PRIMITIVE WOODLAND AND PLANTATION TYPES IN SCOTLAND. I 59 



difference from the other type is observed. They are characterised, 

 in the first place, by the comparative poverty of their undergrowth, 

 juniper being the only shrub ; and secondly, their ground flora is 

 very similar to the vegetation of the surrounding pasture. Even 

 in the more densely stocked of these woods there is not a typical 

 woodland flora, and the dominant plants of the woodland are the 

 grasses which form the chief constituents of the pasture. W. G. 

 Smith, in " The Vegetation of Woodlands," ^ refers to this type 

 of wood as follows : — " The undergrowth is generally grassy, and 

 shows little difference from the adjoining hill-grazings ; in the 

 woods we have examined, the canopy was open and sheep grazed 

 freely through them destroying any seedling trees or shrubs, hence 

 probably arose the pasture-like character of the ground-vegetation." 



My observations seem to confirm the above view that these 

 birch-woods have been considerably modified by the grazing of 

 sheep, cattle and deer. In this connection it was observed that 

 such woods attained a better development, and ascended to higher 

 altitudes, on northern aspects ; in part explanation of which it is 

 suggested that, so far as observation goes, stock of all classes 

 tend to graze and lie on other than northern aspects. Some idea of 

 the length of time over which this modifying influence has acted 

 may be obtained from the fact that the first enclosures of land 

 for grazing were made in the period from 1470 to 1530. A second 

 period of enclosures is recorded to have extended from 1770 to 

 about the middle of the nineteenth century. 



An extreme case of destruction of woods by grazing is seen in 

 the remains of a birch-wood, found on the slope of one of the 

 side valleys of the Heriot Water in Midlothian. This wood takes 

 the form of a long, narrow strip, tailing off into the pasture at 

 either extremity. As the trees are in a state of almost complete 

 isolation, there is really no approach towards the formation of a 

 canopy at all. The individual trees assume a more or less bush- 

 like form, few of them exceeding a height of above 1 2 feet. The 

 crowns are developed out of all proportion to the stems, and 

 appear drawn out in the direction of the prevailing wind. Of a 

 typical woodland ground flora there is no evidence, and the hill 

 pasture association, unbroken and undifferentiated, extends right 

 through the wood. Indeed, this may be taken to represent the 

 final stage of this type of birch " Urwald " before it is entirely 



^ See Transactions of Royal Scottish Arboricziltural Society, vol. xxiv., 

 191 1, part I., p. 20, 



