湿地松生长性状遗传参数的年度变化趋势

对广东省台山市红岭种子园内由60个自由授粉家系所建立的湿地松（Pinus elliottii）子代测定林开展了多年度持续观测,根据其2 a、4 a、6 a、17 a、20 a、22 a生的生长性状数据,分析了该林分的生长表现并估算了树高、胸径和材积的遗传参数。主要结果如下：湿地松子代测定林树高、胸径和材积遗传变异系数分别为3.14%～6.87%、3.87%～5.49%、10.12%～14.62%,年度变化趋势表现出较高的一致性;树高、胸径、材积生长受中等程度的遗传控制,其单株狭义遗传力分别为0.27～0.46、0.21～0.38、0.25～0.40,家系平均遗传力分别为0.56～0.74、0.50～0.75、0.56～0.76。总体上生长性状在成熟期（17 a、20 a、22 a生）的遗传力大于在幼龄期（4 a、6 a生）的遗传力; 6 a生树高、胸径、材积与成熟期相同性状的年-年遗传相关系数为0.57～0.74,成熟期树高、胸径、材积的年-年遗传相关系数为0.99～1.00。如果以22 a生材积作为目标性状,4 a生前根据树高,之后根据材积作早期选择,可期望获得较高的选择效益。     

The variation of microfibril angle in South African grown Pinus patula and its influence on the stiffness of structural lumber

Reduction in the rotation ages of softwood saw-log plantations in South Africa is causing increased proportions of low stiffness sawn lumber at final harvest. It has been shown for some species that the microfibril angle (MFA) of the S2 layer of tracheids is strongly related to the modulus of elasticity (MOE) of wood, even more so than wood density, especially in wood formed during juvenile growth. The objectives of this study were to describe the variation in MFA in young Pinus patula trees and to determine the relationship between MFA and the dynamic MOE of sawn P. patula lumber. Thirty 16- to 20-year-old trees from six compartments from the Mpumalanga escarpment were processed into discs and lumber. The MFA, density and ring width were measured at two height levels using Silviscan 3. The average annual ring MFA varied between 7° and 29°; the pattern of variation depended mainly on height level and the ring number from the pith. The MFA in P. patula followed the same within-tree variation trends as in New Zealand-grown Pinus radiata but the average MFA was lower in absolute terms and differences between height levels were less pronounced. The MFA and density exhibited highly significant Pearson correlations of 0.73 and 0.70, respectively, with board dynamic MOE. A multiple regression model, which included MFA, density and ring width, explained 71% of the variation in the dynamic MOE of boards. A sensitivity analysis on the model showed that MFA and density had approximately similar influences on predicting the dynamic MOE of Pinus patula boards.     

Variation in selected solid wood properties of young Pinus patula from diverse sites in the Mpumalanga escarpment area in South Africa

Regression analyses identified ‘Growth Days’ (an index expressing site moisture availability) as the only site variable contributing significantly to the prediction to wood density (R² = 0.57), whereas the model predicting grain angle included only ‘Altitude’ (R² = 0.60). These results surfaced during an investigative study to quantify various sources of variation in wood properties and to quantify the effect of a number of site factors on wood properties of Pinus patula grown in the Mpumalanga escarpment area of South Africa. For this purpose, 10 trees were sampled from each of 17 diverse sites for wood property analyses. The effects of site, distance from the pith and differences between trees within site on wood density, transverse shrinkage, grain angle and dynamic modulus of elasticity were investigated. The site factors considered included a wide variety of soil and climatic factors. The effect of radial distance from the pith and differences between individual trees within sites were highly significant, accounting for most of the variation in wood properties. Although the effects of a number of site factors were statistically significant, they generally explained relatively small but important variation in wood properties among sites. The study not only quantified the effects of important sources of variation on a few key wood properties, but it also revealed that the extent of differences between sites can be explained in terms of some specific site factors. It is envisaged that the results will contribute significantly towards the refinement of current forest site classification systems for improved decision-making with respect to wood quality in intensively managed plantation systems.     

Pilodyn在桉树活立木材性质评估中的应用

测定了建立在广西22个4年生桉树无性系的Pilodyn值、木材基本密度、边材木材密度、心材木材密度和弹性模量。结果表明：Pilodyn值为9．44—15．41mm、木材密度为0．3514-0．4913g·cm^-3、弹性模量在3．94GPa到7．53GPa之间;Pilodyn值在不同处理、不同方向及不同参试无性系间均存在极显著差异。Pilodyn值与各材性指标间的相关系数在-0．433到-0．755之间,呈显著到极显著负相关。研究表明,Pilodyn方法可以预测桉树活立木的木材密度和弹性模量。     

Radial and between-family variations of the microfibril angle and the relationships with bending properties in Picea jezoensis families

With emphasis on tree breeding for wood quality in Picea jezoensis, we aimed to evaluate radial and between-family variations in the microfibril angle (MFA) of the S₂ layer in the latewood tracheids in 10 open-pollinated families of 43-year-old P. jezoensis trees. In addition, the relationships between MFA/wood density with the modulus of elasticity (MOE) or modulus of rupture (MOR) were investigated. Significant differences in MFA between families were found from the pith toward the bark. MFA showed higher values around the pith area, although some families showed relatively lower values than others around this area. In addition, due to a larger coefficient of variations of MFA near the pith, the potential for juvenile wood MFA improvement may be greater compared with mature wood. MOE was correlated with MFA in juvenile wood and with wood density in mature wood, whereas MOR was mainly correlated with wood density at radial positions in both woods. Therefore, to improve the MOE and MOR of P. jezoensis wood, both MFA and wood density would be factors to consider in both juvenile and mature woods. On the other hand, there are indications that, only wood density would be an important criterion for improving mature wood properties.     

Volume growth and wood density of plus tree progenies of Pinus contorta in two Swedish field trials

Seventy‐four half‐sib families of lodgepole pine (Pinus contorta ssp. latifolia Engelm.) plus trees were measured for vigour, height growth, stem diameter, wood density and ring width in two Swedish field trials at age 9. Height growth, wood density and ring width differed between families within provenances with variance components of 3–8 %. Coefficients of variation were highest for height growth and lowest for ring width. Heritabilities were similar for height growth and wood density but lower for ring width. These genetic parameters seemed to be equal for all provenances. Indirect selection for high dry stem biomass was more effective using height growth than wood density, and a correlated response in wood density of 2.1 % of mean by selecting the 15 highest parent trees was indicated. Juvenile wood density looks uncertain as a selection criterion for mature wood density.     

粉单竹纸浆材材性的地理变异及产地选择

以广东、广西和海南3个省(区)8个产地的粉单竹群体3年生竹秆为研究材料,对其纤维形态、化学成分等纸浆材性指标进行测定,采用方差分析和相关分析方法对上述竹材性状进行遗传变异分析,以揭示粉单竹材性的地理遗传变异规律.结果表明: (1)粉单竹的纤维长度、纤维素和1%NaOH抽出物含鼍在产地间存在极显著或显著差异.纤维长度及纤维长宽比呈现纬度上从南到北(海拔上从低到高)逐渐减小的地理变异模式;(2)纤维素和纤维长度的遗传力分别为O.71和O.84;1%NaOH抽出物遗传力为0.54;木素和纤维长宽比的遗传力分别为O.38和O.13; (3)性状间相关分析表明,竹材产量与1%NaOH抽出物和苯醇抽出物呈显著负相关,与纤维素含量呈显著IE相关;纤维形态与生长、产量指标关系密切;最后,通过主成分分析进行联合选择,初步选出材性质量好、生长旺盛、竹材产量高的广东怀集、广东信宜和广西桂林3个优良纸浆材产地.     

Geographic variation and provenance selection for bamboo wood properties in Bambusa chungii

Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis. Foundation project: This research was funded by both of the International Tropical Timber Organization (ITTO), grant No. PD10/00. REV. 2 (I,F), and the National ‘Tenth Five-year’ Key Program of China, grant No. 2004BA506B0103.     

Corewood in South African pine: necessity and opportunities for improvement

South Africa has made excellent progress in breeding plantation trees fulfilling the primary demands of improved volume growth, stem and branching characteristics, tolerance to pests and diseases, and general adaptability. This has had marked positive impacts on wood quality, as straight stems normally contain no or very little reaction wood, while problems associated with pith eccentricity and wandering pith are kept to a minimum. The breeding of trees with small, well-distributed branches, forming large angles with the vertical axis of the tree stem, reduced performance problems associated with knots and knot-associated features. However, tree breeding and intensive silviculture are causing the average corewood diameter to increase, creating a wood resource that is increasing in variability, especially when combined with earlier harvesting. Reducing the size and improving the properties of the corewood zone have therefore become of utmost importance to ensure that the South African pine timber resource continues to meet quality demands related to strength, stiffness and stability. Breeding programmes to date have created sound bases for further wood quality improvement of the various pine species, especially of the corewood zone. Opportunities for success are excellent as large variation in corewood properties still exists within the current breeding populations, combined with operationally important wood properties, such as wood density, microfibril angle, spiral grain and transitional age, all being under moderate to strong genetic control. Corewood properties seem to be inherited largely independently of tree and growth characteristics, making it possible to combine improvement in these characteristics with desirable wood properties. This paper discusses results from several young field trials, which have shown marked family, species and site differences in wood stiffness. This suggests that there is good opportunity to increase the dynamic modulus of elasticity of corewood by early selection and breeding, using highly reliable non-destructive acoustic technology. The results also proved that vegetative propagation through cuttings has no detrimental effect on corewood stiffness. The latter may even increase with increasing physiological age of the cutting.     

Stem damage of lodgepole pine clonal cuttings in relation to wood and fiber traits,acoustic velocity,and spiral grain

Eight clones from a 16-year-old field trial of clonal cuttings of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were analyzed for growth, growth pattern, and stem damage in the field. In addition, wood and fiber traits (acoustic velocity [AcVel] and spiral grain) were analyzed and wood density, microfibril angle, modulus of elasticity, and radial fiber diameter (FibDR) determined from SilviScan analyzes. Two clones with considerably more bent, broken, and leaning stems differed from the other clones in terms of microfibril angle and modulus of elasticity (MOE) in the outermost annual rings. FibDR and, to some extent, MOE in the outermost annual rings were negatively correlated with the frequency of bent, leaning, or broken stems, while microfibril angle (MFA) was positively correlated. AcVel was negatively correlated with both MFA and the frequency of bent, broken, and leaning stems. We conclude that AcVel could be used as an effective tool to predict severe stem damage and determine stem strength in the field instead of using costly lab-based SilviScan measurements of microfibril angle. If developed further, this approach could be used for large-scale screening of progeny tests when selecting for stem strength.     

Genetic divergence for growth and wood parameters in different clones of Dalbergia sissoo Roxb

The wood analysis for different parameters was carried out in a clonal seed orchard of Dalbergia sissoo Roxb. established during 1997 at Hoshiarpur, Punjab, India. Twelve clones with higher index value were subjected to Euclidean Cluster Analysis based on wood and growth parameters to group into seven clusters. Cluster I and II contained four and three clones, respectively, and remaining clusters had just one clone each. Clone originated from Barielly, Uttar Pradesh of cluster VII was found to be the most divergent clone. Cluster II with three clones maintained greater inter-cluster distance with other clusters. The divergence analysis has confirmed that the clones planted in the clonal seed orchard are sufficiently divergent and seed harvested from the orchard would maintain high diversity.     

Variation in tensile properties and relationship between tensile properties and air-dried density for moso bamboo

This research investigated the variation in tensile properties and the relationship between the tensile properties and the air-dried density for the moso bamboo (Phyllostachys pubescens) by sampling at different heights and radial positions. Results showed that the variation of the longitudinal tensile properties in the radial direction was greater than that in the longitudinal direction. The longitudinal tensile modules of elasticity (MOE) ranged from 8.49 to 32.49 GPa. MOE for the outermost layer was 3–4 times as high as that for the innermost layer. The longitudinal tensile strength (MOR) ranged from 115.94 to 328.15 MPa. MOR for the outermost layer is 2–3 times as high as that for the innermost layer. Linear and curvilinear regressions were done from tested data of MOE, MOR and air-dried density in this paper. The linear equation worked a little better than the curvilinear one to predict the longitudinal MOR and MOE from air-dried density. __________ Translated from Scientia Silvae Sinicae, 2006, 42(3): 72–76 [译自: 林业科学]     

北京低山地区油松人工林立地指数表的编制及应用

使用252块北京市低山地区油松人工林标准地资料,统计分析各标准地优势木平均树高与年龄的关系,以双曲线式拟合树高生长导向曲线,编制出适用于该地区的油松人工林立地指数表;经X2检验、落点检验和树高生长量检验后证明所编表合格;使用该表对252块标准地进行立地质量评价,结果表明,63%的标准地立地质量处在中等水平;油松最适宜生长的立地条件为阴坡厚土.