Dynamics Anasysis Of Root Sprouting During2007-2012in An Evergreen Broad-Leaved Forest In Gutianshan Nature Reserve

Root sprouting is one of the strategies of vegetative propagation, especially after the interference, sprouting trees can take advantage of the parent trees’nutrition to produce new plants and occupy resources and ecological niche quickly, faster than seeding plants, making themselves in a dominant position.The root sprouting regeneration is an important way in forest regeneration.The root sprouting of forest plants affects the community’s update dynamic and succession direction.In this paper,we explore the root sprouting characteristics of an5-ha evergreen broad-leaved forest dynamic plot in Gutianshan National Nature Reserve from2007to2012,and all woody plants’DBH (diameter at breast height)≥1cm. We analyzed the composition of the root sprouting species,sprouting ability,the influence on important value and the correlation between root sprouting ability and parent trees’DBH and habitat.The results are as followings:(1)As far as2012,we had discovered112kinds of woody root sprouting plants in Gutianshan5-ha dynamic plot,8family,13genus and17species were increased compared with2007.The family of Calycanthaceae,Fagaceae,Ericaceae and the genus of Chimonanthus, Rhododendron, Castanopsis and the species of Chimonanthus salicifolius, Camellia fraterna, Rhododendron ovatum, Rhododendron latoucheae have more root sprouting genets. And the dominant families,genus and species are almost consistent in the total number of individuals of the plot.However the order had changed,the reason may be that the plant root sprouting ability is different among all kinds of plants.The most root sprouting genets in tree are Castanopsis eyrei,Castanopsis fargesii,Cyclobalanopsis glauca,in subtree are Rhododendron ovatum,Rhododendron latoucheae,Itea oblonga,in shrub are Chimonanthus salicifolius, Camellia fraterna, Eurya rubiginosa.(2)Root sprouting rates in2012rose by1.98%-73.55%compared with2007. The range of root sprouting number is small. Root sprouting number is between0.67and4.5in2007,and it is between1.0and4.5in2012,but species’root sprouting number has the tend to increase, the largest number of root sprouting by individuals has increased from12to20during the past five years. After suffering from the ice storm in2008, it is shown that all species’root sprouting ability has enhanced.(3) In the forest community, sprouting created the condition of "regeneration niche" for species. This article researched the sprouting influences in the important value of species in2007and2012.The results show that:considering the root sprout factors, each species’important value were changed greatly, such as Cyclobalanopsis glauca,Castanopsis fargesii,Lithocarpus glaber,Chimonanthus salicifolius.The species with strong sprouting ability were changed much more which help the species niche space expand. And the order of species in vertical structure has not changed. Some species still occupy the dominant position, for example Castanopsis eyrei, Schima superba.Daphniphyllum oldhamii in canopy layer, Rhododendron ovatum,Loropetalum chinense,Rhododendron latoucheae in sub-canopy layer and Camellia fraterna, Chimonanthus salicifolius,Eurya rubiginosa in shrub layer, and most species do little to their important value.(4) The study on the relationship between root sprouting ability and the diameter at breast height of parent tree:the data of2007and2012has shown that in the stage of the parent tree Ⅰ and Ⅱ,the three growth forms’(tree, subtree,and sub shrub) sprouting rate and sprouting number are on the rise, the results illustrate that all the species have a large sprouting ability in the early development of parent tree. In111and above the111stages, sprouting ability of different species shows different trends, one reason is that the plant will lose the sprouting ability or have lower sprouting ability after the adulthood initiation, the duration of the sprouting ability has great difference among different species, on the other hand, it may be related to different species such as the size of the diameter at breast height and plant life. (5)There were nine root sprouting species in three vertical level in2007,their distribution situation was largely similar to all their parent trees. Parent tree distribution shows obvious collective phenomenon such as Castanopsis eyrei in canopy layer;Eurya muricata,Corylopsis glandulifera, Rhododendron latoucheae in sub-canopy layer and Camellia fraterna, Chimonanthus salicifolius in shrub layer.in addition, root sprouting plant distribution is consistent with related parent trees. However, as with Cyclobalanopsis glauca,Lithocarpus glaber in canopy layer, Eurya rubiginosa in shrub layer,their parent tree Distribution in5ha plot is dispersive, but their root sprouts plants show the obvious aggregation distribution.Distribution maps of nine dominance species in2007and2012show that each specie has the phenomenon of plant death.The death phenomenon is the most serious as for Cyclobalanopsis glauca and Lithocarpus glaber, the distribution of new root sprouting plants is almost consistent with the habitat of related parent tree, and the most typical species are Castanopsis eyrei and Chimonanthus salicifolius.