杉木多代连栽地长期轮栽柳杉后凋落物的动态

对杉木多代连栽地经柳杉长期轮栽后凋落物的组成及归还动态进行了研究,结果表明:柳杉林分的年凋落量是杉木多代连栽林的2.18倍,两树种凋落物年组成成分的变化规律不同,但杉木和柳杉年凋落物主要都来源于叶、枝和花果,其余的组分归还较少.柳杉林凋落物的归还模式为主峰出现在5月份和8月份,这两个月的凋落量占年凋落量的49.69%,可见,柳杉凋落物主要发生在5月和8月这两个月,而杉木则主要发生在8月份,仅8月份这1个月的凋落量就将近占年凋落量的一半.柳杉各月的凋落物中都以柳杉叶为多,但其他组分的归还顺序各月亦不完全一样,杉木亦有相似的变化规律.凋落物的季节归还模式亦不同:柳杉林凋落物的季节变化呈适现出夏季(35.13%)＞秋季(30.39%)＞春季(26.33%)＞冬季(7.57%),而杉木多代连栽林则呈现出秋季(53.06%)＞春季(24.07%)＞夏季(15.76%)＞冬季(6.48%).

Litterfall Dynamics of the Forest after Long Rotative Planting of Cryptomeria fortunei in the Field of Successive Planting of Cunninghamia Lanceolata

The investigation and analysis were carried out to compare litterfall composing and return dynamics of the forest after long rotative planting of Cryptomeria fortunei in the field of successive planting of Cunninghamia lanceolata.The results showed that the annual litterfall fluxes of Cryptomeria fortunei forest was 2.18 times larger than that of the forest of successive planting of Cunninghamia lanceolata.The changing laws of annual litterfall fluxes of the two kinds of the forests were different.The annual litterfall fluxes of the two forests were chiefly formed by leaves,branches and fruits,and the rest had little contribution.The maximum litterfall fluxes of Cryptomeria fortunei forest appeared in May and August,and the quantity of the two months took(49.69%) of annual litterfall fluxes.The conclusion was that the litterfall of Cryptomeria fortunei forest mainly took place in May and August,but that of the forest of Cunninghamia lanceolata presented in August,taking the half of annual litterfall fluxes.Leaf litter fall of Cryptomeria fortunei had made greatest contribution to the lunar litterfall fluxes of Cryptomeria fortunei forest,but the others had different return order in lunar litterfall fluxes,while the changing law of Cunninghamia lanceolata forest was similar.The return patterns of the two forests in seasonal litterfall fluxes were different.Seasonal litterfall fluxes of Cryptomeria fortunei forests showed that: summer((35.13%))>autumn((30.39%))>spring((26.33%))>winter((7.57%)),meanwhile,the forest of successive planting of Cunninghamia lanceolata showed that: autumn((53.06%))> spring((24.07%))>summer((15.76%))>winter((6.48%)).