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本文就苏铁盾蚧对攀枝花苏铁的危害情况,采用标准样地抽样调查的办法,摸清了危害攀枝花苏铁的蚧壳虫科类,危害情况及分布特点.结合调查结果和盾蚧的生物学特性提出了具体的防治措施. 相似文献
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对攀枝花地区五个林分类型的攀枝花苏铁无性系种群结构进行了研究,结果表明,攀枝花苏铁自然保护区植物群落中的攀枝花苏铁以幼树(Ⅱ)种群数量最多,成年(Ⅲ)次之,幼苗(I)第三,壮年(Ⅳ)种群数量最少,是处于种群增长期的年青苏铁林.高度结构数量分布集中于(Ⅱ)度级,径级结构数量分布出现两个高峰即(Ⅱ)和(Ⅴ)径阶.不同苏铁林分类型其种群结构数量变化有差异,这是苏铁生物、生态学特性影响所致. 相似文献
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本文通过天然阔叶林皆伐迹地,采用人工封促成林与自然更新二种不同更新方法的对比试验,结果表明:采用人工封促成林的更新方法具有明显的优点,即投资少,效益大,林木生长快,单位面积蓄积量可提高50.7%;建议有条件的地方应推广使用该方法。为发展阔叶林生产,保持生态平衡提供了一条有效的途径。 相似文献
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磐安县黄檀林场杉木迹地更新试验简报 总被引:1,自引:0,他引:1
对杉木采伐迹地用日本细叶花柏进行补到促进萌芽更新,其林分生长比杉木纯萌芽更新林分要提前1-2年都闭,且生长快,是杉木成熟林进行采伐迹地更新的一种方法。 相似文献
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Root-freezing damage frequently occurs in forest nurseries operating in cold climates. This type of damage arises because:
(i) environmental cues for root cold acclimation differ from those for shoot acclimation; (ii) the root growing season is
longer than shoot growing season; (iii) strong differences in root cold tolerance exist among species and provenances; (iv)
root tissues are less frost tolerant than those of shoots, and young roots are less tolerant than mature ones; and (v) cultural
practices can adversely affect root cold hardiness. To quantify root-freezing damage, different techniques have been tested.
Electrolyte leakage is the most widely used and provides a good correlation with survival and regrowth. The impact of root-freezing
damage on seedling performance has been studied under controlled and field conditions. Seedlings with root-freezing damage
showed a reduction in survival and growth. Survival was reduced when root-freezing damage are severe. Growth reduction is
mainly explained by a reduction in water and nitrogen uptake. The identification of a threshold in root-freezing damage below
which survival and regrowth would not be affected should be determined for species most commonly used in reforestation.
An erratum to this article is available at . 相似文献
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在灵芝栽培过程中发现野蛞蝓(Agriolimax agrestis)危害灵芝。本文报道六种化学药剂防治野蛞蝓的筛选试验结果:以10%的食盐水防治效果最佳,而且在生产中经济,方便,环保,实用。 相似文献
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通过对黑龙江省森工林区五营林业局红松林三种更新方式的对比分析,指出该林区红松林分的最佳经营方式为人工更新造林。 相似文献
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再论叉叶类苏铁的进化地位 总被引:1,自引:0,他引:1
从裸子植物进化过程、叶脉进化过程、性状分布的普遍性、个体发育的重演原则、每片羽状复叶的叶面积大小等几个方面对Cycas属植物进行再次研究探讨,认为叉叶类苏铁是苏铁属植物中最进化的种群。 相似文献