forest under different management

Introduction Masson pine (Pinus massoniana) is important both economically and ecologically in subtropical mountainous areas in China, and it is vital not only as an important source of commercially harvested timber and charcoal fuel, but also as a pionee…     

Modeling compatible single-tree aboveground biomass equations for masson pine (Pinus massoniana) in southern China

Because of global climate change,it is necessary to add forest biomass estimation to national forest resource monitoring.The biomass equations developed for forest biomass estimation should be compatible with volume equations.Based on the tree volume and aboveground biomass data of Masson pine(Pinus massoniana Lamb.) in southern China,we constructed one-,two-and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations.The prediction precision of aboveground biomass estimates from one variable equation exceeded 95%.The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height,although the contributions to regressions were statistically insignificant.For the biomass conversion function on one variable,the conversion factor decreased with increasing diameter,but for the conversion function on two variables,the conversion factor increased with increasing diameter but decreased with increasing tree height.