更新频度指标对提高人工更新造林成效

更新频度指标对提高人工更新造林成效张同伟，苍松，陈淑霞（黑龙江省森工总局营林局）随着成活率与保存率做为企业的考核指标后、特别是经过第四次企业更新造林普查，发现影响更新造林成效的主要原因之一是密度不均，约占３１．４％左右，占总失败面积的１１．８％。分析...     

人工更新造林成效分析研究

黑龙江省国有林区有计划地开展人工更新造林是从1951年开始的,截止2005年底人工更新造林面积484.3万hm2,其中:保存面积287.4万hm2,面积保存率为59.4%,为总结人工林发展的历史经验,指导人工林经营事业的健康发展,对人工更新造林失败原因、保存面积的树种结构与蓄积进行了分析。     

云南省1991年度人工造林更新实绩剖析

通过对全省42个县276个行政村,827个社,24个国营林场,3个森工局,1991年度人工造林、更新实绩核查,结果为:核实面积与上报面积的比值为0.97690,成活率达85％以上的核实面积比值为0.89719,造林合格面积实绩比值为0.87646,造林成效十分显著。并论述了造林成功的主要经验以及存在的不足之处。     

谈提高人工更新造林成效的新途径

介绍了一种提高人工更新造林的新方法—更新频度的运用。     

人工更新造林抗旱减灾的对策

1　干旱发生的基本情况从 1 997年至 2 0 0 0年 ,绥阳林业局连续4年春、夏季气候异常 ,降雨少 ,蒸发量大 ,大风天气多 ,连续不降雨日数长 ,造成大面积人工幼林苗木死亡 ,甚至个别 1 0年生落叶松也因干旱死亡。特别是 1 997年的干旱最为严重 ,据二道岗森林物候气象站观测记载 ,1     

浅谈人工更新造林成效

作者结合自己多年的更新造林经验,就人工更新造林的主要技术及管理措施提出了自己的见解。     

陕西省人工造林、更新十年成效及前景

本文回顾总结了陕西省人工造林、更新十年的变迁和成效,并提出了存在问题和对策以及发展前景。     

黔南州公益林管理现状浅析及建议

森林生态效益补偿是国家为了巩固生态建设成效,对林权所有者和使用者进行适当补助的惠民政策,自实施以来得到了林区广大群众的拥护和支持,生态得到了保护和发展,林农得到了实惠。本文在对黔南州公益林管理现状进行了深入调研的基础上,分析了黔南州公益林管理存在的问题,并提出了解决问题的办法及建议,促进了公益林管护水平的提高。     

Some factors influencing the increment of forests

It is humbling to read the paper by R.N. Aldrich-Blake (1927)because he deduced many truths that we have since confirmed,and he deduced them with the most subtle of arguments. His articlecould still be used if one were to start building a computermodel to capture the physiologi cal processes of tree growth.His ideas alone would provide a suitable framework for modellingand most of the internal and external factors affecting assimilationand respiration would be included. The model would lack a modernunderstanding of biochemistry, particularly of photo synthesisand the role of nutrients, and Aldrich-Blake did not considerthe important problem of allocating assimilated carbon to thegrowth of different parts of the tree. Our ideas on allocationare now changing and there is emerging evidence for the roleof plant signals in allocation which, in turn, affects the incrementin timber volume.     

Comparative study of the stoichiometric characteristics of karst and non-karst forests in Guizhou,China

Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.     

Deciduous trees affect small-scale floristic diversity and tree regeneration in conifer forests

Abstract

There is a growing interest in the effects of deciduous trees on biodiversity, soil processes and long-term productivity in boreal, conifer-dominated forests. This study investigated whether individual birch trees allowed to grow to maturity in the coniferous forest can have a local effect on floristic richness and regeneration of tree saplings. The ground vegetation was compared in 2?m radius plots around the stem under the canopies of matched conifer–deciduous trees in a mature, conifer-dominated forest, and included in the analysis variables that could potentially mediate the tree effect (soil pH, cover of lichens, bryophytes, leaf and needle litter). The field layer vegetation was more species rich under birch (Betula pendula and B. pubescens) than under conifers (Picea abies and Pinus sylvestris), and several vascular plant species (including saplings of tree species) occurred more often under birch than under conifers. However, when the effect of the number of subordinate trees was taken into account the difference between birch and pine was not significant. The number of tree regenerations (saplings) was lowest under pines, but did not differ between spruce and birch. There were no effects of the canopy species on soil pH or on cover of lichens and bryophytes. The difference in diversity may be caused by the different effects of leaf and needle litter, and it is also likely that canopy structure has an influence via interception and throughfall and by affecting the light and microclimate.     

坝上盐碱地枸杞人工林群落生物量研究

通过对坝上盐碱地枸杞人工林现存生物量的研究,结果估算出当前枸杞现存生物量为25.199 t/hm2。地上部分为13.129 t/hm2,其中枝干的生物量10.265 t/hm2,叶的生物量2.873 t/hm2。地下部分为12.070 t/hm2,且87.4%的根分布于地面下0~100 cm。适当密植有利于生物量的积累,同时可以改良土壤结构。     

影响东北红豆杉细胞培养物生长速度的因素分析

影响东北红豆杉（Taxus cuspidate)细胞培养物生长速度的因素为：生长调节剂的种类及浓度，有机添加物酪蛋白（CH）加入，培养基的种类，光照条件，接种时所处的细胞相等。     

针阔混交林培育效果的研究

通过对辽东山区低产，低质天然次生林采取栽针保阔，人工诱导等经营措施，加速了天然次生林的演替进程，已诱导成垂直结构合理，能充分利用空间和光能的各类类型针阔混交林。人工诱导的异龄复层阔叶红松林，20a生林分总产量高达71．791－74.228m^3/hm^2；人工诱导的同龄阔叶红松林19a生时达48.897-52.400m^3/hm^2；皆改人工营造的针阔混交林16a生时达30.486-73.884m^3/hm^2。     

Identifying factors affecting plantation performance in boreal forests of Ontario

Plantation data from northern Ontario were subjected to stepwise regression analysis to express survival and total height as functions of site factors, planting stock characteristics and age for each of black spruce (Picea mariana [Mill.] B.S.P.), white spruce (P. glauca [Moench] Voss) and jack pine (Pinus banksiana Lamb.).Total height and height increment were affected more significantly, but by fewer factors, than survival. Black spruce survival was the most heterogeneous variable, as six factors accounted for 55.6% of its variability. Between one and five qualitative site factors (represented by dummy variables) accounted for less than 23% and 30%, respectively, of the variability in survival rate and total height. Stock type, planting season, weed control and chemical site preparation showed low but significant correlations with the response variables. Quality index was significant in every case, while shoot:root ratio, root collar diameter and dry weight were significant in some cases. The single most significant variable was plantation age, accounting for up to 30% and 63%, respectively, of the variability in survival rate and total height.     

沙棘薪炭林效益调查分析

通过对朝阳市沙棘薪炭林标准地的调查，表明沙棘薪炭林是解决当地农村烧柴短缺的有效途径之一。另外薪炭林还具有保持水土、提高土壤肥力的显著功能及其促进群众增收的综合经济效益。