陕北榆林风沙区防风固沙林体系结构配置与效益研究

通过对陕北榆林风沙区防风固沙林体系的配置结构、树种组成、防风固沙效益、改良土壤的作用以及对天然植被的影响等的调查、观测和分析,结果表明:其配置结构较为合理,生态效益较为显著.选择运用防风固沙林的防风效益和输沙量为指标,经逐步回归分析发现,输沙量与造林密度、近地表林木分枝数和草本植物盖度相关紧密,树高、冠(灌)幅对输沙量的贡献极小.对防风效益则相反,树高、冠(灌)幅则具有极显著的相关性.同时,降低风速与树高及近地表草本植物的盖度呈正相关;在防风固沙林与输沙量的相关因子中,以防风固沙林的密度和灌木分枝数、草本

Structure Configuration and Protecting Benefit of Yulin Sandbreak Forest System in Northern Shaanxi

The effects of the sandbreak forest system in Yulin sandy area on the sandbreak, soil improvement and natural vegetation recovery were studied by investigating their configuring structure and species. The configuring structure was reasonable and the protecting benefit was remarkable. Progressive regression analysis showed that sediment discharge remarkably correlated with the planting density, the number of the branches near ground and the herbage covering. The shrub breadth and height contribute little to sediment discharge but large to wind reducing,and the wind speed reducing positively correlated with canopy height and herbage covering. The number of the branches near ground and herbage covering played most important roles on sediment discharge. The sandbreak forests improve the microclimate and the soil.