不同林龄柚木人工林心边材生长变异特征

【目的】探明广西大青山林区不同林龄柚木人工林心、边材量及心材年轮数和心材高度的生长变异特征,以期为了解该区域柚木心边材发育特征、心边材量预测及高质量、大径级柚木目标树的高效培育提供基础数据和科学依据。【方法】以广西大青山10、18、31和41年生柚木人工林平均木的解析木为研究对象,对心、边材的方位变异和心、边材量的株间差异进行方差分析,并采用曲线估计法拟合心、边材量与横截面直径、总年轮数之间的回归模型,研究柚木心、边材生长变异特征。【结果】各林龄柚木树干心材半径主要为北向最大,边材宽度则主要为北向和东向最大,各林龄内,树干4个方位的心材半径、边材宽度均无显著差异(P0. 05)。各林龄柚木心材半径、心材面积和边材面积均表现为随树高增加持续减小,边材宽度在树干基部(0～1 m)明显偏大,且在树干一定区域内保持相对稳定。林分心、边材量总体表现为随林龄增加而增大,不同林龄林分间除边材宽度差异不显著外(P0. 05),心材半径、心材面积和边材面积均存在极显著差异(P0. 01)。横截面心、边材量随横截面直径和总年轮数的增加而增加,其中与横截面直径的相关性高于总年轮数,而总年轮数对心材发育早期影响较大。各林龄内,柚木个体的心边材量、心材消失最大高度存在较大的株间变异,其中,心材面积和边材面积的变异程度相近,心材半径、边材宽度和心材消失最大高度的变异程度相近。柚木最早在4年生时开始有心材形成,不同林龄的心材年轮数均表现为随总年轮数增加而增加,总年轮数可解释心材年轮数80%以上的变化,10、18、31和41年生柚木心材年轮数年均增长速率分别为0. 9轮、0. 7轮、1. 0轮和1. 0轮。柚木心材消失最大高度、心材消失的相对高度均与林龄呈正相关关系,即随着林龄的增大,心材在树干更高处消失。【结论】柚木心材形成初始年龄最早为4年生,属心材形成较早的树种。各林龄内,方位对柚木心、边材影响较小。柚木的心材半径、心材面积、边材面积和心材消失最大高度,均表现随林龄增加而显著增加,而边材宽度无显著变化。柚木横截面直径可以更好地解释横截面心、边材量的变化,总年轮数仅能解释柚木前期(31年生)心材量的变化。研究认为41年生柚木心材仍有很大增长潜力,若要达到高质量、大径级的培育目标,还需要更长时间的培育。     

东北主要树种心材与边材的生长特征

以东北东部山区温带森林的7个主要组成树种--红松、兴安落叶松、春榆、水曲柳、胡桃楸、黄菠萝和蒙古栎为研究对象,比较分析各树种心材和边材的生长特征.结果表明:树种显著地(P<0.001)影响边材年轮数和边材宽度,红松、水曲柳、兴安落叶松、胡桃楸、春榆和黄菠萝的平均边材年轮数分别为9.6、9.5、7.9、6.8、5.0和3.9年,其平均边材宽度分别为1.96、1.27、2.55、1.06、0.72和0.46 cm.被测针叶树边材宽度明显大于阔叶树.心材年轮数与形成层年龄、心材半径和边材宽度与树干去皮半径均存在着极显著的正相关关系(P<0.000 1),而边材年轮数随形成层年龄的变化规律因树种而异.心材形成速率和心材起始树龄因树种而异,分别波动在0.677～1.041 a-1和4.3～8.5年.随树干高度增大心材半径和木质部半径递减,边材宽度则在树干基部异常大,1～2 m向上保持相对稳定.心材年轮数随树高递减,但边材年轮数的变化因树种而异,红松边材年轮数递减,落叶松先增后减,水曲柳先减后增,春榆、胡桃楸和黄菠萝的变化很小.各树种心材和边材特征的显著差异,可以反映出其生长状况、水分利用对策、物质生产等方面的差异.     

栽植密度对小黑杨边材、湿心材生长量的影响

以山西朔州地区的人工林小黑杨为研究材料,研究不同栽植密度(2 m×5 m、4 m×5 m、4 m×10 m)对小黑杨边材、湿心材生长量的影响.结果表明:不同栽植密度间边材年轮数差异不显著,而湿心材年轮数差异显著;栽植密度对边材宽度影响不大,而对湿心材宽度影响达极显著水平;对边材面积和湿心材面积影响均达极显著水平.随着栽植密度的减小,小黑杨边材、湿心材宽度及面积均呈增加趋势,但湿心材增加得更快.湿心材比例为60%～68%,且随着栽植密度的减小而增大.总体而言,栽植密度对小黑杨边材、湿心材生长量有不同程度的影响,且对湿心材生长量影响较大.     

楸树心材与边材的生长特征及变异规律

为系统了解珍贵阔叶树楸树心材与边材的生长特征及边心材转化规律,采用树木年轮分析仪对5株楸树不同树高处的圆盘进行年轮数、宽度等生长特征测定,建立心材与树木各生长量之间的回归模型。结果表明:楸树年轮宽度在10～15年达到峰值,可持续10年左右;心材起始树龄为5.26a,心材形成速率为0.90轮/a;属于生长收获周期短、心材形成时期较早且形成速率较快的树种。     

柚木种源生长和与材质有关特性的遗传变异及综合评价

对海南岛乐东尖峰岭27年生柚木6个种源的生长及与材质有关特性进行测定与分析,结果表明:种源间树皮厚度、心材宽度、基本密度差异极显著,树高、材积、枝下高、边材宽度差异显著,而胸径、边材年轮数及心材率差异不显著,说明在种源水平上对柚木进行生长和与材质有关特性的改良具有较大的潜力,尤其进行木材生长性状、基本密度和心材宽度的种...     

交趾黄檀心边材径向弯曲蠕变性能

采用三点加载方式对交趾黄檀心边材试件进行短时间(5 h)内径向弯曲蠕变测试,获得交趾黄檀心边材的弯曲蠕变特性曲线,分别用五单元模型、六单元模型模拟交趾黄檀径向弯曲蠕变过程,对比分析交趾黄檀心材与边材蠕变性能的差异。结果表明:五单元模型可准确地模拟交趾黄檀的径向弯曲蠕变特性;相同应力水平下交趾黄檀心材的蠕变小于边材的蠕变,随应力水平提高,心材的蠕变增大不明显,而边材蠕变明显增大。     

不同林分密度对桉树幼林木材材性的影响

对两种桉树无性系(巨细桉DH201-2和尾巨桉DH32-29)在5种不同林分密度下(1250、1657、2500、5000和6667株.hm-2)的木材材性(包括木材基本密度和纤维形态特征)进行了测量和研究分析(纤维形态特征分两种不同材型分析:心材与边材)。结果表明:无性系DH201-2的林分密度3(2 500株.hm-2)木材基本密度最大,为452 kg.m-3,DH32-29以林分密度2(1657株.hm-2)的木材密度最大,为436 kg.m-3;相同无性系相同林分密度下,边材纤维长度比心材纤维长度长,边材长宽比一般比心材长宽比要大,纤维宽度则无显著差异;无性系DH201-2的林分密度3(2500株.hm-2)和林分密度5(6667株.hm-2)是符合林分蓄积量、木材基本密度和纤维长度最大值的组合。     

黑木相思株内木材基本材性变化与树龄关系的研究

对不同树龄和径向位置黑木相思木材的物理和主要力学性质测定研究表明:黑木相思株内边材、心材密度和主要力学性质随着树龄的增大而增大,径向和弦向的体积干缩率随着树龄的增大而减小;相同树龄黑木相思的边材密度和力学性能比心材小,干缩率比心材大.因此,在利用黑木相思时应对树龄、心边材径向位置加以特别考虑.     

兴安落叶松边材心材生长特征的种源效应

以生长在相同环境条件下的7个代表不同气候地理条件(7个种源:塔河、满归、根河、新林、三站、乌伊岭、鹤北)的26年生兴安落叶松为对象,比较不同种源树木的边材/心材生长和异速生长关系,探索种源地气候条件对边材/心材生长特征的影响.结果表明:胸径(DBH)、边材宽度(SW)、边材面积(SA)、心材半径(HR)、平均边材生长速率(MSGR)等生长特征参数的种源间差异显著,其中最南种源地鹤北的生长特征参数的平均值最大,三站的平均值最小.种源也显著地影响SA、心材面积(HA)与MSGR的关系,但对其生长特征参数与DBH的异速生长关系和心边材比率(HSR)没有显著影响.SW,HR,HSR和MSGR分别与DBH呈极显著的线性关系,而SA和HA与DBH则呈极显著的幂函数关系.除了三站种源之外,种源地的年均温和年降水量都显著地影响兴安落叶松的SA和MSGR.兴安落叶松边材/心材生长特征因长期适应不同种源地的温度和降水等环境条件而发生了显著变化,这种变化主要是通过生长速率差异而不是改变其生长格局实现的.     

章古台地区樟子松年轮宽度和管胞长度的径向变异

对章古台地区不同密度樟子人工林松年轮宽度和管胞长度进行测定,结果表明：章古台地区胸径年轮数30a的樟子松林,已出现生长衰退现象,生长衰退期开始林龄与林分密度有关,降低林分密度可延缓衰退期出现林龄。樟子松管胞长度与距离髓心的年轮数之间存在Y=alnx＋b（Y：管胞长度;X：距离髓心的年轮数．b：第1年轮的管胞长度）关系。不同密度樟子松年轮宽度不同,但管胞长度与未成熟材范围无显著变化,未成熟材范围距离髓心的年轮数均为21～23a。     

Physical and mechanical properties of Pinus leucodermis wood

Abstract

The present work reports on the main physical and mechanical properties of Pinus leucodermis mature wood, one of the least studied coniferous species in south-east Europe. Pinus leucodermis heartwood specimens were found to have average density values of 0.73 g cm^?3 at equilibrium moisture content of 11.5% and average density of 0.64 g cm^?3 under oven-dry conditions. The overall tangential shrinkage was 3.4% and the radial shrinkage was 1.9%. The modulus of rupture was on average 77 N mm^?2, while the static modulus of elasticity averaged 7087 N mm^?2. The hardness of P. leucodermis heartwood using the modified Janka test was 33.4 N mm^?2 in the transverse direction and 48.0 N mm^?2 in the longitudinal direction, while its compression strength parallel to grain was approximately 41.6 N mm^?2.     

Heartwood diameter measurements in Pinus sylvestris sawlogs combining X-ray and three-dimensional scanning

Abstract

Quality sorting of sawlogs based on three-dimensional (3D) or X-ray scanning or a multivariate combination of variables from both methods may be used to decrease the production of off-grade products carrying unwanted combinations of dimension and grade. There is, however, potential for further improving the sorting accuracy if 3D and X-ray raw data are combined at an early stage using path length compensation. From the measured 3D shape, a good estimate of the length of each X-ray path through the log can be made, enabling the calculation of a log density profile from the measured X-ray attenuation. The effect of this technique on heartwood diameter measurements of 423 Scots pine (Pinus sylvestris L.) logs was evaluated. By the addition of 3D data to the X-ray data it was possible to raise the predictability of the heartwood diameter from R ²=0.84 to 0.95 and to improve the root mean square error from 17 mm to 9.3 mm, primarily because of the enhanced contrast between heartwood and sapwood.     

红心材杉木与普通杉木的FTIR光谱比较

采用傅里叶变换红外光谱技术比较红心杉与普通杉的化学官能团.结果表明:两种木材红外光谱特征吸收峰的位置、数目及形状相似.差异出现在波数1 800 ～ 600 cr-之间,红心杉中1 736 cm-吸收峰/(I1736)变得不明显.红心杉中超过50％特征峰吸收相对强度大于普通杉.红心杉的I1510/I1 736和I1 510/I1 372比值均小于普通杉.红心杉I1270/I1230,I1425/I96,I1372/I667和I1372/I2917均大于普通杉.据此,红心杉中木质素和半纤维素含量低于普通杉,而综纤维素含量大于普通杉.红心杉木质素中愈创木基单元比例较高,且纤维素结晶度大于普通杉.     

水肥效应对核桃定植后生长的影响研究

就核桃定植时和定植后施肥量和灌水量对核桃树生长的影响进行研究。在土壤肥力相同的条件下,通过连续4年不同的施肥量、灌水量对比试验,结果表明,株施尿素50 g+磷肥20 g+钾肥20 g+浇水40 kg,每年3月和10月各浇水追肥1次,其树高、地径和冠幅生长量明显高于对照,在处理后期(第四年)施肥量的增加要视水分状况而定,否则会抑制核桃树生长。     

红心材杉木种子园单亲子代测定

以2005年在福建省顺昌洋口国有林场和官庄国有林场营造的红心杉木单亲子代测定林为试验材料,对红心杉单亲子代生长和材性性状的变异、性状间的相关性、遗传控制等进行了研究.两地点多年度方差分析结果显示:除了年度与家系之间的交互效应没达到显著差异之外,其他互作效应都高度显著.单地点、单年份的方差分析结果表明:洋口试验点4年生子...     

侧柏心材和树皮精油的GC-MS分析

侧柏富含树脂.气相色谱-质谱分析结果表明侧柏树干上部心材精油与下部和中部树皮精油的最高相对含量成分均为柏木醇,三者共有组分为4-松油醇、α-柏木烯、罗汉柏烯、雪松烯、γ-依兰油烯、花侧柏烯、榄香醇、柏木醇、α-杜松醇和乙酸柏木酯.其树干下部和中部树皮精油的主要挥发物组分基本相同,而相对含量不同.柏木醇具有抗蚁、抗螨、抗...     

广东三地幼龄檀香生长和结香的早期评价

采用标准地调查的研究方法,调查广东省种植规模较具代表性的3个试验基地内6年生幼龄檀香的生长和结香情况,方差分析结果表明,3个试验基地内种植的同龄檀香,其树高、地径、胸径、净树干高度以及冠幅均差异显著(P<0.001),位于湛江的试验基地内,各种形态指标值均最大,平均树高为6.05m,平均地径为12.72cm,平均胸径为10.27cm,平均净树干高度为2.64m,平均冠幅(南北)为3.20m。利用生长锥对檀香树干进行钻孔取样,分析幼龄檀香的心材形成情况,结果表明,3个试验基地内的6龄檀香均已陆续开始形成心材,自然形成心材的比例为15%～20%。采用溶剂浸提法对钻取的心材提取檀香精油,精油含量在0.66%～1.76%之间;采用气相色谱-质谱联用仪分析檀香精油的成分及各成分的相对含量,结果表明,幼龄檀香精油的主要成分和檀香木油的国际标准成分相同,但含量较低,总檀香醇含量范围为34.31%～37.91%,精油质量没有达到国际标准。早期的生长和结香情况表明,檀香人工林的规模种植在广东表现良好。     

Effect of compression on the liquid absorption of Chinese fir wood with different heartwood-to-sapwood ratios

In this study, the Chinese fir (Cunninghamia lanceolata Hook.) specimens with different ratios of heartwood thickness to sapwood thickness (HS) were radially compressed at different compression speeds, and then absorbed amine copper quat-type D (ACQ-D) preservative solution under the negative-pressure produced by the recovery of compression deformation. The liquid uptake (Al), the recovery rate of compression deformation (Rs) and the chemical absorption (Ac) of samples were determined, as well as the overall distribution of density and effective component of ACQ-D (i.e., copper in wood), the mechanical properties such as surface hardness were also measured. The Al, Rs, Ac values of compressed samples including the whole heartwood ones were higher than those of uncompressed samples, showing that radial compression had an obvious positive effect on improving the liquid absorption of heart-wood. Higher compression speed of 3 mm·min–1 is preferable since the samples with that speed could reach the highest Al and Ac; in addition, more deformation fixation has been produced possibly because of the faster heat and moisture transmission at the higher compressed speed, and more bonds of hydrophobic nature were formed, leading to the higher surface hardness and density. A consistent tendency of the density distribution and the copper retentions along the thickness direction could be explained that the layers with higher density have smaller volumes of void areas, and more chemicals were absorbed and fixed, resulting in the higher copper retentions.     

Some factors influencing susceptibility to discoloring fungi and water uptake of Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and Oriental spruce (Picea orientalis)

Abstract

The heartwood and sapwood from Scots pine (PS), Norway spruce (PA), and Oriental spruce (PO) were tested for susceptibility to discoloring fungi and water uptake. In addition, annual ring width and density were measured. The methods used were Mycologg for testing growth of fungi and a modified version of EN 927-5 to investigate water uptake. For pine, the heartwood showed a lower water uptake and no discoloring fungi growing in the tests. The heartwood had a significantly higher density and smaller annual ring width than the sapwood. In PA the heartwood had significantly lower discoloration than sapwood. The total water uptake in g/m² was significantly higher in sapwood, but not the calculated moisture content. As for wood properties, the density was significantly higher in sapwood compared to heartwood, although there were no differences in annual ring width. Regarding PO, differences in water uptake could be seen between sapwood and heartwood although the densities were similar. These results show that susceptibility to discoloring fungi and water uptake is hard to correlate to a single inherent property when looking at different wood species.