The Breckland 219 



But, for reasons connected with the local climate, these and other broad- 

 leaved species, as well as conifers such as Douglas fir and European larch, 

 are often extremely difficult to estabUsh when planted in the open. The 

 two principal factors which work against them are frost and drought. 

 Frosts in the late spring and early summer are a normal feature of the 

 climate of Breckland. These are often quite sharp (up to 10 degrees of 

 frost is not uncommon in the second half of May), and they fall with 

 great severity on oak, beech, and otlier hardwoods. Douglas fir and 

 European larch also suffer in the same way though less severely. 



Drought also plays an important part in checking the growth of young 

 broad-leaved trees and of conifers such as the larches. The rainfall is low 

 and the soil unretentive of moisture, while, on the grass-covered areas, 

 the dense sward leads to an intense local competition for supplies of 

 moisture and, at the same time, acts as a covering which prevents much of 

 the rainfall from actually reaching the soil. The high temperatures of the 

 summer also tend to have an injurious effect on beech planted in the open, 

 as this species is apt to suffer from sun scorch. The pines, and especially the 

 Scots pine, are remarkably resistant to frost and drought, and for this 

 reason alone they are likely to remain the principal species used in new 

 planting in Breckland. 



At the same time the importance of establishing broad-leaved trees on 

 those soils which are really suited to them has not been overlooked and 

 much experimental work is being carried out on this subject. In particular, 

 methods of introducing beech into young plantations of pine have been 

 studied in some detail. 



The earlier plantations of Scots pine dating from 1922 and 1923 are 

 developing rapidly, although there is much variation in growth, which 

 can probably be correlated with variations in the soil. Already, there are 

 trees up to 25 ft. in height, and a preliminary thinning has yielded produce 

 in the form of fencing stakes, pit-props, small poles, and firewood. The 

 pine plantations have not suffered much damage from fungi apart from 

 the death of small groups of trees apparently killed by Fomes atinosus, and 

 by the fair)^-ring fungus, Paxilhis} Damage by insects has however been 

 more severe, and, in the Scots pine plantations, the pine shoot moth 

 Evetria buoliana has been a dangerous pest for a number of years.* The 

 attacks of this insect have led to the distortion of a large number of trees, 

 and, although the damage has turned out to be less serious than was at one 

 time feared, it has been sufficiendy important to make special treatment of 



' T. R. Peace, "Destructive fairy rings associated with Paxillus giganteus in young 

 pine plantations". Forestry, x, 74 (1936). 



- Studies on the Pine Shoot Moth, Forestry Commission Bulletin, No. 16 (1936). 



