KNUDSON: CAMBIUM DEVELOPMENT IN AMERICAN LARCH 273 
while in Taxodium distichum the same conditions prevail as in 
the broad leaves. 
Buckhout* made during a period of four years caliper measure- 
ments of European larch at intervals of five days during the 
growing season. The measurements were made at breast height 
and the age of trees experimented upon is given as 45 years. He 
found that the formation of leaves was coincident with the begin- 
ning of diameter increase. The beginning of this increase was 
close to April 25, during the four years. He found a gradual 
increase from this date until about July 1, when further growth 
in diameter practically ceased. The data secured from this 
method of measurement are not, as he himself realized, entirely 
conclusive, on account of the errors which may result from the 
swelling and shrinking of wood and bark with the varying moisture 
content. 
From the horticultural side gross investigations have been 
made by Keffer,t Goff,t Cranefield,§ and others on the duration of 
growth in fruit trees. Their work is concerned with the develop- 
ment of shoots and on the duration of wood increase as determined 
by the readiness with which the bark could be peeled. The work 
of these men will be considered in a subsequent paper. 
METHODS OF INVESTIGATION 
For the investigation during 1909, four larch trees of approxi- 
mately thirteen years of age were used. These trees are hereafter 
designated for convenience as trees A, B, C, and D. The trees 
originally grew in a swamp in Oswego County, New York, but 
were transplanted in 1902 to the nursery on the Cornell University 
Campus, on land which slopes gently to the west and is of a well- 
drained, heavy clay soil type. The trees were planted four feet 
apart and were shaded on the east and west sides but not on the 
Sosy ie ee PS” Lae ee oo el ae Sar a ee lens 
* Buckhout, W. A. The formation of the annual ring of wood in European larch 
and the pine. Forestry Quarterly 5: 259-267. 1907. 
+ Keffer, C. A. The early growth and training of apple trees. Tenn. Agr. Exp. 
Sta. Bull. 14: 1-16. 
» EB 
rie 
The resumption of root growth in spring. Wisconsin Agr. Exp. 
Sta. Ann. Rep. 15: 220-228. 1898. 
§ Cranefield, F. Duration of growth period in trees. 
Ann. Rep. 17: 300-308. 1900. 
Wisconsin Agr. Exp. Sta. 
