A Study On Natural Regeneration Of Pinus Yunnanensis After Fire In Different Fire Risk Rank

Pinus yunnanensis is a facultative serotiny tree species.Some cones mature and remain closed for a long time in the canopy to form a canopy seed bank,which has a certain role in protecting seeds in the event of a forest fire.The use of the closed cones of the canopy can achieve seed regeneration after the fire.Due to the complex and changeable topography and climate in its distribution area,on the one hand,the risk of forest fire is different,and on the other hand,serotiny has a large variation within the species.This paper compared the size of canopy seed bank of Pinus yunnanensis and the natural regeneration after the fire in areas with different fire risk rank,and discussed the impact of canopy seed bank of Pinus yunnanensis on the ability of natural regeneration after fire,and the main environmental factors that affected regeneration after fire.factor.The main results of this study were as follows:（1）Pinus yunnanensis in areas with different fire risk rank could be regenerated naturally after being overfired,and most of the burned ground was mainly regenerated,and the seedlings grew rapidly,and there was no squatting period.A few of burnt plnts could resprout,and they had more than one trunk each individuals.（2）The natural regeneration of seedlings of Pinus yunnanensis after fire showed a certain correlation with the cone closure rate.（3）Not all populations of Pinus yunnanensis showed the characteristics of serotiny of cones,and non-serotiny closed cones had a relatively greater contribution to population recovery after fire.The traditional definition of serotiny underestimated the ability of recover of Pinus yunnanensis from fire.（4）The scales of cones of Pinus yunnanensis had a significant protective effect on the seeds inside them when they were burned.The degree of serotiny of Pinus yunnanensis cones in areas with different fire risk rank were different,but natural seed regeneration could achieve after the fire,and the latest cones had made significant contributions to the regeneration.The natural regeneration of Pinus yunnanensis grew better than artificial regeneration in the burned area of Pinus yunnanensis forest.This study suggested If Pinus yunnanensis forests fired,they could recover naturally..