I2 CRAIB—REGIONAL SPREAD OF MOISTURE IN Woop OF TREES. 
Reasons against summer felling have been advanced based 
on the quality of the timber cut then. I have seen no proof 
that summer-felled timber is poorer in quality than winter-felled. 
It is possible that seasonal variations in the composition of the 
sap, apart altogether from the question of the amount of sap, 
may result in the walls of the various tissues being differently 
impregnated during seasoning. But such speculations lead us 
into the question of what seasoning really is, and what chemical 
reactions are involved—still a practically untouched field of 
study. . 
Having dealt with the expression “ the sap is down,’ I feel 
that something must be said of its companion “ the sap is up,” 
even although in doing so I go beyond the trees dealt with in 
this paper. ‘‘ The sap is up,” or, as occasionally put, “ the sap 
is in the bark,” refers to the condition when the bark is easily 
separable from the wood, and this condition of easy separation 
is the result of the cambium swelling up preparatory to the 
year’s growth. Results obtained from more recently examined 
trees show that for this condition it is unnecessary to predicate 
root activity. A more accurate expression would probably be 
“the sap is out in the bark.” 
To the practical man several queries may now suggest 
themselves: Are these new facts as to moisture movements 
to be regarded as of general application to Acer Pseudoplatanus, 
wherever grown? and further, Can anything be said as to other 
deciduous trees ? 
To the first query I can only reply that all the trees examined 
were grown under similar conditions, and that I have, therefore, 
no actual experimental evidence on the point. The impartial 
reader will, however, grant me, I think, that the results are not 
such as lend themselves to explanation by the bringing in of 
environmental factors. It has already been shown that one 
very potent external factor—severe frost—had apparently no 
effect: whatever on the movement or movements of moisture. 
The actual moisture percentages and the stage reached at any 
particular time may be, and I have little doubt will be found 
to be, influenced by external factors, but I see no reason what- 
ever for not accepting my general conclusions regarding the 
spread of moisture in this particular species. 
Do all deciduous broad-leaved trees in temperate regions 
behave in a similar way throughout their leafless period ? 
Although I believe that with slight modifications of detail the 
process will eventually be found to be of general application, 
it is yet too early to be quite positive on the point. It may 
be well to give such evidence as I possess which leads me to 
_ State this belief. 
