SPECIFIC WEIGHT. 57 



III c to II c, I, II w, and III w. What is, however, the 

 resulting sp. weight of the wood ? In II c, e.g., the 

 Spessart, the air-dry sp. weight is 50, while as we approach 

 the warmer climate in I the annual zones become broader 

 and the sp. weight of the wood increases, until in I an 

 average sp. weight of 74 for air-dry oakwood is attained. 

 This follows the old law, the wider the annual zones, the 

 heavier the wood. If we weigh oakwood grown in II w or in 

 III w, although actual figures are wanting, we know that the 

 very broad-zoned wood is soft and spongy and therefore lighter 

 in weight than wood from I.* 



The larch for more than a century has been planted outside 

 its native habitat, the Alps and Carpathians (its zones 



I and II w) ; in warmer localities, III w, and as far as Denmark 

 and Scotland [In Scotland the climate probably approaches 



II w. Tr.]. Its rapid growth in most of these countries and 

 the great width of its annual zones, when compared with 

 mountain larch wood, are well known, as well as the fact that 

 its sp. weight down to 45 is much lower than in its native 

 habitat I, where the sp. weight may be as high as 80. If we 

 proceed upwards from the plains, the old law for conifers holds 

 good that as the annual zones become narrower the sp. 

 weight increases, and as they become broader the weight 

 is reduced. But on considering the uppermost and coolest 

 station of larch, II c, it appears that the very narrow- 

 zoned larchwood again becomes lighter than that from I, 

 while its sp. weight falls to 55. t There is little practical 

 experience of larchwood from the highest regions, or it would 

 be found opposed to the old law that conifers become heavier 

 the narrower their annual zones. 



The spruce also conforms to the new law, for its wood in 

 the long wide regions I and II w possesses an average sp. 

 weight of 45, whilst the broad-zoned sprucewood grown in 



* [In England, the hardest and heaviest oakwood is produced in Kent, Sussex, 

 and Hampshire, as well as in Herefordshire and its adjoining counties. These 

 are the hottest counties in the British Isles, and presumably correspond to I 

 for oak. The best larchwood is produced in Scotland. A study of the 

 comparative sp. weight and of the width of the annual zones of oakwood 

 and larchwood in different parts of the British Isles would be very useful. 

 Tr.] 



f J. Wessely, "Die bsterreichischen Alpenlander u. ihre Forsten." 1853. 



