November, 1912.] 



351 



HOLLOW TREES. 



By W. J. Bean. 



There is no doubt that hollow places in the trunks and limbs of trees 

 formed by decay are better filled up. If the cavity be a large one the ap- 

 pearence of the trunk is thereby improved, and if it be small and proper- 

 ly treated decay is often arrested and new bark encouraged to grow over 

 the filled up cavity. It prevents the entrance and accumulation of mois- 

 ture, and thereby removes one of the chief predisposing conditions of decay. 



Tha majority of such decayed follows have their origin in snags left 

 by branches broken off that have rotted back into the trunk because the 

 new bark has not been able to grow over and seal up the wound. 

 Branches removed by design, or broken off by wind or accident, should 

 always be sawn off close to the trunk, and the sawn surface should then 

 be coated over with ordinary coal tar. If a snag or stump is left the bark 

 cannot grow over it ; damp, fungoid parasites and decay sooner or later 

 follow and gradually find their way towards and eventually into the trunk. 

 Such is the most frequent beginning of cavities in the limbs and trunks of 

 trees. The coating of tar renewed every two or three years, makes the 

 wound watertight and fungus-proof ; its object being to serve as a tempo- 

 rary bark until a new natural covering is formed. It is certain that the 

 life of many trees, historically famous or otherwise notable, might be 

 much prolonged if a close watch against the intrusion of decay into the 

 trunks and main branches was maintained. 



With regard to hollows that have already formed, the following treat- 

 ment is recommended: — First clean nut all the decayed materials, es- 

 pecially the soft brown crumbling wood and the soppy mass frequently 

 found at the bottom. Sound dead wood that has become dry and 

 hard does not matter. Then wash the surface of the wood that is left 

 exposed with a strong solution of carbolic acid. After allowing this a 

 day or two to dry, a good thick coating of ordinary tar should be laid 

 on. This antiseptic treatment is intended to destroy as far as possible 

 fungoid parasites. It now remains to fill up the cavity, If this be a small 

 one Portland cement may be used, and for round holes like those made by 

 wood-peckers a plug of oak cut to fit will do. But if the hollow be a large 

 one, the aid of the bricklayer may be obtained. After the bricks are laid 

 the whole should be surfaced with cement. In the case of black trunks 

 lampblack may be mixed with the outer layer of cement or it may be 

 dusted over thickly with soot whilst wet. An intelligent workman may 

 be able also to imitate the characteristic corrugations or markings of 

 the trunk. 



These, however, are mere refinements. The chief points are, the keep- 

 ing out of moisture and the provision of a surface over which the new 

 bark may grow. If a tree is in a state of vigorous growth, as many hollow 

 trees are, the bark will in time close over the " stopping." But unless some 

 surface is provided ou which the new wood can set itself* it forms thickeued 

 rolls. In very hollow trees open on one side a curious spiral growth of 

 wood is sometimes seen in place of tnese thickened rolls which is due to 

 the new wood continually being deposited on its own inner surface. A 



