With the exception of this one annual ring, or portion of one, the density of the wood substance of the sapwood is nearly the same the year round.
Slight variations may occur due to impregnation with sugar and starch in the winter and its dissolution in the growing season.
The time of cutting can have no material effect on the inherent strength and other mechanical properties of wood except in the outermost annual ring of growth.
The popular belief that sap is up in the spring and summer and is down in the winter has not been substantiated by experiment.
There are seasonal differences in the composition of sap, but so far as the amount of sap in a tree is concerned there is fully as much, if not more, during the winter than in summer.
Winter-cut wood is not drier, to begin with, than summer-felled--in reality, it is likely to be wetter.[47] [Footnote 47: See Record, S.J.: Sap in relation to the properties of wood.Proc.Am.Wood Preservers' Assn., Baltimore, Md., 1913, pp.

160-166.
Kempfer, Wm.

H.: The air-seasoning of timber.

In Bul.

161, Am.
Ry.Eng.Assn., 1913, p.