COMMON TREES 201 



guishing them when not in flower or fruit. The plum has, 

 I think, always hairs on the leaves, at least on the veins 

 of the under side ; but the leaves of a cherry are perfectly 

 smooth and shining. The long transverse lenticels on the 

 brown shining bark are fairly characteristic of cherry. 



NATIVE AND INTRODUCED TREES. 



It is impossible to say with any certainty which of the 

 trees usually planted in England are truly native, and 

 would flourish here if man had never interested himself in 

 the matter. In remote times the woods probably con- 

 sisted exclusively of oak, beech, birch and Scotch fir, the 

 beech being perhaps restricted to the chalk hills of the south 

 of England. Ashes were probably dotted about the lime- 

 stone hills. Alders followed the courses of the streams. 

 Willows of several species flourished under a great variety 

 of conditions and at all levels. There were plenty of hazel- 

 copses on stony ground. Here and there a mountain- ash, 

 a hawthorn, or a wild cherry would spring from a crevice 

 in the rock, where a seed had once been dropped by a bird. 



Under severe conditions oak outlasts nearly all com- 

 petitors, by reason of the toughness of its wood and the 

 open character of its foliage, qualities eminently advan- 

 tageous in wind-swept countries. Birch is even better able 

 than oak to endure storms of wind and rain. Its wood, 

 though tough, is flexible, and the young boughs often hang 

 down. Oak profits by its rigidity, birch by its flexibility. 

 In the scantiness of its foliage, birch goes far beyond the 

 oak. 



Long before the oak and the birch give up the struggle, 

 evergreen trees of a special kind come in. Their leaves 

 are not broad, like the leaves of evergreen trees in Mediter- 

 ranean countries, but small and needle-shaped, giving as 

 little hold to wind and as little lodgement to snow as 

 possible. The deciduous trees as the cold increases become 

 dwarfed, and at length prostrate. On a hill-side in the 

 Dovre or in Lapland, you will often find that the only 



