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851.
852.
通过在山杏幼树干基部嵌套螺纹塑管进行野兔啃食防治技术研究,结果表明:嵌套套管法防治野兔啃食山杏幼树效果达98%~100%,高于涂刷专用防啃剂法10个百分点,每667 m^2节省成本242元。 相似文献
853.
Larix olgensis is a dominant tree species in the forest ecosystems of the Changbai Mountains of northeast China.To assess the growth response of this species to global climate change,we developed three tree-ring width and biomass chronologies across a range of elevations in the subalpine forests on the eastern slope of the Changbai Mountains.We used dendroclimatic analyses to study key factors limiting radial growth in L.olgensis and its variation with elevation.The statistical characteristics of chronologies suggested that elevation is a determinant of tree growth patterns in the study area.Response function analysis of chronologies with climate factors indicated that climate–growth relationships changed with increasing elevation:tree growth at high elevation was strongly limited by June temperatures of the previous year,and as elevation decreases,the importance of temperature decreased;tree radial growth at mid-elevation was mainly controlled by precipitation towards the end of the growing season of the current year.Biomass chronologies reflected a stronger climatic signal than tree-ring width chronologies.Spatial correlation with gridded climate data revealed that our chronologies contained a strong regional temperature signal for northeast China.Trees growing below timberline appeared to be more sensitive to climate,thus optimal sites for examining growth trends as a function of climate variation are considered to be just below timberline.Our study objective was to provide information for more accurate prediction of the growth response of L.olgensis to future climate change on the eastern slope of the Changbai Mountains,and to provide information for future climate reconstructions using this tree species in humid and semi humid regions. 相似文献
854.
Xingliang Liu Qinyan Ma Dongsheng Yang Zuoming Shi Yiming Su Shiqiang Zhou Shirong Liu Yupo Yang 《Frontiers of Forestry in China》2006,1(4):379-386
This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots
(Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m×25 m plot located
on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the
4 plantation types. To estimate the root biomass of an individual tree using D
2
H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm2 varied among plantation population types following the order: L. kaempferi (37.832 t/hm2) > A. fabri (24.907 t/hm2) > L. maxteriana (18.320 t/hm2) > P. balfouriana (15.982 t/hm2). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population
types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88%
for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0–20, 20–40, and 40–60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm2·m) for P. balfouriana, 8.230 t/hm2·m) for L. maxteriana, 24.546 t/(hm2·m) for A. fabri, and 13.211 t/(hm2·m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm2·year) for P. balfouriana, 0.83 t/(hm2·year) for L. maxteriana, 0.71 t/(hm2·year) for A. fabri and 1.64 t/(hm2·year) for L. kaempferi population, respectively.
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Translated from Acta Ecologica Sinica, 2006, 26(2): 542–551 [译自: 生态学报, 2006, 26(2): 542–551] 相似文献
855.
杂种落叶松F2代自由授粉家系纸浆材遗传变异及多性状联合选择 总被引:4,自引:1,他引:4
对17年生7个杂种落叶松自由授粉家系和3个对照子代测定林(共10个处理)的生长和材性性状进行遗传变异分析、相关分析、综合指数评价与选择.结果表明:生长与材性性状家系间、家系内均存在较大的变异,除单位面积管胞数量外,其他性状晚材的变异系数均大于早材;材积、管胞长宽比和树脂道比量变异系数较大(26.2%~85.3%).基本密度、早材微纤丝角、管胞比量变异系数较小(1.4%~8.1%).方差分析表明:处理间综纤维素含量,早、晚材微纤丝角,管胞长宽比,晚材径向直径、胞壁率、壁腔比,管胞比量差异显著;材积、管胞长、弦向直径、早材和晚材单位面积管胞数量差异极显著,家系遗传力为59.3%~92.7%,家系水平的材性改良潜力较大.材积与综纤维素含量成极显著正相关,与早材和晚材微纤丝角、弦向直径、晚材壁腔比和管胞比量成正相关,与管胞长宽比和晚材单位面积管胞数量成负相关;基本密度与材积成微弱的负相关,与综纤维素含量成显著的负相关,与管胞长宽比、早材微纤丝角、晚材单位面积管胞数量成正相关;综纤维素含量与管胞长宽比和晚材单位面积管胞数量成负相关;管胞长宽比与晚材壁腔比成极显著负相关;晚材微纤丝角与管胞比量成显著的正相关.对生长和材性进行综合评价,选出I3,I4,I93个比较理想的多性状指数方程.适合作纸浆林培育的家系为兴7×日77-2、日5×长77-3和日3×兴9.入选率30%时,各性状家系遗传增益分别为:材积34.7%,综纤维素含量7.5%,晚材壁腔比11.0%,晚材胞壁率6.2%,管胞长宽比4.5%,晚材微纤丝角3.2%,管胞比量0.3%. 相似文献
856.
857.
运用Granier热扩散式探针(TDP)法对青海大通黄土高寒区主要针叶树种青海云杉Picea crassifolia和华北落叶松Larix principis-rupprechtii夏季边材液流变化规律进行连续观测,利用自动气象站对周围气象因子太阳辐射(R_s)、空气温度(T_a)、空气相对湿度(R_H)和风速(W_s)进行同步观测,并对气象因子与青海云杉、华北落叶松边材液流通量(F_s)的相关性进行分析.结果表明:(1)边材面积(A_s)与胸径(D_(BH))存在较高的相关性,两者可以用幂函数很好地拟合.(2)青海云杉、华北落叶松边材液流速率(V_s)变化规律主体表现一致,晴天变化幅度最大,阴雨天变化幅度最小.(3)华北落叶松边材液流通量(F_s)仅为0.75 kg·h~(-1),而青海云杉高达1.84kg·h~(-1),为华北落叶松的2.4倍;青海云杉日耗水量(W)在9.56~37.14 kg·d~(-1)之间,而华北落叶松日耗水量W在5.61~14.25kg·d~(-1)之间.(4)青海云杉、华北落叶松F_s与气象因子关系密切.但气象因子的作用过程表现复杂.复相关分析表明:青海云杉、华北落叶松F_s与R_s、T_a、W_s之间呈极显著正相关,与相对湿度R_H呈极显著负相关.按相关程度排序为:R_s>T_a>R_H>W_s. 相似文献
858.
859.
860.
基于边合成边测序( Sequencing By Synthesis ,SBS)技术,使用Illumina HiSeq2500高通量测序平台对长白落叶松cDNA文库进行测序。共获得非重复序列基因58683条,总长度为55283938 bp。将得到的转录本使用BLAST软件将非重复序列基因序列与NR、Swiss-Prot、GO、COG、KEGG数据库比对,通过选择BLAST参数E-value不大于10-5,最终获得29350个有注释信息的基因序列,其中19292个转录本注释GO编号,有9112个转录本在COG数据库中被注释并分为25个功能分类,同时注释到120条KEGG代谢途径。在得到注释的转录本中搜索到木质素相关基因共68条,其中与木质素合成相关基因29条,与木质素分解代谢相关基因27条;找到了147条纤维素相关基因,其中与纤维素合成相关基因103条,与纤维素分解代谢相关基因44条。 相似文献