110 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
Calcareous.—All these soils contain a large quantity of carbon- 
ate of lime, and on the chalk formations the soil frequently 
consists of little else. Owing to this fact, many plants refuse to 
grow on soils of the latter description at all, and therefore the 
choice of plants is more limited for this class than for the other 
two. Amongst the hardwoods, beech takes the precedence in 
England, ash being better adapted for the north, although chalk 
formations are not found in the latter part of the United King- 
dom, and these remarks scarcely apply to it. Many coniferous 
trees, the pines especially, fail to thrive on chalk, but spruce, 
Austrian pine, and cedar do very well. The larch also succeeds 
fairly well up to a certain age, but the dry rot is liable to affect it. 
On wet limestone soils larch should never be planted, as their 
close pasty nature render them totally unsuitable to that tree, 
and blister inevitably results. 
Peat moors or bogs, properly speaking, are not soils, but as they 
are sometimes utilised for growing trees, they may be considered 
as such here. They consist entirely of vegetable matter, being the 
partially-decayed remains of semi-aquatic plants. Until draining 
has drawn off the superfluous moisture, and allowed the air to 
act upon and decompose the inert vegetable matter, plants, or 
rather trees, will not grow on them, but when this has been 
effected certain trees thrive fairly well. Birch, alder, willow, 
aspen, spruce, and Scots fir are the most suitable. When 
thoroughly decomposed and mixed with inorganic matter, they 
often form very fertile soils, suitable for the majority of trees 
that like a light soil. 
To briefly recapitulate what has been already written on the 
choice of plants ; the conditions of soil, climate, and altitude should 
be considered conjointly, and each should be considered as equally 
influencing the growth and ultimate success of a plantation. 
Although mixed plantations may be justifiable in some cases, yet 
a careful examination of the soil and situation, together with a 
knowledge of the climate, should enable a competent forester to 
select one, or at the most two, species as the most likely to give 
the best results, and thereby allow the species selected to receive 
the proper sylvicultural treatment it requires in order to give the 
best yield of timber. Certain trees which are more valuable in an 
early stage than those constituting the ultimate crop may, how- 
ever, be planted as nurses, to be taken out in thinning, and 
one here and there might be left for the sake of variety. Larch 
