NORTH AMERICAN FOREST TREES IN BRITAIN. 1 63 



soon to judge of its merits. A few older trees, introduced as 

 living plants in 1881 and 1889, have thriven well in the poor 

 sandy soil of the pinetum at Kew ; and during the past dry 

 summer were conspicuous amongst the other species by their 

 freedom from chermes, and their extremely healthy dark-green 

 foliage. This tree would seem then to be best suited for a dry 

 and continental climate, and should succeed in Great Britain on 

 the eastern side of the country. 



Of the eastern region of North America the only conifer of 

 first-class importance from the point of view of forestry, Pimis 

 Strobus, has recently, owing to fungus attacks, become difficult, 

 if not impossible, to cultivate in Europe. The red pines, silver 

 firs, spruces, larch and hemlocks from this region all make 

 in the British Isles small trees, often ornamental, but of no value 

 for the production of timber on a commercial scale. Picea alba, 

 the white spruce, may be mentioned as occasionally being of 

 use as a wind-break at high altitudes on poor soils. With regard 

 to the broad-leaf trees of the Eastern region there is a curious 

 law, the significance of which is not quite clear. In the case of 

 genera which have a representative species both in Eastern 

 North America and in Western Europe, the adaptation has been 

 carried to such an exquisite point that the American tree is 

 absolutely unable to grow in England. I may instance Qiiercus 

 alba, which is closely allied to our Qiiercus sessiliflora. Thousands 

 of pounds were spent, according to Loudon, on its introduction, 

 both by acorns and by plants before 1838; yet only one white 

 oak tree is known to exist in England— a stunted specimen at 

 Tortworth, scarcely 20 feet high, which was planted many years 

 ago. Similarly, Fraxinus nigra, the representative of the 

 common European ash in Canada, is unable to live in Great 

 Britain. 



If, however, the American species belongs to a genus, or to a 

 section of a genus, which is unknown in Western Europe, it 

 grows well in Great Britain, especially in the south, where the 

 summer is warm, dry and sunny ; thus Qiiercus rubra, Q. 

 palustris, Fraxinus americana and F. biltmoreana, and genera 

 like Liriodendron, Liquidambar and Robinia flourish in the 

 Thames valley. It is useless, then, to attempt to introduce trees 

 like the American beech, American chestnut and American 

 lime; but we may attempt with success the cultivation of the 

 black walnut, as we have no r\dil\\ e /tiglans. 



