SHAPE OF TREES. 



19 



Percextaoe of Wood. 



Name of Species. 



Aspen 



Birch 



Larch 



Alder 



Spruce 



Scotch pine , . 



Silver-fir 



Elm 



Hornbeam 



Weymoutli pine 



Sycamore 



Beech 



Ash 



Oak 



f)— 10 



5—10 



6— 8 



8—10 



8—10 



8—15 



8—10 



10—15 



10-20 



5—23 



10—20 



10—20 



15—25 



15—25 



5—10 

 5—12 

 12—15 

 12—15 

 15—25 

 15—20 

 15—30 

 15—20 

 l.'i— 20 

 9-20 

 20—25 

 20—25 

 20—25 

 20—25 



The proportion of the different kinds of wood in the case of 

 standards over coppice differs very much from the above, as the 

 branchwood predominates until the standards are old. Thus 

 Laupreclit gives the following percentage figures for branchwood 

 of standards of different ages : — 



Species. 



50—60 years. 



Beech . 

 Oak.... 

 Aspen . 

 Birch . 



59—60 



40 

 35—40 



Over 100 years. 



51 

 42 



40 

 35—44 



28—40 

 18—25 

 25—29 

 34—40 



2, The importance of the shape of the stem from an economic 

 point of view is very great, and will now be considered. A good 

 stem should be straight, free from branches, and as cylindrical 

 as possible. 



(a) Dimensions. — Longitudinal growth usually begins to 

 increase in early youth, and culminates in the pole-stage a certain 

 time before the tree bears seed freely. In the horse-chestnut 

 and many tropical and sub-tropical trees, the terminal shoot 

 blossoms ; the longitudinal growth is thus eventually arrested, 

 and begins to fall off in all trees after the blossoming period 

 has commenced. 



The diameter-growth at first adds less to the mass of the 



c 2 



