1 8 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY, 



chief supplies of lumber cut at the present time. The relative 

 importance of the trenches varies according to the kind and 

 amount of timber tributary to them, and according to their 

 geographical position with relation to the markets.^ 



As has been said, the structural features of British Columbia, 

 and more especially the series of high mountain ranges running 

 more or less parallel to the coast with the intervening valleys 

 and plateaux, are of primary importance from the point of view 

 of climate and forest growth. Four more or less parallel 

 climatic zones or belts are distinguished in Canadian forestry 

 literature. They are as follows : — 



1. The Interior Plateau or Dry Belt. — A tableland lying 

 between the Coast Mountains on the west and the Cariboo and 

 Monashee Mountains on the east ; characterised by a small 

 rainfall and great extremes of temperature, hot summers and 

 cold winters. 



2. The Interior Wet Belt, comprising the Cariboo and 

 Monashee Mountains and the western slopes of the Selkirk 

 Mountains ; characterised by a heavy rainfall and lesser extremes 

 of temperature than are experienced in the Dry Belt. 



3. The Rocky Mountains Belt, comprising the Rocky 

 Mountains and the eastern slopes of the Selkirk Mountains ; 

 characterised by a moderate rainfall, and great extremes of 

 temperature with warm summers and cold winters. 



4. The Coastal Belt, comprising the region west of the axis 

 of the Coast Mountains ; characterised by a heavy rainfall and 

 mild climate. 



The localities where I collected cones were situated in the 

 Dry Belt (Kamloops); the Interior Wet Belt (Craigellachie) ; 

 and the Coastal Belt (Hope and Vancouver). In each of the 

 localities mentioned the forest conditions are fairly representative 

 of the general forest conditions existing throughout the belts in 

 which they are situated, and they can be dealt with at this 

 point. No cones were collected in the Rocky Mountain Belt, 

 but the Rocky Mountain Douglas fir resembles the Douglas fir 

 of the Interior Wet Belt. 



(i) The Dry Belt. — The Interior Plateau, usually referred to 

 in Canadian forestry literature as the Dry Belt, is a tableland 

 extending from the Divide of the Coast and Cascade Mountain 



^ The notes on the physiographic relations are taken almost verbatim from 

 the Forests of British Columbia. 



