3 
fair indicator of the life history of the tree, periods of suppression and 
thrift being indicated, respectively, by zones of correspondingly nar- 
row or broad rings. 
In such timber the 
countings along dif- aesae abe SA 
ferent radii always a goddoy\2 216 | Nal {foe t wah va 2) AP 
give the same stitteseasses= Sestaiesss 
eo eee ane SN Porpasi ho Se bio (219 lle 0!) 9 001% |%00 | ld an 
b) tS por a Es 
hand, the rings of = = nee Bee = 
wery O16, essay oO 048 00% ol Slow! 121, Ooo es i 5080/9 
slow-grown, stems : 
are counted, it hap- 
Seth i= S 
oy 
T 
Hettet 
yt 
pens not infre- Fig. 8—Wood of hickory (ring porous). 
quently that count- 
ing along one radius gives one to five rings more than the counting 
along some other radius. The reason for this is not always appar- 
Fic. 4.—‘* Diffuse-porous”’ woods: ar, annual ring; pr, pith rays which are ‘** broad” at a, “‘ fine” 
at b, ‘‘ indistinct” at ¢ and d. 
ent; in some cases, such a difference in results is due merely to the 
inability of the eye to detect an extremely narrow but otherwise 
4 well-defined 
ring, and the 
error may be 
corrected by 
microscopical 
examination. 
In other cases, 
however, the 
difference is 
based on the 
j actual absence 
Fic. 5.—Cross section of basswood (magnified): v, vessel; nur, pith rays. of one or more 
rings along a given radius, extremely unfavorable circumstances 
having led toa failure of the regular, continuous development of these 
is} 
q ay 
la} mo euaggcs q) 
Sain Welee ss 
\ peut) 
O35) so 
1S OR 
Assees ty Sos = ane 
soo oo 
oa 
oo 
so°D0e 
