Forest , artificial forest , introduction and breeding of trees in 人工造林和樹木引種馴化
Status and breeding orientation of artificial forest in northwest of liaoning 遼西北人工林資源現狀及培育方向
Thinking on commercial logging of artificial forest at implemented areas of ' national natural forest protection ' in yunnan province 天保工程區人工商品林采伐管理辦法探討
Though china has made remarkable achievement in artificial forest creation , such forests have not substantially protected the biodiversity , because of the monotony of the kind of such forests 加之人工林林種單一,雖然部分地區森林覆蓋率較高,但生物多樣性卻沒有得到很好的保護。
Based on the long - term observation of the formation of the vegetation and the ecological features in houyuntaishan mountain area , this paper elaborates on the ecological features of the scattered forest community on the natural environment in the neighborhood and analyzes the degeneration of the artificial forest and its dynamic process as well 摘要在對連云港后云臺山地區植被的種類構成和自然生態狀況長期觀察的基礎上,闡述了森林植物群落對自然環境的生態作用,對區內的人工森林退化問題及其動態過程進行了分析。
2 the comparisons between soil water deficiency in natural and artificial forest land show that : ( 1 ) the concept of " forestland steady moisture capacity " is presented and defined as the lowest soil water content that can not affect the forest regular growth primarily and cause inverse succession in community 2天然林地和人工林地土壤水分虧缺狀況對比: ( 1 )提出了“林地土壤穩定持水量”的概念,初步定義為“不會影響到林分正常生長、發育,不會導致群落產生逆向演替所需的最低土壤含水量” 。
With increase of artificial forest age , the content of soil organic matter decreased sharply . and soil physical , chemical and biological properties of forest became worsen . from soil physical properties analysis , soil silt , clay , physical clay , aggregate degree and structure coefficient in topsoil increased with increase of artificial forest age and soil sand deceased 在土壤物理性質方面,隨著人工云杉林齡的增加,土壤表層粉粒、粘粒、物理性粘粒、團聚度和結構系數降低,砂粒含量增高,土壤飽和持水量、毛管持水量及總孔隙和毛管孔隙在人工云杉演替過程中表現出“ u ”型變化。
The soil organic content in the topsoil decreased with increase of artificial forest age . because the total n and alkali - hytrolyzable n were from mineralization of soil organic matter , their content in the artificial forest decreased with the decrease of soil organic matter 在土壤化學性質方面,各林地土壤有機質含量表層大于底層,人工云杉林土壤表層有機質含量隨著撫育林齡的增加而降低,土壤中全氮、堿解速效氮主要來源于土壤中有機質的礦化,其含量隨有機質的減少而降低。
Soil saturated capacity , capillary capacity , total porosity and capillary porosity showed the trend of the " u " during the successional course of artificial forest , namely , they reduced on the early successional stages , after picea reached mature forest , soil porosity recovered slowly . the content of natural water was mainly affected by capillary porosity . from soil chemical properties analysis , the content of soil organic , humus , ha , fa and ha / fa of topsoil was more than that of bottom layer 即人工云杉幼林向成熟林演替階段,土壤飽和持水量、毛管持水量及總孔隙和毛管孔隙則減少,在40年生云杉林達最低值,之后隨著云杉自疏,微生態改善,林地凋落物分解加快,土壤飽和持水量、毛管持水量及總孔隙和毛管孔有上升的趨勢,毛管持水量是決定林地自然含水量的主要因子。