96 NEW BRUNSWICK FORESTRY CONVENTION 



more southern regions. By an extension of this analysis, we also reach an 

 explanation of why the more southern forms of spruce are less desirable 

 than the northern, and thus we gain an explanation of one of the factors 

 which contribute to the great and recognized superiority of Canadian spruce 

 over that of more southern latitudes. 



LONGITUDINAL SECTION OF SPRUCE 



If a thin slice of spruce be cut off lengthwise and placed under the micro- 

 scope, it will be seen to consist of a series of very long and narrow cells with 

 tapering ends. Whatever process may be employed in reducing this wood 

 to pulp, the object to be achieved is to separate these various cells from one 

 another as completely as possible, but without involving destruction. If we 

 now take a slice cut at right angles to the first, or 



TRANSVERSE SECTION SHOWING RESIN CANALS 



what is commonly designated as a transverse section, the various cells will 

 appear as approximately rounded openings, and the cell walls seem to form 

 a network of tissue. Here and there prominent openings may be seen. 

 These represent the special canals in which the resin is deposited. While 

 they are always 



TRANSVERSE SECTION WITHOUT RESIN CANALS 



prominent in the spruces, they are by no means uniformly distributed, and 

 many sections will show no such structures. From these examples we are 

 able to gather that the cells of the wood are in the form of very long, tubu- 

 lar fibres with tapering ends joined together by a substance which holds 

 them in the form of a tissue. The difference in density exhibited by, the 

 structure of the last two photographs, represent variations in growth at 

 different portions of the growing season. The more dense structure is 

 formed at the close of growth for the year ; it is therefore always on the out- 

 side of the growth ring and is known as the summer wood. The more open 

 structure forming the bulk cf the season's growth, is always produced dur- 

 ing the spring and early summer when growth is most active ; it is thus 

 always on the inner face of the layer and is termed the spring wood. We 



TRANSVERSE SECTION HIGHLY MAGNIFIED 

 may now select a limited area of one of the transverse sections and magnify 



