Fine root biomass and its dynamics of limestone mountain vegetation under different enclosure ages

Soil drilling method was used to study fine root biomass of vegetation under different enclosure ages in limestone area. The results showed fine root biomass was 6.6287 t/hm2 in the stands after 5 years爷enclosure, 2.3063 t/hm2 after 10 years爷enclosure, 3.1316 t/hm2 after 20 years爷enclosure and 2.8316 t/hm2 after 30 years爷enclosure. It declined with the increase of soil depth in each enclosure types and showed significantly higher value in 0~10 cm depth than the other two layers. Annual dynamic of fine root biomass under different enclosure years followed a bimodal pattern.