| Dr.hab.geogr. Maris
Laivins
FOREST TYPOLOGY
To characterise the diversity of forest types the best
option is using forest typological division. Nowadays, in
forest typology the system developed K. Buss 20 years ago is
applied and includes 23 forest types (Buss 1976; 1981).
According to moisture conditions forest types are
classified into 5 orders:
- Forests on dry mineral soils
(Cladinoso-callunosa, Vacciniosa, Myrtillosa, Hylocomiosa,
Oxalidosa, Aegopodiosa;
- Forests on wet mineral soils (the depth of the
peat layer does not reach 30 cm) (Calluno-sphagnosa),
Vaccinio-sphagnosa, Myrtilloso- sphagnosa,
Myrtilloso-polytrichosa, Dryopteriosa;
- Forests on wet peat soils (the depth of the peat
layer exceeds 30 cm) (Sphagnosa, Caricoso-phragmitosa,
Dryopterioso-caricosa, Filipeniidulosa);
- Forests on drained mineral soils (Callunosa mel.,
Vaccioniosa - mel., Myrtillosa-mel., Mercurialiosa-mel.);
- Forests on drained peaty soils (Callunosa
turf.mel., Vacciniosa turf.mel., Myrtillosa turf.mel.,
Oxalidosa turf.mel.).
According to soil or substrate fertility forests are
classified into three forest fertility types or trophic
groups:
- Forests on nutrient poor soils or oligotrophic
forests - cover 10.2% from the total forest area
(Cladinoso-callunosa, Vacciniosa, Calluno-sphagnosa,
Vaccinio-sphagnosa, Sphagnosa, Callunosa mel., Callunosa
turf.mel.);
- Forests on medium rich soils or mezotrophic forests
- cover 56.1% from the total forest area (Myrtillosa,
Hylocomiosa, Myrtilloso- sphagnosa, Caricoso-phragmitosa,
Dryopterioso-caricosa, Vaccioniosa - mel.,
Myrtillosa-mel., Vacciniosa turf.mel., Myrtillosa turf,
mel.);
- Forests on nutrient rich soils or eutrophic forests
- cover 33,7% from the total forest area (Oxalidosa,
Aegopodiosa, Myrtilloso-polytrichosa, Dryopteriosa,
Filipeniidulosa, Mercurialiosa-mel., Oxalidosa turf.mel.).
According to the main economic activity type (forest
drainage) that is human influenced forest productivity,
forests are classified into two large groups:
- Natural forest types (forests on normal moisture soils,
forests on wet mineral soils and forests on wet peat
soils);
- Antropogenic (human influenced) forest types.
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