广西光皮桦林的分类和演替

光皮桦林是常绿阔叶林或山地常绿落叶阔叶混交林遭受砍伐后，在保护较好的情况下自然恢复起来的一种演替系列群落，属亚热带落叶阔叶林的一种类型。本文通过群落分类研究，划分出３个群丛纲和１１个群丛。从这些群丛的外貌、结构和种类成分的变化，可确定其演替的趋向和所处阶段，是合理经营管理它的科学依据。

The classification and succession of Betula luminifera forest in Guangxi

Betula luminifera forest is a seral stage of evergreen broadleaf forest and mountainous mixed evergreen and deciduous broadleaf forest seres, mainly occurs in yellow soil mountain of north Guangxi at elevation of 700～1 300 m, and stretching right to the yellow brown soil mountain of laoshan in Tienlin county at elevation of 1 400～2 000 m toward southwest 3 Association classes and 11 Associations are described as follows: 1 Young growth of Betula luminifera with single tree layer 11 Betula luminifera-Dicranopteris dichotoma Association; 12 Betula luminifera-Melastoma polyanthum-Dicranopteris dichotoma Association; 13 Betula luminifera-Gaultheria yunna- nensis-Dicranopteris dichotoma Association; 2 Middle ageforest of Betula luminifera with two tree layers 21 Betula luminifera-Diospyros lotus-Eurya nitida-Dicranopteris dichotoma + Wood-wardia japonica Association; 22 Betula luminifera-Clethra kaipoensis-Blastus cochichinensis-Woodwardia japonica Association; 23 Betula luminifera + Alniphyllum fortunei-Hydrangea paniculata-Woodwardia japonica + Miscanthus floridulus Association; 24 Betula luminifera-Itea chinensis-Maesa japo- nica-Woodwardia japonica Association; 25 Betula luminifera-Rhus chinensis-Viburnum cylin- dricum-Miscanthus floridulus Association; 3 Mature forest of Betula luminifera with three tree layers;31 Betula luminifera + Carpinusfargesii- Rhododendron cavaleriei + Eurya impressinervis-Maesa japonica-Woodwardia japonica Association; 32 Betula luminifera-Eurya impressinervis -Blastus dunnianus-Woodwardia japonica Association; 33 Betula luminifera + Schima argentea-Clethra kaipoensis + Distylium myricoides -Blastus cochinchinensis-Woodwardia japonica Association Its successional trend toward recovering evergreen broadleaf forest can be fully proved through information analysis of community physiognomy, structure and species composition change between 11 Associations