The Przylesie nature reserve was established by the order of the Minister of Forestry and Timber Industry No. 70 of June 20, 1969. Initially, it covered an area of 14.94 ha. Currently, it covers an area of 17.24 ha (about 5% of the Wysoki Las area), and it is planned to extend it to an area of 30 ha.
The area of the reserve is under strict protection. The reserve protects a fragment of deciduous forests of natural origin, forming transitional forms from oak-hornbeam forests to alders and alder-ash riparian forests. The stand of the reserve part of the forest is single (alder and ash stands with maple and sycamore seedlings) or two-story (upper floor - dominance of pedunculate oak and, as it is supposed, Burgundian oak, lower - hornbeam, ash, sycamore maple, elm, linden) ). The 200-year-old oak stand, which is unique in the whole country, looks particularly impressive. 7 species of protected plants (as of 2012) have been found in the reserve, these are: white sandbuckle (Platanthera bifolia), green grasshopper (Galium odoratum), daphne mezereum (Daphne mezereum), European grasshopper (Asarum europaeum), coral viburnum (Viburnum) opulus), lily of the valley (Convallaria majalis) and common ivy (Hedera helix).