46 EXPLOITATION OF PLANTS 
factors tending towards the failure of economic forestry 
in this country is the inferior quality of the timber 
produced. This is due in a very large degree to the 
fact that most of our forests are too open in character. 
This feature is probably largely a result of the fact 
that in past generations the English oakwoods were 
the source of supply for the oak used in shipbuilding. 
For this purpose the crooked branches were highly 
valued for the making of the ribs and knees. Open 
canopy favoured the production of large, strong, and 
numerous branches such as the shipwrights required. 
Many of our woods of common oak were planted 
shortly after the Parliamentary Commission report 
early in the nineteenth century, when a famine in wood 
for naval construction was anticipated. With the in- 
troduction of iron for shipbuilding about 1836, the 
demand for bent oak rapidly decreased, so that at the 
present day we have in this country a considerable 
quantity of common oak in a mature-condition which 
was grown for a specific demand that no longer exists, 
Unfortunately the very method of growth which was 
most advantageous for the purposes of the shipwright 
is least suited to modern requirements. 
The demand at the present day is for clean, straight 
poles, with straight grain and uniform annual rings. 
The defects which result from understocking may 
be summarised as follows— 
The growth is too rapid, and results in an uneven- 
ness of grain which renders the wood less durable and 
of variable strength. 
The open canopy permits each tree to produce a 
large mass of foliage, and to meet the demands of 
