Winter conditions give fresh interest to tree study. In other
seasons, all kinds of clues for identifying trees were present, like flowers, or
fruit, or leaves.
In winter, except for
the evergreens, a Scout is dependent on two general features: the bark and
the general conformation. This not a disadvantage. When a Scout can
readily distinguish trees by their bark alone, he knows them much more
thoroughly by reason of the closer attention and sharper observation that is
required. This is not that difficult, and can prove to be useful
Sycamore, white birch, chestnut and certain
species of hickory are most readily recognized by their bark. In thick woods
this is the best method of identification, since most of the leaves are too high
above the ground to be of any help. The problem of identifying trees from
this new angle is sure to interest by its novelty, as well as because it
constitutes a greater challenge to the sharp eyes of Scouts.
Besides
giving this opportunity for training in really close observation of leaf-bearing
trees, the winter is the best time for studying the various evergreens and
distinguishing between them. Making a collection of twigs and cones of the
various species will furnish the motive for a successful winter hike. In fact,
the winter camp has been found a most opportune time for instruction for Forestry Merit Badge.
An interesting method of tree
identification can be presented about the fireside by using cardboard models of
winter trees and projecting the shadow of these upon a screen with a
flashlight. Models of this kind can be cut from sketches made on the tree
identification hike.
Identification
As one becomes more familiar with trees in
their winter aspect, the number that can be recognized at a distance becomes
greatly enlarged. We come to know trees by hardly definable traits, much as we
recognize our friends at a distance by some peculiarity of form or gait.
Watching the trees from a distance is a great help in acquiring this familiarity
with tree characters.
The method of branching and other features do not
furnish such precise marks as do the twigs, and cannot therefore be of much
value in a descriptive key. In fact the habit varies considerably among
individual trees of the same species, no two trees having exactly the same
method of branching.
Trees grown in woods in company with other trees
are prevented by shading from the side from developing their normal form and produce
tall trunks with only a little branching. On the other hand trees apart from other
trees have usually been planted for ornament or have originally grown in woods,
but have been left isolated by the cutting down of their neighbors. In the
latter case the habit will be more or less that of a forest-grown tree depending
on the age at which the conditions of light and shade were altered. In the
former case the top of the young tree may have been cut in the process of
transplanting, causing an increased branching at the point of cutting and the
lower limbs may have been trimmed off, giving a greater show of trunk.
These
mutilations, however, have less influence upon the outline of the head or crown
than might be imagined since the tree is generally able to accommodate itself to
such accidents and express its individuality despite them.
The age of the tree is also an important factor in the outline, young specimens
being in general narrower and more conical than in later life, while those in
old age may have lost shape through ice storms, high winds And the attacks of
fungi.
Habit Characters
Two general habit types are recognized: the spreading and
erect. The former is well represented by the Apple and White Elm and the latter
by the Evergreens and those of the Poplars that form narrow conical heads. By
its more erect habit of growth the Sweet Cherry is readily distinguished from
the Sour Cherry and in like manner the Pear from the Apple. It is these habit
differences that form the most ready means of separating the contrasted trees
just mentioned which may closely resemble each other in twig characters. The
angle which the branches make with the trunk is frequently a diagnostic
character of considerable value. For example the ascending and gracefully
outward curving limbs of the American White Elm stand in contrast with the sharply divergent limbs
of the English Elm.
Likewise the horizontal branches of the Tupelo and the
strongly pendant lower limbs of the Swamp White Oak are characteristic of these
species. The relative thickness of the branchlets contrasted in the Sweet Cherry
and the Black Birch and the arrangement of the branchlets whether opposite or
alternate and whether erect or drooping, may further be mentioned as habit
characters.
Bark
Although it is upon the appearance of the bark more than upon
any other character that the woodsman depends in his recognition of timber
trees, it is difficult to give a precise description of it. The color of the
outer bark is an important mark of distinction and is the chief means of
separating the different species of the Birches. The color and taste of the
inner layers of the bark are in some cases also characteristic. The Black Oak,
for example, is best distinguished from other Oaks by the yellow and intensely
bitter inner bark. Similarly, the Black Birch, the Sassafras and the genus
Primus, including the Cherries, have barks with characteristic flavors.
The swamp loving Poison Sumac is the only poisonous tree in New England, so that
after this shrubby form is known there need be no fear of tasting bark and twigs
of any unknown tree-like species in that section. The bark varies in character
according to the age of the tree. In the young tree the bark is smooth but as
the trunk expands from this growth of the wood within, the covering of dead bark
outside is forced to crack in a variety of ways, giving rise to characteristic
fissures and ridges which become more prominent.
The bark of the American Hornbeam remain
smooth, their outer layers expanding with the growth of the tree. The barks of
others, such as the Paper and Yellow Birch, stretch and peel off in thin papery
layers. In the Birches and Cherries the breathing pores (lenticels) become
horizontally elongated to form narrow transverse streaks which are
characteristic for these forms.
When ridges or scales are formed they may be
close and firm and with difficulty removed from the trunk as is the case with
the bark in the Black Oak group. Others may be easily rubbed
off as are the scales of the bark of the White Oak and of most members of the
White Oak group. Bark of this latter type is called "flaky" in
descriptions and this distinction between barks that are flaky and those that
are not flaky is of considerable importance in classification.
Buds
In regard to
their position buds are terminal or lateral. Buds produced at or near the nodes
but not in the axial of a leaf-scar are called accessory buds. Of these there are
two kinds: Superposed buds, located above the axillary buds, and collateral
buds, located at either side of the axillary buds. The former are shown in the
Butternut and the latter in the Red Maple.
Classified according to what they
produce there are flower buds, which contain rudiments of flowers; leaf buds,
which contain rudiments of leaves, and mixed buds, which produce both flowers
and leaves. Flower buds are generally stouter than leaf buds. Most species by
the end of the growing season have formed terminal buds which remain through the
winter and are destined to continue the growth the following spring. In some
species, however, such as the Mulberry, the terminal but, together with the tip
of the twig, dies away and drops off before the beginning of winter, leaving a
small scar at the end of the twig. The presence or absence of the terminal bud
is a very valuable point of distinction and is used widely.
Aside from the
color, the presence or absence of hairs, stickiness, fragrance or other such
surface characters, the position of the buds in relation to the twig may be of
importance. Buds that lie close up against the twig, as those of the small
toothed Aspen, are called appressed, while those that project more or less
away from the twig are called divergent and are found
on the Carolina Poplar. In the Common Locust and a few other forms the buds ire
sunken below the surface of the twig and can be found only by cutting the twig
lengthwise through the leaf scar.
The characters of the bud-scales of most
importance are the shape, the number visible (whether alternate or opposite) and
the number of ranks they form on the bud.
See Also:
