Forest makeover of excavation

Already this year the Gołąbki Forest District (RDSF in Toruń) is starting to reclaim the excavations of the abandoned aggregate mine. The project will take four years and the first effects will be visible in a few months.
14.06.2017 | Kazimierz Popiel, Gołąbki Forest District

Already this year the Gołąbki Forest District (RDSF in Toruń) is starting to reclaim the excavations of the abandoned aggregate mine. The project will take four years and the first effects will be visible in a few months.

In the 1990s, Gołąbki Forest District took over the excavation area left after aggregate mining. The area of former mine occupies almost 6 hectares in Szczepanowo forestry unit. Unfortunately, several-meter deep excavation pits and steep slopes make it impossible to grow trees which would be useful for forest management.

The ‘gap-like’ character of the tree stand there causes trees to take on shrub forms: low branched, multi-shoot and gnarled. In addition, very often the tree stems failed to develop properly in the juvenile phase when their low branches are to be pruned and therefore the plants are deprived of good potential main shoots.

A lack of biologically active soil is also a problem because the organic layer is left at the parent rock level. In such altered and ploughed up area there is also a problem with the groundwater retention and the permeability of soil does not ensure the maintenance of precipitation.

At present, this area is being overgrown with shrubs and pioneer species of trees, e.g. willow, aspen or birch. Places exposed to light, free from trees, are used by herbaceous plants, mainly species of ruderal, synanthropic and forest communities such as wavy hair-grass (Deschampsia flexuosa), wood bluegrass (Poa nemoralis), wood small-reed (Calamagrostis epigejos), garlic mustard (Alliaria petiolata) and Canadian horseweed (Conyza canadensis). In addition to vascular plants, mosses and lichens appear which indicate that the environment is clean and the air is free from harmful emissions.

Foresters have a plan how to reclaim and use the former mine by the forest district.

Already in the fourth quarter of this year, the area will be deshrubbed and cleaned up, also a few-meter layer of clay soil from a nearby mine will be brought there, after that the whole area will be leveled. The clay soil is pH neutral or weakly alkaline and is rich in nutrients.

Cutting off undesired vegetation, cleaning up the terrain and bringing a few-meter layer of clay soil will enable the establishment of a forest plantation. The total cost of all work is estimated at 120 thousand PLN, which means the forest district will spend on this purpose about 30 thousand PLN annually.

The designed species composition will be appropriate for the oak-hornbeam communities, in a slightly depleted version but close to this habitat potential. Therefore, mainly deciduous species will appear, including: oak, sycamore, lime and hornbeam.

Mycorrhized planting material with covered root system will be most recommended. Wherever possible and justified by the quality of the existing trees, the most valuable fragments may become both a shelter for the artificial plantings and their supplements. It is also possible to use a part of the area for the associated plantation of small-leaved linden, which would be based on seed material coming from the plantations in the area of RDSF in Toruń.

The requirements of sensitive biocenotic species will be taken into account while establishing wide ecotonal zones.

The plantations and sapling stands growing on the fertile clay will gain in time the breeding characteristics of such a stand which would serve the purpose of forest management. This is not the only benefit resulting from the restoration of the primeval nature of this area. The next will be developing new, complex ecological structures being the natural controller of humidity and groundwater level, or creating conditions for forest flora, fauna and fungi.