78 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Silver Firs (Abies). 



In the past the various species of silver fir have not been 

 much planted in this country except as ornamental trees. This 

 has been due, in part, to a destructive aphid pest, Dreyfusia 

 JVusslini, a species of the family Chermesidae. Common silver 

 fir {Abies pectinata), Abies grandis, and Abies nobiiis will be briefly 

 considered. 



Abies pectinata. 



This species is a native of Central Europe. There are large 

 forests of it in the Vosges Mountains and in the Black Forest. 

 It appears to require a deep, moist, fertile soil, and is sensitive 

 to late frosts and drying winds. It shows good growth on 

 the west coast of this country. 



After the canopy closes this species is a fairly rapid height- 

 grower and produces a very heavy volume of timber. The 

 timber is almost as good as that of spruce. This species should 

 be given a careful trial, and experiments should be made to 

 determine how the Chermes pest can be met. Some other 

 species of silver fir appear to be relatively immune from attacks. 

 The following are the most promising. 



Abies grandis. 



The habitat of this species is the west coast of North America 

 from North California to north of Vancouver. There is evidence 

 to indicate that this species is fairly safe from Dreyfusia Nusslini, 

 but this should be confirmed by careful experiments. It has 

 not been planted extensively enough in this country to test its 

 growth and the value of its timber, but it does not appear to be 

 much inferior to common silver fir in these respects. 



This species may also be useful for underplanting. 



Abies nobiiis. 



This is also a west North American species, and appears to 

 be practically free from Dreyfusia Nilsslini also. A much less 

 destructive species, D. piceae, occurs in it. 



Abies nobiiis has shown remarkable growth in several parts 

 of the west coast, and also on dry sandy soils on the eastern 

 side of the country. When it begins to bear cones the weight 

 of these often damage its crown. The timber, when green, is 

 practically useless, but when carefully seasoned it is almost as 



