then the presence of the alpine formation, as it is called, in
a particular region, enables us to draw certain conclusions
as to the soil and cUmate of the region, and, conversely,
the existence of a particular type of cUmate and soil conditions
permits us to assume that an alpine community of plants
will be present— that is, we have a geographical generahsation
of great importance. Thus while systematic botany can in
the nature of things make an appeal only to a Umited number
of persons, ecological botany is of importance to all those
who are interested in the utilisation of the surface of the earth,
and that is practically to all humanity.

The broad distinctions of cUmate determine the existence
on the surface of a relatively small number of plant com-
munities, such as woodland, grassland, moorland, desert,
and so forth, and these the ecologist calls formations. But
while a particular type of formation, say the deciduous wood,
may reign over a considerable area, it is not constant in
characters throughout. Thus while oak-woods are frequent
over heavy soils in England, the type of oak-wood is not
always the same ; here we have a type in which the peduncu-
late oak predominates as a forest tree among lower shrubs,
and here one in which tall oaks are few and the shrubs are
the most conspicuous features of the wood. In both cases
it is found that there are associated groups of other plants
which depend more or less closely upon the presence of what
is called the dominant species. Such di\asions \vithin the
Umits of a formation are called associations, and within the
association there may be even smaller vegetation units, the
plant-societies. Meantime, however, it is sufficient for our



68 THE PLANT AND ITS HOME

purpose to recognise the distinction between the formation,
the larger unit, and the association, the smaller.

One other prehminary point must be noticed before we
proceed to consider the chief plant formations of Europe.
The continent, as we have already emphasised, has been the
home of civiHsation for a prolonged period. In consequence
the natural vegetation has been profoundly modified, and
in many cases it is impossible to reconstruct with certainty
the original formations. Nevertheless, the progress of plant
physiology, the study of the existing remnants of the original
vegetation, and historical research make it possible to arrive
at least at some general conclusions as to the appearance of
the plant covering of Europe before it had been radically
modified by man's activities, and these general conclusions
add interest to the study of present conditions.

From a consideration of the whole of the evidence it seems
fairly clear that at least the greater part of Europe, in the
sense in which we are using this term, was originally clothed
in what we may describe as temperate forest. From this
region of temperate forest the Mediterranean region is
excluded, for it had originally its own type of forest, which
persists in part. Further, the steppe region of southern
Russia has probably always had a greater or less extension
westward, though its original western boundary is obscure.

Outside these eastern and southern boundary zones, was
the temperate forest once continuous over Europe ? Pro-
bably not, though its exact limits are difficult to trace. At
present the western seaboard of the continent, especially in
North Germany, Holland and Belgium is largely without
forest, and we all know that treeless moors, or deer-' forests,'
have a very wide distribution in the Highlands of Scotland,
while in Ireland also there is relatively Httle wood. The
question whether these extensive moors and heaths have
always been devoid of trees is a difficult one, and the subject
is rendered additionally thorny by the fact that social and



THE LOESS AREAS 69

even political questions are more or less involved. It seems,
however, tolerably certain that there must always have been
a belt — of undetermined width— of treeless land on the
coast, where the wind rendered forest growth difficult. The
soil also on the moist seaboard is generally more or less
unsuitable for tree growth, though whether this is a primary
condition or a result of deforestation is a debated question.
But, as stated, we may be reasonably certain that before
man in Europe began to alter greatly the characters of the
surface, the widespread and extensive forests of continental
Europe and of the lower grounds of the British Islands
were generally separated from the seaboard by a belt of
moor and heath. Was this all ? Leaving aside the elevated
grounds, to which we shall return directly, we may note
that there is reason to believe that through the forest belt
there always went a band of ground with at best but thin
wood — a band of great importance in connection with the
development of European civihsation. Its origin requires
a Uttle consideration.

During the Ice Age, as can be readily shown by the deposits
left by the ice, the ice from the north overrode a considerable
area in the Netherlands, Germany, and so forth, descending,
for instance, in the west as far as the mouth of the Rhine,
and in the east to the region of the headwaters of the Oder
and the Vistula. At the same time the enlarged glaciers
of the Alps pushed northwards, but the two sheets did not
meet, and between them was a belt of land which at one
period was subjected to cold steppe conditions, and where,
apparently owing to the action of wind, a fine-grained, Ume-
containing deposit called loess accumulated in thick layers.
This loess, which is clay-Uke in appearance, extends from
Picardy to Poland, and includes some of what are now the
most fertile lands of Europe, those specially suited for wheat
and sugar-beet. The loess belt is continued into Russia,
where in part it is mingled with humus {i.e. material obtained



70 THE PLANT AND ITS HOME

from the decay of vegetable matter), and forms the soil of
the famous black earth region, before the war one of the
sources of our wheat.

The loess tracts, as we know from fossil remains, have
been from a very early period favourite regions with European
man. Before he had learnt to pohsh his stone implements,
when he was as yet but a hunter pursuing the animals of the
Ice Age, he hunted in the loess areas, where free movement
was probably relatively easy, where game was more abundant
than in the gloomy depths of the forest, where pitfalls for his
prey and perhaps dwelhngs for himself could be easily dug,
and through all the ages since he has never in Europe relaxed
his hold on these tracts.

Now we know that loess, though suitable for herbaceous
plants, is relatively unsuited to trees, and the loess areas,
so far back as we can trace history, have been at best scantily
wooded. According to some the treeless condition is primitive
— for Neohthic man sowed and reaped here, and his stone
axes, poUshed though they were, would hardly enable him
to effect clearings on a large scale. According to another
singularly ingenious hypothesis, the loess belt was clear of
trees at the end of the Ice Age, because of the steppe condi-
tions which then prevailed. It would, if left to itself, have
become gradually clothed with trees as the chmate improved
after the passing away of the ice, but by this time Neohthic
man had domesticated hoofed animals, and his grazing
herds prevented the estabhshment of forest even over the
tracts which he did not cultivate. This is of course not more
than an interesting guess, but the point of importance is that
in addition to the areas of natural grassland formed by the
eastern steppe, and the moors and heaths on the seaward
margin, Europe, even before man was dominant, contained
an inland belt of land adapted by its thin wood or scrub to
easy clearing with primitive implements, and allowing for
the grazing of herds. These loess lands were the lands of



THE FORMATIONS OF THE FOREST REGION 7i

early settlement, though the coastal lands were also settled
to some extent, as we know from the presence of ' kitchen-
middens.' Between such areas where settlement was rela-
tively easy lay the dark, impenetrable forest, difficult to clear
for primitive peoples, especially as the cUmate made the use
of fire somewhat difficult ; difficult also to plough when
cleared, as compared with the friable loess, and, owing to
its density probably sheltering but httle game, and offering
httle pasture for domesticated animals. These primeval
woods formed the real dividing lines between peoples, and
only their edges, or the natural clearings within them, could
be utihsed by the flocks. The presence of encircUng wood,
however, round the cultivated lands meant that the civihsa-
tion of Central Europe had" from the start a double basis —
the people were at once pastoral and agricultural. Later
the primitive woods were largely cleared by organised efiort,
and the existing forests of Central Europe are the greatly
modified and reduced descendants of the original nearly
continuous wood.

In addition, however, to the loess lands there were other
parts of Central Europe where the primitive forest was absent.
These are the regions which rise above the limi t where tree
growth is possible, and yet are able to produce a seasonal
growth of plants yielding rich fodder, and thus supplementing
the pastures of the lowlands. These are the regions which
are in summer covered with so varied a growth of Alpine
plants, some of which reappear in Arctic regions.

The net result is that the temperate forest region of Europe
offers at least three well-defined plant formations for study :
—(1) The remanants, often greatly modified, of the
original forest (chapter vii.) ; (2) The moors and heaths,
now often of great extent, found especially near the coastal
belt (chapter x.) ; (3) The Arctic-alpine formation of the
heights (chapter ix.), whether of the Alps, of the Scandinavian
mountains, or of the Scottish Highlands, where this flora is



72 THE PLANT AND ITS HOME

only moderately well-developed. Other formations, of more
limited extent, such as those of swamp or sand dune, also
occur, but studies of the three named are sufficient to give
an insight into the methods of the ecological botanist.

We shall discuss them briefly in separate chapters, but
meantime may add in a word that the fourth formation
which can be studied in Europe within easy reach of Great
Britain is that of the Mediterranean region (chapter viii.).
This region was once, in all probabihty, fairly well-forested,
but fragments only of the forest remain, in specially favoured
locaUties. Its special feature, as already suggested, is its
wealth of shrubs, which generally show adaptation to
summer drought, and of herbaceous plants whose activities
are confined to the moister season. Owing to the summer
drought pasture is difficult to obtain, and, except where
elevation or some other cause increases the local rainfall,
cattle tend to be scanty. While the civilisation of Central
Europe was based from the start on pastoral and agricultural
industries combined, that of the Mediterranean region was
always based on a combination of agriculture and fruit-
growing, which is a form of gardening.



CHAPTER VII

THE PRIMEVAL FOREST

' There rolls the deep where grew the tree.'

Wk have suggested in the last chapter that we have to think
of the greater part of Europe as originally forming a sea of
green, from which emerged like islands the higher mountains,
the loess belts, and a band of unknown width on the margin
of the ocean. Dr. Gradmann gives an interesting description
of the probable original hmits of this forest : — ' We obtain
the impression of a continuous primeval forest, stretching
from the Alps to the North Sea and the Baltic, from the
Atlantic coast to the plains of Hungary and the steppes of
Southern Russia, and, further to the north, continued into
the belt of wood which crosses Siberia. Only a few gaps
break the continuity of this primitive forest. Here are the
summits of the Alps and the Carpathians, and the more
important elevations of certain lower mountains, such as the
Sudetes, the Harz, the Black Forest, the Vosges, the Swiss
Jura, which raise their bare summits above the sea of wood.
Here are further the landes and heaths, the salt-marshes and
moors of the coast of the North Sea ; inland are some fresh-
water marshes and larger patches of moor ; except for these
the only gaps are the bare patches over rock falls and masses
of scree, or the clearings due to hghtning, gales, or heavy
snowfalls, destined to be regrown over within a short period.
Only on steep sunny slopes, and perhaps, in regions of very
great dryness, also on the plains, as in the case of the heaths
of South Bavaria, or of certain loess and chalk hills in Central

73



74 THE PRIMEVAL FOREST

Germany, have we to think of the wood as being somewhat
thinner — elsewhere there reigns unbroken the dense, con-
tinuous primeval forest.'

This primitive forest must have been to a very large extent
made up of broad-leaved trees, for the present predominance
of conifers is largely due to man's interference, a point to
which we shall return. Now such a broad-leaved temperate
forest is the characteristic plant formation of a moist chmate,
without excessive extremes. We have spoken of the climates
of Europe, and have distinguished between the oceanic type
which prevails within reach of Atlantic influences, and the
more extreme continental type which is present where these
influences fail to reach. But we must not forget that, com-
pared to Asia, the whole of Europe has a chmate which may
be described as oceanic — hence the contrast between the
broad-leaved forest of Europe and the steppes and coniferous
forests of temperate Asia.

The distribution of the beech, the typical broad-leaved
tree of the oceanic climate, is of great interest in this connec-
tion. Its eastern hmit almost coincides with that which we
have taken as the eastern hmit of Europe in the narrow sense
in which we defined this term in Chapter i. In the north-
west of Europe the beech occurs down to sea-level wherever
the chmate is warm enough ; thus it is absent as an indigenous
tree from the north of Norway and from Scotland, but forms
beautiful native woods in south-east England. But its
distribution is determined not only by the need for a tolerably
long warm period, but also by the fact that it requires a
large amount of moisture in its growing season. Thus its
eastern hmit is indicated, roughly speaking, by a hne from
Konigsberg to Odessa, though, after avoiding the Russian
steppes, it reappears in the Caucasus, where the elevation
brings greater moisture.

The summer drought excludes the tree from the whole
of the lower grounds within the Mediterranean region, but



OAK AND BEECH WOODS 75

it reappears so soon as elevation brings sufficient summer
rain, at least so far south as the mountains of Sicily, Castille
and Central Greece. So susceptible is it, however, to want
of rain, that it has only a Umited extension up the Rhone
valley from Geneva, dying out so soon as it ceases to feel
the moist breath of the lake, i.e. it does not extend very far
beyond the town of Martigny, though it is a very characteristic
plant of Switzerland generally. Again, it is absent from the
lower Rhone valley, as fi'om Provence and Languedoc gener-
ally, and only appears at the town of Lyons, where the
summer cUmate is moister. Thus the tree, which forms
beautiful woods in the vicinity of Lake Geneva, on the Swiss
plateau generally, in the Fore Alps and in the Jura, is worth
careful note, for its presence means that the climate in
summer is relatively moist, and the warm season prolonged.
In earher days, like the different kinds of oaks, the tree had
great economic importance, for its mast, in combination
with acorns, formed a very considerable part of the food of
the herds of pigs, ouce so supremely important in the Ufe
of the inhabitants of Europe. But these were the days
before winter food for cattle was available to any consider-
able extent, and when the fact that the flesh of pigs could be
readily preserved for winter use made the animals of great
value. They still, of course, retain considerable significance,
but the world's supply of swine is increased by the existence
of the maize belt of the United States, which suppUes abun-
dant cheap and fattening food, and has modified the whole
conditions of the trade. Acorn and beech mast cannot now
be said to affect the supply of pork or ham, except in certain
limited areas, e.g. to some extent in Serbia.

The distribution of the beech, as we have just shown,
emphasises the contrast between the oceanic cUmate, in its
various forms, and the Mediterranean one, for the beech will
not tolerate the typical Mediterranean chmate. But it is
worth note that while the beech underlines, as it were, the



76



THE PRIMEVAL FOREST



contrast between the mild moist summer of part of the
north-west and the hot dry summer of the Mediterranean
region, there are other plants of the forest which emphasise
the resemblance between the mild damp winter of the
Atlantic belt and the equally mild and also moist winter of
the Mediterranean. Because of the resemblance between
the two climates at this season certain Mediterranean plants

have succeeded in
extending their
range to the north-
west. The arbutus
(Fig. 8), which
flourishes in south-
west Ireland as it
does also in the
whole of the Medi-
terranean region, is
an excellent ex-
ample, and its pres-
ence indicates the
diSerence between
the climate of
south-west Ireland
and that of any
part of continental
Europe outside the
Mediterranean re-
gion. Another
example, somewhat less familiar, is that of black bryony.
Natives of the south of England, especially of the south-
west, are familiar with this plant from childhood, and feel
no surprise at seeing its graceful trails, -with their splendid
scarlet berries, twining round the bushes of the Alps. On
the other hand, to natives of north-eastern England, the
whole of Scotland, and by far the greater part of Ireland, no




Fio. 8. — The Strawberry tree (Arbutus), an ever-
green shrub or tree, native to the Mediterranean
but also extending to south-west Ireland, where
the mild climate suits it well.



TRANSITIONAL AREAS 77

less than to the Russian, the Austrian and the German, the
plant when first seen in the Alps is a treasure because an
entire stranger. It is a Mediterranean plant which found
its way first to the Alps, whither it was attracted by the
mountain chmate, which in some respects resembles that
of the ocean belt. From the Alps this plant has extended
its range westwards through France to England, Belgium and
so forth.

Many other examples could be given, but the point is
simply that while the broad-leaved ioix-st corresponds
generally to the oceanic chmate and the Mediterranean
scrub forest to the Mediterranean chmate, yet in nature
there are no hard and fast lines, and the transitions from
one type of chmate to another are marked by the plants,
the more adaptable forms of which are able to transgress
the Umits of their own chmate and estabhsh themselves
in neighbouring territory. Part of the reason why man has
thriven so well in Europe is due to the existence of these
numerous transitional belts, both of chmate and of vegeta-
tion, which have enabled him to thrust himself and his
chosen plants in along the hues of weakness, as it were, that
is, in the regions where the native plants had a less strong
hold than elsewhere. His grip of the loess belts through all
the period since his first appearance in Europe is an interest-
ing example of this, and from his points d'appui here and
in the Mediterranean region European man has succeeded in
spreading not only over the whole of Europe but over much
of the rest of the world also.

But what are we to say as to the special characters of the
European temperate forest ? The first point is that, speaking
broadly, the lower grounds and the more fertile regions, with
the exceptions already noted, were originally clothed in
broad-leaved forest, in which, there can be httle doubt,
oaks generally predominated, the beech taking its place in
special cases. Forest in which other trees predominated,



78 THE PRIMEVAL FOREST

like the ash-woods of the Enghsh limestone regions, were
probably always relatively rare.

In the higher latitudes, at the greater elevations, and in
less fertile regions conifers tended to predominate, often
accompanied, however, by the birch, which is very resistant
to cold and wind, and by the alder, which is especially the tree
of damp regions (Plate XV.). In general, as we all know,
conifers keep their leaves through the year, or are evergreen,
though to this statement the larch forms a famiHar exception.
As we shall see later, the Mediterranean forest also is typically
evergreen, so that we have to think of the deciduous broad-
leaved forest of Central Europe as being bounded to the
north and south ahke, no less than at its upper limit, by
evergreen trees. It may seem at first sight strange, in view
of what has been said as to the way in which plants respond
to the effect of the surrounding conditions, that the cold
blasts of the mountain heights, the cold, wind and snow of
high latitudes, and the hot dry air of the Mediterranean
region, should all alike lead to a predominance of evergreen
plants. The reason is in reahty relatively simple. Trees
with broad and tender leaves hke oak and beech divide their
year into two sharply contrasted periods. In winter they
economise water and offer the maximum resistance to cold,
wind and snow ; in summer they demand enormous quantities
of water and have no protection against cold or snow and
little against strong wind — but then they can only live in
climates and at elevations where such risks have not to be
faced in summer. Taking the Scots pine as a typical conifer,
we find that it is so shaped that snow sHps off its branches,
its slender leaves offer Httle resistance to wind, its tough
leaves aUke in summer and winter are protected against cold
and excessive loss of water. It remains, as it were, perma-
nently upon its guard (p. 63), but at any season of the year
can take advantage of favourable conditions, should these
occur. In the case of Mediterranean plants the chief risk



i'LAlK V




Scots pine in the Spey district. Note the characteristic rounded
forms of the hills in the backgroiuul.



NATIVE AND INTRODUCED TREES 79

is not from cold or wind, but from excessive loss of water,
which perhaps cannot be replaced ; these plants again there-
fore remain permanently protected, and present a general
resemblance in their evergreen condition to the northern
conifers, though the details of structure are quite different.

We have spoken of the tendency for oak and beech to pre-
dominate in the broad-leaved woods. They are not of
course the only forest-forming, broad-leaved trees even in
northern Europe, but the point is that the broad-leaved
forest at best contains a relatively small number of trees,
and that these are markedly social, tending to occur in almost
pure woods. This presence of a small number of species is
equally characteristic of the coniferous woods, and is indeed
a general feature of the vegetation of Europe. In the High-
lands of Scotland there occurs only one native forest-forming
conifer — the Scots pine (Plate V,). Switzerland has some half
a dozen forest-forming conifers, a number considerably greater,
but yet still small when compared with the wealth of species
found in western North America, just as the number of our
broad-leaved trees is insignificant as compared with those
found in eastern North America or eastern temperate Asia.

One consequence of this is that not only the majority of
the trees used for ornamental purposes, but even the species
employed in economic forestry are for the most part intro-
duced. It is one of the most interesting facts of geography,
that while Europe has given the recently developed temperate
parts of the world most of their cultivated plants, yet, on the
other hand, she is indebted to those recently developed regions
for a great number of the trees now grown — and in all proba-
bihty the two facts are related. Does this seem far-fetched ?
It is clear at least that the plough of the Ice Age made broad
its furrows over what was to be one great home of civihsed
man. It killed out or drove south very many plants which
once lived there, and which can still hve when reintroduced ;