52 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



In view of the ravages worked by cancer in the larch woods, the 

 principal tree will, for the present, continue to be the Scots fir ; but 

 in most parts of the woods larch may be evenly distributed among 

 the Scots fir, to the number of about seventy trees per acre. Over 

 limited areas, Scots fir, in even-aged mixture with either beech, 

 silver fir, Weymouth (or White) pine, or with Douglas fir, may be 

 grown ; but the mixture of Scots fir with spruce in an even-aged 

 crop is not recommended. Spruce may be raised as a pure crop in 

 low and moist localities with comparatively stiff soil. The Douglas 

 fir presents a very encouraging appearance at Novar ; and in order 

 to determine its ultimate value here as a forest tree, the species 

 should be grown to a moderate extent, both as a pure crop and 

 mixed with others. It has been attacked by a fungus in some 

 parts of Scotland ; when young, it suffers from spring and autumn 

 frost; and it is liable to lose its leading shoot when grown in 

 exposed situations. It appears to stand a considerable amount of 

 shade, and will probably succeed well as an under-crop below larch 

 and Scots fir. In Black Park Corner, at the age of fourteen years, 

 it forms a valuable associate at even ages for the larch, though in 

 this mixture its own lower branches remain, for the most part, 

 green. The Weymouth (or White) pine might be grown to a 

 limited extent. The Austrian or the Corsican pine may replace 

 Scots fir in exposed situations ; and these two trees, with Cembran 

 pine and Mountain pine, will be valuable additions to permanent 

 shelter-belts at the higher elevations. Experiments may be made 

 with other species, as, for example, the redwood (Sequoia semper- 

 virens), the white cedar (Librocedrus decurrens), the hemlock 

 (Albert) and the Menzies spruces, the Grandis silver fir, Lawson's 

 and the Monterey (Macrocarpa) cypresses, and the Canadian cedar 

 (Thuja gigantea). Hardwoods, such as oak, sycamore, beech, ash 

 and others, will as a rule be confined to the lower ground. 



The advantages of mixed woods as compared with woods com- 

 posed of a single species are universally admitted ; but the number 

 of species planted together on one and the same piece of ground 

 should not ordinarily exceed two, and should never be more than' 

 three. Here, where the Scots fir is raised as a pure crop or mixed 

 with larch, the stock will, as a rule, in course of time, be under- 

 planted or under-sown with silver fir, beech, spruce or Douglas fir. 

 These shade-bearing species will profit, in youth, by the shelter of 

 the lighter-crowned Scots fir and larch, which will protect them 

 from frost, while they in return will keep the stock dense after 

 the stage at which pure crops of the last-named species naturally 



