PRIMITIVE WOODLAND AND PLANTATION TYPES IN SCOTLAND. 171 



original forest still remain. The oldest part of the plantation is 

 about 60 years, the remainder being about 40 years of age, and the 

 density of stocking is almost normal. Here, then, in spite of the 

 disturbing influence of exposure after the felling of the original 

 oak forest, and during the first youth of the larch plantation, this 

 ground flora has persisted as such. Nor during a period of 

 changed conditions, lasting for about 60 years, has it altered to 

 any appreciable extent. 



" UrWALD " TYPES COMPARED WITH PURE AND MiXED 



Plantations. 



A very general comparison only between the above types may 

 be attempted. In every case the primitive woodland types are 

 compared with a pure plantation of the same species and in the 

 same locality. In the case of mixed plantations it was thought 

 sufficient to compare the " Urwald " as a whole — irrespective of 

 the species composing it — with the average of mixed plantations, 

 not necessarily in the same locality. 



Birch plantation in contrast to birch " Urwald " shows a 

 greater development in height-growth, as well as being more 

 densely and regularly stocked. The diameter development is 

 usually greater in the primitive birch type. On comparing in- 

 dividual trees, the plantation tree appears to be more " drawn," 

 and has the bole " clean " to a greater height than the other type. 

 The crown of the plantation type, especially in youth, assumes a 

 more or less conical shape, and, in having a small lateral and 

 large vertical extension, it shows an opposite development to 

 the " Urwald " type of crown. The bark of old birch trees in 

 "Urwald" often assumes a rough, corrugated appearance, while 

 in plantations it is invariably smooth. 



In young birch plantations the ground flora is very scanty, as 

 is the case in all young fully-stocked plantations, and appears to 

 have no distinctive feature about it. Later on in the life of the 

 plantation, however, a ground flora establishes itself. It has 

 been observed that this consists mainly of invading plants from 

 the surrounding land, whether this be pasture or woodland. 

 Thus, plants collected from such a ground flora showed adaptations 

 either in root or stem for rapid encroachment. 



A comparison between plantation and primitive forest, in the 

 case of Scots pine, shows that there is not such a marked difference 



