FELLING TIMBER.
The end to be attained in the management of timber trees is to produce
from a given number the largest possible amount of sound and durable
woods. When a tree, under conditions favourable to its growth, ceases
increasing the diameter of its trunk, and loses its foliage earlier in
the autumn than it is wont to do, and when the top of the tree brings
forth no leaves in spring, these facts may be considered as indications
of decline, and that the tree is of sufficient age to be felled. The
state of the upper branches of a tree may be considered to be amongst
the best indications of its soundness, and provided they be in a
healthy condition, the withering of the lower branches is a matter of
comparatively small importance.
Trees may be considered as tall, middle rank, and low, and the size
to which they will attain depends on many different circumstances.
Some trees, the stems of which are short on the average, as the lime,
are virtually of tall growth, from the manner in which a number of
vertical branches of large size ascend from the stem. And other trees,
again, whose branches are comparatively short, are of tall growth, in
consequence of the length of the stems--like the beech.
The average duration of trees differs, as is well known, in different
species, and they exhibit different symptoms of decay. There are oaks in
Windsor Great Park, certainly nearly one thousand years old, and which
exhibit even now no appearance of approaching the end of their life. Mr.
Menzies, the surveyor, in his work on Windsor Great Park, describes some
of the indications of incipient decay which are peculiar to the several
kinds of trees. “When a beech begins to fail,” he says, “fungi appear
either at the roots or on the forks, the leaves curl up as if they had
been scorched, and the tree quickly perishes. In an elm, a great limb
first fails, while the rest of the tree continues green and vigorous,
but in a few years the whole tree suddenly dies. Coniferous trees die
gradually, but quickly. The oak shows the first symptoms at the points
of its highest branches, while the rest of the tree will remain healthy
and sound for years.” This peculiarity of the oak did not escape the eye
of Shakespere, that universal observer, who describes the monarch of the
woods as not only having its boughs mossed with age, but its
“High top bald with dry antiquity.”
The age for felling trees is a subject which calls for the deepest
consideration, but does not always receive that attention which is due
to its importance. Timber growers in their haste to supply the market,
too often fell trees that have not arrived at maturity, the heart-wood
being therefore imperfect, with much sap-wood, and, of course, little
durability; but unfortunately they are the more readily led to do so
on account of the increase in size being very slow after a certain
age. Builders are sensible of the inferior quality of young timber in
respect to duration, and it is their province to check this growing evil,
by giving a better price for timber that has acquired a proper degree
of density and hardness; but, unfortunately, this is an age for cheap
building, without much regard being given as to durability.
Felling should not be too early, for the reasons above mentioned; neither
should it be in the decline of the tree, when its elasticity and vigour
are lost, and the wood becomes brittle, tainted, and discoloured, with
the pith gone, and the heart in progress of decay. Maturity is the period
when the sap-wood bears a small proportion, and the heart-wood has become
uniform and compact. Sir John Evelyn writes, “It should be in the vigour
and perfection of trees, that a felling should be celebrated.” It must
be obvious, however, that it is a worse fault to fell wood before it has
acquired thorough firmness, than when it is just in the wane, and its
heart may exhibit but the first symptoms of decay; for in the former
there is no perfect enduring timber to be got, while in the latter the
greater part is in the zenith of its strength.
Although there are certain symptoms by which it may be ascertained when
a tree is on the decline, it is somewhat difficult to decide just when a
tree is at maturity. From the investigations of naturalists, however, it
may be safe to consider that hard-wood trees, as oak and chestnut, should
never be cut before they are sixty years old, the average age for felling
being from eighty to ninety years, and the average quantity of timber
produced by a tree of that age is about a load and a half, or about 75
cubic feet.
Daviller states (see ‘Cours d’Architecture’) “that an oak should not be
felled at a less age than sixty years.” Belidor considers (see ‘Sciences
des Ingénieurs’) “that one hundred years is the best age for the oak to
be felled.”
It should be remembered that the times mentioned are by no means
arbitrary, for situation, soil, &c., have much to do with it. For the
soft woods, as the Norway spruce and Scotch pine in Norway, the proper
age is between seventy and one hundred years. The ash, larch, and elm,
may be cut when the trees are between fifty and ninety years old; and
between thirty and fifty years is a proper age for poplars.
The felling of timber was looked upon by ancient architects as a matter
of much moment. According to Vitruvius, the proper time for felling is
between October and February, and he directs that the trees should be cut
to the pith, and then suffered to remain till the sap be drained out. The
effusion of the sap prevents the decay of the timber, and when it is all
drained out, and the wood becomes dry, the trees are to be cut down, when
the wood will be excellent for use. A similar effect might be produced
by placing the timber on its end as soon as it is felled, and it would,
no doubt, compensate for the extra expense by its durability in use. In
France, so long ago as 1669, a royal order limited the felling of naval
timber from the 1st October to 15th April, when the “wind was at north,”
and “in the wane of the moon.” Buonaparte directed that the time for
felling naval timber should be “in the decrease of the moon, from 1st
November to 15th March,” in order to render it more durable. In England,
in the first year of James I., there was an Act of Parliament prohibiting
every one from cutting oak timber, except in the barking season, under a
severe penalty.
James I. was not the only English sovereign who has been concerned with
timber trees; for King John was obliged to cancel at Runnemede the cruel
forest laws enacted by his father, William the Conqueror, especially
those restricting the people from fattening their hogs.
Up to a recent period large droves of hogs were fattened upon the
acorns of the New Forest in Hampshire. At the present time the hogs of
Estremadura are principally fed upon the acorns of the _Ballota_ oak; and
to this cause is assigned the great delicacy of their flesh.
A Berkshire labourer, living near Windsor Forest, thus speaks of the
delicacy of acorn-fed pork: “Well, that be pretty like the thing. I
hadn’t tasted the like o’ that this many a day. It is so meller--when you
gets your teeth on it, you thinks you has it; but afore you knows where
you is, ain’t it wanished!”
There is another point in connection with the time of felling timber,
which ought to be noticed. It is a widespread opinion that trees should
be felled during the wane of the moon. This planetary influence is open
to doubt, but the opinion prevails wherever there are large forests.
Columella, Cato, Vitruvius, and Pliny, all had their notions of cutting
timber at certain ages of the moon. The wood-cutters of South America act
upon it, so do their brethren in the German forests, in Brazil, and in
Yucatan. It was formerly interwoven in the Forest Code of France, and,
we believe, is so still. Vitruvius recommends this custom, and we find
Isaac Ware writing of the suggestion: “This has been laughed at, and
supposed to be an imaginary advantage. There may be good in following
the practice; there can be no harm: and therefore, when I am to depend
upon my timber, I will observe it.” The Indian wood-cutters believe that
timber is much more liable to decay, if cut when the moon is in crescent.
An American writer, in 1863, thus writes of his experience in the matter:
“Tradition says that the ‘old’ of the moon, in February, is the best
time to cut timber; but from more than twenty years of observation and
actual experience, I am fully convinced it is about the worst time to cut
most, if not all kinds of hard-wood timber. Birch, ash, and most or all
kinds of hard wood will invariably _powder-post_ if cut any time in the
fall after the tree is frozen, or before it is thoroughly leaved out in
the spring of the year. But if cut after the sap in the tree is used up
in the growth of the tree, until freezing weather again comes, it will
in no instance produce the _powder-post_ worm. When the tree is frozen,
and cut in this condition, the worm first commences its ravages on the
inside film of the bark, and then penetrates the wood until it destroys
the sap part thereof. I have found the months of August, September, and
October, to be the three best in the year to cut hard-wood timber. If cut
in these months, the timber is harder, more elastic, and durable than if
cut in winter months. I have, by weighing timber, found that of equal
quality got out for joiners’ tools is much heavier when cut and got out
in the above-named months than in the winter and spring months, and it
is not so liable to crack. You may cut a tree in September, and another
in the ‘old’ of the moon in February following, and let them remain, and
in one year from the cutting of the first tree, you will find it sound
and unhurt, while the one last cut is scarcely fit for firewood, from
decay. Chestnut timber for building will last longest, provided the bark
be taken off. Hemlock and pine ought to be cut before being hard frozen,
although they do not _powder-post_; yet if they are cut in the middle
of winter, or in the spring of the year, and the bark is not taken off,
the grub will immediately commence its ravages between the bark and the
wood. I have walnut timber on hand which has been cut from one to ten
years, with the bark on, which was designed for ox-helves and ox-bows,
and not a worm is to be found therein; it was cut between 1st August and
1st November. I have other pieces of similar timber cut in the winter
months, not two year’s old, and they are entirely destroyed, being full
of _powder-post_ and grub-worms.”
What shall we say when doctors disagree? The theory given to account for
what is assumed to be a fact, is, that as the moon grows the sap rises,
and the wood, therefore is less dense than when the moon is waning,
because at that time the sap in the tree diminishes. No evidence whatever
can be offered in support of the theory, and one would certainly imagine
that the rise or fall of the sap would depend on the quantity of heat
which reaches the foot of the tree, and not at all on attraction.
All investigations tend to prove that the only proper time for felling
timber is that at which the tree contains the least sap. There are two
seasons in each year when the vessels are filled. One is in spring, when
the fluid is in motion to supply nutriment to the leaves, and deposit
material for new wood; the other is in the early part of autumn, when,
after the stagnation which gives the new wood time to dry and harden, it
again flows to make the vegetable deposits in the vessels of the wood.
At neither of these times should trees be felled; for, if the pores be
full of vegetable juices, which being acted upon by heat and moisture may
ferment, the wood will decay. Of the two periods, the spring must be the
worst, because the wood then contains the greatest quantity of matter in
a state fit for germination.
The results of a series of experiments made in Germany show that
December-cut wood allows no water to pass through it longitudinally;
January-cut wood passed in forty-eight hours a few drops; February-cut
wood let two quarts of water through its interstitial spaces in
forty-eight hours; March-cut wood permitted the same to filter through in
two and a half hours. Hence the reasons why barrels made from wood cut in
March or April are so leaky, as the sap is then rising, and the trees are
preparing to put forth their leaves.
It thus happens that the time for felling is midsummer or midwinter. The
best time for felling, according to some, is midsummer, when the leaves
are fully expanded, and the sap has ceased to flow, and the extraneous
vegetable matter intended for the leaves has been dislodged from the
trunk of the tree by the common sap, leaving it in a quiescent state,
and free from that germinative principle which is readily excited by
heat and moisture, and if the timber were cut while it remained, would
subject it to rapid decay and to operations of worms. Midwinter, amongst
some, is chosen as a time for felling, as it is stated that winter-felled
heart-wood is less affected by moisture, and likely to be the best and
most durable; but as the only peculiar recommendation which that time
possesses is the facility which it affords for gradual seasoning, by
which timber is rendered less liable to split and get distorted, and
slow drying being generally available at any season under shade and
shelter, midsummer appears for many obvious reasons the most expedient.
In general, all the soft woods, such as elm, lime, poplar, willow,
should be felled during winter. In some kinds of trees a little after
midsummer appears to be decidedly the best time for felling. Alder felled
at that time is found to be much more durable; and Ellis observes, that
beech when cut in the middle of summer is bitter, and less liable to be
worm-eaten, particularly if a gash be cut to let out the sap some time
before felling. Mr. Knowles states that, “About Naples, and in other
parts of Italy, oaks have been felled in summer, and are said to have
been very durable.” Most of the trees in southern Italy are felled in
July and August, and the pines in the German forests are cut down mostly
in summer time, and it is stated that their wood is sound.
The following are advocates for winter felling, viz. Cato, Pliny,
Vitruvius, Alberti, Hesiod, De Saussure, Evelyn, Darwin, and Buonaparte.
Some of them consider that winter-felled timber, which has been barked
and notched in the previous spring, loses much of that half-prepared
woody matter, containing seeds of fungi, &c., that there is no doubt of
its superiority to summer-felled timber.
The age at which trees should be felled, and the most suitable time for
the work having been determined, there are two other things which claim
attention.
The _first_ of these is the removal of the bark from the trunk and
principal branches of the tree. For, in oak trees, the bark is too
valuable to be lost; and as the best period for the timber is the worst
for the bark, an ingenious method has been long partially practised,
which not only secures the bark at the best season, but also materially
improves the timber. This method consists in taking the bark off the
standing tree early in the spring, and not felling it till after the
new foliage has put forth and died. This practice has been considered
of inestimable value; for by it the sap-wood is rendered as strong and
durable as the heart-wood; and in some particular instances experiments
have shown it to be four times as strong as other wood in all respects
similar, and grown on the same soil, but felled with the bark on and
dried in sheds. Buffon, Du Hamel, and, in fact, most naturalists, have
earnestly recommended the practice. Evelyn states, “To make excellent
boards, bark your trees in a fit season, and let them stand naked a full
year before felling.”
In regard to the time that should elapse between the removal of the bark
and the felling of a tree, a variety of opinions exist. It was the usual
custom of early architects to remove the bark in the spring, and fell the
trees during the succeeding winter. Later investigations seemed to have
proved that it is better to perform the work three or even four years in
advance, instead of one, although Tredgold appears to think one year too
long. Trees will, in most situations, continue to expand and leaf out for
several seasons after the bark has been removed. The sap remaining in the
wood gradually becomes hardened into woody substance, thereby closing
the sap vessels and making it more solid. As bark separates freely from
the wood in spring, while the sap is in motion, it should be taken off
at that period. When the above method is not adopted, it is well either
to pierce the trunk some time before felling to drain out the sap, or
immediately on its being felled to set it on end.
The _second_ suggestion is, to cut into and around the entire trunk of
the tree, near the roots, so that the sap may be discharged; for in this
manner it will be done more easily than it can be by evaporation after
the tree is felled. In addition to this, if it be permitted to run out
at the incision, a large portion of the new and fermentable matter will
pass out with it, which would remain in the wood if only such material
is removed as would pass off by evaporation. This cutting should be made
in the winter previous to the August in which the tree is to be felled;
and the incision should be made as deep into the heart-wood as possible
without inducing a premature fall of the tree.
The custom of ringing or girdling the tree before felling has been
advocated, on the ground that the seasoning is thereby expedited,
and also more thoroughly effected. This is doubtful, at least, in
oil-containing trees (as teak, &c.), but the practice appears to be
contra-indicated for other reasons: when a tree has been ringed, many
wood-cutters object to cut it down on account of its increased hardness.
This objection might be waived, were it not for another and more serious
one which has been adduced. It is believed to be a fact by some that
trees felled after girdling have the heart shake increased. It is
difficult to explain this, if it be actually the case.
Many suggestions might be made as regards the mechanical operation of
felling trees, with which ancient nations were not unfamiliar:
… “for thou knowest that there is not among us any that can skill
to hew timber like unto the Sidonians.”--1 Kings v. 6.
But as these operations are familiar to all intelligent workmen, it
is only necessary to mention one, viz. the value of removing from the
side of the tree such branches as will strike the ground when it falls,
and, by wrenching, cleave the grain of the wood, and thereby injure the
timber. Such defects, which are often found after the timber has been
seasoned, could not be discovered when it left the mill.
In conclusion, we can truly state that the most extensive felling of
trees for _one building_ only which we have ever heard or read of is the
following:
“And Solomon had threescore and ten thousand that bare burdens,
and fourscore thousand hewers in the mountains.”--1 Kings v. 15.