PRIMITIVE WOODLAND AND PLANTATION TYPES IN SCOTLAND. 1 73 



be distinctly greater than in the other types of plantation. The 

 chief constituents of the ground flora are again pasture plants, but 

 among the others there seems to be a predominance of compara- 

 tively deep-rooted plants. Perhaps, as a result of the heavy leaf- 

 fall, the deeper accumulation of humus-forming material may 

 have the effect of introducing more of these deep-rooted species 

 than are obtained in other types of plantation. 



As compared on the one hand with "Urwald," and on the other 

 with pure plantations, mixed plantations would, in many respects, 

 appear to occupy an intermediate position. At the outset, the 

 height-growth, diameter-growth, crown development and density 

 of stock, generally speaking, may be said to be intermediate. 

 The canopy naturally differs from either " Urwald " or pure 

 plantation, in that the individual crowns forming it may be 

 deeper, more spreading, or flatter, according to the species of 

 tree. This, of course, takes away from the uniformity of canopy 

 which is characteristic of both primitive forest and pure plantation. 

 As might be expected, the form of the individual trees composing 

 such a wood varies according to the species, and thus, from an 

 aesthetic and sporting point of view, a mixed plantation is 

 preferred. Again, in this type, where shade-bearing and light- 

 demanding species are mixed promiscuously, the suppression of 

 part, or, in some cases, the entire crown of one species by 

 another is of common occurrence. It was observed that in 

 plantations of this type evidences of natural regeneration were 

 fairly numerous, and in parts the seedlings showed quite a 

 vigorous development. A feature of all the plantations examined 

 was the almost entire absence of undergrowth of any description. 



The ground flora of such a plantation is by no means the least 

 interesting part of it, and although the variety of species may not 

 be so great as in primitive forest, they are distributed in the 

 plantation in a much more striking manner. The canopy being 

 far frorh uniform, the intensity of light in different parts varies. 

 So that very often, even within the sphere of influence of a single 

 crown, there may occur a marked change in the nature of the 

 ground flora. For example, in Hurley Wood, Penicuik, Mid- 

 lothian, it was observed that spruce {Picea excelsa) allowed 

 only moss and wood-sorrel {Oxa/is acetosella) to grow under its 

 shade at any season of the year. Lime {Tilia Platyphyllos) 

 in the spring allowed a ground flora consisting mainly of 

 lesser celandine {Ranunculus ficaria), Ranunculus repens, golden 



