城市景观红竹林立竹秆形变化规律

为了解城市景观绿化红竹林立竹秆形年际变化规律,对高密度全梢竹一次成景栽植,不实施人工干扰,2005年11月营造的红竹林2007-2009年出笋成竹的立竹胸径、枝下高、全高、胸高壁厚和平均节间长进行了调查。结果表明:随着造林年限的延长,立竹胸径逐年显著增大,而相邻年际间立竹胸径增幅趋于降低;立竹枝下高、全高与立竹胸径呈线性增长关系。立竹相对枝下高、相对全高总体上随造林年限的延长而降低,但不同年度立竹间无显著差异;立竹胸高壁厚随立竹胸径的增大而增大,变化幅度较立竹胸径缓慢,不同年度立竹的相对胸高壁厚差异不显著;随造林年限的延长,立竹平均节间长增大,相对平均节间长减小。不同年度立竹的平均节间长与立竹胸径的差异性表现不一致,相对平均节间长不同年度立竹间无显著差异。     

马尾松桐棉种源造林密度试验初报

通过对马尾松 (桐棉种源 ) (Pinusmassoniana)造林密度试验定位观测表明 ,密度效应明显 ,不同造林密度胸径、蓄积、冠幅、枝下高生长有显著差异 ,但对林分树高生长影响不大。     

造林密度对材用樟树幼林生长和蓄积量的影响

以7年生不同造林密度樟树人工林为研究对象,通过分析林分平均胸径、树高、枝下高、冠幅、单株材积和蓄积量等指标,探究造林密度对樟树幼林林分生长及林分蓄积量的影响。结果表明:1)随着造林密度的增大,樟树林分平均胸径、冠幅和单株材积均呈现减小的规律,造林密度为833株·hm^-2时平均胸径、冠幅和单株材积均最大;2)造林密度对林分平均树高的影响较小,枝下高随造林密度的增大而逐渐增高,造林密度为2 500株·hm^-2时林分枝下高最高;3)随着造林密度的增大,林分蓄积量呈现先增大后减小的规律,造林密度为1 111株·hm^-2时林分蓄积量达到最大值;4)各密度条件下林分胸径生长过程相似,但胸径生长旺盛期的持续时间随造林密度的增大而逐渐减少,造林密度为833株·hm^-2时胸径生长旺盛期持续时间最长;5)不同密度林分单株材积连年生长量呈先增大后减小的趋势,林分单株材积快速增长期持续时间随造林密度的增大而减少;6)综合考虑,樟树人工林适宜造林密度为1 111株·hm^-2,合理造林密度范围为1 111～1 667株·hm^-2。     

马尾松桐棉种源造林密度试验初报

通过对马尾松(桐棉种源)(Pinus massoniana)造林密度试验定位观测表明，密度效应明显，不同造林密度胸径、蓄积、冠幅、枝下高生长有显著差异，但对林分树高生长影响不大。     

福建省麻竹种源造林试验初报

选择福建省自然分布区的6个种源,以及不同生态环境下的麻竹混合品种在永安、漳州进行种源造林试验。结果表明,麻竹的种源有着一定的遗传基础和潜力。2个试验点各种源成活率及新竹生长存在一定的差异,不同种源在试验点的生长每年速率不同,但生长趋于稳定。初步可筛选出宁德、永春、华安等种源的麻竹为优良种源。     

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...     

造林密度和修枝对‘欧美107杨’生长量的影响

以3种造林密度‘欧美107杨’为研究对象,通过测定不同年份胸径、树高、枝下高等,来分析造林密度及修枝对‘欧美107杨’生长量的影响.结果表明,‘欧美107杨’胸径和单株材积生长量随着造林密度的增大而减小,即3种造林密度‘欧美107杨’2a胸径和单株材积生长量由高到低依次为株行距3m×12m、5m×6m、3m×6m,而树高生长量变化趋势正好相反.修枝在一定程度上能促进树高生长和提高枝下高,有利于提高杨树木材质量.     

麻竹丰产栽培技术

采用不同无性繁殖方法培育的麻竹幼苗进行造林比较试验,结果表明:试验营造的麻竹林均可达到速生丰产的目的,1 a可发2~3代,2~3 a即可成林。不同造林方法效果依次为育苗移栽>扦插造林>埋节造林>母竹移栽造林,其中育苗移栽造林的麻竹林平均高可达7.2 m,平均胸径可达5.0 cm,且造林成本也较为经济可行;同时适量使用植物生长调节剂处理,辅以施加适量的尿素、草木灰,栽植后在穴周围盖上25 cm左右厚度的覆盖物,更能促进麻竹的生长。研究结果可为营造速生丰产林提供参考。     

不同立地条件下水曲柳人工林生长状况的初步研究

不同立地条件的水曲柳人工幼龄林生长指标的调查结果表明:缓坡造林,8 a生胸径最大值为6.0 cm,树高最大值为6.5 m;轻微水湿地造林,经2次施肥后,12 a生时平均胸径、平均枝下高生长量较缓坡造林的8 a生水曲柳仅具有微弱生长优势,平均树高、平均冠幅和平均枝下高低于8 a生缓坡水曲柳幼龄林;农耕地10 a生水曲柳人工幼龄林平均树高为4.50 m,为其他立地的150%,最大值为6.8 m,胸径最大值为7.3 cm,单位面积立木蓄积为其他立地的158.3%。水曲柳造林后第四年开始,胸径、树高、材积生长较快,胸径连年生长量由0.65 cm增至0.80 cm以上;树高生长量在4~6 a增长最大,连年生长量达1.00 m,平均生长量也持续在0.60 m以上;材积平均生长量、连年生长量自第四年开始,增幅较大,第六年连年生长量为第五年的1.92倍。     

木麻黄优良无性系去枝与留枝育苗及造林效果分析

对木麻黄优良无性系去枝、留枝及其在育苗造林中的生长情况进行比较,结果表明:木麻黄优良无性系去枝和留枝苗的生根率差别不大,都在88%以上;多枝容器苗地径、苗高、成活率好于去枝,差异极显著。造林后3年调查,留枝苗生长更快,长势更好,胸径、树高及保存率与去枝苗相比差异显著。建议生产上应采用木麻黄优良无性系留枝苗在造林中推广应用。     

Correlations of growth and form characteristics ofEucalyptus camaldulensis Dehnh. provenances in northern Nigeria

Phenotypic, genotypic and environmental correlations between 10 growth and form characteristics ofEucalyptus camaldulensis Dehnh. grown at two locations within the Northern Guinea Savanna zone of Nigeria were investigated. These characteristics were tree height, diameter at breast height (dbh), number of branches and taper. Tree height and dbh were positively correlated with all the form characteristics except taper, which had positive correlations with tree height but negative correlations with dbh. Trees with better stem straightness tended to develop big-diameter branches that made relatively wide angles with the tree hole. Branch diameter had positive correlations with number of branches. Growth ofE. camaldulensis can be improved simultaneously with its first fork height, stem form and branch angle. However, in the improvement programme, the selection pressure has to be maintained on the other characteristics because of the unfavourable correlations between them and the two growth characteristics.     

Modeling internode length and branch characteristics for Pinus radiata in New Zealand

It is recognized that estimation of internode length and maximum branch size is important for the prediction of clearwood in unpruned timber stands, as well as for evaluating the quality and value of logs in general. A review of existing branch models reveals a diversity of approaches as well as a tendency for results to be species specific. Here, a branch model is developed for Pinus radiata in New Zealand, capable of predicting successive internode lengths, the number of branches on each branch cluster, and the size of each branch up to the green crown (GC) at site index age 20. Inputs to the model include tree height and diameter at breast height (dbh) (both at age 20) and basal area per hectare of the top 100 stems. Further optional inputs are an ocular count of the number of branch clusters up to the green crown, and branch factor (BF)—the size of the biggest branch in the first cluster encountered above 6 m. The vertical distributions of internode length and maximum branch diameter are found to reach maxima around 0.3–0.4 of relative height. Internode length and the number of branches per whorl were found to be independent of tree size, site index and stand density. Stems per hectare is not required as an explicit predictor variable but it appears implicitly through tree dbh. Some model output is given and the results are discussed.     

Maturation in Douglas-fir: I. Changes in stem, branch and foliage characteristics associated with ontogenetic aging

Two experiments were conducted to characterize changes associated with ontogenetic aging in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and to identify possible maturation "markers" for this species. In the first experiment (Experiment 1), scions of ages 1, 4 and 9 years were collected from four seed zones in field progeny tests and grafted onto 1-year-old rootstocks. In Experiment 2, scions from five full-sib families of ages 1 and 10 years were collected from one progeny test and similarly grafted. Grafts for both experiments were planted in the field in a completely randomized design. The grafts were measured after two and six growing seasons. In Experiment 1, graft diameter, number of terminal bud flushes per year, number of branches, and branch length decreased with age. Plagiotropic angle and needle weight increased. All variables except needle length had a significant age x seed zone interaction. After 6 years, internodal stem diameters, numbers of nodal and internodal branches, and length and diameter of internodal branches decreased with age, and there were age x seed zone interactions with most variables. In Experiment 2, graft height and diameter, number of flushes, number and size of lateral branches, needle length and weight decreased with age. After 6 years, height and diameter, size and number of nodal and internodal branches, and leaf chlorophyll concentration (measured in April) decreased, but there were relatively few age x family interactions. An analysis based on traits that were significantly affected by age, but that did not interact with seed zone or family, indicated that main stem diameter, nodal branch length and nodal branch diameter were the most consistent and reliable maturation markers.     

福建省毛竹混交林竹林结构比较研究

通过对浦城县古楼乡毛竹阔叶树混交林、毛竹杉木混交林、毛竹杉木阔叶树混交林及毛竹纯林等4种不同经营模式林分比较,结果表明:混交林毛竹个体生物量、毛竹胸径和竹高较大,不同模式林分的胸径、竹高、冠幅等生长因子有显著差异;竹阔混交林较有利于竹鞭孕芽发笋;各模式竹林结构综合评判为一般经营竹林;竹林竹鞭长、鞭径、鞭节生长以竹阔比例为5∶5林分竹鞭较好。     

大木竹秆形结构的研究

调查了浙江南部大木竹的秆形状况,包括秆高、鲜秆质量、尖削度、竹壁厚和节间长等一系列指标.以毛竹为参比竹种,对数据进行统计分析并拟合曲线,结果发现:相同胸径下,大木竹的全高大于毛竹;尖削度较毛竹略小;壁厚随竹秆高度增大而减小的速率比毛竹快;拟合大木竹鲜秆质量-胸径的幂函数方程为:M=0.232 7(DBH)2.1899,与毛竹相比,同样胸径的大木竹鲜秆质量比毛竹大;大木竹的节间长度随高度的变化趋势呈二次曲线,在胸径为4～11cm范围内,节位数10～15处的节间长度最大,可达50～65 cm.     

Yield-density effects on growth and biomass partitioning in Leucaena leucocephala seedlings

Experiments were conducted to study the effects of density on growth and biomass partitioning of Leucaena leucocephala seedlings.Four plantations with densities of 10,000,20,000,40,000,and 80,000 seedlings ha^-1 were evaluated only from 15 to 25 months after planting.At 15 months,crown height and width decreased with increasing density.Seedling height/dbh ratios increased with increasing density.Biomass increased with greater density according to the yield–density effect equation,which was evident for all densities.With increasing age,biomass division to branches and leaves increased,whereas partitioning to roots decreased in the 10,000 and 20,000 seedlings ha-1 plantings.Partitioning to branches and leaves remained relatively steady,while partitioning to roots increased in the 40,000 and 80,000 seedlings ha^-1 plantings.Biomass division into stem and bark components remained relatively steady in all densities.Yield–density and organ yield–density curves shifted upward with increasing seedling age on a log–log graph throughout the experimental period.     

钻天柳嫩枝扦插苗生长特性研究及优良单株选择

对6年生钻天柳嫩枝扦插苗生长特性及优良单株选择进行研究的结果表明,6年生钻天柳嫩枝扦插苗高生长平均4.8578 m,最高6.5 m;胸径生长平均31.3079 mm,最大58.24 mm。胸径、树高分布基本遵循正态分布;钻天柳扦插苗初期栽植苗木等级对钻天柳树高生长影响较大,栽植密度对钻天柳胸径生长影响较大;初步选出优良单株15株,初选优良单株树高平均值5.84 m,超过3块地树高平均值的20.22%,最优个体超过树高平均值的33.81%;初选优良单株胸径平均值50.97 mm,超过3块地胸径平均值的62.80%,最优个体超过胸径平均值的86.02%。     

内蒙古大青山华北落叶松人工林生长模型研究

利用内蒙古大青山32株华北落叶松解析木数据,分析研究华北落叶松人工林的树高、胸径、年龄、材积之间的关系,并选取对数模型、理查德模型、考尔夫方程和逻辑斯蒂方程等4个常用的生长模型对树高、胸径、材积生长量进行拟合.结果表明：效果好的生长模型分别为胸径对数模型y=-24.03＋ 11.28×Log（x＋1.99）,树高理查德模型Y=27.27×[1-Exp（-0.041 ×x）]△1 5735,材积理查德模型y=7495.55×[1-Exp（-0.001×x）]△3.13.经F检验（F ＜0.05） =6.94,呈显著.3个预测模型的标准误差、平均百分误差、平均绝对百分误差都非常小,平均相对误差均在±2.5％以内,预测值与实测值无显著差异（p=0.05）.     

闽西南光皮桦不同家系试验初报

对福建省漳平五一国有林场营建的4年生光皮桦155个家系测定林的生长性状进行了调查分析,以单株材积遗传增益在15%、树高、胸径遗传增益在5%以上作为优良家系的选择依据,从155个家系中初步筛选出32个优良家系,其平均树高6.3 m,平均胸径6.1 cm,平均材积0.0106 m3,平均冠幅为3 m,其树高、胸径、材积的遗传增益分别为11.1%、16.2%、39.7%;以形质优良,绝对生长量大为主要指标,共选出53个优良个体,其平均树高7.6 m,平均胸径8.2 cm,平均材积0.0214 m3,平均冠幅为3.7 m,其树高、胸径、材积的遗传增益分别为26.9%、22.9%、96.0%。     

降香黄檀不同家系测定试验初报

通过对福建省华安县西陂国有林场降香黄檀不同家系的胸径、树高、平均冠幅以及冻害程度等指标的测定与分析,结果表明:降香黄檀不同家系间胸径和树高生长差异极显著,造林后1 a胸径为1.22~2.38 cm,树高为1.55~2.27 m;而冠幅生长差异不显著,平均冠幅为0.30~0.58 m。综合考虑胸径、树高和冻害3个因素初步判断,21、118、8、49、39、43、90、14、115、46、55、16、19等13个家系在福建华安表现较好。