关键词: CO₂浓度增高, 土壤, 蔗糖酶, 木聚糖酶, 纤维素酶, 酶活性

Abstract: 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 istribution 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.

Key words: Free-air CO₂ enrichment(FACE), Soil, Invertase, Xylanase, Cellulase, Enzyme activity