|
|
|
<<
back |
|
 Flora
Puszcza Bia這wieska is one of the most precious
places in Europe from the point of view of the rich flora. It has
features of a lowland primeval forest, which does not exist in any
other part of Europe any more... |
 |
The Bia這wie瘸 Forest
is the place where the last remains of European Lowland primeval
woods have been preserved. Numerous species of organisms which
became extinct in other places have survived here thanks to many
centuries of protection. Moreover, in the Bia這wie瘸 Forest many
common species take forms and sizes that cannot be found anywhere
else. It refers especially to trees. Good examples of this natural
phenomenon are lindens, which resemble oaks in the Forest. The same
refers to sallows, growing as high as 22 m and reaching 40 cm in
diameter, although they are well known as big bushes in the rest of
Europe. Protection of the Bia這wie瘸 Forest has secured not only the
survival of single species, but also of species groups and natural
spatial composition of plant communities. Landscape of the
Bia這wie瘸 Forest consists mainly of woodlands, which constitute
about 96 percent of the whole area. The rest are fields, meadows,
roads, wastelands as well as flowing and standing waters. During the
last ten years the non-forest area has been shrinking quite fast, as
the forest returns naturally to deserted fields and meadows.
The predominant woodland type in the Bia這wie瘸 Forest is gr康 (a
kind of deciduous forest) which constitutes about 47 percent of the
forest area. Bory (coniferous forests) constitute 37 percent and wet
deciduous and mixed forests about 14.5 percent of the area. The
forest stand consists mainly of Norway spruce - 26 percent, Scotch
pine - 24 percent, European alder - 17 percent, pedunculate oak - 12
percent, as well as birch species: European White Birch and downy
birch - 11 percent. Common ash, small leafed lime, Norway maple,
aspen and elms constitute an admixture in the species composition of
the forest stand, even though in some areas they are the predominant
species. Even though the hornbeam is considered a very common
species, it can be mainly seen in the second level of the forest
stand and is very rarely encountered in the species composition of
the main forest stand. In comparison with other Polish woodlands,
the forests of Bia這wie瘸 are characterised by relatively good
preservation of forest stand of natural origin. Almost 40 percent of
the forest area is covered with trees which are more than 80 years
old. The average age of the forest stand is 73 years in the
cultivated part and 130 years in the Special Protection Area of the
Bia這wie瘸 National Park. One of characteristic features of the
Bia這wie瘸 forest-stands is their complex, multilayer and
multi-species structure and age diversity. Protected forest stands
in the Special Protection Area of the Bia這wie瘸 National Park still
have the features of old, primeval, lowland woods, where it was the
Nature, not man, who decided on the species composition and
forest-stand structure.
The most significant factors which influence the species composition
of plant communities on a given area are humidity and the type of
soil (these features decide about the habitats fertility). This
interdependence is very strong in the case of both described
features. The species composition in forests growing on fertile soil
will be totally different from that in forests on poor-quality soil,
even though the humidity is the same. There will be also significant
differences in the case of forests growing on similar soils, but
with different humidity conditions.
A natural mosaic of plant communities has survived in many parts of
the Bia這wie瘸 Forest. The arrangement of forest communities is most
characteristic and schematic in the water-course valleys. It is
easiest to observe when going perpendicularly to the axis of a
stream or a river. Going away from the river, as the ground raises,
one can see the following succession: swampy meadow, gr康 [deciduous
forest] (starting from the humid variant up to the less humid
variants), mixed b鏎 [predominantly coniferous forest], until,
finally, on completely dry and sandy soil one gets into pine
forests. This relatively clear arrangement is disturbed by hollows
without any water outlet, situated on impermeable soil. Such places,
characterised by high, rapidly changing humidity, are typically
covered by ols [swampy alder forest]. In places where humidity level
is constantly high one can see high peat bogs, which are often
covered by swampy coniferous woods.
Among the Bia這wie瘸 plants, the group of vascular plants is the
most numerous - it amounts to over one thousand species, including
19 species of fern, 6 - of club mosses, 7 - horsetails, 54 species
of liverworts and over 200 of mosses. Many species of mosses and
lichens, which probably used to be widespread, have survived only in
such places as the Bia這wie瘸 Forest. They can be encountered only
in the primeval areas, where the natural conditions and human
interference (or rather the lack of it) have made it possible for
them to survive. Most of them are dependent on decaying wood or
trunks, boughs and bark of old trees. Their presence determines the
unique character of the Forest and indicates the preservation level
of its natural resources.
Apart from single plant species, there are also rare plant groups
which have survived in the Forest. Spruce wood growing on peat bogs
- a very rarely encountered forest community in Poland, belongs to
this group. Major characteristics of such spruce woods are: a clear
domination of spruce in the forest stand, almost complete absence of
deciduous trees as well as very rich peat-moss ground cover,
including such rare species as heartleaf twayblade or small
cranberry.
Vascular plants of the Bia這wie瘸 Forest have been relatively
well-explored, even though it does not mean that the species list
has already been closed. Despite the forest thickness, out of 1070
affirmed vascular plants only 664 species can be treated as the
natural components of the Forest ecosystems. The rest are species
which have entered the Forest as a result of human influence. There
are 353 such species and their number is still growing. Some of the
species which have been considered as extinct can be still present
here. An example of an extremely rare plant species is the ghost
orchid, the presence of which has been confirmed on the basis of
single observations in 1888, 1889, 1925, 1930 and 1996.
The most numerous vascular plant families in the Bia這wie瘸 Forest
are:
- the aster family (Compositae) - 108 species,
- the grass family (Graminae) - 85
- the sedge family (Cyperaceae) - 66
- the rose family (Rosaceae) - 59
- the Papilionaceae family (Papilionaceae) - 54
- the pink family (Caryophyllaceae) - 43
- the figwort family (Scrophulariaceae) - 41
- the mint family (Labiateae) - 41
- the Crucifereae family (Crucifereae) - 40
- the buttercup family (Ranunculaceae) - 35
- the Umbelifereae family (Umbelifereae) - 32
- the orchid family (Orchidaceae) - 24
- the buckwheat family (Polygonaceae) - 24
Among the vascular plants in the Forest there are 96 species with
lignified shoots:
trees (26 species), bushes (55) and shrubs (14).
These numbers include also the ambiguous species (gooseberry and
wild apple-tree, Carpathian birch and black poplar) as well as
extinct species (yew tree).
|
|
|
|
Flora - Puszcza Bia這wieska
|
|
