220 



FIRST BOOK OF FORESTRY 



glass to see them. These pores are nearly all of one size, and 



they are evenly scattered through spring and summer wood. 



In pine and hemlock we do not find these pores, though 



in pine we do find little white specks which resemble 



G 



Beech I Sycamore ! Birch . 



FIG. 77. Diffuse Porous Woods 



s.w. 



x -J3 * C 



ar-* 



FIG. 78. Non -Porous Woods 



A, fir; B, hard pine; C, soft pine; ar., annual ring; o.e., outer edge of ring; i.e., 

 inner edge of ring ; s.w. } summer wood ; sp.w., spring wood ; r.d., resin ducts 



pores ; they are resin ducts, however, and are not like 

 the pores we see in other woods. 



The pores, especially the large ones, are easily seen on 

 the sides of boards, and they have much to do with the 



