Impact of Icesnow Damage on Understory Biodiversity in a Cunninghamia lanceolata Stand in Northern Guangdong Province, China

In order to better understand the structure and composition of forest communities suffering from icesnow damage, understory species were investigated in 2011 at five large (80-100m2), five small (30-40m2) and canopy sites in the Cunninghamia lanceolata stand, showing that there were 3, 4 and 3 shrub species and 7, 10 and 5 herbaceous species in the lager gaps, small gaps and canopy sites, respectively. ShannonWeiner diversity index was 101, 109 and 095, Simpson diversity index was 061, 060 and 057, Pielou (JSW) evenness index was 091, 079 and 087, and Pielou (JSi) evenness index was 092, 080 and 086 in shrub layer, respectively, in the controls, small gaps and large gaps. Whereas ShannonWeiner diversity index was 142, 192 and 137, Simpson diversity index was 064, 095 and 071, Pielou (JSW) evenness index was 073, 084 and 085 and Pielou (JSi) evenness index was 074, 105 and 088 in herbaceous layer, respectively, in the controls, small gaps and large gaps. Generally, diversity index was low in large gaps due to strong illumination and high in small gaps due to large spatial heterogeneity.