The largest of the protected areas of the Harghita mountain range is the Lucs peat bog in the Nagykő-Bükke crater, above Sâncrăieni, at the junction of the road leading to the Stinky Bath of Sâncrăieni.The oligotrophic (minor mineral content) marsh located at an altitude of 1080 m on an area of 273 hectares is actually the peaty remnants of a former crater lake, which is also the largest peat bog in Transylvania.
The mats of more than 20 species of variegated peat moss (Sphagnum) are interspersed with peat rosemary (Andromeda Polifolia), cranberry (Vaccinium Oxycoccus), insectivorous plant, i.e. the three varieties of dewgrass (Drosera Rotundifolia, -Obovata, -Longifolia), crowberry (Empetrum Nigrum), woollen violet (Eriphorum Vaginatum), cranberry or "sour cherry" (Vaccinium Vitisidea) and bilberry or coconut (Vaccinium Uliginosum). They are accompanied by the very stunted pine and the vulgar birch, erroneously called dwarf birch, which is unable to grow to normal size on nutrient-poor soil, but there is also a very rare plant that lives nowhere else in the county, namely the relative of the dwarf birch (Betula Humilis), the tiny birch (Betula Nana), which is a tiny shrub growing only 60 cm high! It is a botanical delicacy that should not be confused with its larger brother. Both habitats reach their southernmost point here, and both are strictly protected plant rarities. The popular name of the spruce tree was fixed in the name of Lucsos, where we do not find black gleaming sea-grains, but the swamp is very wet, impassable, full of rotting pine and bear-vacks.
The marsh and the surrounding hillsides were declared a nature reserve in 1955 with an area of 273 ha. Today it is also a Natura 2000 site for the protection of habitats (ROSCI0246.
The moor was formed by the recharge of a former crater lake. Due to the low level of oxygen, organic matter is not fully degraded and thus does not return to the material cycle, especially important for carbon, nitrogen and phosphorus. This is how peatification starts, with which these substances are withdrawn from the cycle. As a result, the replenishment of the moor slows down and nutrient-poor, oligotrophic conditions develop, where specialised plants are able to survive. These plants are very widespread in the northern tundras, but they are very rare in temperate climates, and this makes Lucs special.
The peat bog, about 4.5 m thick, preserves rare ice age remnants like Mohos. The most notable of the relics is the tiny or tiny birch (Betula nana), which has the southernmost point of occurrence in the world. But here you can find peat moss (Sphagnum species), round-leaved dewgrass (Drosera rotundifolia), leguminous woolly locust (Eriophorum vaginatum), black crowberry (Empetrum nigrum), peat violet (Viola epipsila), cranberries, peatgrass, red and bilberry. The wet, sloppy soil covered with sloping peat moss may refer to the name of the wetland. According to other opinions, the forest-pine stand on the moor, which the locals call spruce-pine, gave the name of Lúcsos.
Small pine (Pinus sylvestris) and common birch (Betula pendula) give the moor a tundra appearance. The most important speciality of the moor, however, is the tiny birch (Betula nana), which has the southernmost point of occurrence in the world. Today it occurs in very small numbers in the moor and is therefore endangered. The soil is covered with a sloping peat moss (Sphagnum species) carpet. Among herbaceous plants there is the round-leaved dewgrass (Drosera rotundifolia), which covers the nitrogen deficiency with insects trapped by its leaves.
It breaks down insects with the help of enzymes, after which nutrients are absorbed into the leaf. In addition, leguminous woollings (Eriophorum vaginatum), cranberries (Vaccinium oxycoccos ), peatgrass(Andromeda polyfolia), intoxicants (Empetrum nigrum), red and bilberries (Vaccinium vitis-idaea and V. myrtillus).
The reptile species typical of the wetlands are the live-bearing lizard (Zootoca vivipara) and the crusader (Vipera berus), while puddles formed on forest-growing roads along its edge are breeding grounds for relatively many amphibian species: Carpathian newt (Triturus montandoni), Alpine newt (T. alpestris), spotted and crested newt (T. vulgaris and T. cristatus), yellow-bellied toad (Bombina variegata), turf frog (Rana temporaria), brown toad (Bufo bufo).
Its large wild population is typical of the surrounding forests, where brown bears( Ursus arctos), red deer (Cervus elaphus), wild boar (Sus scrofa), roe deer (Capreolus capreolus), wolves (Canis lupus) andlynx ( Lynx lynx) are common.
Due to its remoteness, the protected area is less exposed to external influences, with the exception of grazing and forest production on the margins of the bog.
The moor is large and difficult to navigate due to the monotonous vegetation in many places, so your visit requires special attention.
Two streams flow from the Lucsos. The Kormos stream collects and drains the moor in the southwest towards Erdővidék, while the Nagyos stream drains the water in the east towards Sâncrăieni.
