Canadian Forestry Journal, Aui/ust, li)lS 1813 



Grow Trees For Aeroplane Building 



By Elliuood Wilson, Chief Forester of The Laurentide Co., 



Grand Mere, P. Q., and Member of Staff of 



Imperial Munitions Board. 



The necessity for getting all the spruce possible for the construction of 

 aeroplanes for all of the Allies has compelled an investigation of all the possible 

 sources of supply. 



Before the war most of the factories in the United States demanded spruce 

 from West Virginia or the east, New England, and were not at all desirous of 

 using Western spruce. Germany was buying up all the supplies of eastern 

 spruce possible and it is on record that when a car of western spruce was in- 

 cluded in a shipment, the German inspector refused it, on the ground that it 

 was western spruce. When the war broke out, it was realized that large 

 amounts of long, clear spruce could be most readily obtained from the huge 

 trees of the west coast and every effort was and is stdl being made to exploit 

 this source of supply. 



Eastern spruce, best in quality. 

 The Forest Service of the United States, immediately, on the entry of 

 that country into the war, made a careful study, with most practical and 

 elaborate tests, of all the possible woods which might enter into aeroplane 

 construction. These tests showed conclusively that there is no superiority of 

 one kind of spruce over another, that the value of wood is dependent altogether 

 on its density and straightness of grain. Eastern and western spruce with the 

 same number of rings per inch and the same air-dry weight are of equal value. 

 Speaking broadly, eastern, spruce is a little better than western because it is 

 slower of growth and therefore has more rings per inch. Since the western 

 trees are very much larger it is possible to get longer and larger pieces of clear 

 material out of them and these work up easier in the factory and consequently 

 are preferred. At first this entailed a large waste as the factories took these 

 long clear pieces and cut them up for the short parts. This source of waste 

 has been reduced but not yet as much as it should be. 



Only one in a thousand pulp logs is useful. 

 The great difficulty with eastern spruce is that it is very difficult to get 

 long lengths and large pieces which are clear. As it grows naturally in the 

 forest, the shade may not have been sufficiently dense during the early years 

 of the tree to kill the lower branches, causing them to be shed. Consequently 

 as the tree continues to grow the branches are gradually incased w'th new 

 wood and cause knots. As the tree increases in size, these old short branches 

 become entirely inclosed and a layer of perfectly clear wood is laid on. In 

 Quebec spruce, for instance, this clear layer, rarely exceeds two inches in 

 thickness for any length worth while. A careful estimate shows that about 

 one log in one thousand of the run as cut for the pulp mills will contain sufl'i- 

 cient aeroplane material to make it worth cutting up, that is, under present 

 factory specifications. Of the spruce sawed up by mills manufacturing lumber 

 from 13/2 to 2% of the total cut may make aeroplane stock. 



Factories demand easiest worked woods. 

 The great difficulty at present is this: — The Allies need every cub'c ''nch 

 of spruce stock which they can obtain. The Aeronautical Board in the United 

 States is short of spruce as is also the French Government. The British 



