NO. I GROWTH LAYERS IN TREE BRANCHES — CLOCK ET AL. I45 



Although TTP 20-24 (table 74) was cut off November 11, 1944, 

 the densewood at 3.7 cm. was weakly developed. This branch gives an 

 example of a lens appearing outward on the branch. 



Table 74.— TTP 20-24 



3.7 cm. o.g cm. TF 

 1944 I see I see i 



I dL 



Table 75.— TTP 20-25 



3.8 cm. 1.8 cm. 0.5 cm. TF 



1943 I see I 



1944 2 see 2 see i see 2 



In TTP 20-25 (table 75), in contrast with TTP 20-22 and 23, each 

 diameter flush of 1944 is represented by one tip flush. Thus at 3.8 cm., 

 the branch has three tip flushes for three diameter flushes for two 

 years. No doubt can exist as to the time the diameter and tip flushes 

 were formed. 



The densewood of 1943 is thin and weak. For 1944, at 3.8 cm., 

 the densewood of the outer growth layer is weak, whereas that of the 

 inner growth layer is very strongly developed; at 1.8 cm., the two 

 bands of densewood are equally developed ; at 0.5 cm., the densewood 

 of the outer growth layer (the only one present because the section 

 was taken from the second or outer tip flush) is thin, weak, and 

 poorly developed. 



Multiple growth layers in an annual increment and the unequal de- 

 velopment of densewood, strong on intra-annuals and weak on annu- 

 als, constitute phenomena which would have made dating wholly 

 uncertain had not tip growth been measured. 



The densewoods terminating the annual increments in TTP 20-26 

 are weak on all sections, whereas that of the intra-annual of 1944 is 

 strong. With the one sharp, complete, entire growth layer of 1943, 

 TTP 20-26 can be analyzed as three diameter flushes for two tip 

 flushes for two years. This contrasts with the analysis of TTP 20-25 

 which comes out as three diameter flushes for three tip flushes for 

 two years. 



Sections at 2.y cm. in TTP 20-27 (table 76) came from the second 

 tip flush of 1943. The diffuse growth layer of 1943 at 4.9 cm. is 

 extremely faint ; in fact, it is suggestive only of the first tip flush of 

 1943 which is set off from the second flush by a constriction of the 

 branch. It is indeed so faint that one would pass it by had he not 



