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Current silvicultural treatments in beech forests are aimed at achieving thick logs without discoloured hardwood. Therefore
intensive thinning is applied already in younger stands with the objective of large-sized trunks at an age of 100 years. However,
this approach bears the risk that dead wood structures and broken trees are completely removed from the forest. The impact
of three different silvicultural management intensity levels on wood-inhabiting fungi over decades was investigated in a large
beech forest (>10,000 ha) in southern Germany in 69 sampling plots: A Intensive Thinning and Logging with high-value trees,
B Conservation-Oriented Logging with integration of special structures such as dead wood and broken trees and C Strict Forest
Reserves with no logging for 30 years. The analysis of community showed marked differences in the fungus species composition
of the three treatments, independent of stand age. The relative frequencies of species between treatments were statistically
different. Indicator species for naturalness were more abundant at sites with low silvicultural management intensity. Fomes fomentarius, the most common fungus in virgin forests and strict forest reserves, is almost missing in forests with high-management intensity.
The species richness seemed to be lower where intensive thinning was applied (P = 0.051). Species characteristic for coarse woody debris were associated to low management intensity, whereas species with
a significant preference for stumps became more frequent with increasing management intensity. A total amount of dead wood
higher than 60 m3/ha was found to enable significantly higher numbers of species indicators of naturalness (P = 0.013). In conclusion, when applying intensive silvicultural treatment, the role of dead wood needs to be actively considered
in order to maintain the natural biocoenosis of beech forests. 相似文献
145.
Most of Pinus brutia (Ten.) Holmboe forests are grazed, as silvopastoralism is well adapted in the Mediterranean environment. However, little
attention has been paid to the demographic dynamic of the understorey vegetation even though it is strongly affected by the
absorbed radiation. The purpose of this study was to examine the adaptation of herbaceous plant species under a Pinus brutia canopy, in Northern Greece. Monocultures of four plant groups (annual and perennial grasses, annual and perennial legumes)
were sown in experimental areas of 50%, 70% and 100% light intensity. The density of annual and perennial grasses and perennial
legumes were decreased by the shade cast by the Pinus brutia canopy. Population density of the annual legumes was little affected by light intensity: the annual grasses Bromus mollis L. and Lolium rigidum Gaudin; the perennial grasses Dactylis glomerata L. var. palestine, Festuca arundinacea and Agropyron cristatum (L.) Gaertn; the perennial legume Medicago sativa L. var. romana; the annual legumes Medicago lupulina L. and all the tested varieties of Trifolium subterraneum adapted well to the 50% light intensity habitat. 相似文献
146.
对黑龙江省孟家岗林场40年生红松母树林300、450、600、700和1 300株/hm2(对照)疏伐处理后14个性状的进行统计分析,结果表明,疏伐处理对14个性状均产生极显著影响.除枝下高外,其余性状均值均有较大程度的提高,其中单株结实质量、树冠体积和公顷结实质量分别提高了47.79%、33.6%和28.65%.此外,不同性状之间存在极为复杂的相关性.聚类分析和主分量分析将上述性状分成3大类,分别代表了树冠、种子品质和结实性状.这3类性状在各主成分上得分值的加权和比较分析表明,孟家岗林场42年生红松母树林疏伐抚育最佳密度是450株/hm2. 相似文献
147.
马尾松抚育间伐强度效应试验 总被引:6,自引:0,他引:6
1997年在福建省福安市甘棠镇眉洋村的15年生马尾松人工林中进行不同抚育间伐强度试验,2001年进行调查,结果认为,在一定范围内,其胸径生长随间伐强度增大而增大;增大抚育强度增加单株材积,但单位面积蓄积量减少;不同抚育强度对林分总收获量无显著影响。 相似文献
148.
149.
为探讨修枝强度、林农间种、异龄林等因素对洞庭湖洲滩钉螺孳生的影响,对拐棍洲有螺滩地杨树人工林的螺情分布进行了长期定点调查。结果表明:4年生杨树林,修枝次年林分内的活螺框出现率、活螺密度均低于修枝当年,其中1/3修枝强度次年林分活螺框出现率、活螺密度较修枝当年分别降低了68.00%和80.80%。林农间种的杨树林较翻耕不种和不耕不种的杨树林抑螺效应显著,翻耕而不间种的杨树林,活螺框出现率与不耕不种的1年生杨树林一样,但活螺密度却较不耕不种下降了47.20%。异龄林营造后,活螺密度大致呈下降趋势,营造后的第2、3、4年时活螺框出现率、活螺密度分布较营造当年下降73.33%、50.00%、77.67%和75.96%、43.94%、83.85%。林分郁闭后,全面翻垦的林分活螺框出现率、活螺密度均比不翻垦的林分低直至趋于零。除了高程(32.64m)较高的林分外,其他高程全耕不种林分内活螺框出现率、活螺密度均低于全垦间种。 相似文献
150.
辽东栎伐桩萌苗的发育规律 总被引:4,自引:0,他引:4
通过对黄土高原黄龙山林区辽东栎林固定样地连续6年的调查,研究间伐强度分别为13.4%(弱度间伐)和30.0%(强度间伐)的辽东栎伐桩萌苗的存活与生长规律.结果表明:1)间伐第1年,辽东栎伐桩均有萌生枝发生,每桩萌生枝数量和萌生枝高度在不同强度间无显著差异;2)萌生枝数量受伐桩高度和直径的影响,当伐桩高度较低时,萌生枝数量随伐桩高度的增加而增加,超过20cm后随之减少,呈三次抛物线关系;伐桩萌生枝数量随着伐桩直径增加呈现先增加后减少的趋势,直径30~50cm的伐桩萌生枝数量最多;3)伐桩萌生枝数量与最长萌生枝高度呈显著线性负相关,存在“萌生枝数量——高度权衡”现象;4)间伐第6年,伐桩的存活率为97.01%,强度间伐区萌生枝高度显著高于弱度间伐区;5)调查期间,辽东栎伐桩萌生枝数量逐年下降,伐桩产生的萌生枝数量越多,后期萌生枝死亡的数量也越多,表明伐桩能够自我稀疏,存在“萌代主”现象.在黄土高原地区,辽东栎伐桩萌芽潜力很大,应合理利用;间伐时伐桩高度应尽量低于20cm;伐桩直径在30~50cm更有利于其无性更新;间伐后伐桩应及时除蘖定株,促进萌生枝生长;间伐强度30.0%(强度间伐)更有利于辽东栎伐桩萌生枝的生长. 相似文献