Effects of Seedbed Density on One-Year-Old <Emphasis Type="Italic">Fraxinus angustifolia</Emphasis> Seedling Characteristics and Outplanting Performance

To assess the effects of seedling spacing on one-year-old seedling morphology in the nursery, seeds of three provenances of Fraxinus angustifolia were sown at five different seedling spacings within rows of two different spacings in the seedbed. Subsequent growth performance of one-year-old seedlings was assessed by planting in the forest. Within row spacings were: 4.3, 5.0, 6.3, 8.3, and 12.5 cm, and there were five rows at 20 cm apart, or three rows at 33 cm apart across the 1.2 m wide seedbeds. Both spacings within and between rows significantly affected shoot height, root collar diameter, root dry weight and shoot dry weight, but not root/shoot ratio. Wider spacings produced larger seedlings, but only the wider spacing within rows significantly increased fine and coarse root mass. Provenances showed significant differences in diameter, root/shoot ratio, and fine and coarse roots, and they also showed interactions with row spacings in height and diameter measurements. One year after outplanting, diameter growth was significantly related to provenance, and diameter growth was 88% greater for trees from 33 cm nursery row spacing than those from 20 cm nursery row spacing.     

栽松留阔模式思茅松的生长及抗松梢螟效果的研究

采用3种不同的留阔抚育方法与常规抚育进行比较,研究各种抚育对思茅松生长及抗松梢螟效果的影响,结果表明:栽松留阔模式对思茅松高、径、冠幅生长和生物量积累影响不大,并且能够保持较多的物种,能有效阻挡松梢螟的侵入,减少松梢螟的数量。     

雷州林业局6年生尾叶桉人工林生长量及生物量研究

桉树是我国南方重要的速生纤维树种,在林业产业中发挥了重要的作用。本文通过对雷州林业局6年生尾叶桉人工林生长量及生物量的调查研究发现:随着树龄的增加,树高及胸径生长也逐渐增加,但树高的增幅逐渐变缓,胸径的增幅变化不大;用最小二乘法来估计尾叶桉各组分的生物量可行性高,模拟效果好;生物量随树龄增加显著,初期树叶生物量增加较快,3a后树干、树皮的生物量积累速度增加,到6a时,树干生物量占总生物量的50%以上,占地上部分生物量的58%以上。研究结果为尾叶桉短周期纤维材的培育提供了重要技术指导。     

Models for estimation of tree volume in the miombo woodlands of Tanzania

Volume of trees is an important parameter in forest management, but only volume models with limited geographical and tree size coverage have previously been developed for Tanzanian miombo woodlands. This study developed models for estimating total, merchantable stem and branches volume applicable for the entire miombo woodlands of Tanzania. We used data from 158 destructively sampled trees, including 55 tree species collected from wide geographical and biophysical ranges. We developed general and site-specific models with diameter at breast height only as the independent variable, together with models with both diameter at breast height and tree height. Leave-one-out cross-validation was used to evaluate the models. The total tree volume models that included diameter at breast height and tree height had appropriate predictive capabilities with relative root mean square errors (RMSE_r) ranging from 30.5% to 47.6%. The RMSE_r for total tree volume models with diameter at breast height only ranged from 39.9% to 48.0%. The site-specific models had slightly lower RMSEr values relative to the general models. The relative mean prediction error of the general total tree volume model with diameter at breast height and tree height was lower (0.6%) than those of the previously developed models (?30.7% to 31.2%). Based on the evaluations, we recommend the general total tree models to be applied over a wide range of geographical and biophysical conditions in Tanzania.     

巨尾桉人工林地径与胸径、树高相关模型的研究

根据巨尾桉人工林样木的地径D0、胸径D及树高H观测数据,采用多模型选优法和逐步回归法求解方程,经分析对比后分别建立了地径与胸径、地径与树高相关的2个数学模型:lnD=3.7275-18.6673/D0;H=32.0925-244.050 3/D0。应用这2个模型,配合一元材积表或二元材积表就可测定被伐木的材积。     

Trends in tree growth and understory yield in silvopastoral practices with southern pines

Farm-level simulators such as the Agroforestry Estate Model use as inputs either yield tables or outputs from forest modeling tools. Forest models rely upon assumptions on site index, stem diameter (DBH) distribution, wood production and tree mortality, which may or may not apply to agroforestry practices. Differences may arise because of the effects on tree growth of unusual spacings and configurations, fertilizer, pruning and grazing regimes, and tree-understory relationships as well. We examined data from published or existing field trials to determine mid- and long-term trends in tree growth and understory yields in silvopastoral practices with southern pines (Pinus spp.) in the United States. Tree DBH and height were greater in practices with improved pastures than in those with spontaneous grasses. Understory affected DBH more than height and, therefore, DBH-height relationships differed among practices. Sigmoidal models predicted that tree height will peak at different age depending on tree spacing and understory type. These changes may affect the accuracy of site indices and wood yield predictions. Livestock gains decrease linearly with increasing stand basal area and stand age, although forage yields sometimes decay exponentially. In one of the experiments, livestock gains decreased to almost zero at age 19 but with stand basal areas at that age markedly differing (14 and 25 m² ha^–1) for two different spacings. Additional data would allow to generate empirical algorithms to obtain farm-level simulations of broad application, improve economic analysis and generate hypotheses to guide future experimental work. This revised version was published online in August 2006 with corrections to the Cover Date.     

高阿丁枫人工林幼中林期的生长规律

对西双版纳普文试验林场的21年生高阿丁枫人工林进行了样地调查, 选取平均木作树干解析, 据此全面分析了高阿丁枫人工林幼中林期的直径、树高、材积生长过程以及林分状态、林木的年生长节律和结实状况,结果表明在此期间高阿丁枫人工林林木的树高生长旺盛期在3~5年, 胸径在3~7年, 材积在15年以后增长较快; 林分中林木分化不明显; 年生长期长。林分尚未进入数量成熟期。     

基于多项生长指标的楠木胸径估测模型研究

收集了楠木胸径、树高、枝下高、冠幅等生长指标,分别参照常规的线性、乘幂、指数、对数及双曲线等单因素变量模型,构建了基于多项生长指标的胸径估测方程.结果表明,基于树高、枝下高、冠幅等多项生长指标的胸径估测较单因素变量估测模型效果更优;楠木胸径估测的首选模型为:D=205.6074e-74.0621/H+0.0027e12...     

水胡黄天然次生林分紫椴更新技术

紫椴是小兴安岭阔叶红松林伴生树种,也是珍贵用材树种。作者在黑龙江省伊春市双丰林业局燕安、青林两个林场,做在不同抚育强度条件下的更新实验,通过树高、高生长、地径、成活率、冻害率、冻害长度、鼠害等调查,进而得出不同抚育强度条件对紫椴树种更新生长的影响。     

富锦地区杂种落叶松优良家系选择初步研究

富锦林木种子园6年生子代测定林生长结果表明:22个处理间和处理内遗传变异丰富,树高平均变异系数为28.91%,胸径平均变异系数为47.79%.处理间生长性状差异极显著,日5×长78-3、日5×兴12、日5×兴9、兴7 ×日77-2树高和胸径生长均排在前5名,入选优良家系,其树高平均值超出当地生产对照、白刀山种源、乌伊岭...     

林木调查因子生长率之间的关系研究

以湖南省会同县的杉木为例，研究了直径生长率与树高生长率、材积生长率的相关关系。采用生长量修正法建立了杉木单木竞争生长量模型，回归拟合出树高生长指数κ的相关模型作为中介模型，推手出了杉木直径生长率、树高生长率、材积生长率的预估模型。     

罗平县水沟林场杉木优树的收集与当代无性系品质鉴定

通过自1999年在罗平县水沟林场开始的杉木优树家系收集建设的实践,总结完善了杉木优树收集区的营建配套技术。收集的曲靖市13个杉木优树及引进的文山20个杉木优树家系的田间试验结果显示:在所收集的各家系无性系间,其高、径、冠幅的生长性状存在着极显著差异,经优中选优,评选出最优无性系11个,可优先在林业生产上推广应用。     

无性系和株行距对杨树人工林生长和树冠结构的影响

【目的】探索无性系、株行距及两者交互作用对杨树人工林的林木生长和树冠结构的影响。【方法】采用双因素随机试验设计,通过调查36块13年生杨树样地胸径、树高、活枝下高和冠幅等指标,以综合指数法构建3个林分综合指数(生长指数、冠形指数、干冠协调指数)。【结果】南林95杨和南林895杨的胸径、树高和生长指数显著高于南林797杨(P <0.05)。南林797杨的冠幅、树冠体积和树冠圆满度显著高于南林895杨,与南林95杨差异不显著(P> 0.05)。株行距为6 m×6 m和4.5 m×8 m的林分胸径、冠形指数和生长指数均显著高于5 m×5 m和3 m×8 m林分,不同密度林分对树高影响不显著(P> 0.05)。在相同密度条件下,正方形和长方形配置对东西和南北冠幅有显著影响,较大株行距促进树冠生长,但对胸径、树高和平均冠幅等影响不显著(P> 0.05)。无性系和株行距对冠长、活冠比、树冠表面积和干冠协调指数影响均不显著,且无性系和株行距对林木生长和树冠结构均无显著交互作用(P> 0.05)。【结论】杨树无性系对林木胸径、树高和树冠结构的影响大于株行距。综合考虑林木生长和树冠结构等两个方面,在类似的立地条件上,相比于其它无性系和配置方式,以南林95杨在种植株行距为6 m×6 m(278株/hm^2)时具有培育大胸径林木的潜力,适于培育速生、优质大径材。     

Growth and yield models for uneven-sized forest stands in Finland

Uneven-sized forestry is gradually gaining popularity and acceptability also in the Nordic countries. This is because of the willingness of the public and some forest owners to avoid clear-fellings and pursue more near-nature forest structures. It has also been realized that the profitability of uneven-sized forestry may be competitive with even-aged forestry. In Finland, management of uneven-sized stands is hampered by the lack of information about the dynamics of such stands, and about the yield and profitability of uneven-sized forestry. This study developed models which allow managers to simulate the growth and yield of uneven-sized stands in Finland, making it possible to predict the yield and analyze the sustainability of different management options. The model set consists of individual-tree diameter increment, height and survival models, and a model for ingrowth. The modeling data consisted of two long-term field experiments of uneven-sized forest management, a set of temporary sample plots measured earlier for growth modeling purposes, and the sample plots of the third National Forest Inventory of Finland. The application area of the models covers all growing sites, all main tree species, and the whole surface area of Finland. According to the models, the sustainable harvest of a fertile (Oxalis-Myrtillus site) uneven-sized Norway spruce forest varies between 5.5 and 7 m³ ha⁻¹ a⁻¹ in Central Finland, depending on the length of the cutting cycle, stand density, and shape of the diameter distribution. It is profitable to harvest large diameter classes more heavily than small ones. Due to the large amount of data the models for diameter increment are highly significant and reliably show the growth level of trees in uneven-sized stands. The weakest models are the ingrowth models, which are based on a clearly smaller data set than the other models.     

Growth and yield models for Dahurian larch plantations

IntroductionDahurianlarch(L8risgmeliniiRupr.)isoneofthemostimportanttimberspeciesinChina.AsaresuItofovercuttingforseveraIdecades,thenaturaIDahurianIarchforestresourcesaredecliningrapidly.PIantationsofdahurianIarchhavebecomeanimportantpartofforestpreserveresourcesinDaxing'anMountains.ConsequentIystudyingthegroWthofDahurianlarchandformingtheforesttabfesareofsignrficancetofor-estproduction.ThispaperpresentsinformationongroWthandyieIdmodeIsofDahurianlarchpIantations.MethodsDataof4O5stema…     

Eucalyptus benthamii Maiden et Cambage growth and wood density in integrated crop-livestock systems

Integrating trees in agricultural landscapes is a promising option to sustainably provide goods for society while increasing biodiversity, securing animal welfare, and generating profits for stakeholders. The choice of the species and knowing how timber quality is affected when trees are integrated to crop and/or livestock enterprises can provide additional insights into the usefulness of timber after harvest, and wood density is one of the most important properties in this regard. The present study aimed to evaluate how Eucalyptus benthamii growth and wood density are affected in integrated crop-livestock systems when compared to monoculture forestry 74 months after planting in subtropical environments. The integrated systems were in an alley cropping design where crop and/or grazed pasture were temporally rotated in between tree lines (14?×?2 m trees spacing), and those systems were compared to monoculture forestry (3?×?2 m spacing). Tree trunks (n?=?60) were sampled in five diameter classes of each treatment by cutting disks in six positions of the trunk (0.1 m, 1.30 m, 25%, 50%, 75% and 90% of the total height) (n?=?360). Trees growing in integrated systems increased trunk diameter at breast height by 24.7%, increased wood fiber production per tree by 17.9%, and produced wood 9.0% less dense than in the monoculture forestry system. Monoculture forestry increased tree height, and there was no difference of trunk volume among the production systems. The results suggest that integrated systems can produce timber with lower wood density, but faster individual tree growth than in forestry monocultures. Such a system can promote sustainable intensification of agricultural production, and enhance provision of complementary ecosystem services.

     

思茅松人工幼林留阔抚育方式的试验研究

在景谷县文朗试验林场的思茅松人工幼林内,进行了3种保留林分中阔叶树抚育方式的试验。通过与常规抚育方式作比较,研究了不同留阔抚育方式,对林地土壤化学性质的影响;对思茅松幼林的生长和抗松梢螟虫害能力的影响。结果表明:思茅松人工幼林的留阔抚育方式对幼林期思茅松的高、径、冠幅生长和生物量的积累影响不大;在3年生前不会引起林地土壤养分下降,并能使林分保留较多的物种,保障思茅松人工林中的生物多样性,有效阻止松梢螟对思茅松幼林的入侵,减少林内松梢螟的数量。因此,思茅松幼林期的留阔抚育方式可在生产中应用。     

5个造林树种在寻甸羊街的生长适应性研究

云南松、华山松、川滇桤木、圆柏、蓝桉等5个树种在昆明寻甸羊街相同立地条件下生长适应性研究结果表明,各树种间生长均存在极显著差异,川滇桤木造林成活率和生长量明显优于其它4个树种,具有较强适应能力,其树高、地径、冠幅等3个生长性状具有较高的一致性,并超过了兰桉、云南松、华山松的各项指标低于川滇桤木,但其地径、冠幅生长性状均高于兰桉,表现出了良好适应性.运用非线性回归分析,建立5个树种的树高和地径的曲线模型,模型拟合性好,相关指数的平方(R2)均在0.98以上,反映出5个树种4 a生的生长规律,为当地造林树种的筛选提供依据和参考.     

A comparative study of the use of laser scanner data and field measurements in the prediction of crown height in boreal forests

Abstract

This study compares the results of the prediction of crown height characteristics using airborne laser scanner (ALS) data and intensive field measurements in boreal forests. The data consisted of 31 sample plots located in Kalkkinen, southern Finland. Crown height models were constructed at both the tree and plot level. Scots pine, Norway spruce and birches were used. The models included independent variables of tree levels, such as tree height, crown area and independent plot-level variables, i.e. canopy height and density quantiles and proportion of vegetation hits. Field measurement-based models used tree height and diameter at breast height as the independent tree-level variables, whereas basal area, mean diameter and height were used as the plot-level variables. The results indicated that the ALS-based crown height models were more accurate than the field measurement-based models when plot-level information was used as independent variables. However, the field measurement-based tree-level models for Scots pine and Norway spruce were more accurate than the ALS-based models. Even so, the accuracy of the different models was very similar and the study data set was quite small. The results of this study can be used for different tree growth studies and for the assessment of tree stock quality in boreal forests.     

杉木人工林生长率模型的研究

生长率 (Ｇｒｏｗｔｈｐｅｒｃｅｎｔａｇｅ)是指某一测树因子的连年生长量与其原有总量的百分比。它是用来说明树木相对生长速度的重要指标 ,常用于对同一树种在不同立地条件下或不同树种在相同立地条件下生长速度的比较及未来生长量的预估等。现以湖南省会同杉木为例 ,就杉木