陆地阔叶林在中央各州的所有森林中约占65％。树种为栎树,其中包括黑栎(Quercusvelutina Lam.),白栎(Q.alba L.),大红栎(Q.coccinea Muenchh.),赤栎(Q.rubra L.),沼生栎(Q.prinus L.)。这些栎树生长的土壤和地形条件变化很大,因而立地质量和树木生长很不相同。比较集约的经营需要为每一树种确定立地质量。近几年来,广泛应用树干解析和节间测定法编制立地指数曲线,其计算技术已有许多人作过详细叙述。 Terrestrial broad-leaved forests account for about 65% of all forests in the Central States. The species is oak, including Quercus velutina Lam., Q. alba L., Q.coccinea Muenchh., Q.rubra L., .prinus L.). The soil and topography of these oak trees vary greatly, and therefore site quality and tree growth are very different. More intensive operations need to establish site quality for each tree species. In recent years, the extensive application of trunk analysis and internode determination of the establishment of site index curve, the calculation technology has been described in detail by many people.