由单一树种组成的林分称为纯林;由两个或两个以上树种组成的林分称为混交林。营造混交林的意义极其重要。混交林的生态效益、经济效益和社会效益都高于纯林。其抗逆性、物种多样性和稳定性都超过纯林,混交林对空间、阳光和林地能充分利用,其低抗自然灾害(风折、雪压、霜冻、火灾、病虫鼠害)能力强。营造混交林是生态建设、生态安全、生态文明的迫切需要,是现代林业建设又好又快科学发展的必然趋势。因此,每年造混交林的比重都不断增 Stands consisting of a single species are called pure forests; stands consisting of two or more species are referred to as mixed forests. The significance of creating mixed forests is extremely important. The ecological benefits, economic benefits and social benefits of mixed forests are higher than pure forests. Its resistance, species diversity and stability are all higher than that of pure forests. Mixed forests can make full use of space, sunlight and woodlands, and their ability to resist natural disasters (wind, snow, frost, fire, pest and rodent) Strong. To create a mixed forest is an urgent need of ecological construction, ecological security and ecological civilization, which is an inevitable trend of sound and rapid development of modern forestry. Therefore, the proportion of mixed forest each year is increasing