78 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
VI. On the Preserving of Timber for Estate Purposes. 
By D. F. Mackenzre, Factor, Mortonhall, Midlothian. 
On account of the scarcity of matured home-grown timber, as 
well as perhaps the difficulty of selling to advantage such timber 
as we produce, any process by which its term of “life” can be 
extended will be of considerable benefit to landowners, large and 
small, as well as to all others who use the home-grown article. 
There is no doubt that if timber was felled in its proper season, 
that season being from the middle of November to the middle of 
February, a little earlier or later according to the forwardness or 
backwardness of the seasons, the duration of wooden structures 
would be increased by at least 10 per cent., being a very consider- 
able saving in the cost of maintenance. Further, by the applica- 
tion of a thorough preservative process to the timber, the longevity 
of the structure would be increased over 300 per cent. 
As is well known, wood, or timber, consists of vascular or fibrous 
tissue built up of bundles representing masses of tubes distinct in 
themselves, but fused together by the medullary system. These 
tubes, vasa, or pores contain large quantities of albumen and other 
solid, liquid, or gaseous matter, stored up ready for the use of the 
plant, and by the very intricate way in which these cells or tubes 
are connected, and the arrangement for passing the ligneous matter 
from one cell or tube to another, the tree is enabled, when the 
other necessary conditions are present, to increase its length and 
thickness. It is the contents of these cells that give trouble, by 
attracting the various forms of fungi and insects, which are always 
ready to attack the tissue of plants and trees in searching for their 
food, and thereby causing decay. Hence the necessity of applying 
some preventative. 
The amount of “sap,” in the shape of water, that has to be 
removed in preparing the wood for the preserving process, is 
very considerable, being in young firs an average of 40 per 
cent.; in matured fir timber slightly over 28 per cent.; in 
broad-leaved trees from 40 to 45 per cent.; while willows and 
poplars contain as much as 50 to 595 per cent. of moisture in 
winter. In timber cut in spring and summer, the amount of 
moisture is much greater. When the sap is expelled, the wood 
shrinks considerably, both in the direction of the medullary rays 
and also at right angles to them. Hence the desirability of 
