Factors affecting distribution of castanopsis calathiformis (skan) Rehder & E.H. Wilson seedlings beneath maternal tree crowns in forest restoration plots

Abstract

Castanopsis calathiformis (Skan) Rehder & E.H.Wilson is one of indigenous tree species in the Fagaceae that was planted in 1998 in a restoration plots in a deforested area near Mae Sa Mai village, Chiang Mai, in this area there is no recorded of the tree species. Over time, C. calathiformis grew into large, healthy trees and have produced seeds into the plot. These have germinated and dense carpets of C. calathiformis seedlings and saplings have formed under the maternal trees and no other plant species can grow in those areas, which may affect the vegetation structure in the future. The objectives of this study are to (1) compare seeding populations of C. calathiformis with two other tree species in Fagaceae Family (Quercus brandisiana Kurz. and Quercus semiserrata Roxbin) within these restoration plots, (2) determine seed predation and seed dispersal around the C. calathiformis maternal trees and (3) compare distribution of C. calathiformis seedling in forest restoration sites and natural forests. The results showed that the seedling density of Q. brandisiana and Q. semiserrata was significantly lower than C. calathiformis. The density of C. calathiformis seedling declined significantly with increasing distances from the maternal trees and there was no relationship between characteristics of the maternal trees (height, DBH and crown width) and the density of C. calathiformis seedlings. The study of C. calathiformis seed dispersal and seed destruction showed that this species had high germination rate (87.01%). Only 14.1% of seed was destroyed and one third of that could germinate (germinated seed = 4.31% and non-germinated seed =9.76%) experiment no seed of C. calathiformis was removed from the plots. No seed predators were recorded by camera trap that were set up near C. calathiformis maternal tree. However, we found leopard cat (Prionailurus bengalensis) within the area. For natural forest, the result shows that seedling density of C. calathiformis in natural forest (collected data in Khunpuay Temple) was significantly lower than that in forest restoration plots and the increasing of seedling density was not related to distance from maternal trees. This study provided suggestion that planting C. calathiformis in restoration sites outside its natural habitat should be considered carefully, because it may affect vegetation structure, species diversity and efficiency of forest restoration process.