1921] KORSTIAN—DIAMETER GROWTH 461 
graph has several practical applications. In connection with the 
measurement of permanent sample plots, the question has often 
confronted the forester as to when diameter growth occurs and 
whether it is coincident with height growth. It is very frequently 
much more desirable from the standpoint of expediency to measure 
the plots during the summer than in the fall and winter, when the 
trees are known to be in a dormant condition. An economic con- 
sideration is in connection with the peeling of logs and poles, where 
this practice is necessary. It is a well known fact that peeling is 
most easily done when the sap is flowing freely, which is also the 
time of the greatest growth activity. It can be seen, therefore, 
that a determination of the beginning and ending of the period 
of actual growth will suggest the time during which peeling can 
be accomplished most easily. An accurate record of the march of 
diameter growth, when correlated with the different site factors, 
will aid materially in the determination of those factors most influ- 
ential in conditioning tree growth, which is necessary as a basis for a 
rational silvicultural practice. 
UNITED STATES ForEST SERVICE 
GDEN, UT 
LITERATURE CITED 
. Buckxuout, W. A., The formation of the annual ring of wood in Euro- 
pean larch and ie white pine. Forestry Quarterly 5:259-267. 7. 
FrrepricH, Dr., Zuwachsautograph. Centralbl. gesammte Fereescs. 
Penta 1905 (pp. 456-461). 
GROSSENBACHER, J. G., The periodicity and distribution ’ radial growth 
in trees ee their relation to the development of ‘“‘annual” rings. Trans 
Wis. Acad. Sci. 18:1-77. 1915 (with an appended tieerephy of 119 
citations). 
Hartic, Rost., Das Holz der deutschen Nadelwaldba 1885 (pp. 35-38). 
Hartic, Tx., Anatomie und Physiologie der Holzpflanzen. 1878 (p. 368). 
6. HASTINGS, G. T., When increase in thickness begins in our trees. Science 
12:585-586. 1900. 
7. Knupson, L., Observations on the inception, season, and duration of 
cambium development in the American larch (Larix Jaricina). Bull. Torr. 
Bot. Club 40:271-203. 1913 
Rercue, K., Zur Kenntniss ‘ fs INI ORE einiger chilenischen Holz- 
gewiichse. leh Wiss. Bot. 30:81-115. 18 
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