CONIFEROUS FOREST TREES IN GREAT BRITAIN 79 



good as that of common silver fir. The seasoning of timber is 

 a question which affects all our conifers, but especially the 

 softer timbers. 



Douglas Fir (Pseudotsuga Douglasii). 



Douglas fir was introduced into this country almost a century 

 ago. There are, however, only a few plantations even 50 years 

 old. This species is widely distributed in western North 

 America, viz. from a latitude of about 55 north through all the 

 Rocky Mountains system to southern New Mexico, Arizona, 

 and northern Mexico, and from the eastern base of the Rocky 

 Mountains to the Pacific. Its distribution, however, is not 

 continuous, there being areas from which it is absent. With 

 such a wide distribution under different climatic conditions, 

 it is fairly certain that there are different races of this species. 

 Up to the present two varieties have been recognised in this 

 country. 



1. The Green Douglas or Oregon variety. This is the 

 principal variety planted in this country, and may be taken as 

 the form found under the best conditions of soil, rainfall, and 

 temperature, such as near the sea-level in southern British 

 Columbia, Oregon, etc. 



2. The Blue Douglas or Colorado Douglas. This is the form 

 found in the southern extremity of its range where the rainfall is 

 much less. 



This is no doubt a very rough division, and the growth of 

 Douglas fir under various conditions in its habitat should be 

 investigated. Should there be a hill type in the Rocky 

 Mountains it might be more generally useful in this country 

 than the typical lowland type. 



For this tree to attain a height of, say, 100 feet in 50 years 

 a deep and fertile soil is necessary. It would, however, compare 

 very favourably with other species if a height of only 70-80 feet 

 was reached. This may be possible on relatively poor soil. 

 In the opinion of the author experiments should be made to 

 determine the rate of growth and production of Douglas fir on 

 relatively poor, thin soils such as, at present, frequently carry 

 an indifferent crop of Scots pine. The different races should 

 all be tried under such conditions. There is sufficient 

 evidence to suggest the experiment, and even though it was a 

 failure there would be no great loss, while, if it was a success, 



