CHAP, in.] Characteristics of Trees 49 



vegetation (and, even for Beech, a summer rainfall of twelve 

 inches would suffice according to Ramann J ), yet when rain does 

 not fall on the average once every 6 to 8 days throughout the 

 summer months, the woodland crops are, in the dry climate 

 of central Europe, exposed to more or less danger of being 

 killed off by being unable to obtain from the soil the constant 

 supplies of moisture requisite for the maintenance of healthy 

 and vigorous growth by means of normal transpiration ; or in 

 other words, they are liable to suffer from drought and to die off. 



So far as the climate of Great Britain is concerned, it is, 

 both as regards temperature and atmospheric precipitations, 

 suited to all the species of woodland trees that occur in 

 central Europe ; but the Mountain Ash, the Wych Elm, the 

 Scots Pine and the Birch are more characteristic of, and 

 grow better in, Scotland than in England, where again the 

 Beech, the pedunculate Oak, the English Elm, and the Silver 

 Fir thrive better than in the northern half of the main island. 

 Pine, Spruce, Larch, Silver Fir, sessile Oak, and Sycamore, are 

 naturally the inhabitants of upland tracts and mountain ranges, 

 whilst Ash, Alder, pedunculate Oak, Aspen, Elm, and Willow- 

 belong rather to low-lying localities ; Beech, Hornbeam, 

 Maple, and Birch seem capable of thriving equally well on 

 plains or on hilly country. But, on the whole, the nature of 

 the climate, soil, and situation mainly determines the quality 

 of any~given^5pecTes of tree m any particular locality. 



Very little is as yet known regarding the absolute amount 

 of atmospheric warmth necessary for the most favourable 

 development of the different kinds of woodland trees. But 

 experience has shown that Elm and pedunculate Oak require 

 most warmth ; that Black Pines, Silver Fir, Beech, Weymouth 

 Pine, sessile Oak and Scots Pine can thrive with less than 

 Birch, Maple, Sycamore, Ash, Alder, and Spruce ; whilst Larch 

 does with least. 



So far as their development is apt to be prejudicially 

 1 Forstliche Bodenkunde und Standortslehre, 1893, p. 311. 

 E 



