6o PROCEEDINGS COTTESWOLD CLUB 1912 



Forestry, or sylviculture, is the growing of trees in masses 

 for profit, and is not the same as arboriculture, which is the 

 growing of trees singly, chiefly for beauty. A forester must often 

 force his trees to take on an unnatural shape in order to get tall, 

 straight timber free frf)m branches, as this is what is required 

 by timber-merchants. He must also get the largest possible 

 quantity per acre. This is done by regulating the density of 

 the woods, owing to the effect of light and shade. Water is 

 taken in by the roots, and ascends to the leaves. The leaves 

 take in carbon dioxide from the air. The chlorophyll or green 

 colouring matter in the leaves manufactures out of the water 

 and carbon dioxide, sugar, which is the food of the tree. This, 

 however, can only be done in sunlight, so if a tree is shaded 

 too much it dies ; also if a branch is kept in the dark it dies. 

 The different species vary in their light requirements, oak, ash 

 and larch requiring much light, beech and silver fir bearing 

 some shade. A plantation should be made with the plants as 

 closely crowded as possible, consistently with keeping down 

 the expense, in order to get a cover over the ground as soon 

 as possible, and to get the crop into a thicket early. Where 

 there are no rabbits, and not too much weed growth, a dense 

 crop can sometimes be got cheaply by natural regeneration ; 

 when this is impossible, planting at four feet apart is usually 

 dense enough. Closer planting is too expensive. In the thicket 

 stage, between the 12th and 20th years, a struggle for existence 

 is set up, the weaker trees die for want of light, and the better 

 trees are forced upwards, growing tall and straight owing to 

 their struggle upwards for light. Their branches die off as 

 they are shaded by surrounding trees. If the struggle goes on 

 too long, all the trees will grow too thin and lanky, and, there- 

 fore, a thinning is made to reduce, without stopping, the 

 struggle. The worst trees are cut, leaving the best, and the 

 cover must be kept complete. The struggle is then continued 

 and another thinning is necessary in about ten years' time. 

 This continues as long as the wood is growing vigorously. In 

 the second half of the fife of the wood the thinnings are made 

 more heavily, the crowns then increase, and the trees grow in 

 girth instead of in height. With oak, at about the 30th to 

 40th year, it is found impossible to keep the wood sufficiently 



