引言 许多研究者认为防风林的孔隙度对防护范围及质量的影响极大。处理象板条之类的人工风障,通常用简便的数学运算评价孔隙度;而研究防风林和各种林带这种形状为开孔并且分布无规律的天然风障,其孔隙度的确定要困难得多。Fryrear用光电元件测量 Introduction Many researchers believe that the porosity of windbreaks has a significant impact on the extent and quality of protection. Artificial wind barriers such as planks are often used to evaluate porosity by simple mathematical calculations. It is difficult to determine the porosity of windbreaks and various forest belts, which are open-celled and irregularly distributed natural wind barriers Much more. Fryrear is measured with optoelectronic components