①主要樹(shù)種與主要樹(shù)種混交; ②主要樹(shù)種與伴生樹(shù)種混交; ③主要樹(shù)種與灌木樹(shù)種混交; ④主要樹(shù)種、伴生樹(shù)種與灌木的混交
(1)遺傳改良途徑 (2)結(jié)構(gòu)調(diào)控途徑 (3)立地的選擇與調(diào)控途徑