新播长白落叶松苗期施肥效果分析

应用正交实验设计,对新播长白落叶松苗期进行了N、P、K施肥试验,结果表明:N、P影响苗高、地径、植株干物质重量;>5 cmⅠ级侧根数量的差异为极显著;K差异不显著。通过对25个组合的LSR多重比较,最佳施肥量为:N肥20、P肥50、K肥15 g.m-2苗木生长与N、P、K供应呈多元线性回归关系。     

不同林分密度桉树幼林抗风性比较研究

通过对两种1年生桉树无性系(巨细桉DH201-2与尾巨桉DH32-29)6种林分密度(1250株.hm-2、1667株.hm-2、2500株.hm-2、5000株.hm-2、6667株.hm-2、10000株.hm-2)进行生长量、根系和风害的调查,并分析林分密度、生长量和根系与抗风性相关性,结果表明:DH201-2以林分密度1667株.hm-2的生长量最大,而DH32-29胸径和冠幅以1667株.hm-2最大、树高以5000株.hm-2的最高;两个无性系间各个密度生长量差异显著;DH201-2以密度2500株.hm-2的抗风性最好,DH32-296个密度的抗风性均较差;相同林分密度下DH201-2根总数与根直径在0~2cm的根数显著比DH32-29多,DH32-29冠幅显著比DH201-2大,因此DH201-2易断干,而DH32-29易倒伏;相同林分密度下DH201-2比DH32-29抗风性强。     

Spacing of silver birch seedlings grown in containers of equal size affects their morphology and its variability

Silver birch (Betula pendula Roth) seedlings were grown individually in containers arranged in rows radiating from a central point (Nelder plot) at densities spanning the range from 207 to 891 plants m(-2). Height of one set of seedlings was measured at weekly intervals and additional seedlings were harvested each week for dry mass and leaf area measurements. Height and shoot:root dry mass ratio increased with plant density. Seedling-to-seedling variability in dry mass, but not height, increased with increasing plant density. The red to far-red (R:FR) photon ratio in horizontally propagated radiation decreased with increasing density, even when plant densities and leaf area index values were low. In a separate experiment, elongating internodes of seedlings were irradiated locally by red and far-red light emitting diodes and stem elongation measured. Far-red light markedly increased stem elongation, suggesting that changes in light quality sensed by growing internodes are involved in the observed responses to growth density.     

黑龙江东部地区樟子松人工林单木生物量研究

文章研究以黑龙江东部地区不同年龄、不同密度及不同立地条件的樟子松(Pinus sylvestris var. mongolica )人工林作为研究对象,基于 26块标准地中139株标准木的树干解析和生物量数据,以树木各测树因子为自变量建立樟子松人工林单木的树干、树枝、树叶及全树重的生物量预测模型;并研究了不同年龄樟子松林分的生物量结构.研究结果表明:樟子松人工林单木各分量生物量的最优模型形式均为CAR模型,各最优模型的变量主要为胸径(D)和树高(H)因子,D2H能够很好地反映树干的干重,胸径和树高能够很好地反映树枝、树叶及全树重的变化;樟子松单株生物量随着年龄的增大而增加,树干的生物量占全树重的比例随年龄的增大而增大,枝和叶的生物量变化趋势与树干相反,都随着年龄的增大而减小.文中研究的不同年龄阶段樟子松人工林的生物量结构变化规律及相应的预测模型,可为进一步了解樟子松人工林生物量的积累提供依据.     

元江县尾叶桉扦插苗造林适应性调查研究

对用尾叶桉扦插苗2001~2004年在元江县造林的林木进行胸径及树高生长调查及分析.结果表明:在490 m的低海拔干热河谷地区,4.5 a生尾叶桉的平均树高达20.1 m,年均高生长4.5 m;平均地径达22.8 cm,年均生长5.1 cm,其生长量均超过国家速生树种标准的4倍以上;在海拔1 100、430、800、1 500 m范围内,尾叶桉树高及胸径生长差异不显著,与海拔2 100 m和1 750 m生长的树木相比,差异达极显著水平,说明尾叶桉的适生海拔范围是430~1 500 m;在相同立地条件下,尾叶桉平均年树高生长量分别比兰桉、赤桉和柠檬桉高0.8、0.7和0.9 m,平均胸径生长量比兰桉、赤桉和柠檬桉高1.8、3.2和3.3 cm.     

影响桉树插穗生根的几个因素研究

通过6年的桉树扦插育苗研究，总结出影响插穗生根有6个因素：（1）母株来源，组培苗作母株的插穗比扦插苗作母株的生根状况好；（2）母株年龄，母株在1-3年生时采穗条扦插生根率高；（3）穗龄，桉树穗条上长有3-4对成熟叶时扦插成活率高；（4）穗条留叶面积，在扦插不良季节，桉树扦穗留叶至1/3面积的生根率最高，而地扦插良好季节，桉树插穗留叶至2/3面积生根率最高；（5）扦插季节，桉树扦插最佳季节为每年的11月份至次年的4月份；（6）植物生长调节剂，吲哚丁酸（IBA）作生根激素使用效果比萘乙酸（NAA）好。     

Growth,photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis) grown in natural shade

We compared growth, photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis Muell. Arg.) plants growing in natural shade (33, 55 and 77% reduction in incoming radiation) to control plants growing in full sunlight. Stem diameter and plant height, measured over a 15-month period, were greatest in plants grown in full sunlight, and both parameters decreased with increasing shade. At 7 and 14 months after planting (MAP), total plant dry mass was highest in control plants and lowest in plants in 77% shade. Expansion of the fourth leaf whorl, monitored at 5-6 MAP, was slowest in plants in 77% shade and fastest in unshaded plants, which had more leaves and higher leaf areas and inter-whorl shoot lengths. In response to increasing shade, specific leaf area increased, whereas leaf weight ratio and relative growth rate decreased. Chlorophyll a/b ratio decreased with increasing shade, indicating shade-induced partitioning of chlorophyll into light-harvesting complexes. Compared to the response in unshaded plants, CO2 assimilation saturated at lower photosynthetic photon flux densities in plants in 77% shade, with a lower upper-asymptote to the light response curve. Chlorophyll fluorescence revealed no evidence of sustained photoinhibitory damage in unshaded plants. Dynamic photoinhibition decreased with increasing shade, with the greatest depression in the ratio of variable to maximal fluorescence around midday. We conclude that shade adaptation and shade-induced reductions in dynamic photoinhibition account for the enhanced early growth of rubber in light shade.     

元宝枫叶数量变化对生长的影响

摘除整株叶片的1 3、2 3、3 3叶量对元宝枫生长影响的研究表明:不同采叶量和采摘时间显著影响着元宝枫的株高、地径、叶面积和叶生物量干质量,而对冠幅影响不显著。随着采叶量的增加,对元宝枫的影响显著加强;采叶时间的影响依次是6月>4月>8月。4月采叶3 3显著抑制株高、地径、叶面积和叶生物量干质量增长;6月采摘对株高和地径的生长影响显著,但对叶面积和叶生物量干质量的影响不大。     

Fresh-wood bending: linking the mechanical and growth properties of a Norway spruce stem

To provide data and methods for analyzing stem mechanics, we investigated bending, density and growth characteristics of 207 specimens of fresh wood from different heights and radial positions of the stem of one mature Norway spruce (Picea abies L. Karst.) tree. From the shape of each stress-strain curve, which was calculated from bending tests that accounted for shear deformation, we determined the modulus of elasticity (MOE), the modulus of rupture (MOR), the completeness of the material, an idealized stress-strain curve and the work involved in bending. In general, all mechanical properties increased with distance from the pith, with values in the ranges of 5.7-18 GPa for MOE, 23-90 MPa for MOR and 370-630 and 430-1100 kg m(-3) for dry and fresh wood densities, respectively. The first three properties generally decreased with stem height, whereas fresh wood density increased. Multiple regression equations were calculated, relating MOR, MOE and dry wood density to growth properties. We applied these equations to the growth of the entire stem and considered the annual rings as superimposed cylindrical shells, resulting in stem-section values of MOE, MOR and dry and fresh densities as a function of stem height and cambial age. The standing tree exhibits an inner stem structure that is well designed for bending, especially at a mature stage.     

Improvement in accuracy of aboveground biomass estimation in Eucalyptus nitens plantations: Effect of bole sampling intensity and explanatory variables

Two sets of aboveground biomass equations were fitted for stem only and stem plus crown predictive variables in Eucalyptus nitens plantations in Northern Spain. A sample of 40 trees was chosen after a complete study of variation in tree height and diameter in the region. The trees were felled and the biomass was divided into the following components: wood, bark, thick branches, thin branches, twigs, leaves and dead branches along the stem. Bole biomass was estimated by systematic subsampling of one 5 cm-thick disk every 0.5 m. Such intensive subsampling enabled determination of the effect of subsampling intensity on accuracy and bias of wood estimation, considering two ratio-type estimators: stem weight to dry matter, determined by the complete weighing (CW) method (i.e. of the fresh weight of the entire stem) and volume to dry matter, determined by the partial weighing (PW) method. The changes in moisture content and basic density along the stem explained the serious risk of dry mass or weight overestimation when a systematic subsample is considered. The average basic density was usually found at a relative height of 30-35% along the stem. The default choice of the bottom disk or log as the first section resulted in overestimations for the CW method and underestimations for the PW one. The biomass equations were fitted by seemingly unrelated regression, with corrections for heteroscedasticity carried out by weighted fitting. Diameter at breast height was the best explanatory variable, and the inclusion of height did not improve the accuracy, except for wood. The inclusion of crown variables improved the predictive ability for crown fractions, increasing the accuracy for estimating thick branches (by 10.8%), twigs (by 19.1%) and leaves (by 17.3%). The biomass of each fraction decreased in the following order: wood > bark > thick branches > dead branches along the stem > leaves > thin branches > twigs. The changes in these percentages with diameter class and the predictive ability of the fitted equations were also studied.     

营养面积控制法在石岩寨林场华山松林抚育间伐中的应用

通过在石岩寨林场666．67hm^2华山松林中选取29块样地，实测9组不同径阶树高、冠幅及枝下高数据，利用营养面积技术，建立树冠面积与立木胸径的回归方程，确定不同径阶应保留的标准密度，间伐强度蓄积为40．1％，间伐强度株数为39．98％，间伐蓄积为51359m^3，出材量32330m3。     

不同炼苗密度对桉树轻基质幼苗的影响

通过对5个月生4种不同炼苗密度的尾巨桉优良无性系 DH_32-29幼苗树高、地径及各器官生物量进行调查分析，结果表明：4种不同炼苗密度间苗高无显著差异；而地径差异达到极显著水平，并呈极显著负相关；不同炼苗密度单株间及各器官生物量均差异显著，单株生物量、叶片、茎干与根系的生物量均随炼苗密度增加而降低；考虑到空间利用率、通风保水性及疾病易感程度综合分析，炼苗密度以45株·盘^-1效果最佳。     

千烟洲试验站几种常见灌木生物量估测

通过测量地径、株高和冠幅3个测树因子以及枝、叶、根的干重,利用SPSS的回归分析方法,比较了线性模型、相对生长模型、对数模型和多项式模型4种模型共22个方程,分析了盐肤木、白檀、满树星、长叶冻绿4种灌木的生物量模型,认为:地径、树高和冠幅可作为很好的测树因子来估测灌木生物量,其中以地径作为单一因子也可以达到较好的估测精度。     

涝渍胁迫对转多基因库安托杨生长及生理性状的影响

以库安托杨转多基因株系(D5-9、D5-18、D5-19、D5-20、D5-21、D5-24、D5-26)和未转化株系(对照CK)为试材,研究不同水分处理(水涝胁迫、浸渍胁迫、正常供水)对其生长及生理性状的影响。结果表明:随着胁迫的加剧,各株系株高、根系生长和生物量累积呈下降趋势,而地径生长有所增加。浸渍、水涝胁迫下对照株系的净光合速率均最低,分别为11.99、10.37 μmol·m^-2·s^-1,比正常供水分别减少了14.0%和25.6%;浸渍胁迫下D5-26的净光合速率最高,为13.95 μmol·m^-2·s^-1;水涝胁迫下D5-19的净光合速率最高为12.01 μmol·m^-2·s^-1。蒸腾速率、水分利用效率、气孔限制值、叶绿素a、叶绿素b和总叶绿素含量均下降,叶绿素a的降幅小于叶绿素b,叶绿素a/b值先降后升,而气孔导度和细胞间隙CO₂浓度增大。PSⅡ的实际光化学效率、电子传递速率、潜在光化学活性和最大光化学效率均降低,初始荧光产量和最大荧光产量增加。涝渍胁迫对所有供试材料的生长及光合、叶绿素荧光等生理性状均有影响,但对转多基因株系的影响明显较对照小,且株系间存在差异。以生长、光合参数和叶绿素荧光参数为指标对供试材料进行综合评价,各株系的抗涝能力从高到低的排序为:D5-26>D5-19>D5-18>D5-21>D5-9>D5-20>D5-24>CK。     

5年生11种桉树无性系生长量与生物量比较

对雷州半岛5年生11种桉树无性系的林分生长量、生物量和生产力进行了研究。结果表明：11种无性系间胸径、树高、单株材积均差异极显著,林分蓄积量分布在114.57~206.75 m3.hm-2,其大小排序为：DH201-2〉LM1〉DH32-22〉LH1〉GL9〉EC33〉EC48〉U6〉TM3〉EC42〉EC40;11种桉树无性系林分各组分生物量都以干的最大,叶的最小;DH32-22、GL9、LH1、EC48、EC48、EC48、TM3和U6各组分排序为干〉根〉皮〉枝〉叶,DH201-2、EC33和LM1各组分排序为干〉根〉枝〉皮〉叶;11种桉树无性系林分生物量大小排序为：LM1〉DH201-2〉EC33〉LH1〉DH32-22〉GL9〉U6〉EC48〉EC42〉EC40〉TM3;11种桉树无性系林分生产力大小排序为：DH201-2〉LM1〉EC33〉LH1〉DH32-22〉GL9〉U6〉EC48〉EC42〉EC40〉TM3;从生长量、生物量和生产力的角度看,DH201-2、DH32-22、EC33和LM1的林分蓄积量、林分生物量和林分生产力较大,比较适合作为能源林树种在雷州半岛种植;U6、EC48、EC42、EC40和TM3生长较为缓慢,生物质转化效率不高,不适合作为能源林品种。     

桉树与环境

本文收集了国内外的一些桉树与环境关系的研究资料。依据众多的研究成果分别从桉树与水分,桉树与土壤养分,桉树水土保持,桉树与其它生物的关系等方面论述了桉树与环境的相互关系;同时阐述笔者对云南发展桉树的看法：桉树每生产单位干物质所消耗的水分和养分少于其它植物,桉树对绿化荒山,保持水土,增加经济收入是有益的。因此,有计划、有步骤地继续在云南发展桉树实有必要。     

Functions for Biomass Estimation of Young Pinus sylvestris,Picea abies and Betula spp. from Stands in Northern Sweden with High Stand Densities

New silvicultural regimes with high within-stand competition require new functions for estimation of standing stock and growth of biomass components, since the allometry of trees is changed by light competition. This paper presents functions for estimation of the aboveground biomass dry weights for stem wood, stem bark, branches and leaves of young (diameter at breast height <10 cm) Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and birch (Betula pendula Roth. and Betula pubescens Ehrh.) trees growing in dense mixed stands. The functions were derived from a sample consisting of 84 Scots pine, 43 Norway spruce and 66 birch trees from six stands in northern Sweden with high stand densities (>10000 st ha^-1). The logarithmically transformed power function displayed a good ability to stabilize the variance of dry weights and showed a good fit to the material (0.37< R ² <0.99). A comparison with the most commonly used biomass functions in Sweden today showed that they overestimated the weight of stem wood and branches, while the weight of foliage was underestimated. The nature of these discrepancies suggested that the precision of biomass estimations might also be improved for young trees at wider spacing.     

Coffee‐leaf extract and phosphites on the curative control of powdery mildew in eucalyptus mini‐stumps

The aim of this study was to evaluate the effectiveness of a plant extract obtained from the leaves of coffee plants infected by Hemileia vastatrix (NEFID), different formulations of phosphites and the combination of the extract and phosphites in controlling powdery mildew in eucalyptus mini‐stumps, as well as to study the effects on the production of mini‐cuttings and their rooting percentage. The experiments were conducted on two eucalyptus hybrids (‘urocam’ and ‘urograndis’) in a clonal garden and greenhouse. First, the NEFID plant extract and phosphites of copper, zinc, potassium and potassium/manganese were evaluated to determine their effectiveness in controlling powdery mildew and their toxic effect on the fungus' morphology. Subsequently, we analysed the direct fungitoxicity, curative efficiency and anti‐sporulating action of the NEFID extract and various combinations of phosphites with or without the extract, and we also evaluated their effects on shoot production and rooting in eucalyptus mini‐cuttings. The NEFID plant extract and phosphites of Cu, Zn and K/Mn were more effective than the fungicide pyraclostrobin + epoxiconazole in the control of powdery mildew. Potassium phosphite was not effective in controlling the pathogen. Among the tested mixtures, the combination of 50% NEFID plant extract and 50% copper phosphite was the most effective because it exhibited direct toxicity on powdery mildew, a high curative efficiency, anti‐sporulating action and no adverse effects on the production of shoots or rooting in eucalyptus mini‐cuttings.     

Weeds in <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> subsp. <Emphasis Type="Italic">maidenii</Emphasis> (F. Muell) establishment: effects of competition on sapling growth and survivorship

The effect of herbaceous vegetation on growth and survival was assessed in planted eucalyptus saplings grown under four levels of weed cover. Seedlings of Eucalyptus globulus subsp. maidenii were planted with 0 (W0), 25 (W25), 50 (W50) and 100% (W100) weed cover. Weed species composition and aboveground biomass was determined. Soil water content was evaluated by the gravimetric method. Seedling leaf area, diameter and height were evaluated at planting and during the 3 months following establishment. Tree height, diameter and stem volume was estimated at 12, 24 and 36 months. First year tree survival was recorded. The ratio of cumulative stem growth under W100: cumulative stem growth under W0 was used to measure competitive performance. Regression analysis was used to determine competition thresholds. Weeds seriously threaten the growth of E. globulus subsp. maidenii. Early negative effects of competition on growth were evident as from the second month after establishment, and both seedlings and 1-year-old saplings were more affected than 2- and 3-year-old ones. A “minimum-response threshold” was determined near 500 kg/ha (corresponding to W25 cover). No clear effect was found between sapling survival and weed biomass.