9 THE OAK 



characters have also been described, but it is admitted 

 that the forms vary much, and it is very generally con- 

 ceded that these two geographical race-forms may be 

 united with even less marked varieties into the one 

 species Quercus Robur. 



The amount of timber produced by a sound old oak 

 is very large, although the annual increment is so re- 

 markably small. This increment goes on increasing 

 slightly during the first hundred years or so, and 

 then falls off; but considerable modifications in both 

 the habit of the tree and in the amount of timber pro- 

 duced annually, result from different conditions. Trees 

 grown in closely-planted preserves, for instance, shoot 

 up to great heights, and develop tall, straight trunks 

 with few or no branches, and considerable skill in the 

 forester's art is practised in removing the proper number 

 of trees at the proper time, to let in the light and air 

 necessary to cause the maximum production of straight 

 timber. 



Oaks growing in the open air are much shorter, 

 more branched and spreading, and form the peculiar 

 dense, twisted timber once so valuable for ship-building 

 purposes. Such exposed trees, other things being equal, 

 develop fruit and fertile seeds thirty or forty years sooner 

 than those growing in closed plantations. 



The timber itself is remarkable for combining so 

 many valuable properties. It is not that oak timber is 

 the heaviest, the toughest, the most beautiful, &c., of 

 known woods, but it is because it combines a good 



