华北落叶松、日本落叶松育苗密度的探讨

从苗木高生长、地径生长对日本落叶松和华北落叶松的不同育苗密度进行了试验总结，提出了上述2个树种较合理的育苗密度。论述了单位面积留苗数量和侧根条数的关系：地径越粗侧根数越多。大体呈现地径每增0．1cm，侧根增多1条的规律。     

An application of mixed-effects model to evaluate the effects of initial spacing on radial variation in wood density in Japanese larch (Larix kaempferi)

The effects of initial tree spacing on wood density at breast height were examined for 22-year-old Japanese larch (Larix kaempferi). The experiment involved the use of three plots with different initial tree spacing densities (300, 500, and 1000 trees/ha). For five trees selected from each plot, the total tree height, diameter at breast height, height to the base of the live crown, and crown diameter were measured. Ring width and wood density for individual growth rings were determined by X-ray densitometry. A mixed-effects model was applied for fitting the radial variation in wood density in relation to initial spacing. Models having various mean and covariance structures were tested in devising an appropriate wood density model. The model, consisting of the mean structure with quadratic age effects and heterogeneous first-order autoregressive covariance, was able to describe the radial variation in wood density. Closer spacing of trees (1000 trees/ha) resulted in a faster increase in wood density from the pith outward than for more widely spaced trees, indicating that initial tree spacing may influence the age of transition from juvenile to mature wood.     

人工林日本落叶松木材物理力学性质的研究

通过试验和统计分析的方法，研究了人工林日本落叶松木材的物理力学性质及其与密度与主要力学强度的相互关系。结果表明；人工林日本落叶松硬度和主要力学强度适中，与长白落叶松和兴安落叶松相比，日本落叶松结构相对均匀，弦径干缩差异性小，可满足各种木制品的生产要求。     

树龄对日本落叶松木材物理力学性质的影响

选取日本落叶松为试验材料,开展不同树龄日本落叶松物理力学性质的比较研究.结果表明:43年生、30年生和17年生日本落叶松木材气干密度分别为0.607,0.567和0.507 g/cm3,气干体积干缩率分别为7.7％,7.7％和7.1％;全干到气干体积湿胀率分别为5.1％,4.9％和4.5％;抗弯弹性模量分别为17.527,16.775和12.510 GPa,抗弯强度分别为121.1,110.3和90.9 MPa,顺纹抗压强度分别为56.8,51.8和44.0 MPa.随着树龄增大,日本落叶松木材密度、顺纹抗压强度、抗弯强度和抗弯弹性模量等各项物理力学性能指标提高,差异干缩逐渐变小.日本落叶松木材的气干密度与抗弯弹性模量、抗弯强度、顺纹抗压强度呈线性正相关,相关系数分别为0.760,0.816和0.900.     

Clonal variation of carbon content in wood of Larix kaempferi (Japanese larch)

Variations in carbon content in wood among 102 clones, selected from almost the entire natural distribution area, were investigated in Larix kaempferi. The average carbon content was 50.50%, 50.94%, and 50.80% in sapwood, heartwood, and whole wood, respectively. The difference in carbon content between clones was significant. The clonal repeatabilities were 0.46, 0.38, and 0.44 in heartwood, sapwood and whole wood, respectively. The coefficients of variation in the clonal mean carbon content were only 0.43%, 0.42%, and 0.41% in heartwood, sapwood, and whole wood, respectively. This small genetic variation and resulting small relative genetic gain of carbon content indicate that the genetic improvement of carbon content by selection has a small effect on the genetic improvement of carbon sequestration capacity by selection in L. kaempferi.     

小陇山林区日本落叶松纸浆材应用前景探讨

在分析当前我国造纸原料市场和小陇山林区日本落叶松木材的纸浆性能的基础上，提出了小陇山林区日本落叶松纸浆材林的经营措施，进行了应用前景分析。     

不同林龄日本落叶松与华北落叶松生长的比较

从树高生长、胸径生长和材积生长方面,对4a生、8a生、10a生、25a生和38a生的日本落叶松和华北落叶松进行比较分析。结果表明：各年生日本落叶松生长优于华北落叶松,整体上日本落叶松也优于华北落叶松,并且其高生长、胸径生长和材积生长随着林龄的增加而逐渐增加。     

Genetic variation in wood stiffness and strength properties of hybrid larch (Larix gmelinii var. japonica × L. kaempferi)

Genetic parameters for wood stiffness and strength properties were estimated in a 29-year-old hybrid larch stand (Larix gmelinii var. japonica × Larix kaempferi). The study included 19 full-sib larch families from Hokkaido, northern Japan. Implications of these genetic parameters in wood quality improvement are subsequently discussed. Traits included in the analyses were the dynamic modulus of elasticity of green logs (E _log), the modulus of elasticity (MOE), the modulus of rupture (MOR), compression strength parallel to the grain (CS) in small clear specimens, wood density (DEN), and diameter at breast height (DBH). DEN had the lowest coefficients of variation and MOE the highest. The narrow-sense heritability estimates of E _log, MOE, MOR, and CS were 0.61, 0.44, 0.60, and 0.43, respectively, and those of DEN and all mechanical properties increased from an inner to outer position within the stem. E _log and DEN had high positive phenotypic (0.52–0.83) and genetic (0.70–0.92) correlations with MOE, MOR, and CS. The mechanical properties of the inner position of the stem had rather high phenotypic and genetic correlations with those of the outer position and overall mean. The predicted gains in wood stiffness (E _log and MOE) were higher than those of the strength properties (MOR and CS). The predicted correlated responses in MOE, MOR, and CS when selecting for E _log and DEN were 72.6%–97.8% of a gain achievable from direct selection of these traits. DBH showed an insignificant correlation with all mechanical properties, although selection of this trait had a slightly negative effect on the mechanical properties.     

Variation in radial growth and wood density of Cyclocarya paliurus across its natural distribution

New Forests - As a multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medicinal use. However, it remains unclear to what extent geographical...     

Effect of growth on wood properties for Japanese larch (Larix kaempferi): Differences of annual ring structure between corewood and outerwood

To investigate the relations between growth and the wood properties of Japanese larch (Larix kaempferi), six sample trees of varied ages and radial growth were felled and the ring width, ring density, percentage of latewood, and some other factors were determined. There were significant differences in ring density and percentage of latewood between sample trees with vigorous growth and those with poor growth. In corewood the ring density decreased with increasing ring width for all sample trees, whereas in outerwood this trend did not appear. Moreover, the latewood width increased with the increment of ring width only in outerwood, whereas there was almost no change in the corewood. The variation in patterns of ring width, ring density, and percentage of latewood in the radial direction and the relation with height was also studied.Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997     

Inheritance of male flower production in Cryptomeria japonica (sugi) estimated from analysis of a diallel mating test

Context

Clonal variation of flower production has been investigated thoroughly in coniferous tree species because of the importance of flowering in seed production from seed orchards. However, the inheritance of flower production by progeny test has not been previously studied well, so the heritability of male flower production of Cryptomeria japonica, the most important species for forestry and the main cause of pollinosis in Japan, was estimated to provide fundamental data for pollen control in seed orchards and plantation forests.

Methods

Male flower production in C. japonica was investigated for three years using 20 full-sib families created by a diallel mating design with six parents using gibberellin treatment to promote flowering.

Results

The narrow-sense individual tree heritability of male flower production in each year was estimated as ranging from 0.777?±?0.339 to 1.050?±?0.346 by sib analyses. The contribution of general combining ability to the total variance varied from 24.1 to 35.6?%. The highest contribution of specific combining ability was 1.42?%. By selecting the top 50?% of parental clones for reduced male flower production, the genetic gain in lowering male flower productivity was predicted as 46.1?C53.0?%.

Conclusion

Our results suggest that male flower production in C. japonica is under strong genetic control and that control of male flowering by breeding is possible with a well-designed program.     

Simulation of the growth ring density of Larix olgensis plantation wood with the ARMA model

Because growth ring data have temporal features, time series analysis can be used to simulate and reveal changes in the life of a tree and contribute to plantation management. In this study, the autoregressive(AR) and moving average modeling method was used to simulate the time series for growth ring density in a larch plantation with different initial planting densities. We adopted the Box–Jenkins method for the modeling, which was initially based on an intuitive analysis of sequence graphs followed by the augmented Dickey–Fuller stationarity test. The order p and q of the ARMA(p, q) model was determined based on the autocorrelation and partial correlation coefficient figure truncated on the respective order.Through the residual judgment, the model AR(2) was only fitted to the larch growth ring density series for the plantation with the 1.5 9 2.0 m^2 initial planting density.Because the residuals series for the other three series was not shown as a white noise sequence, the modeling was rerun. Larch wood from the initial planting density of2.0 9 2.0 m^2 was modeled by ARMA(2, 1), and ARMA((1, 5), 3) fitted to the 2.5 9 2.5 m^2 initial planting density,and the 3.0 9 3.0 m^2 was modeled by AR(1, 2, 5).Although the ARMA modeling can simulate the change in growth ring density, data for the different growth ring time series were described by different models. Thus, time series modeling can be suitable for growth ring data analysis, revealing the time domain and frequency domain of growth ring data.     

短轮伐期日本落叶松家系生长性状遗传参数的变化

以湖北省建始县长岭岗林场 15年生日本落叶松自由授粉家系子代测定林为研究对象 ,研究纸浆材轮伐期内不同年龄阶段生长性状的家系间遗传变异、早 -晚相关关系及主要遗传参数随时间变化的趋势 ,确定早期选择年龄及早期选择因子。结果表明 :各年龄胸径、树高不仅在家系水平上存在着极显著的变异 ,家系内个体间也存在着丰富的变异 ,具有很大的遗传改良潜力 ,家系和家系内个体选择是日本落叶松改良的主体 ;性状的方差分量、遗传力、变异系数在树木生长过程中一直处于动态变化中 ,并表现出一定的规律性 ;胸径、树高的早 -晚相关十分紧密 ,且这种相关关系主要受遗传因素制约 ;对胸径和树高进行家系早期选择的最适年龄为 6年生 ,进行家系内个体选择年龄为 8年生 ,胸径作为早期选择指标较树高更能准确地表达成熟时的信息。     

Age trends in the genetic parameters of wood density and the relationship with growth rates in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1

Age trends in variance components and heritability of overall wood density, earlywood and latewood density, and latewood proportion were investigated in 29-year-old trees of 19 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F₁. The age–age correlation and optimum selection age for these traits were also estimated and genetic and phenotypic correlations between wood density and radial growth rate were calculated for each growth ring. Intraring wood density data were obtained using X-ray densitometry. The coefficient of additive genetic variance was stable over all ages, whereas the coefficient of environmental variances gradually decreased with increasing age, resulting in increases in heritability estimates with age for overall density. The latewood proportion had the highest heritability estimates at all ages, ranging from 0.44 to 0.66. Overall density and its various components at 28 years of age showed strong genetic correlations with their respective traits at all younger ages. Optimum selection ages for the wood density traits ranged from 8 to 14 years, at which point maximum gain efficiencies per year were obtained. There were negative correlations between wood density and radial growth rate at early ages, although these relationships tended to be weaker with increasing age. These results suggest that selection at a young age is effective for wood density, but particular care must be taken in selecting trees with an improved radial growth rate because rapid growth will result in a low-density wood product, especially in the early growth period.     

Genetic variation in wood density and correlations with tree growth in Prosopis africana from Burkina Faso and Niger

? Variation in wood basic density and its correlation with tree growth were investigated at 13 years in a provenance/progeny test of Prosopis africana in Niger. The test included progeny from 256 trees sampled from 24 provenances in the Sahelian ecozone of Burkina Faso and Niger.

? Variation in wood density was significant due to provenances and families within provenances. Individual tree heritability was higher for wood density than for growth traits. Provenance means for wood density increased from the more humid to the drier parts of the sample region. Phenotypic correlations indicated that larger trees tended to have denser wood.

? Clines suggest that natural populations of P. africana from the drier parts of the sample region have the genetic capacity to produce denser wood, compared with populations from the more humid parts of the region. Correlations and heritability estimates suggest that selection of faster-growing trees may produce a small gain in wood volume but little (if any) gain in density in the subsequent generation. Multi-location provenance/tests are needed to confirm this tentative conclusion.

     

Genetic variation of wood tracheid traits and their relationships with growth and wood density in clones of Pinus tabuliformis

To improve wood quality for pulpwood industries, it is important to examine not only wood density but also its components, especially tracheid characteristics.We studied genetic variations in the following tracheid traits by earlywood(EW) and latewood(LW): tracheid length(TL),double wall thickness(WT), radial lumen diameter(R_D1), tangential lumen diameter(T_D1), radial central diameter(R_D2), and tangential central diameter(T_D2).We also studied the relationship with the following growth traits: diameter at breast height(DBH), height(H), crown breadth south-north axis(NSC), crown breadth east–west axis(EWC), ring width(RW), latewood percentage (LWP), and wood density(WD).All sample materials were collected from a 33-year old clonal seed orchard of Pinus tabuliformis Carr.Genetic variation among clones was moderate for all tracheid traits, 9.49–26.03%.Clones significantly affected WT, R_D1, R_D2, T_D1, T_D2, and the two ratios WT/R_D1 and TL/T_D2 in EW but had no effects in LW.Clones significantly affected TL in LW but had no effects in EW.H2/C was higher in LW(0.50) than in EW(0.20) for TL, while H2/Cwas higher in EW(0.27–0.46)for other tracheid traits and the two ratios(TL/T_D2 and WT/R_D1) than in EW(0.06–0.22).WD and TL were significantly positively correlated, but WT and TL were negatively correlated both at individual and clone levels;all tracheid diameters and the four ratio values(EW_WT/R_D1, LW_WT/R_D1, EW_TL/T_D2 and LW_TL/T_D2), were strongly positively correlated with DBH, H,NSC, WEC and RW, and strongly negatively correlated with WD both at individual and clone levels.The most important variables for predicting WD were LW_TL,EW_WT and R_D1 in both EW and LW(r~2= 0.22).Selecting the top 10% of the clones by DBH would improve DBH growth by 12.19%(wood density was reduced by 0.14%) and produced similar responses between EW and LW for all tracheid traits: a reduction of0.94 and 3.69% in tracheid length and increases in tracheid diameters(from 0.36 to 5.24%) and double wall thickness(0.07 and 0.87%).The two ratios WT/R_D1 and TL/T_D2 across tissues(EW and LW) declined 0.59 and 4.56%,respectively.The decreased tracheid length and the ratio between tracheid length and diameter is disadvantageous for pulp production.The unfavorable relationship of tracheid traits with wood density indicate that multiple trait selection using optimal economic weights and optimal breeding strategies are recommended for the current longterm breeding program for P.tabuliformis.     

Full-diallel-based analysis of genetic parameters for growth traits in Japanese larch (Larix kaempferi)

New Forests - Genetic parameters were estimated for tree height (H), diameter at breast height (DBH), and volume from a progeny trial conducted in Japanese larch (Larix kaempferi) in Liaoning,...     

Effects of elevated CO2 concentration on growth, annual ring structure and photosynthesis in Larix kaempferi seedlings

We evaluated the effects of elevated carbon dioxide concentration ([CO2]) and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch (Larix kaempferi (Lamb.) Carr.). Seedlings were grown in phytotron chambers in an ambient (360 ppm) or an elevated (720 ppm) [CO2] in two nutrient regimes for one growing season. Elevated [CO2] reduced stem height and increased stem basal diameter compared with ambient [CO2]. The effect of elevated [CO2] on growth tended to be greater at high-nutrient supply than at low-nutrient supply. Elevated [CO2] had no significant effect on ring width or the number of tracheids per radial file. There was no obvious difference in cell wall thickness or the relative area of the cell wall between seedlings grown in ambient or elevated [CO2]. Although growth in elevated [CO2] resulted in a slight increase in cell diameter, the increase had a relatively minor effect on the relative area of the cell wall. Net assimilation rate increased in response to elevated [CO2]; however, the increase in whole-crown photosynthetic rate (Total Agrowth) in seedlings in the elevated [CO2] treatment was minimal because of the smaller specific needle area and acclimation of the photosynthetic characteristics of the needles to the growth [CO2]. In conclusion, we observed no obvious enhancement in the capacity for carbon fixation in Japanese larch seedlings grown in the presence of elevated [CO2] that might be attributable to changes in stem growth. However, elevated [CO2] caused changes in the temporal pattern of stem growth and in some anatomical features of the tracheids.