A New Study of Some Problems Relating to the Giant Trees [pp. 305-316]

Sonme Problemns Relating to the Giant Trees.
characteristic arms above their heads. The
nut pine of the bare New Mexican hills
looks like a low apple tree; while the pines
of our alpine summits seem to be not trees
at all, but bushes rather.
One interesting problem in this connection would be, to ascertain the comparative
rate of growth of a given tree at different periods during its life-time. A rough approximation may be made by dividing the whole
cross-section into annular zones of an equal
number of rings say one hundred eachand computing the area of each zone separately. This work was done for the Pavilion tree, and the results appear in the table
below. The figures in the column of areas
represent the comparative growth of each
century accurately enough from the economic, i. e., the lumberman's, standpoint. The
biologist, however, who would seek to measure the life-force itself by measuring its total
effect on a given line, must not neglect the
factor of height-at least, up to the point
where it became constant. This also has
been roughly attempted 1 in the last column
of the table, whose figures give the approximate volumes of growth in each century,
the maximum growth being taken as unity.
Thus revised, the steep ascent from the first
to the fourth century becomes steeper still.
The magnificent record of the fourth and
fifth centuries, to my mind, indicates the
distancing of all rivals, and the era of expansion in the sunlight and free upper air. The
fluctuations that follow we may figure to
ourselves as the records of disaster and recuperation; of loss of great branches by
storm, or scorching of its roots by fire; and
of the healing of these wounds in great measure, and of vigor restored, till in the twelfth
century a second maximum was reached
scarcely inferior to the first.
1 By assuming that 3oo years brought the tree to its
full stature, and that during this period the height varied as the diameter of the tree. Exception, of course,
may be taken against either assumption; but neither
one can be very far from the truth. For the data in the
second column, I am indebted to the kindness of Mr.
James L. Sperry, proprietor of the Hotel and Groves
who recently measured for me the spaces between the
ioo-year marks of my own previous count.
TABLE SHOWING THE GROWTH
OF THE PAVILION TREE.
Centuries.
I
2
3
4
5
6
7
8
9
I0
II
12
Width of Zone. Area of Zone.
INCHES. SQUARE INCHES.
I4.- 5 66i
I0.4 1287
8.7 I 599
8.9 2128
7.6 1 22I11
5.3 1756
5.2 I 869
5.0 2008
4.3 I1831
4.0 1807
4.2 2006
4.2 2118
Ratio of
Volumes.
77
308
557
963
I000O
794
841
908
828
817
907
958
In regard to the old age and death of
these trees, the following points seem fairly
established:
A very large proportion of them survive to
old age. Prostrate Sequoia trunks are nearly all great trunks. There must therefore be
wonderful immunity from disease and from
fatal accident.
There is much evidence to prove that in
general they perish by actual overthrow while
still alive. They lose their grip upon earth,
rather than upon life. So, at least, in the
Calaveras groves, have gone all that have perished from natural causes within the limit of
human records. Scarcely any dead Sequoias
are found standing.
This overthrow is in no proper sense an
accident. Most of the older trees are visibly
and literally leaning to their doom. The final
storm determines only the moment of the
catastrophe, not at all the manner of it-probably not even its direction. This leaning of
the Sequoias is so closely connected with the
question of the manner of their death, that it
demands something more than a passing notice. Young Sequoias are erect, as are all
their tribe. With the change of habit already alluded to comes an overreach of the
southern branches toward the sun. These
branches grow to an enormous size, and carry
a vast weight of foliage. The later leaning of
the tree is in the line of this unbalanced
weight, and must be caused by it. A study of
the fallen trees bears very significantly upon
this point. In the north grove thirty-six fallen
trees were found, whose point of origin and
314
[March,