404. SECTIONAL TRANSACTIONS.—M. 
treatment is necessary. Old drains may require cleaning, but the soil is 
usually in good condition. 
In land which has not already carried a forest crop, wide variations of 
soil type are to be found, and it is in this case that a study of soil conditions 
from the genetic standpoint may prove very useful. 
On steep slopes drainage is usually sufficiently good to preclude the cutting 
of drains, but in regions of high rainfall peat formation sets in very quickly, 
with the result that some draining is often necessary. 
On the flatter ground draining is usually an essential operation, and in 
some cases the only one necessary. In other cases even draining is not 
sufficient, and the application of some manure is necessary to prevent the 
young plants from going into check. 
When a hard pan is present it is desirable but not always possible to break 
it. This may be done by deep ploughing. When the pan cannot be 
reached by the plough, ordinary ploughing may give rise to sufficient 
aeration so that the pan becomes soft enough to allow the tree roots to pass. 
Dr. G. K. Fraser.—Peats and peaty soils (10.50). 
True peat soils in Britain belong to two main groups: (i) Topographical 
or Basin Peats, which develop in areas of high ground water or of free 
stagnant water ; (ii) Climatic Peats, which are alpine in Britain as a whole 
but form the normal soils under the high rainfall of the north and west of 
Scotland, the organic soil forming above not only high ground water profiles 
such as gley, but also on drier profiles such as sand podzols. 
In Scotland, the climax vegetation of these. types is characterised by a 
mixture of Scirpus cespitosus and Calluna vulgaris, with a moss layer in which 
the Sphagna Acutifolia group predominates. This climax is reached in 
the east of Scotland as a rule only on ancient peats of early post-glacial 
origin, but under the high rainfall of the west it develops on moderately 
shallow peat of recent origin. 
Although very poor in available nutrients, the chief disability of these 
peats is insufficient aeration. The peat of the west of Scotland is less 
tractable than that of the east, since it is more highly dispersed and more 
plastic, and therefore less easily drained and less easily penetrated by 
manures. It therefore requires either very intense or very prolonged 
measures of amelioration for its improvement. 
Mr. E. WYLLIE FENTON.—Some aspects of the influence of grazing on 
vegetation (11.10). 
There are few acres of vegetation in Britain which are not affected by the 
grazing factor. When grassland or arable land is left derelict—and no 
grazing occurs—it sooner or later reverts to wood, scrub, or heath. The 
nature and extent of grazing definitely affects the vegetation. Of all animals 
probably goats are the most destructive as far as scrub or woodland is 
concerned. Among wild animals, deer and rabbits are the most destructive, 
but damage by mice, squirrels, birds, caterpillars and grubs must not be 
forgotten. 
The indirect influence of grazing is very important, such as burning moors 
and rough grazings, since under such conditions regeneration of trees is 
practically impossible. The replacing of cattle by sheep on many of the 
hill grazings of Scotland has much to do with the spread and increase of 
bracken. The indiscriminate destruction of the original vegetation has 
