THE STEM. 13 



growth follow pretty nearly the general laws relative to the distribution 

 of rain : thus (1). In mountainous regions of the temperate zones 

 more rain falls than in the level districts, because mountains arrest the 

 clouds, and a condensation of vapour ensues from collision with their 

 cold summits, and there are found the densest forests and most luxuriant 

 growth. (2). The precipitation of rain decreases in proceeding from the 

 Tropic of Cancer to the Arctic Circle; in like manner it may be roughly 

 stated that, except in maritime districts, the size attained by coniferous 

 trees and their rate of growth diminish in a like ratio. (3.) The rainfall 

 also decreases in passing from maritime to inland countries ; it is also 

 found that the growth of coniferous plants is influenced by the same 

 law. The same general facts are observable in England : thus in 

 Cornwall and Devonshire the average annual rainfall exceeds 40 inches, 

 while in the Eastern Counties it is often below 20 inches. The 

 numerous reports published in the horticultural journals show that 

 the rate of growth of Coniferse in the south-west and west of England 

 is much greater than in the eastern counties. And so in Scotland. 

 On the west coast and in parts of Perthshire the annual rainfall 

 reaches 50 inches, in particular spots very much more, while on the east 

 side of the country it is not more than 30 inches. The finest Coniferae 

 in Scotland are found where the temperature and rainfall are highest. 



In further illustration of these laws, the following are well-attested 

 instances. The mountain ranges in the Xorth American continent in 

 the neighbourhood of the Pacific Ocean, extending through California, 

 ( )regoii, and British Columbia, were, and are still in places covered 

 with the densest coating of coniferous vegetation known, and there 

 the summer temperature is high and the annual rainfall 

 copious. In the eastern parts of the Continent, where it is much 

 drier and colder, the Weymouth Pine (Pinus Strobus) attains a height 

 of 100 feet; in nearly the same latitude, near the Pacific Coast, its 

 near ally, the Sugar Pine (Pinus Lambertiana), towers to nearly 

 three times that height. The Balsam Firs of Canada and Carolina 

 (Abies balsamea and A. Fraseri) are low short-lived trees, not often 

 more than 50 feet high ; their congeners, the Western Balsam Firs of 

 California and Oregon (A. yrandis and A. concolor) are giants 200 feet 

 high, and live for centuries. In the humid climate of the 

 Himalaya, the Deodar Cedar, Hemlock Fir (Tsuya Brunoniana) and 

 some of the Junipers attain dimensions far exceeding those of their 

 nearest allies in other parts of the eastern continent. In Europe all 

 the principal mountain ranges abound in coniferous forests, affording 

 valuable timber; while in the plains, where the rainfall is much less, 

 many kinds are dwarfed, and others cannot be made to thrive even 

 under cultivation. Under the tropical rains of Mexico the deciduous. 

 Cypress rivals in size its great Californian cousins, while further north, 

 in the United States, it is often a moderate-sized tree 120 feet high 

 or thereabouts. 



The stems or trunks of the larger coniferous trees increase in 

 height and diameter very rapidly after the first years of their 

 " infancy," when the plant has become established. Thus the 

 Wellingtoiiia in this country grows at the rate of from 24 to 30 inches 

 in one year, and Thuia yiyantea and Cupressus man-ocarpa have 

 been known to make an addition of nearly four feet to their height 

 in one season. Abies Nordmanniana and A. nobitts, which commence. 



