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THE
SHRUBS AND TREES OF THE MIXED WOODS
As we
have already observed in the account of the Pine Forests, woods and
forests compose only a small proportion of the surface of the Highlands.
Of this area the amount under mixed woods is very small.
However,
woods containing oaks, birch, rowan and aspen occur in many parts of the
Highlands. In all the larger valleys and glens, as in the Tay valley, the
pass of Killiecrankie, the Trossachs and around Inverary, beautiful woods
occur, rivaling in variety and loveliness the woods of the more hospitable
south. Again, in the western Highlands, wherever shelter from the wind
and cold are obtainable, large stretches of mixed woods occur. In the
more exposed places thickets of birch take the place of the mixed woods
and may be encountered up to about 1,000 feet above sea level. Above this
level the birch woods give place to the pine and moorlands.
Beyond
this height the short season, the fierce winds, the severe frosts and the
acid soil mixed woods impossible.
In the
southern Highlands and in sheltered places in the western Highlands, the
oak is the most important tree. Elsewhere in the eastern and central
regions, as well as the far north, woods are much scarcer and are usually
composed of birch, which is also very common everywhere in the Highlands.
In the
following description I shall describe the various trees to be found in
the mixed woods of the Highlands and the various flowering plants which
flourish beneath their shade. I will commence with the oak.
The Oak (Quecus sessilifloria)
The oak
woods are very beautiful, but if one would see them at their best, one
should see the woods around Arisaig Bay and Beasdale in the far away
western Highlands.
It was
late October when I first visited this delectable region. I was a day of
brilliant sunshine, whilst the sky was pale azure blue. All around the
bay the beautiful oak woods came down to the scintillating sea, their
dying leaves a find golden brown, contrasting with the dark brown slopes
of the higher hills. The soft west wind gently rustled among the dry
leaves which seemed to whisper to one another as if they were mimicking
the waves that hissed upon the sandy shore.
As I sat
on the mossy roots of one of the oaks, I became aware of the real beauty
of these woods in all the splendour of the autumn. Rugged grey trunks and
gnarled branches dressed in russet brown; brave trunks that had survived a
thousand winter storms, the very emblems of strength and endurance.
Beneath, the mossy ground was covered with a crisp carpet of dying leaves
where the red squirrel was searching for the last acorns before commencing
his long winter sleep, and where the fairly-like roe-deer moved so gently
that one would think they were afraid to disturb the long sleep of the
withered leaves or the spirits that must inhabit this lovely spot.
As I
looked across the bay I saw the jagged peaks of Sky, silhouetted like a
row of shark’s teeth against the blue sky, and the strange peaks of Rum
peeped over the rugged headlands enclosing the bay.
Behind
me, beyond the low ridge, I saw the massive peak of Ben Nevis, over forty
miles away, standing out majestically against the eastern sky, its ancient
head and shoulders white with newly-fallen snow. It stood dark and
menacing as if King Winter had already taken up his residence there and
was regarding these lovely regions with his icy eyes, waiting for the day
when he could come down and claim them too.
The Oak (Quercus
Robur) is perhaps the most typically British of all trees and is in
many ways a very picturesque one. Its massive, rugged trunk and gnarled
mighty branches are unmistakable whether in mid-winter, when it stands
bare to the winds and rain, or in the full beauty of mid-summer.
It is a
beautiful tree, in its pale-green coat of springtime when its branches are
gaily decked with catkins, or in mid-summer when it is clothed in a deep
green coat of dense foliage, or in autumn when it has changed its somber
green for a beautiful russet-brown, or again in winter when one can see
its massive grandeur like that of a naked athlete.
The oak
of the Highlands is a slightly different species to the common oak of the
south and is know as Quercus sessiliflora.
Unlike
Quercus Robur, it will grown on light soils if not too shallow. For
this reason it is chiefly found in the valleys where it ascends the sides
until the soil becomes too thin for its requirements. Naturally, it
requires protection from fierce winds and extreme cold and this reason
limit’s the areas suitable to it growth in the Highlands.
Quercus sessiliflora is a straight trunked tree
with less spreading and less massive branches than the more common oak.
It is slow growing and lives to a great age. It may attain a height of
eighty or ninety feet in deep rich soil, but in the Highlands fifty feet
is about the maximum attained.
The
strong massive branches are covered in great numbers of crooked, gnarled
twigs and are thickly clothed with leaves which commence to break from the
buds about the beginning of May after the catkins have bloomed. They are
dark green above and oblong in shape with a very sinuate margin. They are
glabrous, the under surface being of a pale green. These leaves are
retained until the autumn, when they change to a deep brown and are
gradually shed as the autumn gales howl through the woods. The young
trees, however, usually retain the old brown leaves till the next spring.
The
flowers of the oak are of two kinds and are found separately upon the same
tree.
The male
flowers consists of catkins, which are about two inches in length and
several occur together.
The
female flowers are either solitary or several in a cluster and consist of
a perianth of green scales, within which is enclosed the ovary and the
three styles which project beyond the perianth ring.
The
flowers are wind pollinated, and for this reason they appear before the
leaves can hinder the passage of the pollen from the males.
The fruit
of the oak is the familiar shiny green acorn in its hard green cup. The
fruit of Quercus sessiliflora has no stalk, and this is the chief
structural difference between it and Quercus Robur.
My
readers who know something of the English countryside must all have
delightful memories of the Wild Cherry (Prunus Cerasus) in blossom
in the southern woodlands in May, and must have been charmed by the
snow-white masses of flowers and the delicate beauty of the individual
blooms. It is, I think, above all flowers the one which best portrays the
beauty of spring, fresh, pure and dainty in its chaste beauty, with its
reddish trunk surrounded by a sea of bluebells and shy primroses, while
the blackbird sings from the topmost branch his praises to the Creator of
all this loveliness.
In the
Highlands, unfortunately, the Wild Cherry is rare, and except in the
southern fringes is not even a native plant.
Its place
is taken, however, by another species, the Bird Cherry (Prunus Padus),
which is a lovely tree if less conspicuous than the wild cherry. Its
small clustered blooms make up for their lack of size by their delicate
fragrance, which, borne upon the air with the faint perfume of opening
birch, the aromatic odour of bog myrtle, and the mixed odour of the pine
and moss and mountain air, is the very embodiment of all that is so
delightful in this wild mountain country.
Perfumes
and odors bring back to the memory many places and incidents. Thus the
rich odour of burning peat will bring back memories of that little white
croft in Skye, nestling in the shadows of the Coolins, where one spent a
never-to-be-forgotten holiday; if I but smell the sweet briar I am
transported to the smooth rolling downs of the south, and the honey scent
of heather brings back the delightful days I passed in the Cairngorms
whilst rambling over their empurpled sides.
So with
the Bird Cherry. It brings back memories of spring in Speyside, of pale
green birches sparkling with rain drops, of the murmur of rushing burns,
their sides golden with marsh marigolds and beautified by the innocent
blooms of the cuckoo flower and the bird cherry itself. Its pale flowers
star the woodsy edges of roadsides and streams, and its perfume tempts the
passer-by to pluck the sprays of its fragile blooms to return with them to
his apartment, where its subtle perfume will keep fresh his springtime
memories.
The Bird
Cherry never forms a large tree as the Wild Cherry does, and is usually a
large, spreading shrub of from eight to ten feet in height, although in
sheltered spots it may attain to the dignity of small tree.
The
leaves are usually oval in shape with a very finely-toothed border, and
are smooth and shiny on the upper surface.
The
flowers, which are rather small, are conspicuous not only by their sweet
perfume, but also because they are arranged in close, long racemes which
may be as much as six inches in length and contain many flowers. These
racemes are produced on short leafy branches.
The
flower is constructed on the usual rose plan, with a central receptacle
from which springs a single carpel (usually several in Rose Family). From
the sides of the receptable arise the many stamens and five creamy white
petals. Nectar is secreted in a ring around the receptacle. The stigma
is mature before the anthers so that cross-pollination will take place
when insects arrive from old flowers to the newly-opened ones. But as the
stigma remains mature after the anthers have opened, self-fertilization
will take place if cross-pollination has not already been arrived at. Thus
the flowers are always certain to set seed.
After
fertilization the corolla fades and the ovary swells to form a small,
round, black fruit which contains a very hard, rugged stone containing the
seed. These small cherries, although very bitter, are much eaten by birds
and thus the seeds are dropped at a distance form the parent plant.
 The Birch (Betula alba)
If one
was asked what was the loveliest tree in Britain I am sure many would
reply the birch. This dainty tree, often no more than a large shrub, is
one of Nature’s masterpieces. Beautiful specimens are to be found in the
lovely woods of the Trossachs. I have memories of idle summer days on the
sylvan shores of Loch Achray where, lying on the mossy turf, I have
dreamily watched the branches of the birch curving gracefully down to the
water’s surface and gently agitating it like fairy fingers, its thin
leaves whispering softly as if they also were afraid to break the
tranquility.
No
Scottish scene would be complete without the birch. Not for it the
sheltered valleys and lowlands, but the rugged hillsides and the wild
glens, where we may find it struggling with the elements, precariously
rooted on the face of steep precipices and crags; beside thundering
waterfalls and raging torrents, by mountain tarns and on wind-swept moors,
it reigns supreme.
To find
it at its most beautiful, however, we must wander among the relics of the
Old Caledonian Forest. Magnificent trees may be found by lonely Loch
Tulla. Their silver trunks gleam bright in the sun in vivid contrast to
the black pines, and nothing more graceful than their drooping branches
can be imagined. Autumn by Loch Tulla is unbelievable, the pines with
their black leaves and red branches, the silver of the birch and the amber
of their leaves, the bronzes, yellows and oranges of the ferns, and the
blue of the loch and sky combine to make s symphony in colour.
It is
beautiful at all seasons. In winter the twigs of a birch wood give the
impressions of a purple mist hanging over the hillside; in spring the
bright freshness of its leavs and their delicate fragrance are not matched
by any other tree; in summer after rain, when every leaf holds an
iridescent crystal at its tip, it is the real ‘Lady of the Wood’; in
autumn its fallen leaves give brightness and beauty to the scene and
alleviate the feeling of sadness an autumn wood always engenders.
The birch
is found at higher elevations than any other tree in the Highlands, often
reaching 3,000 feet. It forms broken thickets on the steep, craggy sides
of the glens, open scrubby woods upon the sandy moraines of Speyside, and
pure woods in many parts of the Highlands, especially in the more exposed
and elevated parts of the valleys where the strength of the wind precludes
any other trees.
A birch
wood is not a dark or gloomy place, as is a beech wood in summer. Its
small, thin leaves give little shade, and as the trees rarely grow
thickly, there is usually a well-developed undergrowth. Bracken, heather
and brambles cover the ground, whilst the beautiful mountain ash often
bears it company. The Wood Amemone, Chickweed Winter-green and Wood
Geranium are often found in these woods, as are the Dog Violet and
Cow-wheat.
It rarely
attains more than eighty feet, and at its highest range is often no more
than two feet in height. Its trunk is slender and covered by the
characteristic silvery bark. The lower part of the trunk is usually
fissured and grey, but higher up the bark is smooth, thick and tough, and
of a beautiful, clear white; its toughness is shown by the fact that in
fallen trunks the wood may be reduced to power contained in a cylinder of
bark.
The trunk
branches toward the summit and ramifies to form a large number of slender,
very wiry twigs which droop towards the extremity. They are perfectly
adapted to withstand gales and fierce gusts of wind.
The
branches are thickly covered by small, thin, triangular leaves which are
of a tough consistency and quite smooth above. Owing to their thin
texture they form little humus.
The
flowers, as in the case of the oak, are produced in catkins. The male and
the female catkins are both found on the same plant at the extremities of
the branches. The males are pendulous and light green in colour, but
become reddish on opening in April. The females are erect and much
smaller, but are often produced on the same twigs as the males. Seven
tiny flowers are covered by a tiny scale. Each pistil produces two
delicate styles that stick upright and project beyond the scale.
The
flowers are wind pollinated. They mature when the leaves are fully out,
but this does not hinder the passage of the pollen as the leaves are so
small.
After
fertilization the female catkins form little cone-like bodies, each flower
producing a tiny nut. Each nut has a pair of tiny, brown wings, and in
late summer they fly for considerable distances from the parent plant.
For this reason, if protected from grazing animals, the birch will
continually increase its territory and as it is very hardy it can compete
against all comers. It is also very quick growing and is able to
consolidate its newly-won positions in a remarkably short time. For this
reason, land not fit for agriculture is soon invaded, and if not cleared
becomes a typical birch wood community.
In many
parts of Scotland, especially in the northern Highlands, the birch woods
are a perfectly matured association with their own particular fauna as
well as flora. Some of these woods may well be the most ancient flora of
these islands.
We have
actually two species of birch tree in Britain, the Silver Birch (B.
alba) and the Hairy Birch (B. pubescens). The latter is the
common birch of the Scottish woodlands and grows on more acid soil than
the former. The silver birch, however, is frequent in most parts of the
Highlands and so is often confused.
In B.
alba the leaves are smooth, whilst the young branches hang gracefully
and, although devoid of hairs, are often warty in appearance. The fruit
also helps to distinguish it, the wing being twice as wide as the seed.
In B.
pubescens the leaves are usually hairy, the young twigs are erect and
downy, whilst the seed wing is hardly wider than the seed.
Mountain Ash (Pyrus Aucuparia)
The
Mountain Ash, or Rowan, as it is called in Scotland, is one our most
handsome trees. It is a glorious sight in May with its large, shapely,
pinnate leaves and large panicles of creamy-white flowers, which often
almost conceal its foliage. In the autumn its masses of bright, orange-red
berries, shading to scarlet, make it a striking and very ornamental part
of the landscape.
It is a
tree of broken precipices and wild rocky hillsides, where it struggles
upwards at many strange angles, its roots pushing deep down into the rock
crevices and anchoring it securely against the winter gales. It is in
these places the Rowan is to be seen at its best. It is also frequent in
the forests and woods. In young woods it grows quickly, but once it
attains the height of fifteen to thirty feet in grows but little, and on
being overtopped and overshadowed by other trees, it seems to give up the
life struggle and gradually disappears from the flora.
On the
rocky hillsides, however, there are few or no tree high enough to overtop
it, indeed few except the birch even to compete with it and so, where
sheltered from too much exposure to the wind, it attains its finest
development.
The trunk
is usually straight and branches at the middle to give the tree a very
bushy appearance.
The
leaves are very beautiful, and remind one forcibly of those of the Common
Ash which, however, belongs to a different family. Each leaf is a large
structure and consists of six or seven pairs of leaflets and an odd,
terminal one. Each leaflet has a very short stalk, is oblong in form, and
its margin is serrate, ie. toothed like a saw. They are smooth above, but
the lower surface is covered by a grayish down. These graceful leaves, by
being cut up into many leaflets, offer less resistance to strong winds
than a large, simple leaf would do. For this reason trees which usually
grow in exposed situations have small leaves, e.g. birch, conifers and
aspen.
The
flowers are displayed in dense, branched corymbs at the extremity of the
branches. They are produced in such profusion that the tree appears to be
a mass of bloom in May, the leaves being almost hidden.
Each
flower is a miniature rose in form. The cup-shaped calyx is covered in
grayish down and adheres completely to the ovary, its five loves
alternating with the creamy-white petals. The stamens are numerous and
form a ring around the three spreading styles.
The
flowers produce a very sweet, almost sickly perfume which attracts myriads
of honey -bees to partake of the abundant nectar secreted at the base of
the calyx cup.
After
fertilization the calyx and ovary swell and become fleshy, to form a
rounded, orange-scarlet berry, or rather a pome, which is constructed in a
similar fashion to that of the apple. In this plant both calyx and ovary
share n the formation of the fruit.
The ripe
berries are greedily devoured by thrushes and blackbirds. The seeds pass
through the birds without damage, the birds’ digestive juices actually
aiding germination by softening the hard seed-coat.
This is
very efficient manner of seed distribution as the birds may fly a long
distance from the parent tree before dropping the seeds. It must be
remembered also that the seed is dropped along with other waste matter
which it can use whilst a seedling. It thus get a good send off on its
life struggle.
Aspen (Populus tremula)
This is
another common tree in Highland woods and is a member of the Poplar tribe
which is included in the Willow Family. It may be found up to 1,600 feet
in the Highlands and is thus quite a hardy tree. It rarely forms a pure
wood, but is found scattered among the other forest denizens.
It does
not attain a very great size. Its root system is rather extensive, but
the roots do not descend very deeply into the soil. For this reason it
sis more common on damp soils where there is little risk from drought.
The roots send up large numbers of suckers which form thickets around the
base of the tree. These scarcely develop in the woodlands as they are in
the shadow of other trees. In more open situations, however, they form a
ring of vegetation around the tree and may develop into tress themselves.
The Aspen
is remarkable for its peculiar, restless foliage which seems to be in a
state of perpetual motion, even on the calmest day in summer. The old
Highlanders believed this was so because of the Cross of Calvary was made
from aspen woods and for this reason it leaves can never rest.
The
reason for this restlessness is due to the fact that the long leaf stalk
is compressed vertically in its upper part and is hence too weak to keep
the leaf in a horizontal position, thus the slightest breeze is enough to
put it in motion.
The
leaves are small and rounded in form, of a thin texture, and with a
toothed margin. They are deep green above, but almost silvery beneath
although they are completely smooth. As they tremble in the wind, the
alternation of dark and light surfaces gives a very strange and yet
beautiful effect, which is accentuated when the tree is seen against the
dark foliage of a pine corpse, or against the background of black clouds
preceding a thunderstorm in summer.
The
flowers of the Aspen like those of the Sallow are produced before the
leaves. To find them we must visit the tree in early April in the
Highlands. The tree will then be seen to be covered by large, wolly
catkins which look, for all the world, like large, hairy caterpillars.
The male catkins are produced on different trees from the females.
The
flowers are constructed similarly to those of the Willow, but the scales
are deeply divided and are covered with long, brownish hairs. The catkins
differ from those of the Willow in the fact that they are always pendant.
This is because they are completely dependent on the wind for pollination
and in their hanging position can take full advantage of the wind, and as
they sway the pollen is shaken out of the anthers and transported in a
cloud to the female catkins. The male flowers each have seven or eight
stamens as against one or two in the Willow. This is because the wind
pollination must be produced to make pollination more certain. Fort his
reason also the stigmas are much larger than in the Willow.
After
fertilization the ovary forms a green capsule in which many seeds are
produced. From each seed arises a tuft of long, silky hairs. In the
summer of the capsules open and hosts of silky seeds fly away long
distances upon the breeze, to fall far from the parent plant.
This tree
is thus dependent on the wind for its existence, as without it, its
flowers could not be pollinated and its seed could not be distributed. |
