湿地松多效益经营模式林分采伐技术研究     

王青春孙海放  吴从健彭倚云 《林业研究》2004,15(1):69-72,J003

在利用Richards函数对湿地松生长进行拟合和利用动态规划方法在计算机上直接模拟抚育间伐的基础上，初步确定了江西省丘陵区湿地松多效益经营模式林分的采伐技术。研究结果表明：湿地松多效益经营模式林分始伐年龄为8．10年，主伐年龄为25年，最优抚育间伐方案为间伐3次(含始伐)，时间分别为第8、12及16年，间伐强度分别为每公顷950、700、300株，最后保留株数为每公顷550株。表2参7。  相似文献   

Genetic Variation among 11 Abies concolor Populations Based on Allozyme Analysis     

Zhang Jin-feng Li Hui Dong Jian-sheng Wang Jun-hui Key Laboratory for Genetics  Breeding in Forest Trees  Ornamental Plants  Ministry of Education  Beijing Forestry University  Beijing  P. R. China 《中国林学(英文版)》2005,7(1)

In order to obtain information on the genetic structure of Abies concolor and the genetic variation among 11 popula- tions introduced from America to China, allozyme analysis based on starch gel electrophoresis technology was used. 24 loci of 10 allozyme systems were mensurated, and the genetic structure and genetic diversity of the 11 populations of A. concolor evaluated. The results show that the genetic variation among is significant, and the genetic variation within A. concolor populations is more important. In contrast with other conifers, the variation of A. concolor is above the average level of conifers, and higher than the same level of Abies. The percentage of polymorphic loci (P) was 62.5%, the number of alleles per locus (A) 2.08, the number of ef- fective alleles per locus (Ae) was 1.37, the expected heterozygosity (H) 0.204, and the Shannon information index (I) 0.351 7. There is a short genetic distance (D=0.061) and a low gene flow (Nm=0.839 4) among the 11 introduced populations of A. concolor with high genetic variation. The genetic differentiation coefficient (Gst) was 0.229 5, which is higher than that of the mean in Abies or Pinus.  相似文献   

植物RNA介导的病毒抗性研究进展     

魏志刚  杨传平  朱大群  赫崇新 《东北林业大学学报》2002,30(3):56-59

对目前RNA介导的病毒抗性的特点、机制以及与转基因沉默的异同作一概括，并对RNA介导的病毒抗性在植物功能基因组学研究中的应用作了简单介绍。  相似文献   

日本落叶松半同胞家系对比试验研究初报     

张亚东  黄国伟  杜超群  全永寿  许业洲 《湖北林业科技》2013,(6):13-16,88

摘要：本文以日本落叶松半同胞家系试验林为对象,通过对造林1年后的保存率和生长量调查分析,比较不同家系的早期表现。试验林平均保存率为98．4％,平均地径、平均树高生长量分别为8．06mm、59．1cm。结果表明：试验林保存率、生长量均差异显著,来自种子园的半同胞家系生长量优于来自母树林和人工林选择优树的半同胞家系,其中11,16,18,25号家系表现较好。  相似文献   

天山云杉枯落物持水特性的空间异质性     

范静  刘华  白志强  臧润国  刘贵峰  郭仲军 《东北林业大学学报》2013,(5):56-60

对新疆天山北部由西至东5个地点(昭苏、新源、呼图壁、天池、奇台)天山云杉枯落物持水特性进行研究。结果表明:昭苏、新源、呼图壁、天池和奇台天山云杉枯落物总储量分别为(9.00±0.47)、(8.48±0.32)、(8.92±0.52)、(11.10±0.33)、(10.74±0.30)t.hm-2。5个地点天山云杉枯落物的持水量、持水率随浸泡时间的增加均呈递增趋势,且半分解层的值均大于未分解层的;枯落物吸水速率随浸泡时间的增加呈递减趋势且半分解层吸水速率均大于未分解层。天山云杉枯落物的持水量与浸泡时间呈对数关系,其函数表达式为Q=kln(t)+p;吸水速率与浸泡时间呈幂函数关系,表达式为Y=kt;持水率与浸泡时间呈对数关系,函数表达式为S=kln(t)+p。5个地点天山云杉枯落物的总持水量由大到小的排序为天池、呼图壁、新源、昭苏、奇台,并且天池地区的总持水量与其他4个地区有明显差异。枯落物平均持水率由大到小的排序为呼图壁、新源、天池、昭苏、奇台,其中奇台与呼图壁和天池间有明显差异,奇台与新源和昭苏间无差异。  相似文献   

江西大岗山毛竹林碳贮量及其分配特征   总被引：4，自引：0，他引：4  

王兵  王燕  郭浩  赵广东  白秀兰 《北京林业大学学报》2009,31(6):39-42

采用收获法研究了江西大岗山毛竹林生态系统的碳贮量及其分布特征。结果表明:毛竹各器官碳密度波动在0.463 0～0.491 7 g/g,其大小顺序为竹枝竹秆蔸根竹蔸竹叶。随着毛竹年龄的增长,碳密度无明显的变化规律。在毛竹林植被层中,碳密度依次为:竹枝竹秆竹鞭蔸根鞭根竹蔸竹叶林下植被枯落物。毛竹林生态系统土壤层碳密度以0～20 cm层最高,且各层次之间碳密度差异极显著。毛竹林生态系统碳贮量为243.22 t/hm2,其中土壤层碳贮量占84.03%,植被层占15.97%。毛竹林生态系统年固碳量为12.15 t/（hm2·a）。其中植被层年固碳量为11.36 t/(hm2·a),土壤层年固碳量为0.79 t/(hm2·a)。   相似文献   

Spatial and temporal patterns in summer ichthyoplankton assemblages on the eastern Bering Sea shelf 1996–2007     

M. S. Busby  J. T. Duffy‐Anderson  K. L. Mier  L. G. De Forest 《Fisheries Oceanography》2014,23(3):270-287

Larval and early juvenile fishes were sampled from the eastern Bering Sea (EBS) shelf from 2001 to 2005, and in 2007. Data from these collections were used to examine spatial and temporal patterns in species assemblage structure and abundance. The years 2001–2005 were unusual because the EBS water temperature was ‘warm’ compared with the long‐term mean temperature. In contrast, 2007 was a ‘cold’ year. The abundance of the five most numerous taxa at 12 stations common to all years sampled (1996–2005, 2007) were significantly different among years. Larval and early juvenile stage Theragra chalcogramma (walleye pollock), a commercially important gadid, were by far the most abundant fish in all years. Bottom depth alone best explained assemblage structure in most years, but in others, bottom depth and water column temperature combined and percent sea‐ice coverage were most important. Abundance of T. chalcogramma larvae increases with water column temperature until 5°C and then becomes level. Higher abundances of Gadus macrocephalus (Pacific cod) larvae occur in years with the greatest percent sea‐ice cover as indicated by GAM analysis. Larvae of Lepidopsetta polyxystra (northern rock sole) increase in abundance with increasing maximum wind speed, but decrease at a later date during the last winter storm. The data are consistent with the hypothesis that oceanographic conditions, specifically water temperature and sea‐ice coverage, affect the spatial and temporal pattern of larval abundances. In general, ichthyoplankton species assemblages can be important early indicators of environmental change in the Bering Sea and potentially other subarctic seas as well.  相似文献   

Comparative productivity of Prosopis cineraria and Tecomella undulata based agroforestry systems in degraded lands of Indian Desert     

G. Singh 《林业研究》2009,20(2)

Tree-crop interactions were monitored by measuring tree growth characters of Prosopis cineraria L.and Tecomella undulata L.and yields of Vigna radiata(L) in agroforestry systems in degraded lands of Indian Desert.Potential competition for resource between the trees and associated crop was analyzed by measuring soil water contents, soil organic matters and NH4-N at different depths of soil layers i.e., 0-25 cm, 25-50 cm and 50-75 cm in the experimental plots.The plots size were 16 m × 18 m(D1), 20 m × 18 m(D...  相似文献   

2008年森林防火10件大事     

国家森林防火指挥部办公室 《森林防火》2009,(1):7-9

1 国务院召开全国森林草原防火工作电视电话会议 2008年3月20日,国务院在北京召开全国森林草原防火工作电视电话会议,中共中央政治局委员、国务院副总理回良玉同志出席会议并发表重要讲话.  相似文献   

2009年全国森林防火工作要点   总被引：1，自引：0，他引：1  

国家森林防火指挥部办公室 《森林防火》2009,(1):10-10

(1)认真实施<森林防火条例>.分级开展<条例>的专题宣传和专项培训,举行<条例>解读答疑和知识竞赛,制作<条例>宣传挂图、公益广告和电视宣传片.及时修订完善相关地方法规、部门规章、应急预案和标准规程,全面推进依法治火工作.  相似文献