Seed dispersal and changing seed characteristics in a Pinus halepensis forest after fire.

Seed density, seed colour and the number of seed damaged by birds were monitored for several months, after a late-spring fire, in two Aleppo pine (Pinus halepensis Miller) stands growing in South Italy. In one stand (S(1)) the trees were completely burned ('charredrsquo), in the other one (S(2)) the trees were only lsquoscorchedrsquo, with a crown in part still alive after fire. 37% and 61% of seeds were released during the first month, respectively in S(1) and S(2). Damaged seeds accounted for 43% and 23% of seeds collected in the whole period, respectively in the charred and in the scorched stand. In both stands the percentage of empty seeds increased in late-dispersed seed lots. The colour of released seeds changed with time: dark grey-brown seeds were released at first, whereas late-dispersed seeds showed a yellowish colour. The principal component analysis performed on the categorical colour variables produced a good discrimination between seed lots collected at different dates. Seed dispersal and the characteristics of released seeds have been discussed in relation to the post-fire recruitment process and, in particular, to the possibility that the predation risk by granivorous birds may be reduced by a mimicry effect of seeds to the underlying soil.