THE AMERICAN BOTANIST. 
27 
closely set together on the twigs, and because both twigs and 
leaves are relatively delicate, the boughs which they help to form 
are fern-like in general appearance and constitute a very elYective 
filter, by which w^ater may be "combed" out from the fog. In the 
effectiveness of this filtering process, w4iich is said to be a good 
method for removing water from the fog, lies, I believe, an im- 
portant reason why the redwood loves the zone subject to fogs. 
So far as I know, there is no method in use for determining the 
amount of fog precipitation. The amount of water in a fog 
which extends vertically 1,000 feet may be equal to o.i inch rain- 
fall. But, of course, only a small portion of this is precipitated. 
This amount, however, can be greatly increased if the fog is 
passed through such a filter as is formed by a redwood forest, and 
under such conditions the amount of water taken out of the fog 
by the trees is considerable. I have been told by a gentleman who 
owned a large ranch in the redwood belt, and whose observation 
was quite trustworthy, that whenever there was a fog, especially 
if accompanied by a wind, the soil beneath the trees appeared as if 
drenched by a heavy rain ; and that, further, in cases of fires in his 
forest, if a fog came up, accompanied by wind, the fires could be 
brought under control. 
The relation of the redwood to fog precipitation is shown in 
another way, which although sufficiently bizarre in itself, is 
vouched for, and may lend a hint to a possible method of estimat- 
ing the amount of water precipitated in this manner. On the 
"hog back" of the Santa Moreno mountains lives a woodchopper 
in a place once heavily covered by a redwood forest, but where 
there is left only an occasional large tree. Like other mountain- 
eers, he must use w^ater for culinary purposes, at least, and in lieu 
of a convenient spring or well, he has devised a unique "tree- 
well." The chopper has fashioned the ground beneath a large 
redwood into the form of a trough at the lower end of which he 
has placed a barrel, and I have it on good authority that in this 
primitive manner he obtains sufficient water for his needs. — From 
an article by W. A. Cannon in Torreya. 
