Io CRAIB—REGIONAL SPREAD OF MOISTURE IN Woop OF TREES. 
is that the bole and crown parts of the trunk are in continuity 
so far as these processes are concerned. The reason for ex- 
amining two transverse cuts from just below and just above 
the lowermost branches of the crown was that I had thought 
the branching might have some influence on the moisture dis- 
position. In this I was evidently mistaken, so far at least as 
the winter condition is concerned, for the graphs show no sudden 
change at the junction of crown and bole 
A glance at what I have spoken of as the intermediate region 
in the storage condition shows that in the graph it is represented 
almost by a straight line rising gently towards the centre. 
For the purposes of plotting results the units for the annual 
ring and for the moisture percentage were finally fixed by trial, 
so that this region should be represented by almost a straight 
line. The reason for this was that in the storage condition it 
was observed that this intermediate region showed a steady 
increase in moisture percentage towards the centre wherever 
the annual zones of wood were at all uniform. Higher per- 
centages resulted from close-grown timber and lower from faster ~ 
grown. Hence for evenly grown timber I believe the graph of 
that part would be represented by a straight line. That 
narrow annual rings contain higher percentages of moisture 
finds its counterpart in the various methods for preserving 
timber by impregnation, where, I believe, it has been found that 
more of the preservative is absorbed by narrow- than by wide- 
ringed wood. 
As already stated, this survey includes thé extreme limits 
of what used to be regarded as the felling season. From the 
time that, to use the common expression, “‘ the sap was down ”’ 
to the time ‘“‘ the sap was up”’ was it not generally accepted 
that the moisture content was uniform or nearly so? I have 
qualified this statement as to uniformity somewhat because 
increase in the total amount of moisture present in a deciduous 
tree in its leafless condition had already been proved.* Hartig 
states that the moisture-content of Birch increases from 
September when it is at its minimum, to March when its 
maximum is reached, and that in the case of Beech the month 
of maximum moisture-content is December. These results, 
it must be borne in mind, are applicable to Central Europe, 
and need not necessarily be absolutely true for this country. 
No statement was hazarded as to which part of the tree took 
up additional moisture or as to how this moisture once in the 
trunk was got rid of. The expression “the sap is down,” I 
think I have proved meaningless as regards Acer Pseudoplatanus 
at least. There is an ascent of sap throughout the season, as 
= * R. Hartig, Untersuch. a. d. forstbot. Inst. Miinch., 11. 
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