The natural regeneration pattern and process of Korean pine population under natural Poplar-birch forest in Xiaoxing’an Mountains

According to a great deal of field investigation and detailed indoor analysis, the natural regeneration pattern and process of Korean pine population under natural Poplar-birch forest has been uncovered. The results show that the regeneration quantity and quality of Korean pine population under mountainous Poplar-birch forest and mountainous white birch forest are better than those under valley moss-grass White Birch forest and virgin broad-leaved Korean pine forest. Korean pine population shows aggregated distribution, the mass-occurrence period of Korean pine population is behind the mass-occurrence period of Poplar-birch population. Various aged Korean pines growth is affected by different stand structure factors. Man-made lighting tending can accelerate the regeneration process and increase the regeneration quality of Korean pine population. It is feasible to set up regeneration recombination of upper layer White Birch and lower layer Korean pines.     

西藏巨柏种群天然更新与群落特征研究

巨柏(Cupressus gigantea)为雅鲁藏布江地区分布的特有种,属国家一级保护植物。本文通过在米林-朗县雅鲁藏布江河谷13个面积为1 000 m2的巨柏林样地调查资料,按照近河谷和远河谷山坡的地理分布差异,统计分析了巨柏的种群天然更新特征;通过对群落的组成与结构的分析,初步阐述了巨柏群落的物种组成和结构特征。结果表明,雅鲁藏布江巨柏的更新情况比较差,种群年龄结构不稳定,整体上呈现了明显的种群衰退现象。通过种群的年龄结构分析,反映出了巨柏种群的失衡事件主要发生在最近几十年内,即0.6 m高度10 cm树径范围。巨柏林内物种组成结构单一,乔木层为单一巨柏种,灌木层和草本层的优势种数较少。鉴于巨柏种群环境沙化影响加剧、天然更新能力下降等因素,种群的延续面临较大威胁,需进一步加强该种群的保护和研究。     

试论银茶复合经营的特点和经济效益

银茶复合经营具有良好的生物学基础,能形成合理而稳定的群体结构。复合经营与纯茶园相比,可充分利用空间,增加光能利用;炎热季节在树冠下能降低光照强度和温度;能增加耕作层含水量,提高抗旱能力;增加枯枝落叶,提高土壤肥力等,使银杏和茶叶质量提高,产量增加、效益提高。     

白蜡虫优良种虫及种群性比组成的研究

白蜡虫(Ericerus pela Chavannes)是我国特产资源昆虫,国内产区很多。实验表明各产区繁育白蜡虫的产量与质量差异显著,其中以金沙江下游云、贵、川三省相接壤的白蜡虫产区,繁育的白蜡虫产卵数量多、雄卵比率高、产蜡时间长、产蜡量多,同时蜡虫的产量高,是我国白蜡虫的优良种虫。     

Clearcutting forestry and Eurasian boreal forest grouse: Long-term monitoring of sympatric capercaillie Tetrao urogallus and black grouse T. tetrix reveals unexpected effects on their population performances

Along the succession gradient of the boreal forest ecosystem, black grouse Tetrao tetrix inhabits the early and capercaillie Tetrao urogallus the latest stages. When converting old forest to clearcuts and plantations, commercial forestry has therefore been assumed to affect capercaillie negatively and to be favourable to black grouse. During a 30-year period (1979-2008) we monitored sympatric populations of the two species in a forest in southeast Norway based on annual spring and autumn censuses and radio-marked birds. During this period, the proportion of old, semi-natural forest was halved and clearcuts and young plantations increased accordingly. The grouse populations did not change as predicted. While the trend in August numbers of adult black grouse declined, males more than females, abundance of adult capercaillie remained unchanged. Number of males at leks showed similar patterns. Equally surprising, breeding success (number of chicks per female in August) of both species increased, thus indicating that the populations were regulated more by variation in adult survivorship than by recruitment of young birds. No correlations were found with changing climatic factors (precipitation and temperatures in winter and spring, snow depth and time of snow melt), except that year-to-year breeding success was positively correlated with minimum temperatures during 2 weeks posthatch. The results are explained by a combination of more flexible habitat selection than previously assumed and a changing predator regime: In the early period, nearly all capercaillie leks were located in old, semi-natural forest, but as plantations grew older (>30 years), new leks were established there. Similarly, while young capercaillie broods used old semi-natural forest almost exclusively when the study started, they frequently used middle-aged plantations, especially those with a ground cover of bilberry Vaccinium myrtillus, when these became common in later years. The increasing breeding success could largely be explained by more females rearing chicks successfully, presumably due to a marked decline in the main nest predator, the red fox Vulpes vulpes. A practice of thinning of the old, semi-natural forest some years prior to final harvesting probably facilitated predation of black grouse by goshawks Accipiter gentilis. Contrary to many beliefs, our results indicate that both capercaillie and black grouse are quite tolerant to changes in forest management regimes. In our study, numerical and functional responses of predators (mainly red fox and goshawk) apparently played a more important role in regulating grouse numbers than habitat factors per se.     

野生滇牡丹资源调查与分析

2008-2009年对野生滇牡丹种质资源集中分布中心云南中部至西北部进行了比较全面的调查与分析,内容包括了滇牡丹生境和群体生长、单株开花状况等。分析了滇牡丹开花物候期及其影响因子、群落结构、种群数量动态变化等。最后总结了野生滇牡丹种质资源现状,以及适于滇牡丹生长和繁殖的立地条件及其保护措施。       

不同修剪整形方法对大铃铛枣产量的影响

通过大铃铛枣树实施主干疏层形、自然开心形、多主枝自然圆头形和超强度修剪等4种剪枝整形对枣树产量的影响试验,结果表明,超强度整形的枣树产量最高,667m2样地达848.4kg,优质果产量占97.8%以上。实施超强度修剪整形是大铃铛枣园增加经济效果的一项关键经营措施。     

重庆缙云山慈竹种群年龄的初步研究

慈竹(Neosinocalamus affinis)系四川分布面积最大和用途最广的合轴型竹种。作者在重庆缙云山慈竹种群年龄研究过程中,发现慈竹种群之无性系个体的年龄与其个体生物量和各器官生物量相关密切,其器官数量也呈显著相关;慈竹秆的形态学特征与其个体的年龄,地下茎和地上茎(秆)的分枝级数与其年龄均呈直线相关。地下茎分枝级数(RSB_x)与其年龄(A_(rs))的回归模型:A_(rs)=(RSB_x_(max) 1)-RSB_x,相关系数Υ_(rs)=-1.0000,O_(x-1)=0;秆分枝级数(CB_x)与其年龄(A_c)之相关模型为A_c=CB_x,相关系数Υ_c=1.0000(一年生个体除外),O_(x-1)=0。     

大青杨群体变异及其选择的研究

大青杨种内群体间变异十分丰富,为了选出最佳群体,直接用于造林,进行了全分布区群体选择的研究。本试验在大兴安岭地区对9个产体群体的大青杨做了生长、生根、抗寒、抗锈病的主要经济性状的测定,然后进行综合评定,选择出最佳群体。     

料慈竹种群结构与产量的研究

本文以料慈竹的竹丛生长变化为研究对象,在相同林分内按设计设置固定样丛,试验期间逐年结构调整。每年调查新竹生长量并号竹,进而统计分析。结果表明,竹丛内保留1～3年生竹的新竹产量高,竹丛内各龄竹株百分率基本相近的新竹产量大,采伐强度以每年各龄竹按20％～40％采伐为宜;丛间密度以每亩42～74丛为好,丛内立竹密度以保留26～35株／丛则有利于产量的提高。