内蒙古山地华北落叶松、樟子松与白桦的生长分析——以那日斯太林场为例

对内蒙古乌兰察布市那日斯太林场华北落叶松人工林、樟子松人工林和白桦次生林生长现状的分析结果表明,华北落叶松的树高、胸径、材积生长量均大于樟子松和白桦。且华北落叶松在该地区除了具有较强的适应性外,更具有早期生长快和优良的速生性。而樟子松在该地区的适应性较差,树高、胸径、材积生长状况均不如其他引种地区,但其胸径和材积生长优于当地乡土树种白桦。今后应对该地区的樟子松人工林和白桦次生林进行抚育间伐,提高该树种的生长潜力和生态效益,充分发挥其绿化荒山、荒地,美化环境的生态效应。     

东北白桦变色菌的分离方法

针对白桦木材易变色的特点,探讨了东北白桦变色菌的分离方法。结果表明：分离变色茵时采用80%的酒精液作为表面消毒剂比采用0．1%的升汞液更为适宜；采用PDA作为分离培养基较为适宜。     

光皮桦苗高生长期划分有序样本聚类分析

以光皮桦苗高月净生长量为样本 ,采用有序样本聚类分析将光皮桦苗高生长过程划分为 4个时期 ,出苗期为 5月 1 0日～ 5月 31日 ,幼苗期为 6月 1日～ 7月 31日 ,苗高速生期为 8月 1日～9月 30日 ,苗木生长后期为 1 0月 1日～ 1 2月 31日 .苗高速生期时间推迟到 8～ 9月 ,原因是由于当年 5月上旬播种 ,播种时间推迟 ,速生期苗高生长量占苗木全年总生长量的 5 1 .87% .提出了各期的关键育苗措施 .保证苗高速生期有充足的水肥条件 ,延长苗高速生期提高生长量     

CO2浓度和温度升高对川西亚高山红桦幼苗根系结构的影响

CO2浓度和温度升高对植物产生了深刻的影响,为从多角度对这种影响进行研究,该文利用封闭式生长室系统控制CO2浓度和温度,以红桦幼苗为材料,研究了CO2浓度升高、温度升高以及二者同时升高对川西亚高山红桦幼苗根系结构的影响。结果显示:①与对照相比,CO2浓度升高处理显著增加了红桦细根的生物量（最大增幅达152％）、根 幅（增幅为10％～22％）、0～10 cm土壤层根系总长度、5～10 cm层根夹角。②温度升高处理使红桦细根生物量2004年6、10月增加,8月减少,但只有0～5 cm土壤层与对照相比差异显著;根幅6、8、10月分别减少16％、7％、30％;5～15 cm土壤层根系总长度、0～10 cm土壤层根夹角显著(P0.05)减少。③二者同时升高处理使红桦各层细根生物量８月增加最多,0～5 cm、5～10 cm、10～15 cm土壤层分别比对照增加237％、51％、107％;根系总长度减少,但0～10 cm土壤层根夹角增加。表明CO2浓度和温度升高均改变了红桦根系结构, 且对浅层根系结构影响较大,这是红桦对气候变化的一种有利适应。      

生长季白桦树干液流密度的特征

应用热扩散技术测定了帽儿山不同径级白桦样木生长季的树干液流,并初步分析和对比了优势木、中等木和被压木树干液流密度的特征及季节变化趋势。结果表明,白桦树干液流密度变化具有明显的昼夜节律性,一般呈单峰曲线;白桦优势木液流密度明显大于中等木和被压木,中等木和被压木液流密度值非常接近;不同天气条件下液流密度日变化规律大不相同,阴雨天液流密度值较小且变化曲线十分不规则,波动性较大,甚至出现多峰曲线。生长季,优势木、中等木和被压木日液流通量最大值均出现在6月初至7月中旬,分别为2623.97、1744.50、1689.82L.m-2.d-1;优势木日液流通量最小值出现在7月下旬至8月初,中等木和被压木日液流通量最小值均出现在生长季末期。随季节的推移,生长季各月份液流密度均值基本逐渐减小,白桦优势木6、7月份液流密度平均值较大,8月份和9月份液流密度均值较接近,10月份明显减小;中等木液流密度平均值7月份最大,6、8、9月份液流密度均值较接近,10月份液流密度波动微弱;被压木最大值出现在6月份,7、8、9月份液流密度月均值变化不大。     

应用RAPD技术对东北地区白桦种源遗传变异的分析

用随机扩增多态DNA（RAPD）分子标记方法对白桦13个种源115个个体进行了遗传变异的比较分析。通过14个随机引物扩增共检测到233个位点。各种源多态位点百分率差异明显，在20.17%-32.19%之间，多态位点百分率最高的是帽儿山种源和清源种源，最低的是绰尔种源。遗传变异在大兴安岭、小兴安岭和长白山3个区域间占23.88%，种源间遗传变异占27.99%，种源内个体间遗传变异占48.13%。根据种源间的遗传距离，构建了白桦13个种源的遗传关系聚类图，结果大兴案岭地区的白桦和源聚为一类，小兴安岭、张广才岭、完达山和长白山分布区的白桦种源聚为另一类。同时，根据地理气候因子和遗传距离对白桦13个种源进行了种源区的划分，为种子调拨提供了依据。     

白桦变色菌的分离、纯化与筛选

基于白桦变色菌的存在以及白桦在自然干燥过程中易产生变色的特点,从微生物学的角度,着重进行了白桦变色菌的培养、分离与筛选。研究表明:白桦在自然干燥过程中易受到变色菌的侵染;通过木材接菌试验,筛选出了诱使白桦变色的菌种。     

西南桦人工幼林生长与立地条件的关系

根据样地调查资料，分析了西南桦人工幼林生长与立地条件的关系。结果表明：林分上层高和平均高与立地腐殖质层厚度、坡位（由山顶到山脚）呈正相关，与土壤紧实度和石含量呈负相关。通过逐步回归，建立了林分上层高、平均高与坡位、腐殖质层厚度和土壤石含量之间的方程，为西南桦人工林立地选择和立地质量评价提供了依据。     

Earthworm communities in birch stands with different origin in central Finland

The aim of the study was to compare earthworm communities in anthropogenous birch stands with different origin in Finland. A total of nine forest sites were investigated: three birch stands (Betula pendula) planted ca. 30 years prior to the study after clear-cutting of spruce stands (“Birch after Spruce”, BS), three birch stands planted ca. 30 years earlier on arable soil that had been under normal cultivation until forestation (“Birch after Field”, BF), and three “Natural Deciduous” forests (D). Earthworms were sampled in May and October 1999 using a combination of formaline extraction and modified wet funnels. There were conspicuous differences between replicates of similarly managed forests. Earthworms were totally lacking in one of the D sites, while another had an abundant and diverse community. Only Dendrobaena octaedra was present in one BS site, while the two others harboured also Aporrectodea caliginosa and three Lumbricus species. All these species were also present in the BF sites, where their total biomass (ranging from 70 to 138 g (f.w.)/m²) was 2.6 times the average in BS, and of the same magnitude as the average in natural deciduous stands. A separate experiment revealed that L. terresris and A. caliginosa, which are not found in the surrounding coniferous forest, are able to live and reproduce in the soil of the D site where they were absent. It was concluded that earthworm species survive and reproduce in birch stands established on arable soil, where they have invaded during the long cultivation. On the other hand, their possibilities to disperse from cultural landscapes determine their presence not only in birch stands established in earlier coniferous forests, but also in “natural deciduous” forests where source populations are not present in the surroundings.     

长白山岳桦-暗针叶林过渡带根系呼吸对土壤总呼吸的贡献

Total and root-severed soil respiration rates for five plots set up 50 m apart in a Betula ermanii Cham.-dark coniferous forest ecotone on a north-facing slope of the Changbai Mountains, China, were measured to evaluate the seasonal variations of soil respiration, to assess the effect of soil temperature and water content on soil respiration, and to estimate the relative contributions of root respiration to the total soil respiration. PVC cylinders in each of 5 forest types of a B. ermanii-dark coniferous forest ecotone were used to measure soil respirations both inside and outside of the cylinders. The contribution of roots to the total soil respiration rates ranged from 12.5% to 54.6%. The mean contribution of roots for the different plots varied with the season, increasing from 32.5% on June 26 to 36.6% on August 3 and to 41.8% on October 14.In addition, there existed a significant （P 〈 0.01） logarithmic relationship between total soil respiration rate and soil temperature at 5 cm soil depth. Also, a similar trend was observed for the soil respiration and soil water content at the surface （0-5 cm） during the same period of time.