| 1. | Differences among pinus sylvestris provenances were observed at one year of age but not at two years . 欧洲赤松种源间的差异仅在一年生时可以看到,两年生时就看不到。 |
| 2. | The causes and management of the decline of pinus sylvestris var . mongolica 樟子松枯死原因与防治技术研究 |
| 3. | The soil nutrient , microorganism and enzyme activity are studied and analyzed in pinus sylvestris var . mongolica plantations in zhanggutai area 摘要对章古台不同林龄樟子松人工林土壤养分、微生物及酶活性进行了测定和分析,结果表明:各林地的土壤养分、微生物和酶活性均表现出差异。 |
| 4. | The new addition of cyaneus in actinomycetes group in rhizosphere soil and non - rhizosphere soil may be fundamental reason for the second rotation effect . ( 4 ) compared to the young stand of pinus sylvestris var 二代林放线菌类群中具有兰色类群和玫瑰紫亚类,樟子松林则没有,而樟子松林土壤具有的放线菌中的金色类群和绿色类群,二代林则没有。 |
| 5. | The strategy and measures to prevent the soil degradation of pinus sylvestris var . mongolica were put forward , including application of thinning rationally for existing dense plantations and establishment of mixture forest for new plantations 解决当前人工林退化的主要措施是因地制宜进行间伐或轮伐,改善林地微生态条件,尽量避免营造人工纯林,建议营造混交林。 |
| 6. | The study has investigated and compared soil physical , chemical , biochemical properties of eight stands on paired sites in mountainous regions of northeastern china , trying to look for the mechanism of soil degradation and the change trend of soil properties in different age of plantations in relations to forest productivity . the eight stands are 4 first rotation of larix olgensis plantations with different age classes , the second rotation of larix olgensis young stand , pinus sylvestris var 本文通过固定和典型样地,对东北山地不同生长发育阶段落叶松人工林和二代落叶松幼龄林以及与二代落叶松幼龄林同一块林地的樟子松幼龄林、天然次生林、落叶松水曲柳混交林等8个林型土壤质量进行了对比与分析,深入探讨了落叶松人工林土壤质量降低的机理和不同发育阶段土壤质量变化规律以及与森林生产力变化的关系,并提出了林地土壤质量调控措施。 |