莲花山主要森林群落空间格局的分形特征

应用信息维数对莲花山主要森林群落的空间格局进行了研究.结果表明:森林群落的格局强度尺度变化程度由高至低的次序为:岷江冷杉一糙皮桦一白桦群落(Q4)1.84＞云杉-紫果云杉-糙皮桦群落(Q2)1.53＞岷江冷杉群落(Q3)1.14＞紫果云杉-云杉-岷江冷杉群落(Q7)1.10＞华山松群落(Q5)0.99＞岷江冷杉人工林(Q1)0.82＞辽东栎群落(Q6)0.45;群落格局信息维数的差异反映了更新状况的差异,揭示出群落个体分布的非均匀性状况.综合3种分形维数,确定各亚高山寒温性森林群落生长与更新状况的次序为Q4＞Q2＞Q3＞Q7＞Q5＞Q1＞Q6.各群落总体平均记盒维数为1.76,关联维数为1.71,信息维数为1.12;各森林群落生长状况较好,个体聚集程度较低,更新状况一般.分形维数谱将不同森林群落的空间结构特征明确区分开来.

Fractal characters of spatial patterns of main forest communities in Lianhua Mountain

By using information dimension,this paper studied the spatial patterns of main forest communities in Lianhua Mountain in Gansu Province of China.The results showed that the scale variation degree of the pattern intensities of the communities was in the order of Abies faxoniana-Betula utilis-Betula platyphylla community(Q4)1.84>Picea asperate-Picea purpurea-Betula utilis community(Q2)1.53>Abies faxoniana community(Q3)1.14>Picea purpurea-Picea aspirate-Abies faxoniana community(Q7)1.10>Pinus armandi community(Q5)0.99>Abies faxoniana plantation(Q1)0.82>Quercus liaotungensis community(Q6)0.45,which reflected the differences in community regeneration status and revealed the unevenness of individuals distribution in community.By integrating three types of fractal dimension,the growth and regeneration status of the forest communities was Q4>Q2>Q3>Q7>Q5>Q1>Q6.The overall averaged box-counting dimension of the communities was 1.76,correlation dimension was 1.71,and information dimension was 1.12,suggesting that the growth status of the communities was good,the degree of individuals aggregation was low,and the regeneration was usual.The spectrum of fractal dimension could reflect the differences in the spatial structural characters of forest communities.