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31.
枫桦红松林凋落物分解真菌生态群的研究   总被引:3,自引:0,他引:3  
小兴安岭枫桦红松林凋落物分解真菌生态群共签定出99属种,其中树上活体分解寄生菌10种、兼性菌5种,微型腐生菌36个属、腐生担子菌47种。根据凋落物分解真菌在分解过程中所处的生态位不同,分为四个生态群:叶面寄生分解真菌(以Melampsora, Uncinula等为代表)、叶面兼性分解真菌(以Mycosphaerella,Lophodermium为代表)、叶栖初生腐生分解真菌(以Lophodermium nitens为典型代表)、叶栖习居次生腐生分解真菌(微型真菌以Alternaria,Trichoderme等为代表,腐生担子菌以Clitocybe,Russula等为代表)。在凋落物分解真菌方面,为枫桦红松林生态系统研究,提供了重要科学资料。  相似文献   
32.
ABSTRACT

Soil erosion is a major socioeconomic and environmental problem in Turkey. Almost 86% of the land in Turkey has suffered various degrees of soil erosion. The objective of this study was to determine whether differences in tree species affect soil characteristics and microbial activity in degraded soils. Results from this study showed that organic C (Corg) was highest in the black locust soil at 0–20 cm depth and lowest in the bare land. Microbial biomass C (Cmic) increased in the order black locust > Scotch pine > bare land at two soil depths. One-way ANOVA demonstrated that afforested soils contain significantly higher microbial biomass C than those in the bare land soils. Microbial quotient (Cmic/Corg) of soils are positively influenced by afforestation as the bare land soils exhibited lower microbial quotient than the associated Scotch pine and black locust soils. Microbial communities in black locust soils were energetically more efficient—had a lower metabolic quotient (qCO2)—with a higher Cmic/Corg compared to those in Scotch pine soils. However, the microbial quotient in our study was still below range and cannot reach equilibrium again 15 yr after afforestation. Restoration of degraded lands could be a long-term process from microbial activity in the observed regions.  相似文献   
33.
柔枝松引种试验初报   总被引:1,自引:0,他引:1  
为了掌握柔枝松在中国的生长适应情况,对柔枝松引种后1 a生苗木的生长情况进行了研究,并选择乡土树种油松、华山松和白皮松作为对照。结果表明,柔枝松种源1和种源2的场圃发芽率分别为24.25%和25.25%,均低于油松(36.5%),但高于白皮松(18.25%)和华山松(13.25%);成活率比乡土树种低;柔枝松的苗高生长较慢,柔枝松种源1和种源2的1 a生苗苗高分别为3.1 cm?和3.6 cm?,低于油松(6.3 cm)、华山松(5.2 cm)、白皮松(4.3 cm);柔枝松种源1和种源2的1 a生地径,分别为0.175 cm?和0.178 cm,低于油松(0.208 cm)但与华山松(0.182 cm),与白皮松(0.178 cm)相差不大;柔枝松种源1和2主根平均长度分别达到了19.1 cm1、4.8 cm,均长于乡土树种,两个柔枝松种源之间相比,种源2优于种源1。  相似文献   
34.
In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine(Pinus tabuliformis). This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78(±0.85) and 1.06(±1.15) m, and the average diameters at breast height(DBH) were 3.21(±1.38) and 2.91(±1.38) cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00(±1.14) and 2.24(±1.20) m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has the potential to be an effective approach for establishing multifunctional forest.  相似文献   
35.
The pathogenic fungi Verticillium alboatrum and Diplodia scrobiculata were assayed for biological control of Diplodia pinea on Aleppo pine (Pinus halepensis) in Catalonia (north-eastern Spain). Young shoots were pre-treated with inoculations of either V. dahliae or D. scrobiculata, by placing colonized agar plugs on wounds made by removing a single needle fascicle. An inoculation with D. pinea was performed 15 days later. Two months after the shoot inoculations, the canker length on the stems was measured and the percentage of shoot dieback calculated. Verticillium dahliae and D. scrobiculata were found to significantly reduce the canker length of D. pinea (P < 0.05) when compared with positive controls. Diplodia pinea was slightly more sensitive to V. dahliae than to D. scrobiculata, but no significant differences (P > 0.05) were observed in the mean canker length between the two treatments. Trees pre-inoculated with V. dahliae resulted in 31.12% shoot dieback, while those pre-inoculated with D. scrobiculata resulted in 32.18% shoot dieback, compared with positive controls (42.85%).  相似文献   
36.
油松、辽东栎混交林中生化他感作用的研究   总被引:32,自引:0,他引:32  
研究了油松(PinustabulaeformisCarr.)、辽东栎(QuercusliaotungensisKoidz.)混交林中的生化他感作用,结果表明:油松、辽东栎纯林及松栎混交林下的枯落叶、半分解枯落叶及表层土壤水浸液对油松及其它植物的种子发芽和幼苗胚根、幼茎生长有显著的影响,一般在高浓度下表现为强烈的抑制作用,低浓度下作用不显著或起促进作用。其中辽东栎枯落叶水浸液的抑制作用最为强烈,混交林中枯落叶的抑制作用有所下降。说明在某些条件(干旱、混交比例和混交方式不当)下,两树种混交可引起林地生化他感物质富积,从而导致油松生长不良,林地生产力下降。解释了实际林地的现象,为营造松栎混交林提供了依据。  相似文献   
37.
高脂马尾松营养袋育苗技术   总被引:1,自引:0,他引:1  
文章总结了培育高脂马尾松营养袋种子苗的播种、育苗及其管理技术方面的一些成功经验.  相似文献   
38.
利用中国林科院热带林业实验研究中心2009年森林资源二类调查数据,分别利用目标线性规划与传统森林轮伐公式计算热林中心马尾松纯林和杉木纯林用材林年采伐量,比较分析同一个经理期(2009—2019年)两种计算方法的不同;结果表明:轮伐公式计算的采伐量一般偏大,且目标规划单位面积年经济收益是轮伐公式获得经济效益的10 20倍。利用目标规划法在同时实现材积收获量最大、出材量最大、净现值收益最大的目标前提下,对森林结构进行调整,使资源分布满足可持续经营的要求,即尽可能达到法正状态。  相似文献   
39.
该文利用贵州省台江县马尾松造林技术试验林 4~ 10年生林分的逐年测定资料 ,以林分平均树高和平均胸径为基准变量、各主要造林技术措施和林分年龄为说明变量 ,对建立马尾松林分生长的数量化回归模型进行初步研究 .结果表明 ,采用数量化回归途径建立马尾松林分生长的预测模型是可行的 ,且所建模型具有较高的预测精度 ,但用于拟合回归模型的数据以采用林龄为 4a以上的测定资料为宜 .通过对回归模型偏相关系数的定量分析 ,可以确定马尾松人工林培育的关键技术措施是立地控制、遗传控制和密度控制 ;同时 ,还可根据各项造林技术措施和林分年龄 ,预测马尾松林分的生长 .  相似文献   
40.
间伐强度对湿地松木材性质的影响规律研究   总被引:5,自引:1,他引:5       下载免费PDF全文
通过对不同间伐强度处理 (未间伐、弱度 (伐去株数 18 6 % )、中度 (伐去 35 7% )、强度 (伐去5 2 9% ) )的 19年生湿地松林分其林木木材的主要材性指标进行全面测试分析研究 ,结果表明 :间伐后 8a ,间伐强度对湿地松木材气干密度、全干密度、径向全干缩率、体积全干缩率、差异干缩、顺纹抗压强度、抗弯强度、弹性模量、径向抗剪强度及端面硬度有显著影响 ;随着间伐强度的增大 ,树干年生长轮平均宽度、木材差异干缩是增大的 ,而随间伐强度的增加木材气干密度、全干密度有不同程度的减小 ,木材顺纹抗压强度、抗弯强度、抗弯弹性模量、硬度等主要力学性质则是呈先增加后减小的趋势。  相似文献   
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