218 FIRST BOOK OF FORESTRY 



rings, because one is formed each. year. These rings are 

 valuable age marks, since they tell us a good deal about 

 the history of the tree. 



Let us now take pieces of oak, maple, and yellow pop- 

 lar, and of pine and hemlock, and cut the ends with a 

 sharp pocket knife, moistening them first and making the 

 cut a little slanting. We observe that the rings on the 

 oak are easily counted and are distinguishable by a line 

 of little holes or pores; those of the maple and yellow 

 poplar are distinguished by a fine line, but not a line of 

 pores; and those of the pine are divided by a line of 

 darker wood, which sometimes forms a broad brown band, 

 especially in yellow or hard pine. 



Spring Wood and Summer Wood. The inner portion of 

 the ring, usually on the concave of the arc, is naturally 

 formed earlier, and the outer part later in the season ; we 

 call them, therefore, the spring wood and the summer 

 wood of the ring. In the yellow pine these two are 

 sharply defined; the spring wood is of a light yellowish 

 color, and the summer wood of a dark orange brown. In 

 maple and many other woods they are not sharply defined, 

 but it is convenient, just the same, to use the terms in 

 talking of these woods. 



Looking at Figs. 56 and 57, we notice that the patterns 

 of rift and bastard or tangent boards are principally due 

 to the difference between spring and summer wood. The 

 dark bands in yellow pine are summer wood ; the scratched, 



