欧美杨107杨立木生长应变分布规律

选取欧美杨107杨为研究材料,通过对正常生长欧美杨107杨立木表面轴向生长应变和伐倒木内部残余轴向生长应变的测定,分析表面生长应变和内部残余生长应变的分布规律.结果表明:正常木表面轴向生长应变的变化幅度范围为:-853.10--213.43με.Z2和Z5在周向上表面轴向生长应变的变化幅度较大,而Z1,Z3,Z4变化幅度相对较小;在不同树干高度研究中,表面轴向生长应变在树干基部向上与整体树干高度10%位置之间,生长压应变(即生长拉应力)随着树高增加逐渐增大,随后数值开始下降;双因素方差分析表明,不同单株和不同周向位置对表面轴向生长应变影响不显著,但不同高度对生长应变影响显著;欧美杨107杨正常木内部残余轴向生长应变变化幅度范围-1279.00～960.20με,其径向变异模式为在树干外围表现为轴向压应变(即拉应力),由树皮向里,在中心板南侧第5或6年轮和中心板北侧第4或5年轮处,轴向压应变转换为拉应变(即压应力),随后Z2和Z5在中心板南向第3年轮处出现拉应变最大值,而Z3则在中心板北向第3年轮处出现拉应变最大值,各单株在内部残余轴向生长应变径向变异的整体趋势图如开口向下的抛物线,其顶点在髓心处,其二次曲线回归方程为y(生长应变值)=815.02 X2(测试点序号)-69.345 X-1 902.403,R2=0.775***.     

欧美杨107杨生长应变与木材解剖特征和干缩性质之间的关系

选取正常生长和偏心生长欧美杨107杨为研究材料,测试其表面轴向生长应变,并测定应变测试位置处木材的纤维形态和干缩性质,分析应变与木材性质之间的关系.结果表明:1)随着生长应变数值的增加,正常生长立木纤维长度、胞腔径、长宽比、径向全干干缩率、弦向全干干缩率出现微弱的下降趋势,而纤维宽度、双壁厚、壁腔比、轴向全干干缩率出现微弱的上升趋势,正常生长立木生长应变与所有纤维形态指标和干缩性指标之间的相关系数均不显著;2)随着生长应变数值的增加,偏心生长立木双壁厚、长宽比、径向全干干缩率、弦向全干干缩率、轴向全干干缩率出现较快的下降趋势,而纤维宽度、胞腔径同时出现较快的上升趋势,纤维长度出现微弱的上升趋势,偏心生长立木生长应变与双壁厚、轴向全干干缩率、径向全干干缩率、弦向全干干缩率、壁腔比、弦向全干干缩率、长宽比的负相关关系显著,与腔径、纤维宽度的正相关关系显著,与纤维长度之间相关系数不显著;3)对于不含应拉木正常生长的立木,其生长应力与木材纤维形态和木材干缩性质之间关系较为微弱;对于含应拉木偏心生长的立木,由于应拉木材性与正常木之间的差别,其生长应力与多数木材纤维形态指标和木材干缩性质指标之间关系较为紧密.     

欧美杨107杨偏心生长应变分布规律

树木在生长过程中容易受到许多外界因素的干扰,如地形、风吹、雪压、相临木竞争等,使得树木偏离原有的生长状态,发生树干倾斜、弯曲、树冠偏冠等现象(Alméras et al.,2005;John et al.,2003;Yamashita et al.,2007)。在这些因素的干扰下,树木为了更好地获得生存空间必须形成一个抵御机制。立木中生长应力的存在及其分布方式是其抵御外界     

秃杉树干不同高度处直径生长规律

利用秃杉标准木的解析数据,根据分形理论和R/S分析法,探讨秃杉树干不同高度处直径的相对生长量与树干相对高度之间的生长变化规律。结果表明,树干不同高度处直径相对生长量与绝对高度之间没有相关性,但与树干相对高度之间呈极显著相关;不同高度处直径的增量生长持续强度也不同;并进一步探讨引起树干不同高度处直径生长量不同的原因。秃杉树干相对高度在0.5～0.8之间的直径相对生长量较高,生产中可在树木高生长高峰期来临前,采取各种措施促进树木高生长,从而促进树干材积生长,减小树干的尖削度。     

马尾松与4种阔叶树混交林生长效果调查分析

对马尾松与4种阔叶树种混交效果进行了试验研究。结果表明,马尾松与枫香、黄檀、麻栎混交后,促进马尾松生长效果显著,混交林中马尾松的平均胸径和平均树高都显著大于纯林,林分生产力高,结构稳定。而马尾松与马褂木行状混交林郁闭后,马尾松的生长受抑,平均胸径和平均树高都低与其纯林,林分分化严重,稳定性差。     

不同阔叶树种和马尾松混交造林的生长效应

采用5个处理3次重复的完全随机区组设计对闽楠、裂斗锥与马尾松混交林生长效应进行研究。结果表明：混交对林木生长有促进作用,混交林中闽楠的胸径、树高、林分生物量明显高于闽楠纯林,混交林中裂斗锥的胸径和林分生物量也显著高于裂斗锥纯林,两种混交林林分生物量均高于各自纯林;不同林分林下植被生物量大小排序为混交林大于纯林,混交林均不同程度的提高了林下植被生物量和凋落物量。     

马尾松、木荷纯林及混交林的生长差异分析

对马尾松、木荷的纯林及混交林人工林的生长差异进行分析,结果表明:1)马尾松、木荷的纯林与混交林不同林分类型的生长量均存在显著差异,同一树种混交林比纯林的生长表现更好,表明混交林可促进林分的生长.2)不同林分类型的死枝下高、活枝下高和冠幅也均具有显著差异,混交林的自然整枝能力比纯林强.3)混交林的变异系数总体上比纯林大,混交林林分生物多样性丰富,诱导变异因素多,表明混交林存在更大的变异表现.4)树高、胸径、活枝下高等各性状指标之间存在显著相关关系,表明林分生长力强弱与自然整枝能力有关.     

湖南栎类-马尾松天然混交林单木生长模型研究

建立湖南栎类-马尾松天然混交林单木材积和断面积生长模型,为该林分的提质增量提供科学指导。选取湖南省9个地区共23块栎类-马尾松天然混交林,构建栎类、马尾松单木材积和断面积生长模型。通过分析可知:两种树种的材积和断面积生长模型均以Richards生长模型为最优,其确定系数(R~2)最高,残差平方和(SSE)最小;混合效应模型模拟结果显示,栎类单木材积和断面积生长模型的随机效应在参数a_1处最好,而马尾松的材积和断面积生长模型的随机参数分别为b_1和a_1+b_1;相比基础模型,混合效应模型的拟合精度(P)、确定系数均有所提高,平均误差(ME)、平均误差绝对值(MAE)、相对平均误差(RME)和相对平均误差绝对值(RMAE)均大幅降低。结果表明,天然林林木的材积和断面积生长受树种与立地类型差异的影响较大,而混合效应模型能够充分考虑立地之间的差异,可以很好地解决这一难题。     

25年生马尾松生长和木材基本密度家系变异与选择

以福建省华安县西陂林场的25年生来自省内不同产地的46个马尾松自由授粉家系试验林为试材,研究了达主伐年龄时马尾松生长、干形和木材基本密度的家系差异以及性状间的相关性,并依据不同培育目标选择优良家系。结果表明,马尾松生长、树干圆满度和木材基本密度皆存在显著的家系差异,其中生长和树干通直度变异相对较大,而树干圆满度和木材基本密度变异较小,变异系数在10%以下。生长和干形性状受到弱至中度的家系遗传控制,家系遗传力为0.23 0.46;木材密度受到的遗传控制相对较强,家系遗传力为0.46。性状遗传相关分析结果显示,选择速生种源可同时改良树干圆满度,但对树干通直度和木材基本密度影响不大。根据不同用材对材质材性要求,选出24个纸浆纤维材优良家系和6个锯材优良家系,平均木材干物质量和胸径生长皆为对照的1.16倍。     

闽西山地马尾松人工林生长规律研究

对33年生马尾松人工纯林进行树干解析,结果表明在整个生长过程中,树高连年生长量最大值出现在10年,平均生长量最大值出现在10～15年之间.第1次间伐年龄应在15年左右,20～25年时树高连年生长量急剧下降;第2次间伐年龄可适当提前到22年.直径连年生长量最大值出现在10年,连年生长量与平均生长量在20～25年时相交;材积连年生长量在30年生时达到最大值,数量成熟年龄大约在55年左右.     

植物生长调节剂对美国山核桃生长的影响

总结了不同国家美国山核桃Carya illinoensis生产中使用的植物生长调节剂种类和方法,综述了不同植物生长调节剂对美国山核桃营养生长、抗性、果实质量和产量的影响,以期对我国美国山核桃产业发展具有指导作用。     

东北过伐林椴树生长过程与生长模型的研究

利用吉林省汪清县金沟岭林场收集的38株过伐林椴树解析木资料,研究椴树年龄与树高、胸径、材积之间的相关关系,分别拟合椴树最优树高-年龄、胸径-年龄、材积-年龄的生长方程,经检验达到精度要求,为预测该地区椴树树高、胸径、蓄积的生长提供理论依据。     

值得关注的巴西Guararapes公司——创新与增长

巴西的Guararapes公司一直生产传统产品中密度纤维板(MDF)和胶合板,在多年经营中,表现出了适应力和明智,在危机时期尤为显著.1984年公司从一个小木材厂起步,20年后,通过出口胶合板,Guararapes公司不断扩大其产品品种,满足本地区的需求.近年公司投资兴建了新的MDF生产线,并扩大了两个胶合板厂,雇员增至1 900名以上,拥有高科技生产设施,在50多个国家有客户.     

Monitoring Growth Trials

The forestry industry predominantly depends on privately-owned forests which are foreign-owned, capital intensive and export oriented. The man-made forests cover 102 000 ha, about 6% of the total area of Swaziland. The two largest plantations, Usutu and Peak Timbers, account for 71% of the total plantation area in the Kingdom.

Pines and eucalypts are the two main genera planted for pulp, mining timber, sawtimber and droppers. There are nine companies engaged in the processing of wood into various products.

The land classified as marginal in Swaziland on account of low rainfall (less than 600 mm) occurs in low-veld, with characteristic tree species like Acacia nigrescens (umkhaya), Acacia tortilis (sitfwetfwe) and a fruit tree Sclerocarya caffra (umganu). In this region, plantation agriculture of citrus trees and sugar cane is only possible under irrigation. In terms of low inherent soil fertility in the highveld, plantation forests are grown on acidic granite and gneiss and also on land whose average gradient is more than 15%. Biotically induced marginal land occurs because of man and his activities: overstocking of livestock, uncontrolled burning of the veld during the dry winter, inadequate soil husbandry, increase in demand for various forest products and infrastructural development.

Low rainfall between 1974 and 1976 killed Eucalyptus grandis and Pinus taeda and reduced the growth rate of Pinus patula. Most of the forest sites in Swaziland are marginal land on account of granite and gneiss-derived soils of low pH, i.e., 4,5 to 5. Between 1981 and 1982, 27 t of different fertilisers were used in order to achieve an MAI of at least 17 m³/ha/a of utilisable material for Pinus patula on a 22 year rotation.

Usutu Forest and Peak Timbers Plantations have progressively contributed to the economy of Swaziland since the 1940s. In 1978, forest plantations and forestry oriented industries contributed about 24% of the total export earnings. During 1980, 95% of the unbleached kraft pulp was sold outside Southern Africa, while 3,1% of the total forest products was consumed in Swaziland. The forest plantations have improved the general infrastructure, including roads and educational and recreational facilities in the areas where they occur.

Resettlement schemes have also been undertaken among the displaced people.

The interest of the Swaziland Government lies chiefly in regulation and control of the forest sector, to optimise the existing resources to the benefit of the Swazi people, mainly for economic use of the land and water resources and encouraging national participation, at both wage employment and management levels, as well as implementing forest legislation.

Plantation forest activities have, however, several disadvantages to be cited: They are land extensive and therefore tend to encroach on land used for communal grazing and hunting, bee collecting and firewood and fruit gathering, all of which are difficult to quantify in monetary terms. The Euro-American philosophy of replacing open communal land with fenced boundaries marked by cairns, with penalties on contravention, cannot be readily accepted.

The forest product needs for the rural community come from the Swazi Nation Land, covering 65% of the total area of Swaziland. The biotic factors have much reduced the original area of vegetation cover which has resulted in the use of non-conventional material like cow dung, maize stalks, leaves of Aloe marlothii (inhlaba) and tall grass for fuel. The commercial forests are located far from the population centres, thus making transportation of the forest waste an uneconomic venture.

The Forestry Section, under the Ministry of Agriculture and Co-operatives, is working in close co-operation with the Rural Development Area (R.D.A.) programme to raise the general standard of living in the rural areas by establishing woodlots. In the current five-year National Development Plan, the Government plans to establish 13 000 ha of woodlots, carry out an indigenous forest inventory, implement forest legislation and train forestry personnel at all levels.

With the assistance of R.D.A. Project Managers, the donga-ridden areas on the biotically induced marginal land are fenced off and then planted with suitable tree species.

Black wattle, Acacia mearnsii, introduced in Swaziland at the beginning of this century, is predomminantly used for bark production. It covers 5 000 ha on Swazi Nation Land and 2 500 ha on Title Deed Land. Lack of proper management of black wattle has turned it into “jungles” in the Highveld, where land is not used for agricultural production. The yield of wet wattle bark is low on Title Deed Land, i.e. 15 to 20 t/ha. The bark is marketed on a basic bark quota system managed by a wattle growers committee of Pietermaritzburg. Wattle growers of Swaziland have now formed a cooperative to enable them to transport the bark economically.

The spread of black wattle has checked the formation of dongas in biotically induced marginal areas, but at the same time there is a general resentment among the rural community who believe it is eating up their grazing land. The public believe also that eucalypts are responsible for the drying up of streams and encouraging lightning in the rural areas.

Indigenous Acacia species are drought resistant, more favoured as fuelwood, but their MAI is very low and their seed is very difficult to collect and extract. Even when using exotic tree species in establishing woodlots, proper provenances are not easy to obtain.

Agro-forestry is being undertaken particularly in RDA's where individual farmers get tree seedlings from the forestry nurseries and plant them among agricultural crops.     

英国的"Grown in Britain"运动

第一篇 “Grown in Britain” 过去的12个月,旨在为英国国产木材开拓市场的“Grown in Britain(产于英国)”运动取得了不平常的成绩,预计今后的6个月会更红火.2013年,其工作重点是使运动及其目标被公众尽可能多地了解,为此组织了一系列活动,而在10月份的“Grown in Britain”周达到了高潮.     

植物生长调节剂对刨花润楠苗木生长的影响

为找出可以加快刨花润楠苗木生长速度的生长调节剂,采用不同植物生长调节剂(PP_(333)、NAA、GA_3)及其不同浓度(0、60、120、240、480mg L~(-1))对刨花润楠幼苗进行叶面喷施试验,测定各处理后的苗高生长量,结果表明:PP_(333)阻碍苗木正常高生长,其余各种浓度的GA_3、NAA都有促进刨花润楠的苗木生长,以浓度240 mg L~(-1)GA_3或浓度480mg L~(-1) GA_3促进刨花润楠苗高生长作用最显著,浓度240mg L~(-1) NAA次之。     

木荷单木生长模型构建及生长特征分析

以木荷次生异龄林为研究对象，选取3种经验生长方程和3种理论生长方程拟合木荷单木的直径、树高以及材积的生长过程，然后利用连年生长量与平均生长量的关系分析木荷直径、树高以及材积的生长特征。结果表明，理论生长方程在模拟精度以及生物学解释上均优于经验生长方程，木荷的单木直径最优生长方程为Richards方程：D=37.21×〖(1-e^(-0.0493×A))〗^2.0102，树高最优生长方程为Gompertz方程：H=19.43×e^(-2.7091×e^(-0.0848×A) )，材积最优生长方程为Logistic方程：V=0.2734/(1+416.8914×e^(-0.2752×A) )。木荷单木生长模型的构建及生长特征的分析为木荷次生异龄林的质量精准提升提供一定的参考价值。     

8年生粗皮桉生长应变及生长遗传变异

对雷州半岛粗皮桉种子园8年生粗皮桉的11个种源、58个家系立木的生长应变及生长性状的遗传特性进行了研究.结果表明：（1）在种源水平上,生长应变和树高差异均不显著,胸径在0.01水平下差异显著.（2）在家系水平上,生长应变在0.01水平下差异显著,胸径在0.05水平下差异显著,树高差异不显著.（3）胸径的家系遗传力和单株遗传力分别为0.235和0.134,受较低强度的遗传控制;生长应变的家系遗传力和单株遗传力分别为0.695和0.533,受较高强度遗传控制.（4）生长应变和胸径之间无论在遗传上还是表型上均无显著相关关系.     

GROWTH OF MONGOLIAN OAK

GRANDPERIODOFGRoWTHMongolianoak(Q.mongolica)wasamaintreespeciesofthesecondaryforestsinHeilongjiangProvince.Thesecondaryforestswereforn1edfromthevirginforestwhichwasrepeatlydestroyed.ThatdecidedthatmostofmongolianoaksoriginatedfromthestumpsproutingforthenaturalstandsItwasreportedthatalmostalltheoaktrees1essthan2oyearso1dinthenaturalstandsweresproutingorigin,buttheseed1ingsincreasedwiththeirageintheeasternHeilongiiangProvince(ChenBoxianetal,l965).Thegrandperiodsofgrowthoftheoakwithdiff…     

Growth stresses in beech

Summary Measurement of the potential deformations contained in standing trees, induced by growth stresses were made using an extensiometric technique which is described. The same extensiometric transducers and methods were also used to evaluate the elastic mechanical properties of green wood necessary to transpose the numeric values of longitudinal microdeformations into mechanical stresses. Measurements were made on 86 different beech trees located in the principal regions of France. The data obtained not only established the feasibility of the method but permitted an objective numeric evaluation of the level of potential deformations found at the base of individual trees. The results could be correlated with the forest environment and also certain morphological and anatomical anomalies within the trees.This study was partly supported by the French Government (Délégation Générale à la Recherche Scientifique et Technique — Décision no 74-7-0723).