38 THE STRUGGLE FOR EXISTENCE. 



is repeated often enough, they must, other circumstances being si- 

 milar, be easily beaten in the strugle for existence by their more 

 favoured neighbours. The same result must follow, but of course 

 in not so marked a manner, even if the new flush of foliage has 

 completely come out. On the other hand, if a fire occurred before 

 the buds of a tree had begun to swell up preliminary to bursting 

 forth into leaf, their vitality, owing to their containing a compara- 

 tively small quantity of moisture, would be less affected than if they 

 had already begun to swell up and were full of moisture. 



Forest conflagrations, occuring while any species is in a state 

 of vegetative repose, are always followed by a sudden outburst of 

 activity which is more marked in proportion to the nearness of the 

 normal season of activity for that species. The premature activity 

 thus resulting, provided excessive injury has not been sustained, 

 may be advantageous for the species in question as compared with 

 its equally injured but less favoured rivals. 



(iv) Thickness and vitality of the bark. Some species, like sal, 

 Pi mis long/folia, Diospyros Melanoxylon, &c., form early a thick 

 bark, which may be fibrous and corky, as in sal, or principally corky, 

 as in the two other species just named. This thick bark is obvious- 

 ly a very great protection to the larger individuals and a still greater 

 one to seedlings and saplings, whose small diameter exposes them to 

 be easily killed as far as the pith itself. The advantage of possess- 

 ing a bark that reforms readily over burns, cracks, &c. is too evi- 

 dent to require proof. Pinus lonyifolia and Boswellia serrata are 

 endowed with this characteristic in a very remarkable degree, large 

 \vounds being completely closed up in a very short time. It is the 

 possession of this quality and of a thick corky bark that to a great 

 extent enables the pine in question, although a conifer, to resist the 

 effects of forest fires almost as well as broad-leaves trees. It is un- 

 questionable that the presence of a glutinous secretion, by covering 

 up wounded surfaces, increases the vitality of the bark. 



(v) The number and vitality of dormant buds. Dormant buds 

 enable plants to bring out a new flush of leaves, or to renew any 

 damaged portion of their crowns, or even to shoot up again when 

 they have been burned down to the ground. The larger their num- 

 ber is and the greater their vitality, the larger will be the number 

 that will survive and be able to repair the injuries suffered in a con- 

 flagration. All the broad-leaved species possess dormant buds right 

 down to the collum of the root in the soil, and these buds continue 

 alive for a very long period: longer in the case of some species than 

 in that of others, but ahvavs for a great manv years. On the other 



^~ } . *j 



