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杜仲人工林中的邻体干扰 总被引:1,自引:0,他引:1
本文研究了四川地区杜仲(Eucommia ulmoides)人工林,杜仲个体生长速度与邻体效应之间的相互关系。以杜仲个体为基株,3m为半径圆内的个体均被定久为邻体,采用张大勇改进的干扰指九模型和杜种的生长速度进行回归分析,发现杜仲生长速度与邻体干扰指数之间有显著的线性关系,研究结果表明,杜仲林内,杜仲个体之间表现为强烈的种内竞争,个体生长的动力来自杜仲各个体对资源竞争所引起的自疏作用,邻体干扰效应的存在是确定杜仲人工林合理经营密度的重要理论依据。 相似文献
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辐射松(PinusradiataD.Don)原产于加利弗尼亚海岸,被引种到世界各地,现在是南半球主要的人工林造林树种。1990年以来辐射松被引种到长江上游四川省阿坝州的干旱河谷地区,幼树的成活和早期生长表现良好。本文的主要内容包括:辐射松在原产地和引种地的生长情况,种源和遗传上的差异,环境限制因子和辐射松的气候生境,病虫害,引种不成功的经验教训以及辐射松在生态恢复中的应用。文中还简述了辐射松在阿坝干旱河谷地区的早期生长情况,列举了在长江上游干旱河谷地区引种辐射松可能遇到的问题以及所需开展的研究。图4表5参90。 相似文献
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在四川省会东县可河乡,采用Li-6400光合测定系统,对希蒙得木Simmondsia chinensis2个种源4年生人工林的光合特性进行野外测定。结果表明,希蒙得木的二氧化碳补偿点为56~62μmol.mol-1,羧化效率0.081 4~0.094 6,暗呼吸速率1.15~1.18μmol.m-2.s-1,光补偿点31~35μmol.m-2.s-1,光饱和点1 308~1 592μmol.m-2.s-1,表观量子效率0.033~0.037,属典型阳性的C3植物。叶片净光合速率日变化呈单峰曲线,光能利用效率平均5.641~5.999 mmol.mol-1,水分利用效率1.0 mmol.mol-1。图8表2参24 相似文献
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以希蒙得木自然分布区和引种驯化的7个地理种源为研究对象,采用盆栽控水方法设7个水分梯度。结果表明,在水分胁迫下,希蒙得木不同种源各个生理指标表现出相似变化规律。希蒙得木幼苗叶片相对含水量逐渐减少,细胞膜透性呈缓慢递增的趋势;不同种源幼苗叶片游离脯氨酸含量、SOD活性、CAT酶活性、POD活性、MDA含量、可溶性糖含量、可溶性蛋白含量、ABA含量出现不同程度的上升趋势,在胁迫到35~42天时达到高峰,随后有所降低,但在相当一段时间内保持稳定。希蒙得木叶片中IAA的含量随着干旱胁迫程度的增加和水分胁迫时间的延长而降低。 相似文献
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用材林经营主要技术措施及研究实例 总被引:1,自引:1,他引:0
1用材林经营主要技术措施1·1提高生产力的经营措施-林地施肥1·2林分密度调控措施-间伐林分间伐需要研究解决的技术问题:间伐时间(时机、间隔期)、间伐强度、间伐对象。间伐作业需要考虑:间伐的成本和经济收益。同时需要相关的政策、法规、技术标准的支持。1.3合理确定采伐年龄(轮伐期)-森林成熟的论证1.4森林永续利用(可持续利用)-采伐量调整2提高生产力的经营措施-林地施肥的研究实例试验时间:1986年~1993年。试验对象:杉木(2 a生、3 a生、7 a生);马尾松(2 a生);湿地松(2 a生、3 a生);香樟(2 a生)。试验内容:肥料种类(氮、磷、氮 磷)、施… 相似文献
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四川阿坝辐射松引种长期森林健康风险初步评估 总被引:2,自引:0,他引:2
Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley The newly introduced P. radiata are exposed to two kinds of forest health risks: they may be attacked by (a) indigenous pathogens and pests against which they may not possess any resistance or (b) by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical appmach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding conifemus forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are pmvided to improve forest vigour and to reduce the forest health risks pos 相似文献