Effects of prescribed fires on the survival and release of seeds of Kielmeyera coriacea (Spr.) Mart. (Clusiaceae) in savannas of Central Brazil

Abstract

Effects of prescribed fires on survival and release of seeds of the woody species Kielmeyera coriacea (Clusiaceae) were investigated in two plots of cerrado sensu stricto, a savanna vegetation of Central Brazil. The first plot was burnt in June, at the beginning of the dry season, and the second in August, in the middle of the dry season. Seed survival was measured after fire in both areas and related to internal and external fruit temperatures measured during the June fire. The proportion of open fruits per individual of K. coriacea was also assessed at two-week intervals. Maximum external temperatures during fire (393 to 734ºC) were strongly reduced inside the fruits (61 to 63ºC). Before the June fire, the majority of the fruits were closed in both plots. Most fruits in the June plot opened within two weeks following the burning while, in the same period, most fruits remained closed in the August plot. Fifteen days after the prescribed fire in the August plot most fruits opened, as observed in the June plot. No germination was observed in seeds from closed fruits collected before the fire, while those from fruits that were closed during the burning showed a high mean germination rate (June = 79 ± 12%; August = 69 ± 14%). The results indicate that fruits of K. coriacea are good insulators for seeds during fires and that seed release is anticipated independently of the burning season.