The diversified relief of the terrain of ziemia chelminska (the
historical area situated between the rivers Vistula, Drweca and Osa)
was formed by a receding glacier during the last glacial period -
the Vistulian. The basic types of landscape of this region are
moraine plateaux and lake districts. Depending on the predominant
geomorfological forms itis possible to distinguish in it a number of
natural regions: the Basin of Torun, the Lower Vistula Valley, the
Drweca Valley and the Chelmno Plateau.
The Torun Basin is a lens-like expansion (up to 25 km wide) of the
ice-marginal valley of the Vistula - Notec - Warta. Its floor is
filled up with terraces descending from the uppermost one at 72-80
m a.s.l. to the flood terrace at 35 m a.s.l. On the upper terraces
there has developed a dune field, which is the largest form of this
type in Poland.
The gap reach of the Vistula Valley (from Bydgoszcz - Fordon) is
a younger valley reach than the Torun Basin, which is functionally
linked with Notec - Warta ice-marginal streamway. The steep (50-60 m
relative height) valley sides are cut by numerous deep erosional valleys
forming ravines. The width of the Vistula Valley, however, shows a lot
of variation. In the gap reach near Fordon it is ca 3 km, but it
increases sharply in the basins: the Unislaw Basin (9 km), the Chelmno
Basin (7.5 km) and the Grudziadz Basin (18 km). Those basins evolved
through lateral meander erosion of the Vistula after the river had
deflected north to the Baltic.
The Drweca Valley evolved during glaciation as an ice-marginal streamway
eroded by meltwaters flowing west to the Notec-Warta ice-marginal
streamway. It is 3 to 7 km wide and cuts into the ground to as much as
50-60 m deep.
The above described valleys are characterized by generally very steep
sides which together with considerable differences of level helps the
erosional and corrosional processes in the marginal zone degrading
systematically the adjoining moraine plateaux. Evidences of this are
numerous ravines and old erosional valleys in the valley sides.
In the morphological structure of the Chelmno Plateau three zones can
be distinguished, running more or less latitudinally. Moving from the
Drweca ice-marginalstreamway to the north, they are: the dead ice
forms zone, the zone of end moraines and glacial forms connected with
them, and the ground moraine zone. Typical of the landscape of the
first of them is the occurence of a large number of closed undrained
depressions developed as a result of melting of dead ice remnants and
of numerous convex forms developed in dead ice, such as kames and
eskers. The end moraines zone occurs in the central part of the Chelmno
Plateau. Characteristic elements of the relief of this part of plateau
are moraine hills (up to 25 m rel. height), numerous undrained
depressions, "pools", and lake channels. The ground moraine zone, devoid
completely of end moraine deposits, stretches over the northern part
of the Plateau between the end moraines and the Osa valley and is cut by
numerous channels.
A characteristic feature of the climate of Ziemia Chelminska is
the clear line separating the areas in the Vistula Valley with lower
precipitation (mean 525 mm) and the definitely better supplied with
water plateau areas. Generally speaking the amount of precipitation
rises eastward, coinciding with the rise in the absolute height of the
terrain. However, the water balance is unfavourable owing to the
rather low values of the annual precipitation (below the mean value
for Poland), which is reflected in water deficiency, particularly
in agriculture.
The soils of ziemia chelminska evolved mainly on moraine and fluvioglacial
deposits, and a small percentage of them on fluvial and organic ones.
On the plateau there occur mainly brown and grey-lessive soils, which
constitute more than 50% of the area of the province of Torun. Podzolic
soils occupying ca 33.5% of the area of the province generally evolve
from previous nutrient-poor sands under the influence of dry pine forests.
Besides those there can be found scattered small enclaves of mucky and
peaty soils, black earths and alluvial soils distributed in river valleys,
kettles or outwash plains [2].
Long ago forests used to cover 90% of the area of the province of
Torun. With the expansion of agriculture the forest has been confined
to land considered too poor for farming, though even from those it
has been partly removed. At present larger forest complexes occur only
in the marginal zones of the plateau, and only 18% of the Torun province
is covered by forest communities. The worst blow for the primeval
forests of ziemia chelminska was the dynamic colonization of the country
and the legal and economic reform, or the so-called German Law, which
was in force from mid-XIII to XIV century
[3]. Vast areas of forest were
then cut down to leave space for farming as well as to get timber for
local needs and trade. Dendrochronological studies in historical buildings
of Torun and Chelmno have demonstrated that the XIV c. pine timber
was all obtained locally. Later, XV c. and younger timber constructions
in Torun were erected from pine trunks coming from distant places, and
most probably rafted to Torun, which may be regarded as evidence that
by the end of XIV c. local forests had been cut down
[1].