Radial Variation in Sap Flux Density as a Function of Sapwood Thickness in Two Eucalyptus ( Eucalyptus urophylla ) Plantations

Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.

Heartwood, sapwood and bark content of teak trees grown in Karnataka, India

We evaluated heartwood, sapwood and bark content in teak trees. A total of 27 sample plots were laid out in teak plantations raised by State Forest Department in Kamataka covering different age groups （11-36 years）, density （516-2061 trees/ha） and sites. From these planta- tions, a total of 130 trees were felled for estimating the yield and bark content in relation to diameter at breast height （DBH）, age and density. Bark content ranged from 22.2%-54.3%. Heartwood and sapwood con- tent were analyzed by sampling five trees each from two different planta- tions, one 30 years old at 553 trees.ha-1 and the other 32 years old at 911 trees.ha-1. The highest heartwood proportion of stem wood volume （over-bark） was 56.3% and the lowest was 37.1%.

Variations in bark thickness and sapwood density of Calophyllum inophyllum provenances in Australia and in Sri Lanka

Sapwood density and bark thickness of Calophyllum inophyllum L. （a multipurpose durable timber species） were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4–15 mature trees having girth at breast height over bark （GBHOB） at 100–150 cm were selected on the basis of the population size. Significant （p0.05） hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.

Movement of boron from ulexite and colemanite minerals in sapwood and heartwood of Cryptomeria japonica

This study evaluated boron diff usion from raw boron minerals ulexite and colemanite with low water solubility in comparison to disodium octaborate tetrahydrate(DOT).Tests were conducted using sugi(Cryptomeria japonica(L.)f.D.Don)sapwood and heartwood blocks conditioned to 30,60,and 90%target moisture content.The blocks were fi lled with the boron compounds through treatment holes and diff usion was observed at three assay zones across the blocks after 7,30,60 or 90-day incubation period at room temperatures.For comparison,ethylene glycol was also introduced into the holes to elevate boron diff usion.As expected,diff usion increased with increased moisture content and levels were higher at the 60%and 90%moisture levels compared to the 30%level.With some exceptions,boron levels did not follow consistent gradients with distance away from the treatment hole.Incorporation of ethylene glycol helped increase boron levels,even in heartwood blocks.Boron levels were higher from the ulexite source than from colemanite;however,DOT treatments resulted in the highest boron diff usion rates as a result of greater water solubility compared to both raw boron minerals.The results suggest that ulexite together with ethylene glycol may be useful in both sapwood and heartwood materials when kept at high moisture levels for extended periods.

Allometric relationships between primary size measures and sapwood area for six common tree species in snow-dependent ecosystems in the Southwest United States

High-elevation,snow-dependent,semiarid ecosystems across southwestern United States are expected to be vulnerable to climate change,including drought and fi re,with implications for various aspects of the water cycle.To that end,much less is known about the dynamics of transpiration,an important component of the water cycle across this region.At the individual-tree scale,transpiration is estimated by scaling mean sap fl ux density by the hydroactive sapwood area(SA).SA also remains a key factor in eff ectively scaling individual tree water-use to stand level.SA across large spatial scales is normally established by relating SA of a few trees to primary size measures,e.g.,diameter at breast height(DBH),tree height(H),or canopy diameter(CD).Considering the importance of SA in scaling transpiration,the primary objective of this study was therefore to establish six species-specifi c(aspen,maple,white fi r,ponderosa pine,Douglas fi r,Englemann spruce)allometric relationships between SA and three primary size measures(DBH,CD,or H)across two high-elevation,snow-dependent,semiarid ecosystems in New Mexico and Arizona.Based on multiple statistical criteria(coeffi cient of determination,index of agreement,Nash–Sutcliff e effi-ciency)and ease of measurement in the forest,we identifi ed DBH as the primary independent variable for estimating SA across all sites.Based on group regression analysis,we found allometric relationships to be signifi cantly(p<0.05)diff erent for the same species(ponderosa pine,Douglas-fi r)across diff erent sites.Overall,our allometric relationships provide a valuable database for estimating transpiration at diff erent spatial scales from sap fl ow data in some of our most vulnerable ecosystems.

Experimental determination and modeling of equilibrium moisture content from the sapwood of Mexican pine (Pinus pseudostrobus Lindl.)

A desorption isotherm is a very important basis in the understanding of drying process. In this study, the desorption isotherms from the sapwood of Mexican pine （Pinus pseudostrobus Lindl.） were determined by the gravimetric method （discontinuous control of sample weight） at 30℃ and 50℃. The salt method was used in the range of water activities from 0.11 to 0.89. The results show that the desorption ability of Mexican pine sapwood increased with temperature at a given relative humidity. The experimental data was further simulated with the models, i.e., BET, GAB, Oswin and Henderson models. The GAB, Oswin and Henderson models allow the representation of the entire desorption isotherms. The BET model showed a better fit for water activity lower than 0.35, with a mean relative deviation of 0.0286 at 30℃ and 0.0167 at 50℃. Simultaneously, the BET model gave a better representation of moisture content in the monolayer saturation region. Overall, the GAB model ensured the best simulation of the entire isotherm, while the Henderson model displayed the worst simulation.

大花序桉心边材变异规律和候选基因挖掘研究

为探究大花序桉(Eucalyptus cloeziana)心材比例差异显著的不同家系间心边材变异规律,挖掘心材变异相关的候选基因,为珍贵用材树种高效培育及育种利用提供基因资源。以18 a生的2个心材比例差异显著的大花序桉家系为材料(家系1和2),各制作解析木3株,沿着树干以1 m为区间分段截取圆盘,测量东西和南北2个方向的带皮直径、去皮直径、总年轮数、边材年轮数、边材直径,并开展心材和边材径向和轴向分析。同时利用各解析木胸径处初生木质部样品进行DNA混池测序,发掘等位基因频率差异显著的SNP位点并挖掘相关功能基因。结果表明,大花序桉边材宽度和心材半径的方位变异中家系2大于家系1,平均差值分别为0.7和5.5 cm,在随树高的变异中,家系1和2的心材半径和心材年轮数的下降速率分别为0.40和0.64及0.43和0.36。两家系间基本密度差异显著,家系1为0.80~0.82 g/cm^(3),家系2为0.75~0.78 g/cm^(3)。基本密度与树高、横截面半径和心材半径呈显著负相关,与顺纹抗拉强度、弦面硬度和部分力学性质呈显著正相关。利用DNA混池测序共筛选到两家系间基因频率显著差异的SNP位点1842个,SNP注释分析表明位于基因间、上游区域、下游、外显子和内含子区域的SNP位点分别为55.8%、18.3%、16.3%、5.1%和4.4%。基因功能注释及富集分析发现SNP位点区域的基因主要与植物细胞分裂、植物细胞膜和植物蛋白激酶相关。通过大花序桉心材比例差异大的两家系间解析木径向和轴向分析,探讨了它们的心边材变异规律,结合DNA混池测序,挖掘了心材变异相关的SNP位点并筛选出一些木材形成相关候选功能基因。

醉香含笑不同树高处心边材挥发性成分的差异

为探究醉香含笑不同树高处心边材挥发性成分的积累规律及香气应用价值,利用顶空固相微萃取-气相色谱-四极杆飞行时间串联质谱法(HS-SPME-GC-QTOF-MS)对醉香含笑2个不同树高处心材、边材的挥发性成分进行非靶向代谢组学分析。采用主成分分析法(PCA)、正交偏最小二乘-判别分析法(OPLS-DA)、层次聚类分析法(HCA)分析不同树高处心边材挥发性成分差异,并鉴定差异代谢物。结果表明:醉香含笑2个不同树高心边材共鉴定出92种挥发性化合物,筛选出35个差异代谢物,其中边材中的单萜类、醛类、烷烃类化合物在边材中的合成水平显著高于心材,且随着树高的增加而积累。

温度对巨峰葡萄节间和带节茎段导水特性的影响

[目的]研究旨在明确巨峰葡萄枝条木质部导水能力与温度的量化关系,探索节对水分运输效率与安全性的影响。[方法]以巨峰葡萄1年生枝条为材料,在0.5~40℃温度范围,利用低压液流计法测试节间和带节茎段的导水率、比导率及导水率损失(PLC)随温度的变化,分析节与节间茎段导水特性的差异。[结果]巨峰葡萄茎段导水率和比导率均与温度呈极显著的线性关系。当温度从0.5℃升高至40℃,节间茎段的初始导水率、最大导水率、初始比导率、最大比导率分别升高154%、198%、157%和200%。节间茎段的导水率和比导率显著大于带节茎段,且差异随着温度升高呈增大趋势。节间茎段的PLC显著大于带节茎段,而带节茎段的导水率和比导率受温度的影响小于节间茎段。利用线性回归方程可对不同温度下的导水率和比导率进行预测。导水率和比导率与各温度下水的粘滞系数进行权衡后,各温度下的权衡导水率和权衡比导率没有明显差异。[结论]葡萄茎段导水率和比导率随着温度升高而增大,节对水分运输的效率和安全性有权衡作用。

装饰单板漂白染色处理的色差调控机理

装饰单板色差主要是由木材心边材木质素和抽提物含量的不同所导致的。木质素和抽提物中丰富的发色基团及助色基团使木材心材颜色加深,与边材形成明显的色差。采用漂白染色处理方法可以对装饰单板进行色差调控。为进一步分析色差调控机理,通过扫描电子显微镜(SEM)、红外光谱(FT-IR)、X射线光电子能谱(XPS)对漂白处理前后的黑胡桃单板微观结构和化学成分进行测试分析,研究木材心边材微观结构、内含物、木质素等物质中发色基团含量的变化,分析木材色度变化形成的机理。研究结果表明,漂白处理后心边材色差ΔE从11.48降至2.97,而染色处理可赋予装饰单板特定的色彩;扫描电镜、红外光谱和XPS分析结果显示,漂白处理的装饰单板导管内含物明显减少,去除了部分木材表面的脂肪酸类内含物。漂白过程中O/C值降低主要与木质素降解,以及主要的发色基团共轭CO双键被破坏导致O元素的含量降低有关。木质素所含有的共轭CO和CC发色基团产生了部分降解,这是漂白处理导致单板色度变化的主要原因。同时,木质素降解导致细胞壁产生皱缩,木材内部孔隙增多,利于染液在单板内部均匀渗透。而单板在染色过程中没有与染料发生化学结合,只是物理吸附的过程。

Estimating tree and stand sapwood area in spatially heterogeneous southeastern Australian forests

Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production.Understanding the effects of increasing disturbances,due for example to climate change and forest harvesting,requires detailed information on how forest density and structural attributes relate to transpiration.Mean annual transpiration of eucalypt forest communities is often strongly correlated with total cross-sectional sapwood area.Our aim was to test an efficient method for estimating sapwood area at_(1.3)m height(SA_(1.3))in a large number of trees to understand the spatial heterogeneity of tree and stand sapwood area within and between forest communities,and develop allometric relationships that predict SA_(1.3)with forest inventory data.We also apply tree competition models to determine the degree to which the relationship between SA_(1.3)and tree basal area at_(1.3)m height(BABA_(1.3))is influenced by competition.Methods We visited 25 recently harvested southeastern Australian forest sites consisting of 1379 trees and 5 Eucalyptus species to evaluate a new efficient data collection method for estimating SA_(1.3)with tree taper and stump dimensions data using mixed effects models.The locations of 784 stumps within one 5-ha site were accurately mapped using an unmanned aerial vehicle(UAV),and four distance-dependent tree competition models were applied across the site to explain within-stand variation in the ratio of SA_(1.3)to BABA_(1.3).Data from 24 additional sites,consisting of ten 15 m radial plots per site,were used to analyse within-site variation in R_(Ha)(the ratio of stand sapwood area SA_(Ha)to stand basal area BABA_(Ha)).The radial plots were merged within each site to evaluate between-site variations in R_(Ha)across the landscape.For predicting SA_(Ha)with forest inventory data,we computed the relationship between SA_(Ha)and a new index of total stem perimeter per hectare,defined as√BA_(Ha)N_(T),where N_(T)is tree stocking density.Important Findings Our 1379 measured stems represent the most comprehensive measure of sapwood area,surpassing the 757 measured stems in native eucalypt forests published in literature.The species-specific R_(Ha) varied considerably across sites and therefore extrapolating SA_(Ha)with spatially distributed BABA_(Ha)maps and a generalized R_(Ha) would introduce local uncertainty.We found that the species-specific stem perimeter index was more effective at capturing variability in SA_(Ha)across the landscape using forest composition,structure and density data(R^(2):0.72–0.77).The strong correlation between tree SA_(1.3)and BABA_(1.3)improved slightly using tree competition models(R^(2)increased from 0.86 to 0.88).Relating SA_(Ha)to routinely measured forest inventory attributes within permanent plots and Light Detection and Ranging(LiDAR)data may provide opportunities to map forest water use in time and space across large areas disturbed by wildfire and logging.

Study on Longitudinal Gas Permeability of Air-dried Masson Pine Sapwood

Measurement of the longitudinal gas permeability was made for air-dried sapwood specimens from Masson pine （Pinus massoniana）. Results showed that air-dried Masson pine sapwood was one of the most permeable softwoods. The inv,,stigated specimens had an average longitudinal gas permeability of 4.60 ×10^13 m^3/m, and the permeablity ranged from 1.06×10^-13 to 1.12×10^-12 m^3/m. The Kruskal Wallis Test indicated that, generally, there was no correlation between the longitudinal gas permeability and the trees from which specimens were prepared, and tree height had no significant effect on the longitudinal gas permeability.

巨尾桉木材气味化合物分析

【目的】明确巨尾桉挥发性有机化合物(VOCs)成分和气味特征,阐明其来源和释放机理,为巨尾桉的科学利用提供参考。【方法】利用气相色谱–质谱–嗅闻(GC-MS-O)技术,测试不同含水率下巨尾桉心材和边材释放的VOCs成分、气味化合物气味特征和气味强度等指标。【结果】巨尾桉共释放41种VOCs,其中13种是气味化合物,桉叶油醇、樟脑、莰烯是巨尾桉释放的主要单体气味化合物,且巨尾桉心材和边材释放的萜类气味物质差异显著,龙脑和γ-松油烯仅存在于巨尾桉心材。木材含水率显著影响巨尾桉气味化合物中萜类、醛类、烃类和醇类等组分的释放,随着含水率的降低,边材气味化合物释放量总体上呈现下降趋势,心材气味化合释放量则表现出先升高后降低的规律;受含水率的影响边材释放物中质量浓度变化显著的组分是萜类和醛类化合物,而心材释放物中变化明显的组分是萜类和醇类。含水率高于30%时,心材气味化合物释放量显著高于边材,含水率10%~30%时则释放量明显低于边材。萜类是构成VOCs和气味化合物的最大组分,释放出樟脑气味和松香味。醛类化合物是第二大组分,主要贡献果香味。樟脑和果香气味是巨尾桉的主要气味特征,甜花香、杏仁油、松香、皮革等气味起修饰作用。随着含水率降低,巨尾桉边材和心材的气味强度呈现先升高后降低的趋势,边材受含水率影响波动幅度最大的气味特征是果香,而心材受影响最大的则是樟脑味。相较于刚采伐的巨尾桉释放出强烈的樟脑味,干燥处理后,樟脑味减弱,与果香相辅相成。【结论】巨尾桉释放出了丰富的萜类化合物,可以有助于抗炎杀菌,对人体有保健作用;干燥后木材散发出的气味可以使居住者感到轻松愉悦、精神饱满,适合应用于室内和康复景观中。

基于胸高处边材面积、胸径和冠基部直径的杉木单木叶生物量预测模型

【目的】基于多个变量分别构建杉木单木叶生物量预测模型,并选择出预测效果最佳的模型,为杉木叶生物量的精准预测提供参考。【方法】以21块不同林龄样地共63株解析木为例,分别基于胸高处边材面积、胸径和冠基部直径3个变量,考虑其他与叶生物量相关的单木和林分因子,以样地为随机效应因子构建非线性混合模型,采用指数函数、幂函数和常数加幂函数消除数据间的异方差性。根据模型评价指标赤池信息准则(AIC)、贝叶斯信息准则(BIC)和对数似然值(Log Likelihood)选择最佳模型,并对不同参数的混合模型进行似然比检验。采用留一交叉验证法,计算模型决定系数(R^(2))、总相对误差(TRE)和平均绝对误差(MAE),对模型预测效果进行检验。【结果】基于3个变量以幂函数为异方差结构构建的混合模型效果最好,混合模型均优于基础模型,且基于冠基部直径构建的模型预测效果最佳。【结论】以基于冠基部直径构建的非线性混合效应模型(模型16)作为预测杉木单木叶生物量的最佳模型,符合管道模型理论。各变量均具有一定生物学和统计学意义,野外调查较易获取(非破坏性)。模型具有一定实用性,且预测精度较高(R2=0.8051)。本研究结果可为其他树种构建单木叶生物量模型提供参考。

预蒸处理对辐射松脱脂效果及干燥质量的影响

采用预蒸与常规干燥结合的方式对辐射松(Pinus radiata)锯材进行脱脂和干燥处理,分析预蒸处理对辐射松边材和心材含水率、脱脂率和干燥质量的影响。结果表明:预蒸处理可以缩短心材的干燥时间,对边材的影响不大。由于边材含脂率低、渗透性好,预蒸处理对边材的脱脂率影响不大,预蒸与常规干燥结合以及常规干燥两种工艺处理边材的脱脂率均在60%左右;对于心材,预蒸处理促进松脂迁移,预蒸组的脱脂率大于对照组,但心材初含水率低、渗透性差,导致心材脱脂率低于边材。预蒸组和对照组工艺处理的试材均表现出良好的抗松脂渗出效果,预蒸组表观质量更好。预蒸处理对辐射松边材和心材的干燥质量基本无影响,但需注意防范心材螺旋纹理造成的木材干燥过程中扭曲变形缺陷的发生。

大花序桉边心材酚类成分分布及鉴定

【目的】为探究大花序桉边材和心材酚类物质在细胞结构上的分布情况及心材聚集主要酚类成分。【方法】以9年生大花序桉为研究对象,采用激光共聚焦拉曼光谱仪表征边材和心材酚类物质的分布情况,再利用超高效液相色谱–质谱联用仪(UPLC-Q-Exactive-MS)鉴定木质部酚类成分及其分布。【结果】心材拉曼吸收强度明显高于边材,且细胞角隅处酚类物质含量明显高于胞间层和次生壁。进一步测定大花序桉边材和心材总多酚含量,心材中总多酚含量比边材高22.378 mg/g,表明心材形成过程中细胞角隅沉积了大量的酚类物质。通过UPLC-MS/MS首次从大花序桉木材的甲醇提取物中共鉴定了21种酚类成分,主要包含酚酸和衍生物类、黄酮类、鞣花酸衍生物、葡萄糖衍生物和可水解单宁酸,提取物中相对含量较高的为鞣花酸、鞣花酸-鼠李糖苷、没食子酸、鞣花酸-戊糖苷和甲基氯葡糖醇–O–甘露醇–葡萄糖。其中,心材的鞣花酸和没食子酸相对含量明显高于边材,再通过定量分析可知鞣花酸在边材和心材的含量分别为0.560、9.283 mg/g,没食子酸含量分别为0.019、0.043 mg/g。【结论】明确了大花序桉心材形成过程中酚类物质聚集于细胞角隅中,且心材主要积累成分为鞣花酸。

广西弄岗喀斯特森林9种主要树种水力结构功能特征及其相关性分析

为了解喀斯特地区树种适应水分亏缺生境的内在机制,选择广西弄岗喀斯特森林9种主要树种,分析树种间水力结构及相关性状的差异及相关性。结果显示:供试9种树种间的最大边材比导率、最大叶片比导率、胡伯尔值、木质部导管直径及木材密度存在极显著(P<0.01)差异,其中,海南椴〔Diplodiscus trichospermus(Merrill)Y.Tang〕的最大边材比导率、最大叶片比导率以及木质部导管直径均最大,但胡伯尔值和木材密度最小。干季和湿季,供试9种树种间木质部导水率丧失百分比(PLC)均存在极显著差异,且金丝李(Garcinia paucinervis Chun et How)的PLC值均最高,分别为44.39%和38.92%。除闭花木〔Cleistanthus sumatranus(Miq.)Muell.Arg.〕、海南椴和淡黄金花茶(Camellia flavida Chang)外,其他6种树种PLC值在干季和湿季间无显著(P>0.05)差异,表明喀斯特地区树种耐干旱能力普遍较强。相关性分析结果表明:单叶叶面积与最大边材比导率、木质部导管直径和叶片净光合速率呈极显著(P<0.01)或显著(P<0.05)正相关,但与木材密度呈极显著负相关。综上所述,喀斯特地区木材密度较大的树种虽然耐旱性较强,但木质部水分运输效率会降低,进而使叶片净光合速率降低;反之,木材密度较小的树种虽然有利于木质部水分运输效率提高及碳固定,但是其耐旱性降低;水力结构功能特征间的关系既存在协同也存在一定的权衡。

华北落叶松树干不同组分营养元素含量分析

掌握林木营养元素的积累与分布对研究森林生态系统物质循环和能量流动具有重要意义。为探究华北落叶松人工林养分循环过程,以塞罕坝机械林场华北落叶松人工林为研究对象,采用方差分析,进行不同龄组(幼龄林、中林龄、近熟林和成熟林)华北落叶松树干各组分C、N、P、K元素含量的差异性分析。结果如下:(1)树干各组分的营养元素含量随林龄增加呈现一定变化。心材中C元素含量随林龄增加呈先下降后上升的趋势,边材及树皮中的C元素含量随林龄增加不具有显著性变化,近熟林时期心材C元素含量与幼龄林、成熟林时期均具有显著性差异;心材中N元素含量随林龄增加呈下降的趋势,边材和树皮中N元素含量随林龄增加变化不显著,幼龄林与近熟林心材中的N元素含量具有显著性差异;心材和树皮中P元素含量随林龄增加呈“下降-上升-下降”趋势,边材中P元素含量变化不显著;心材和树皮中K元素含量随林龄增加呈下降的趋势,边材中K元素含量随林龄增加变化不显著。(2)C、N、P和K在树干各组分中分配规律并不相同,整体来说,C元素含量为心材>树皮>边材,N、P和K元素均为树皮>边材>心材。不同龄组的华北落叶松C、K元素含量具有极显著差异,P元素含量具有显著差异,N元素含量无显著差异,不同组分的N、P、K元素含量具有极显著差异,而C元素含量无显著差异。

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0.46cm。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<0.0001),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0.677～1.041a-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,1～2m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。

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。