The Preparation of Plantation RubberMorgan, Sidney
Science
The Preparation of Plantation Rubber
Morgan, Sidney
Rubber
The following figures must not be taken as typical. They represent the
average results from several tasks in a young field from which all
ill-grown and deformed trees had been removed. It is immaterial what the
units represent, as they are purely arbitrary and were selected for the
purpose of obtaining a fairly wide range.
Any trees which failed to yield sufficient latex to reach the first mark
were registered at zero. The following percentages were obtained:
Zero 3 per cent.
Above mark 1 6 "
" " 2 16 "
" " 3 42 "
" " 4 12 "
" " 5 14 "
" " 6 6 "
" " 7 0 "
" " 8 1 "
" " 9 0 "
---
100 "
It may be remarked that, judging by ordinary standards, it was impossible
to discriminate between good yielders and others, and if thinning were to
be done on the usual lines it is quite possible that some of the best
yielding trees would be removed.
Taking the mark No. 5 as the datum line, it will be noted that 79 per cent.
of the trees come below and 21 per cent. above. In the latter proportion
the majority lie close to the datum line. It will be seen that there are
outstanding yielders even amongst these young trees, and that it would be
possible to mark about 10 per cent. of the stand per acre at once for
removal in the first round of thinning.
In the case of old trees it is possible that one would encounter greater
extremes of yields than those shown in the foregoing table, especially if a
certain amount of thinning had been done previously on empirical lines.
Sufficient has been written to show that the only reasonable basis for
selection of trees in thinning is that of yields; and it is obvious that if
the method be adopted the future yield per acre of any area is bound to be
in excess of the same area as thinned on rule-of-thumb lines.
YIELDS PER TREE.--A great feature is made in estate reports of the figure
showing the average yield per tree per annum. Assuming an area to be
yielding at the average high rate of 540 lbs. per acre per annum, with an
average stand of ninety trees per acre, the yield per tree per annum
averaged over all trees is 6 lbs. Keeping in mind the test-figures on a
previous page, it will be obvious that some of these trees may have given
very much more than 6 lbs. during the year, and some less. In view of
present information it would not be surprising to find that a few might
have been yielding upwards of 15 lbs. per annum. Unfortunately this
information is only to be obtained by individual tests, and under normal
estate conditions the facts escape notice. Cases are known in which
out-standing individual trees have been known to yield at the rate of 25
lbs. and more per annum.
[Illustration: WIDELY PLANTED YOUNG AREA, JUST READY TO BE BROUGHT INTO
TAPPING.]
Public-domain text, read in full here on John Shaqi.
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