GROWTH IN TREES. 25 
greater than 2 mm. at the upper instrument, differences which might 
be seen in comparison of different diameters at any part of the trunk. 
This layer showed a thickness of 4 mm. in the boring on a different 
radius, on the lower and upper part of the trunk. 
A number of tile pipes were now sunk in the soil in an area around the 
tree, so that water might be conducted to the absorbing roots and 3,000 
gallons of water were poured into these holes on July 1, 1920, with the 
result that an enlargement was visible a day later, which was slightly 
MAY 3 1920 
SPM. BAM 6PM. GAM 6PM. 6AM 6PM, 6AM. 6PM 6AM 6PM 6AM 6PM. aM 
nN 
q 
hp 
an |_| cS pee 
eee ae Nias ee eee an Tn es ee —— > Ml 
M. 6PM 6am 6PM 6AM 6PM 6AM. 6PM 6AM 6PM. GAM 6PM. GAM 
A 
Fig. 5.—Dendrographic records of the changes in the trunk of a Monterey pine made by the two 
instruments attached to No. 1, asin fig. 4. Record A is from the lower part of the trunk and B 
from the higher point, for the week beginning May 3, 1920. The sheet is marked into 6-hour 
periods and the spaces represent 10 mm., the actual changes in the trunk being X 8. Enlarge- 
ment and partially equalizing daily variations are displayed. 
JUNE 28 1920 
6PM. BAM. 
6PM. 6AM. 6PM. 6AM 6PM 6AM. 6PM 6AM 6PM 6am. 8PM 6AM 
dlp. ala 
AW ay — 
Ke Lf en mnt eens Gaia ee ae eet Em ee en OO 
JUNE 28 1920 B 
6PM BAM. 6PM. 6AM. 6PM. BAM 6PM. 6AM. 6PM 6AM 6PM 6AM. 6PM. 6AM 
A 
ee eee 
— | oer | | reper | | +——+. ——7 
Li 3000! gals wate! 7 
Fray pve. ko Set. mprnuys 
A 
Fig. 6.—Equalizing daily variations of trunk of Monterey pine No. 1 for week beginning June 
28,1920. Application of water to soil around roots after 6 p. m. on July 2 was followed by upward 
course of record lines from both instruments. Variations X 8 on 10 mm. scale. 
greater at the lower instrument (fig. 6). Additional water was given 
on each of the 2 days following, and enlargement continued at the upper 
instrument until about August 16. During this period of 16 days an 
enlargement of 2 mm. in diameter had taken place at the upper 
instrument, 9 meters above the ground, and of 4 mm. at the lower 
instrument, 1 meter above the ground (fig. 7). Enlargement at the 
base continued until September 15, at which time a further thick- 
ening of 2 mm. had taken place, making a total thickening of 9 mm. 
at the base. Both measurements were in agreement with borings 
taken in January and February 1921. Then followed a month of 
