in 



AMERICAN MUSEUM GUIDE LEAFLETS 



noted for their narrow 

 sapwood arc locust, 

 nnillx'iTv, ( >sage orange 

 I Fig. 6 , chestnut and 

 larch. 



Also in the wood of 

 each cylinder <>r ring, 

 there may be a differ- 

 entiation in color and 

 often in structure, that 

 pari of the cylinder 

 \\ hich growj rapid h in 

 the spring proving light 

 in color and perhaps 

 porous (spring wood) 

 (Fi»s. ( .l and 10). In 

 fact, it i-- difficult to 

 count the annual rings 

 in birches, hornbeams, 

 maples, poplars and 

 willows, trees in which 

 so little summer wood 

 i- ii ad ■, thai the spring wood of one year appears to adjoin the similar 

 spring wood of the next year. 



We speak of the 

 beginnings and addi- 

 tions of wood as c\ 1 i 1 1- 

 ders, hut, in truth, they 

 are cones, as a consid- 

 eration of Figs. 7 and 

 8 will prove. A cul 

 through the central pan 

 of a log so thai the saw 

 practically cuts through 

 a radius of each cone 

 will produce a board 

 with its surface show- 

 ing wood bands or 

 lines relatively parallel 

 (Figs. II an 1 L3; radial 

 or quartered cut of 



FIG 9. CROSS SECTION OF CHESTNUT 



Showing the porous "spring wood" and more 

 compact "summer wood 



FIG. 10. CROSS SECTION OF DOUGLAS SPRUCE 



Indicating variation of spring and summer wood 



