TREE-PRUNING IN ECONOMIC FORESTRY
Where trees are grown for profit, they will, if properly managed, prune
themselves, and where for ornament the natural outline is far better
than any of the contortions and symmetrical shapes that have been
recommended by various writers on the subject.
A broken or dead branch may be removed, a rival leading shoot cut away,
or an ungainly or dangerous limb amputated, but here all pruning should
cease, the practice being wholly wrong and unreasonable, and without
one recommendation to be adduced in its favour. In an economic way the
finest plantations of either coniferous or hard-wooded trees in this
country are those where the individual specimens are growing so thickly
together that the branches are killed outright for fully one-half
of their height. Here the stems will be straight and clean, and the
timber when converted free from the knots and warping that are so
characteristic either of standard specimens or such as have been grown
too thinly on the ground.
Every one knows that an Oak growing alone or along the margins of
a wood is in nine cases out of ten branched almost to the ground,
and the bole in consequence rough and ill-fitted for any particular
constructive purpose, and the same may be said of every other tree,
be it hard-wooded or coniferous. Larch and Scotch Fir trees growing
along the margins of plantations are rough and knotty, and sell at a
considerably lower figure compared with those further in, where the
branches have been killed back gradually as the trees increased in
size.
The same thing is markedly the case in young woods of ash, oak and
chestnut, where they have been grown sufficiently thick on the ground
to kill off the lower branches, and also to cause the trees to rise
straight, clean and tapering. It is a well-known fact, too, that the
timber of trees so grown is far more elastic and realizes a much higher
price than that of the same age grown under conditions where pruning
might have been a necessity. A case of this kind came under my own
notice only a short time ago in which one-half of a plantation of
hard-wooded trees realized fully one-fourth more than the remaining
half. It came about in this way. Both ends and a large patch in the
centre of the wood had been thinned out severely for the purpose
of planting game covert. The trees, standing thinly on the ground,
branched out and soon covered the open spaces where underwood had been
planted. In thinning the whole plantation the trees on these particular
parts were very rough and knotty, and bore no comparison to those where
they had been left moderately thick on the ground, in consequence
of which the boles were straight, clean and tapering. This case is
specially noteworthy, inasmuch as the trees over the whole area were
growing under exactly similar conditions as to soil, shelter, etc., and
were of the same age and species.
Great and irreparable damage has been done to woods and plantations in
this country by too heavy thinnings, by commencing the thinnings at too
early a period, and by adopting the book method of leaving the trees
at measured distances apart and a stated number to the acre according
to the age of the plantation. Such rules can never be expected to work
satisfactorily, the size of trees depending so much on the character
of the soil, exposure of the woodland, and other peculiarities of the
particular district in which they are planted.
[Illustration: PRUNING TOOLS]
Timely and judicious thinning should never be neglected, but it is the
over-thinning, whereby branches and knotty trunks are produced and
the supposed need for pruning follows, that I wish to deprecate and
entirely dissent from. Grow your timber trees so thickly on the ground
that the stems are induced to become straight, clean and branchless for
the greater part of their height, and on no account admit sufficient
light and air to cause the lower branches to be retained intact, or, in
other words, at all times retain an unbroken leaf canopy. The necessity
for pruning will then be entirely done away with, and a more valuable
class of timber produced. The losses sustained through injudicious
planting and the unnecessary and ruinous practice of pruning have
taught a lesson that is fraught with good for the tree planter of the
future.
=When Pruning is Admissible.=—There are a few cases, however, where
pruning is quite justifiable, and where the abuse of a system should
furnish no argument against its legitimate use. Hedgerow and field
timber, for the sake of the live fences, the grass, or the grain crop
in the vicinity, may require attention in the way of judicious pruning.
Again, pruning is sometimes a necessity where standard trees are grown
in conjunction with coppice wood, as by shortening the lower branches
the undergrowth in consequence becomes much improved. In the case
of town trees, too, where it is necessary to restrict the spread of
branches, pruning is resorted to, as also with old and heavy-headed
elms and other trees in our parks and public gardens.
=Pruning Live Branches.=—In and around London, as well as many other
large centres of industry, the hacking and hewing—pruning we cannot
call it—to which trees are subjected is barbarous in the extreme, and
calls for the strongest denunciation. To annually prune and elbow
in such noble forest trees as the lime and plane, in order that the
restricted growth may render them suitable for the cramped positions in
which they have been unwisely planted, is little short of vandalism.
The lime and plane, perhaps, suffer most in this way, for as soon as
they have overgrown the allotted space an annual system of pruning
back the branches is resorted to, the result being great mop-headed
protuberances at the points where amputation took place, which not
only rob the tree of its graceful natural appearance, but render it
susceptible to disease and insect pests. There is no need to specialize
cases where this most objectionable system is carried out, for a walk
around our squares and gardens will unfortunately reveal how prevalent
is the maltreatment of trees in the way of pruning. There might be some
excuse for planting our noblest forest trees in cramped and unsuitable
positions were there no other species of smaller growth that would
take their place, but the Pyrus, Cratægus, dwarf Acacia, Mulberry,
Catalpa and Sumach surely give us sufficient scope for choosing trees
of restricted growth for confined positions and so do away with the
barbarous system of pruning which the use of large-growing species
necessitates.
[Illustration: BAD EFFECTS OF PRUNING]
Even in the case of dwarf avenues and screens it is quite unnecessary
to use such large-growing trees as the lime and plane where pruning
must oft be resorted to, for an avenue or screen of thorn or mulberry,
the beam tree or mountain ash would be more suitable, and in the end
far more natural and artistic in appearance.
To sum up in a few words, my contention is that no tree should be
planted in a position where, in order to keep it within due bounds, a
systematic clipping and pruning has to be resorted to.
=Pruning Dead Wood.=—Opinions differ greatly as to whether or not
dead branches should be removed from park and woodland trees. It is,
however, mainly a matter of taste, and a point on which two of the
largest owners of woodlands in this country hold distinctly opposite
opinions, though at the same time it cannot be denied that the careful
removal of all dead and dying wood from a tree is highly beneficial.
Pruning should, however, only be extended to such trees as are in a
fairly healthy condition, with well-developed heads, and containing
only a moderate quantity of dead wood, there being many fine old
specimens that would be rendered unsightly in the extreme and receive
no benefit from removal of the dead and dying timber, but this has
direct reference to trees standing singly throughout the park, and not
to specimens in the woodland.
In many of our parks and woodlands at the present time there exists
an undue quantity of dead and dying wood, which may be attributed
to natural decay, the quality of the soil, and in some instances to
long-standing neglect in the matter of non-attention to wounds which
have been caused by wind-broken limbs and branches. Such trees would
be greatly improved, both in health and appearance, by judicious
removal of the dead branches and attention to old wounds in order to
prevent the ingress of water, the decay of many branches being directly
attributable to this cause. That an undue quantity of dead wood will
induce injurious insect pests, such as the goat and wood leopard
moths, which attack healthy trees, is well known, and was exemplified
in one of our London parks recently where numerous young thorns and
various species of Pyrus were injured by the latter. In removing dead
branches cut them well back into the living wood in order to induce
fresh growth at the point where amputation takes place. The removal of
large dead limbs from old specimen trees is an operation that requires
a great amount of skill, and should only be entrusted to those who have
had practical experience of pruning in its various phases. As before
stated, the removal of dead wood is merely a matter of sentiment,
though of its practical utility there can be no doubt, and in all cases
where the stag-headed trees are conspicuous, the removal of the dead
wood is to be recommended.
=Pruning Shrubs.=—Generally speaking, shrubs are pruned with little or
no consideration as to whether they will be benefited by the operation.
While symmetry and regularity of outline are to be admired in a shrub,
these qualities should never be gained at the expense of natural grace
and production of flowers. The judicious pruner will, therefore, aim at
preserving the peculiar habit of each shrub as far as possible, while
interfering but little with the production of flowers. The various
species of Deutzia, Forsythia, Philadelphus and Weigela flower on the
wood of the previous year’s growth; therefore such shrubs should be
pruned immediately after the flowering season—say in June, but never in
spring or winter—at least, if the production of flowers is to be taken
into account. Again, the various species of Syringa, Spiræa, Lonicera
and Hibiscus may safely be pruned during winter, the flowers being
produced on the young wood; while _Hydrangea paniculata grandiflora_
must be severely pruned in early spring, for only by so doing will the
greatest wealth of flowers be produced. _Chimonanthus fragrans_ should
be pruned in February; while the various species of Ceanothus should
not be touched till all danger of frost is past. _Kerria japonica_
should be pruned in autumn, when old wood may be cut away.
All pruning operations should be carefully carried out with a sharp
knife and not with the pruning shears, the point of amputation being
always close to an eye or bud. Too severe pruning should be avoided,
a judicious thinning out of the branches being far preferable to
indiscriminate shearing and cutting back.
=How and when to Prune.=—The latter part of May or beginning of June
is undoubtedly the best season for pruning the majority of hard-wooded
trees, as during that time the motion of the sap is most vigorous, and
in consequence the wounds caused by amputation heal most quickly.
There are a few exceptions—the birch, sycamore and maple—where, on
account of profuse bleeding, pruning had best be postponed till after
full foliage has been attained.
Much mischief has been done by the pruning knife, and still more by the
handbill and saw when placed in the hands of inexperienced workmen—a
fact that is apparent to any interested person who visits various parts
of the country.
When conducted with care, on sound principles, the effect of pruning
on the class of timber referred to is highly beneficial, whereas, when
done in a haphazard way and by an inexperienced hand, it is often
attended with great danger and grave results.
In cutting or foreshortening small branches, a sharp pocket-knife will
be found most convenient, but when large limbs have to be removed the
pruning saw should be brought into request. The branch to be removed,
especially if of large size and weighty, should first be cut through at
any convenient distance from the main stem, thus preventing splitting
and tearing of the bark, after which the stump may be neatly sawn
through as close to the bole of the tree as possible. Undercutting by a
few draughts of the saw will here also go far in preventing tearing of
the wood and bark. So as to render the saw-cut smooth and prevent water
lodging on the surface, the face and edge should be neatly dressed with
an adze or sharp pruning knife, and then painted with tar. When cutting
over an upright-growing branch, such as in pollarding trees, etc.,
never cut on the horizontal, but always in a sloping direction, so that
the rain may pass off quickly.