固原退耕还林区经济林木甘肃鼢鼠防治经济阈值研究

对固原退耕还林区经济林木鼠害情况进行调查.结果表明:林木死亡率与鼢鼠密度之间呈显著相关关系:y=-1.923 4 3.432 0x(r=0.934 8).根据退耕还林区鼢鼠对不同定植年限山杏林木的危害造成的损失、防治费用和林木价格等,研究了固原地区退耕还林区经济林木鼢鼠防治阈值,并确定山杏定植1年时防治阈值为1.907只·hm-2,定植2～4年时为0.989～1.273只·hm-2,定植4～6年时为0.859～0.989只·hm-2.同时,以林木被害率和鼠口密度为指标,确定了退耕还林区经济林木鼠害程度划分标准.     

中华鼢鼠的防治技术

中华鼢鼠俗称"瞎老",在大宁县分布较广.近10多年来,随着全县油松林地面积的增加,大面积危害油松林木,咬断根系,吃掉根皮,使整株油松死亡.据对全县几个乡镇的调查,危害油松幼树死亡率达到15%～31%,破坏了整个林分结构.而且,树龄10年、树高3m的大油松常被咬死,危害十分猖獗.此外,鼢鼠还啃食林地其他植被和草类.在鼢鼠分布密度较大的坡地,由于林地植被被啃咬,使植物生态群落衰退,土壤有机质减少,夏季雨水冲刷洞边系统,造成新的水土流失.     

中华鼢鼠防治技术

中华鼢鼠俗称“瞎老”,在大宁县分布较广。近10多年来,随着全县油松林地面积的增加,大面积危害油松林木,咬断根系,吃掉根皮,使整株油松死亡。据对全县几个乡镇的调查,危害油松幼树死亡率达到15%～31%,破坏了整个林分结构。而且,树龄10年、树高3m的大油松常被咬死,危害十分猖獗。此外,鼢鼠还啃食林地其他植被和草类。在鼢鼠分布密度较大的坡地,由于林地植被被啃咬,使植物生态群落衰退,土壤有机质减少,夏季雨水冲刷洞边系统,造成新的水土流失。1形态特征中华鼢鼠体长18cm～30cm。体短粗,略呈圆筒状,背面稍平,头宽而扁,耳壳退化,额头有一白色斑…     

柏毒蛾的发生与防治要点

柏毒蛾,属鳞翅目毒蛾科,主要危害侧柏、柏木、桧柏等,2003～2004年黄山地区有20公顷柏类受到该虫侵害,被害林地树叶尖端被食,枯萎脱落,严重影响林木的正常生长.     

渭北主要造林树种细根生长及分布与土壤密度关系

采用野外样地调查和盆栽试验的方法 ,研究了土壤密度对渭北主要造林树种细根生长及分布特征的影响。结果表明 ,在 0～ 10 0cm的深度内 ,不论是阴坡还是阳坡 ,油松林地的土壤密度均表现出随土层的加深逐渐增大的趋势 ;刺槐林地的土壤密度大于油松林地 ,且各土层间的差异不大。油松林地各土层土壤密度与不同径级根系长度存在显著的负相关关系。盆栽基质密度对不同树种苗木根系的生长和发育的影响虽各异 ,但在基质密度和孔隙度适中的条件下均生长良好 ,生物量达到最大。盆栽基质的密度对刺槐和油松根系的生长和发育的影响最显著 ;侧柏和山杏的细根生长发育受土壤密度的影响较小 ,其根系生物量在不同密度的基质中没有明显变化。     

山西省疏林地主要树种生态功能评价

笔者主要对山西省疏林地主要树种油松、刺槐、落叶松和侧柏进行生态功能评价。首先采用专家咨询打分方法对影响生态功能的生态因子进行选取和划分,然后运用层次分析法分析生态因子的权重,并根据K=1/∑WiXi求出疏林地主要树种的平均生态功能指数,最后对其树种的生态功能进行评价。结果得出,油松、落叶松、侧柏和刺槐的平均生态功能指数分别为0.628 5,0.583 7,0.438 5,0.436 9.表明油松和落叶松的生态功能相对较好,而侧柏和刺槐的生态功能相对较低。     

延安城郊防护林外貌结构及林下植物的多样性

在延安对刺槐、油松、侧柏纯林及刺槐 侧柏、刺槐 油松混交林等几种黄土高原主要人工林群落外貌结构、林下植物多样性特征进行了研究.结果表明:混交林群落外貌结构较为复杂,林下植物群落类型各不相同;林下植物的Simpson多样性指数和Shnnon-wiener多样性指数分别为0.902 57～0.674 88和2.012 88～1.479 67,刺槐 油松林最高,16年生刺槐纯林最低;32年生刺槐纯林林下植物优势度最高者是糙隐子草,16年生刺槐纯林则为牡蒿,其它林型都是铁杆蒿;本地区选择防护林类型时,应优先选择刺槐 油松或刺槐 侧柏混交,对已有的成熟或衰退刺槐纯林可采取择伐萌蘖抚育,并间植油松或刺柏,形成针阔混交林.     

不同造林模式对渭北黄土高原林地土壤及土壤微生物化学计量的影响

本研究以农田为对照,通过对陕西永寿县农田、人工纯林(刺槐、侧柏和油松)和混交林(刺槐+油松、刺槐+侧柏及侧柏+油松)两种造林模式下土壤和土壤微生物碳、氮、磷及化学计量的分析,探究造林模式对土壤养分循环的影响。结果表明造林显著改变了土壤和土壤微生物碳、氮、磷含量及化学计量特征,其影响程度不仅受到造林模式的影响,同样受树种组成和树种特性的影响。     

太行山低山丘陵花岗片麻岩区典型林地土壤持水能力研究

为分析太行山低山丘陵花岗片麻岩区典型林地的土壤持水能力,选取刺槐、油松×侧柏、核桃3种典型林地土壤进行土壤物理性质及其持水能力测定分析。结果表明:土壤容重、孔隙度、饱和蓄水量在3种典型林地之间存在差异。土壤容重变化在1.36～1.47g/cm~3之间,随着土层深度的增加而增大;核桃林土壤容重最小,总孔隙度最大,饱和蓄水量、毛管蓄水量最大,油松×侧柏混交林土壤容重最大,总孔隙度最小,饱和蓄水量、毛管蓄水量最小。总体发现,核桃林土壤持水能力较强,刺槐林次之,油松×侧柏混交林土壤持水能力较弱。     

人工地箭捕杀中华鼢鼠法

落叶松、油松、樟子松已成为乌盟地区的主要造林树种.目前中华鼢鼠对林木的危害日趋严重,在鼠害最严重的林地内,林木受害率几乎等于死亡率。为了有效地控制中华鼢鼠的危害,经过多年的实践,到目前在乌盟“三松”林区使用地箭捕杀中华鼢鼠是最好的一种防治方法。比法从春季土壤解冻至秋季土壤冻结,不受时间、地点的限制,具有成本低、结构简单、命中率高、使用方便等优点.如果每100亩林子用1付箭子移动地捕杀就可控制害鼠危害.     

The need for planted forests and the example of radiata pine

Ten thousand years ago our 5 million hunter-gatherer ancestors used, over the period of a year, about 200 species of local food items. Now, the nearly 6 billion global population gets 70 percent of its food from nine species of plants, one species of bird, and two species of mammals. This is despite global access to about 50,000 edible plants, as well as large numbers of bird and other animal species. We have concentrated our agricultural efforts on those species which are the most desirable, the most convenient, the most productive, and the most easily stored. Of equal importance, the species must be responsive to both genetic improvement and to management manipulation (i.e., domestication). Globally, very little of our food, except fish, now comes from wild sources.Although we use at least as much wood as we do food, wood supply (which still comes mostly from natural forests) is only now becoming limiting. There are no energy-efficient or environmentally acceptable substitutes for wood. The most likely means we have of satisfying the increasing global demand for wood is to obtain more of our wood from deliberately planted forests. Management of planted forests will increasingly parallel intensive agriculture. One consequence is that, of the 1,000 tree species we now use globally, we may eventually get most of our wood from four or five species. One of these tree species will be radiata pine (Pinus radiata D. Don). Radiata grows fast on a wide range of sites, has desirable wood properties, and responds well to both genetic improvement and stand management. The planted forest technology for radiata pine is probably the most advanced of any potential tree species. The evolution and success of radiata pine in New Zealand has major implications and lessons for the rest of the world.     

灵宝地区苹果园春季深翻防控中华鼢鼠调查分析

中华鼢鼠(Myospalax fontanierii Milne-Edwards)在河南灵宝地区主要危害苹果、梨、樱桃等多种林果树木.2008-2010年3年时间,对灵宝川口林场燕子山林区苹果园内中华鼢鼠的危害状况进行了详细的调查研究.结果表明,苹果园内中华鼢鼠种群密度为3～4只/hm2,略高于中华鼢鼠的种群密度经济阈...     

漳州地区松林疫情调查

漳州地区松林疫情调查表明:松毛虫(Dendrolimus panctatus)、额毛小蠹(Dryocoetes lu-teus)、松瘤小蠹(Orthotomicus erosus)和角胫象(Shirahoshizo coniferae)在该地区分布较广;松褐天牛(Monochamus alternatus)、松针褐斑病(Lecanosticta acicola)及部份外省检疫对象发现有危害;目前尚未发现松材线虫(Bursaphelenchus xylophilus)和松突圆蚧(Hemiberlesiapitysophila)的分布与危害,但已受到直接威胁,必须严加防范。     

Carbon stock density in planted versus natural <Emphasis Type="Italic">Pinus massoniana</Emphasis> forests in sub-tropical China

Key message

Carbon stock density was quite similar in planted vs natural forest of Masson’s pine ( Pinus massoniana Lamb.) in China across three ages (7, 15, and 50 years). The stock in the standing trees was larger in planted than in natural forests, but this difference was compensated by larger stocks in the soil and the debris of natural forests.

Context

Most studies on the carbon stocks are focused on management strategies to maximize carbon stocks. We still lack data comparing planted vs natural conifer forests.

Aims

We compared carbon storage in the different compartment (vegetation, soil, debris) along a chronosequence of Masson’s pine plantations vs natural forests.

Methods

We investigated 58 Masson’s pine (Pinus massoniana Lamb.) forest stands (20 m?×?50 m plots), that differ in stand management (planted and natural forests) and age (young, middle-aged, and mature ages) and then calculated the carbon stock densities of vegetation biomass (tree, shrub, and herb), debris, and soil.

Results

The carbon stock densities in the planted and natural Masson’s pine forest ecosystems ranged from 78 to 210 Mg ha^?1 and from 97 to 177 Mg ha^?1 respectively. The carbon stock densities in the vegetation were significantly greater in planted forests than in natural forests. A lower carbon stock density in debris and soil alleviated the increase of biomass carbon stock densities in planted vs natural forests, leading to similar carbon stock densities at ecosystem level. The carbon stock densities in the vegetation increased with age, whereas those of debris and soil remained stable.

Conclusions

Planted forests of Masson’s pine sequester similiar amounts of carbon at ecosystem level to those in natural forests, reinforcing the idea that planted pine forests can contribute to the mitigation of greenhouse gas emission.

     

Comparison of stand dynamics after dieback caused by pine wilt disease among pine forests with different management regimes in western Japan

In pine forests damaged by pine wilt disease, in western Japan, the effect of protection regimes of pine trees on the stand dynamics were examined in the following four stands: (1) lightly damaged stand (age 30–40 years) with no procedure in operation for protecting pine trees; (2) severely damaged stand (age 30–40 years) with no procedure in place for protecting pine trees; (3) severely damaged stand (age 50 years) with a selective cutting of infected trees; (4) severely damaged stand (age 30–40 years) with a selective cutting of infected trees. All the stands had been abandoned before the pine wilt disease damage. The understory structure of the severely damaged stand with no protection procedure was similar to that of the lightly damaged stand. Frequent invasion by tree species and acceleration in the growth of understory trees occurred after the dieback in the selective cutting stand. These results suggest that a deficiency in the canopy layer caused by the dieback resulted in low disturbance intensity in the early stages after the dieback, but the selective cutting increased the intensity by the reduction in the understory as well as the canopy layer. The intensity of the disturbance in the selective cutting stands was larger in the younger stand because it had a higher density of selectively cut pine trees. The different stand structure of pine forests occurred after the dieback because the intensity of the disturbance varied as a result of the selective cutting operation and the stand age.     

柞蚕场封山育林对植被恢复的影响

对柞蚕场、柞蚕场封山育林6a、9a的植被调查数据进行了分析,结果表明:柞蚕场封山育林可明显促进蒙古栎等乔木的生长和郁闭,但由于萌生,林木的水平分布多呈现聚集于母树的丛状分布;封育后由于林分郁闭,林内光照降低,灌木和草本植物的盖度有所减少;通过多样性指数测度,封育后乔木层、灌木层、草本层的多样性指数均高于柞蚕场;封育后由于森林凋落物的增加使枯落物存储量不断增加,可改善土壤肥力、提高林地涵养水分的功能.     

Comparison of stand structure and growth between artificial and natural forests of Pinus sylvestiris var, mongolica on sandy land

Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in “Three North” regions (North, northwest and northeast of China), but many prob-lems occurred in the earliest Mongolian pine plantations in 7hanggutai, 7hangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively.Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11,22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings‘‘ disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.     

秦岭林区天然油松林结构研究初报

对秦岭林区天然油松林年龄结构，直径结构分析研究表明，天然油松林按林层和林龄可划为单层异龄林和复层异龄林两类。单层异龄林的天然更新表现出明显的连续性和阶段性，而复层异龄油松林的年龄结构出现多世代波动现，直径结构的波动随林龄的增加，其偏度具有一定的方向性。     

安徽省青阳县栎类阔叶林树木生长规律研究

本文以46年生栎类解析木为基础,运用DPS统计软件进行回归分析,分别采用Logistic、Richards、Compertz、Mitscherlich、Gauss、Log-modified、Density7种理论方程与二次曲线对栎类进行拟合,建立栎类树高、胸径、材积的最优数学模型,对其生长规律进行分析。结果表明：建立的生长模型中Richards方程拟合效果最好、精度最高。故选择Richards方程为栎类树高、胸径、带皮材积、去皮材积生长模型。栎类树高的平均生长量在20年时达到最大值,而树高的连年生长量最大值出现在14年,在20年时平均生长量与连年生长量相等。栎类胸径的连年生长曲线与平均生长曲线在24年时相交。栎类材积生长量在14年前生长较缓慢,在46年内还未出现材积平均生长量的最大值。材积的连年生长量曲线与平均生长量曲线在46年内还未相交,说明其未达到成熟龄。探讨了安徽省青阳县天然次生栎类阔叶林的生长规律,为栎类阔叶林合理利用和培育提供参考。     

不同程度马尾松毛虫危害对松林植被群落的影响

采用样点调查法对不同程度马尾松毛虫危害松林的植被群落进行了调查。结果表明:不同程度马尾松毛虫危害对松林林分密度的影响不显著,但对松树生长量有着不同程度的影响,中、重度危害可降低松树的高度和胸径(重度危害三年后高度、胸径分别下降0.34 m和1.8 cm),轻度危害则可促进松林的生长;马尾松毛虫危害可适度改变松林的郁闭度和地表植被的盖度(中、重度危害后三年盖度分别上升15%和20%),对林下植被的恢复与生长有一定的促进作用;松林植被物种多样性分析表明,中、重度马尾松毛虫危害可有效增加林地植被物种的多样性,轻度危害则对林地植被物种多样性影响不大。