Changes in plant species diversity over 5 years in Larix kaempferi plantations and abandoned coppice forests in central Japan

We studied the forest layers (understory and overstory) of two forest types (Larix kaempferi plantation and secondary, broad-leaved, abandoned coppice forest) according to stand development in order to examine differences in the changes in plant species diversity over the 5 years from 1999 to 2004. Increased stem density in the plantations had decreased the species diversity in the overstory, whereas species diversity in the understory was stable. However, species replacement was greater in the understory than in the overstory for both forest types. In the understory of both forest types, more small-animal-dispersed species and tall tree species had colonized, and the frequency of occurrence of some bird-dispersed tall tree species had increased. These results support our previous studies, which used a chronosequence approach and found that older plantations contained more animal-dispersed tall tree species than young plantations.