DISCOLOURATION. 147 



[E.Hermann* states that the red heartwood of beech is 

 caused by the obstruction of the cells of the medullary rays 

 and part of the fibres of ordinary heartwood by thyloses 

 and gum, which completely fill the vessels. Crystals of 

 oxalate of lime also occur. The gum is formed from starch 

 by metastasis. Eed beechwood is harder and heavier than 

 normal beechwood. It is quite impermeable by water and 

 antiseptics. When occurring in patches it is not a commence- 

 ment of decay but a defensive coating cutting off injured parts 

 from sound wood. Mycelia from rotting wood cannot infect it. 

 Certainly it may be used for railway-sleepers, being more 

 durable than beechwood injected with zinc-chloride. Although 

 creosote will not inject red beech heartwood, the latter is of 

 itself highly durable and when the softer wood around it is 

 injected it is perfectly safe from fungoidal attacks. Mathey 

 states that its price in France, owing to the prejudice against 

 it, is about 2d. a cubic foot less than ordinary beechwood. 



This red heartwood must not, however, be confounded with 

 unsound beech heartwood and it is probably owing to the 

 possibility of confusion arising between them that timber- 

 merchants object to purchase it. Tr.] 



2. True decay in beechwood is caused by a brown or 

 greyish-brown colouring-matter. According to common 

 opinion, decay in heartwood originates when decomposing 

 matter from broken boughs, snags or holes in the upper part 

 of a tree descends the stem. But irrespective of the facts : that 

 decaying heartwood surrounds the pith ; that in the central 

 zones of heartwood there is scarcely any movement of water, 

 which in trees does not follow gravitation, and that the injured 

 vessels of branches become filled with thyloses, which are so 

 many obstacles to the passage of colouring-matter that does 

 not proceed from, cell to cell ; no reliable proofs are forth- 

 coming to connect decay from broken boughs with decaying 

 heartwood. 



Mayr states that injuries by mice or voles to young 

 saplings cause decay in the heartwood. If the gnawed 

 sapling is not girdled by such an injury, the exposed wood 



* Kernbildung dei 1 Rotbuche, " Zeitschrift f. Forst u. Zagdwesen." October, 

 1902. Mayr says that railway-sleepers should not be made of red beechwood. 



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