28 GROWTH IN TREES. 
This tree stood about 4 miles from the base of the mountain and the 
instrument was transported this distance by pack animals and put in 
action on April 4, 1918, being visited weekly until the end of October. 
The record showed some enlargement, beginning April 14, with a 
cambium temperature of 13° C., with readings as high as 28° C. in the 
" following 10 days. When observations were taken on April 23, the 
temperature of the cambium was 10° C. and enlargement had ceased. 
A slight swelling occurred May 13-20. On May 22 a shrinkage began 
OCT. 13 (919, 3 
ao OFM. 6AM. 6PM. 6AM. 6PM. 6AM 6PM 6AM 6PM. 6AM. 6PM. 6AM. 6PM 6AM 
AUG. (6 1919 
] pelle 
| aE ee ee ee ee eet eae 
3, JULY I 1919 
to =r 
a, MUNE 13.1919 
— aa ee ear SS a ee Cee ee ee 
» MAY 28 1919 
== 
MAY 20 1919 
“APRIL 15 1919 
a Lt ™ | “| faamemmrt | 
Fig. 9.—Dendrographic records of Chihuahua pine, with variations X 5 on 10 mm. intervals. 
Some enlargement shown in week beginning April 15, 1919; shrinkage during week beginning 
May 20; enlargement in week beginning May 28; daily equalizing variations of wide amplitude 
in week beginning June 13; reduced variations and shrinkage in week beginning July 11; increased 
variations and actual increases in diameter in week beginning August 16, and reduced daily 
variations in late October. 
which in 6 days amounted to 1 mm., or half the total increase during 
the previous two months. Increase began on May 28, which amounted 
to about 2 mm. on June 14, at which time equalizing variations began 
at tree temperatures of 23° to 27° C., which continued until June 28. 
Now, in the extreme hot mid-summer, shrinkage began which con- 
tinued until July 20, or until about 3 weeks after the summer rains 
began. During this time a shrinkage of about 2 mm. had ensued, 
which was equivalent to about three-fourths of the gain up to this 
date. A period of increase, ending August 23, resulted in a gain of 
