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Carolinian forests have soils that are very well developed with
considerable organic matter from leaves that are deposited each
fall.
Autumn
leaf 'litter'. Photo by John MacRae. |
There
is usually a noticeable surface layer of leaf 'litter' present,
which allows an abundance of beetles and other invertebrates to
colonize the forest floor. It is also uncompacted and loose enough
to allow plants with underground storage organs such as bulbs to
thrive there.
These soils are typically moist due in part to the forest floor
being covered with leaf litter and shaded by the tree canopy. The
suns energy reaches the soil only in limited quantities and so water
in the soil does not evaporate very quickly.
Underneath the upper organic soil layer is a very different kind
of soil that can be found across most of Southern Ontario: glacial
till. You can get an idea of how deep this soil layer is by examining
ravines that are so common in this region and which may be many
metres deep. Look closely and you will discover the inorganic character
of this glacial till soil underneath the more organic soil layer.
| 'glacial
till': a jumble of materials that has been deposited by
glaciers as they advance or retreat across a landscape, including
boulders, rocks and gravel in a matrix of sand, clay or silt. |
| 'organic':
a word with several meanings, in this context it means having
its origins in living material such as decomposed plant tissues. |
Glacial
till underlies all of the terrestrial habitats in the Hamilton area
(other than the Escarpment), but forest ravines are one of the easiest
places to see it yourself — a unique treat!
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