172 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



between the two as in the case of the other species compared. 

 For example, 66 feet may be taken as the average height of 

 Locheil Forest, which height was observed to compare favourably 

 with Scots pine plantations in the same locality. On the same 

 quality of locality, namely " average," a comparison with Scots 

 pine 130 years old, at which age the maximum height-growth has 

 been reached, does not show a great difference in the relative 

 heights.^ Also the proportion of clean bole to the total height of 

 the tree is, in the primitive forest type, often quite as large as in the 

 plantation type. With regard to diameter and crown, " Urwald " 

 shows a much greater development than the plantation type. On 

 the other hand, the plantation has a greater density of stock, 

 and is also more regularly stocked than natural forest. In volume 

 the bole of the individual " Urwald" type of tree approaches very 

 closely to that of a perfect cylinder, and has, therefore, a " form 

 factor" which is more nearly equal to unity than that of a 

 plantation tree. 



The ground flora of such plantations, even at the age of 100 

 years, is very scanty indeed, and may be taken to consist mainly 

 of bracken {Pteris aquilina), pasture grasses, wood-sorrel {Oxalis 

 acetosella) and species of mosses. Indeed, it may be said that, 

 spruce and beech plantations excepted, Scots pine has the most 

 feebly developed ground flora of any plantation on this area. 

 Scots pine plantations and " Urwald " afford us, perhaps, the best 

 examples of natural regeneration in Scotland. In this connec- 

 tion the plantations of Curr, Skye and Ballnagowan in Speyside are 

 probably without equal, while in parts of the primitive forests of 

 Abernethy, Glenmore, Rothiemurchus and Ballochbuie a full crop 

 has been established by natural regeneration. 



Natural oak forest always shows a very poor development in 

 height-growth when compared with oak plantation. In addition, 

 as already mentioned, the clean bole of the tree in oak " Urwald " 

 rarely exceeds a height of about 20 feet, while 40 feet is a fair 

 average in plantation oak. The crown and diameter development 

 is greater in the primitive type, while the density of stock is seen 

 to be much less than the plantation type. A comparatively small 

 crown, developed at a considerable height from the ground, is 

 a feature which characterises the plantation oak. . The variety of 

 species composing the ground flora of oak plantation appears to 



^ See Manual of Forestry, by Sir William Schlich, K.C.I.E., vol iii., 

 appendix iii., pp. 364, 365. 



