^ MONTHLY. 
Vol. XVIII.] COLOMBO, JULY 1st, 1898. [No. 1. 
RESEARCHES IN PRUNING 
FRUIT TREES.* 
^-^ri^' practitioner who has to do with 
nkh^ gn. the pruning of fruit trees, if he has 
ES'^^ studied the subject, knows how various 
pjy^ views of the different cultiva- 
y tors who have written concerning it, 
Ig^^^^J many of them being diametrically op- 
po3ed[to^each|ofcher, so that the less-experienced reader 
is apt to be greatly puzzled as to the course he should take. 
These differing opinions have their rise in the fact that 
the practices of the older cultivators are constantly being 
repeated without further proof. In recent years 
Herr Koopmann has published his researches and 
observations, extending over many years in a very 
excellent work, entitled Gnuid lehren des Ohsthaums- 
ehnittes ; or, Pnnciples of Pruning Fruit-trees. 
This work can be most warmly recommended to 
the notice of all pomologista, but as it is one that 
requires careful study, we can only notice here a 
few striking observations on subjects of every-day 
practice in gardens. 
It is a rule of general acceptance that the hard 
cutting-back of a young tree results in the strengthen- 
ing of the shoots, although some pomologists believe 
that hard-cutting weakens the tree, and consequently 
has the opposite effect. 
Koopmann, in order to put these contradictory 
views to the test, carried out experiments on a row 
of ecinalli--developed trees, as to the comparative 
lengthening and thickening of the shoots after pru- 
ning. He found that 1-year-oId grafts reached their 
greatest length when they were not cut-back, which 
agrees with the view of Gaucher, that by the rear- 
ing of standard trees, they should not be cut-back. 
The thickening of the stem, and the production of 
wood is, however, not so great if the lateral shoots 
be not shortened. When the yeara's growth is re- 
* The subject-matter of this article was contained 
in a lecture giren by Herr W. Lauche, at a meet- 
ing of the K. K. Gartenbau Gesellachaft of Vienna, 
Match 16, 1897. 
latively of sufficient strength, stems intended for 
standard trees should not be cut back ; but when 
this is not the case, then cutting back must be per- 
formed. These experiments showed that the stem 
development was greatest when seven-tenths were cut 
off. leaving but three-tenths. By harder cutting 
back than this, the resultant shoot was shorter. 
Tnkinc; into consideration, however, the entire nro- 
duction of wood, it was found that the removal of 
two-thirds of the length resulted in the greatest 
possible strengthening of a tree. This agrees with 
the fact that the lateral shoots should be also cut 
back two-thirds of their length. 
Experiments were made on pinching the summer 
shoots of fruit-trees, and it was found that every 
shoot that was pinched suffered a weakening of one- 
tenth as compared with the lengthening of a natural 
or unpinched shoot. The earliest is the most suit- 
able time to pinch, or when the shoots are about 
4 inches long, and only the terminal bud should be 
taken. If more than this be removed, the lower 
buds push out strongly, and the object of the pin- 
ching is defeated. 
It is an important point in the management of 
pinched trees, that, only in the second year does a 
permanent weakening occur if the pinched parts 
are pruued, and the small lateral shoots shortened 
back, then the shoots remain permanently weak. On 
the contrary, if the pruning is performed on parts 
of a tree below the pinched shoots, the results and 
purposes of the pinching are frustrated. 
We are also enlightened as to the results of 
Ringing. The breadth of a ring should on no ac- 
count exceed 4 to 0 millimetres, this being the most 
suitable because the excised space gets covered im 
the first season ; whereas narrower rings allow 
the bark to unite too quickly, and broader ones 
prevent an union taking place. A suitable time for 
ringing a tree is just previous to its flowering. 
Especially deserving of notice are the effects of 
ringing on the growth of the roots; riugiug forming 
a hindrance to the descent of the sap, the roots 
being thereby decidedly weakened. Beyond this wa 
find that ringing not only weakens the branch on 
which it is performed, but likewise the branches 
below the ringed part break water. Ringing should 
not be carried out on all the branches of a tree at 
one time, but at the utmost on the half of them, 
and on naturally weak-growing trees it should be 
omitted. 
Koopmann struck a note of warning in reference 
to scraping and slitting the bark, not to carry these 
operations too deeply into the innermost tissues of 
the bark, recommending slitting to be carried out 
over the basal enlargement of the branch as far as 
the stem; and he points out its importance in caseg 
of canker caused by frost or sun-burning. He ad- 
vised the cutting of parallel lines, beginning abov« 
