579 
printed below by permission of the authors, presents the 
results in a convenient form, but a study of the report 
itself is necessary to appreciate the value of the experi- 
ments upon which the conclusions are based. 
Records have been kept during the last twelve years of 
the behaviour of apple trees when pruned to different ex- 
tents. The trees were chiefly dwarf trees on the paradise 
stock, and the main series of experiments were made on 
three varieties, possessing very different habits of growth. 
Measurements of the height of the trees, the spread of 
the branches, and the diameter of the stems led to the 
conclusion that the less the tree was pruned the larger 
did it become, and this conclusion has now been confirmed 
by lifting more than half the trees and ascertaining 
their weight. At the end of twelve years (the trees then 
being fifteen years old), those which had not been pruned 
at all were 20 per cent. heavier than those which had been 
moderately pruned, whilst those which had been hard- 
pruned were 16 per cent. lighter. The difference in weight 
between the unpruned and moderately pruned trees was too 
great to be accounted for by the weight of wood removed 
in the pruning, so that pruning not only does not increase 
the actual size of a tree, but it results in less new wood 
being formed. 
These results were further established by pruning to 
different extents similar branches on ‘the same tree. The 
less the pruning done the greater was the number, length, 
and weight of the new shoots formed, and the greater, 
also, was the increase in girth of the original branch. 
From every point of view, therefore, “the pruning of a 
healthy, growing tree seems to be inimical to wood-form- 
ation. , 
It is as regards the crops, however, that a reduction of 
pruning shows to greatest advantage. With the dwarf 
apple trees, the crops during the first five years were more 
than twice as great from the unpruned trees as from the 
moderately pruned ones, and more than three times as 
great as from the hard-pruned ones; in the second period 
of five years the differences were still greater, and in the 
twelfth year (when, however, one variety only was in bear- 
ing) the unpruned trees yielded nearly three times as much 
as the moderately pruned ones, and the hard-pruned trees 
had practically no crop at all. Similar results were 
obtained during the past season with trees of fifty-three 
and eighty varieties on the crab and paradise stocks re- 
spectively, the crops from moderately and hard-pruned trees 
being in the proportion of three to one in both cases. 
There was no appreciable difference in the size of the fruit 
from trees pruned to different extents, so that the values of 
the crops were proportional to the weights. The trees, 
however, were not allowed to overbear, the fruits being 
thinned to two to the truss. 
Confirmatory evidence of the antagonism of pruning to 
fruiting was obtained by counting the fruit-buds formed on 
similar branches of the same tree, which had been cut back 
to different extents. 
Ail these results refer to healthy trees which are still 
young enough to be growing vigorously. With a tree 
which is older, and has attained maturity, the results are 
somewhat different, not as regards fruiting, but as regards 
branch-formation. With a tree of this age, branch-form- 
ation, under natural conditions, has ceased, but if it be 
pruned new branches are formed to supply those removed, 
but they are formed only at the expense of the fruit. Most 
of the dwarf apple trees (now fifteen years old) used in 
these experiments seem to have reached this stage; hard 
pruning in their case now results in an increase of the 
new wood formed, though the reverse was the case when 
they were younger, but the crops are still reduced by the 
pruning, and even more so than in former years. 
What applies to a tree which has passed the age of 
active growth, and has reached maturity, applies also to 
a tree which has ee, stunted, or has had its growth 
arrested by root-injury, for instance, when it has been 
transplanted. The dencteney of vigour of a freshly planted 
tree. is shown by the small size of the leaves and the 
tendency to form fruit-buds instead of wood. The correc- 
tion for fruiting is, as has been shown, hard pruning, and 
it is, therefore, most important that freshly planted trees 
NO. 1954, VOL. 75 | 
NATURE 
| APRIL II, 1907 
should be cut back hard so as to prevent precocious fruit- 
ing, which would generally result in permanent stunting. 
To delay this cutting back until the end of the first season 
would appear to be a very wrong procedure. It has been 
found that with trees which were not cut back the size 
of the leaf was, on the average, 24 per cent. less, and the 
new wood formed 45 per cent. less, than with similar 
trees which were cut back; such vigour as the tree 
possessed went to form fruit-buds, which, when the cutting 
back was eventually performed, werc removed altogether, 
or suppressed in favour of growth. A year’s growth is 
practically lost by thus deferring the cutting back, and the 
ultimate result was found to be that the trees thus treated 
continued to form wood in subsequent years, whilst those 
which had been cut back at once were fruiting; so that 
the crop borne by them during the first ten years was 
only one-third of that borne by the latter. 
Experiments on apples, pears, and plums show that the 
date of cutting back a freshly planted tree is immaterial 
so long as it is done before growth begins, that is, before 
about the middle of April. If delayed until the middle of 
July, the season’s growth is much reduced, and the tree 
will probably suffer in subsequent years. This point was 
investigated more fully in the corresponding case of the 
hard cutting back, or lopping, of older trees (plums), which 
had become slightly stunted. The operation increased the 
amount of new wood formed by the tree, and the results 
were the same so long as the lopping was done during the 
dormant season. Lopping towards the end of May resulted 
in less growth during the year, but this was more than 
compensated by an additional growth during the succeeding 
season. It is doubtful, however, whether anything is 
really gained by anticipating the autumn lopping (as is 
sometimes possible), and doing it in the preceding early 
summer, for it was found that the trees thus treated did 
not appear to be so healthy in foliage as those which were 
cut back subsequently. This was especially so where the 
cutting back was postponed until July, for trees cut back 
then made very little growth during the remainder of that 
season, and were deficient in growth in the following 
season as well. 
Apart from the cutting back of freshly planted trees, the 
present results are emphatic in showing that the less 
pruning is done the better. But this does not imply that 
no pruning at all should be done. The removal of branches 
which cross or rub each other, as well as that of any 
unripened wood, is evidently desirable, and no doubt a 
certain amount of pruning, in order to obtain a compact 
and shapely tree, should be done during the first few years 
after planting. But a tree which is growing freely, and is 
properly tended in other respects, will require very little 
pruning to keep it in shape. With precocious or weak- 
growing varieties more pruning will be necessary, and 
more is required with standards than with dwarfs, for in 
the former case it is very desirable that a compact head 
and strong stem should be obtained before any heavy crops 
are borne. 
STANDARDS AND EXACT MEASUREMENT. 
HE inaugural address delivered by Dr. R. T. Glaze- 
brook, president of the Institution of Electrical 
Engineers—the full text of which is published in the 
current number of the Journal of the society (vol. xxxviii., 
No. 181, p. 4)—is likely to be remembered as one which 
stands apart among the various addresses which have been 
delivered in past years, owing to the fact that the subject 
treated is so rarely discussed or dealt with in ordinary 
engineering papers. 
The subject in question, that of standards and exact 
measurement, is one which does not appeal to all, but 
is of special interest at the present time, when so much 
has been done of late by the Engineering Standards Com- 
mittee to bring about more efficient work and more 
uniform results in the various branches of engineering. 
Dr. Glazebrook, in opening his address, gave a_ brief 
account of the history of standardisation from the first 
report of the Electrical Standards Committee of the British 
Association in 1862 down to the present day. This first 
