THE QUALITY OF CONIFEROUS TIMBER, 



113 



quality of coniferons timber produced in the North of Europe 

 and in Canada, 



(2) At high elevations, and so the popular belief in the good 

 quality of the timber of cone-bearing trees grown in mountain- 

 ous regions receives confirmation. 



(3) In close woods, where the dense umbrage excludes the 

 sun's rays. Professor Hartig's researches bring out very 

 strikingly the superior quality of coniferous timber yielded by 

 dense woods, as compared with that produced by isolated or 

 semi-isolated trees. His views, as set forth in " Das Holz der 

 Nadelwaldbaume," are shortly as follows. Where the stems of 

 Conifers are well protected from the sun's rays the cambium does 

 not become active for about three weeks after growth in thick- 

 ness has begun in similar trees whose stems are not thoroughly 

 shaded. This delay carries the trees over the period of the 

 year when the conditions are unfavourable for the production of 

 cells w^ith thick walls and small lumina — that is to say, the 

 period when much of the spring-wood is formed. He maintains 

 that the inferior character of the wood produced early in the 

 season of growth is entirely due to the want of a sufficiency of 

 nourishment to thoroughly lignify the young wood-cells. If the 

 cambium cells have been stimulated into activity by heat, they 

 are forced to divide to form new wood, but the wood then 

 formed is very deficient in lignine, and is therefore lacking in 

 durability. But if the temperature is kept below the stimulating 

 point, and the cambium cells remain inactive till after the 

 unfavourable climatic conditions of late spring or early summer 

 are past, then, according to Hartig, when the formation of wood 

 does begin it can proceed under circumstances favourable to the 

 production of improved quality. By that time the days are 

 longer, the skies less clouded, and the weather more genial, and 

 consequently, assimilation being more active, the cambium and 

 young wood-cells are well provided with formative materials. 



Not only is it very desirable that the boles should be well 

 protected from the sun's rays, but also complete shading of the 

 surface of the ground is one of the first principles of modern 

 sylviculture. This prevents grass and other forest weeds from 

 covering the ground and diminishing the amount of water at the 

 disposal of the trees. A covering of herbaceous ground vegetation 

 also retards the rapid accumulation of liumus which tends so 



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