Declared at the turn of the years 1967-1968, the Jizerské hory Mountains PLA covers the territory of Jizerské hory Mountains (with the exception of the ridge Černostudnicní hřeben), which is more or less delimited by the towns of Liberec, Frýdlant, Nové Město pod Smrkem, Kořenov, Tanvald and Jablonec nad Nisou. In the east, it extends toward the Polish border, while also sharing its boundaries with Krkonoše National Park.
The PLA is an area of 368 sq km. The forest cover stretches over 73% of the region (269 sq km), which was one of the reasons for the protected status. The lowest PLA point (325 m above sea level) is located at Raspenava, whilst the highest mountain top in the Czech part of the Jizerské hory Mountains is Smrk with its elevation of 1124 m. Other major summits include Bukovec (1005 m above sea level), which is the highest basalt heap in Central Europe.
The long-term immission load on the Jizerské hory Mountains caused mainly due to the Zittau Basin industrial area had negative effects on health of the forests, soil conditions and water quality. The negative action of air pollution, along with the invasion of insect pests and improper forest management, culminated in the 1970s and especially in the 1980s. At that time, large-scale logging took place, which virtually removed all the spruce stands throughout the plateau creating extensive clearings, the reforestation of which is something the forest managers have been facing until now.
These vast areas cleared due to immission as well as damaged forest stands on the one hand and extremely valuable parts with preserved natural communities on the other hand, which especially involves the large complex of beech forests on the northern slopes of the mountains, the remnants of climax spruce forests and unique peat bog communities of rare flora and fauna make this protected area one of very contrasting territories.
The non-forest landscape with prevailing meadows and grazing land plus well-preserved buildings of traditional vernacular architecture is another important part of the PLA. In addition to the forest-related issues, which includes high numbers of game, a threat of degradation of foothill grasslands and pastures due to reduced farming operations appeared very recently.
The aim of nature conservation is to preserve valuable ecosystems as well as making the best efforts to completely restore the damaged natural environments, whilst giving enough space for social and economic life of municipalities and sustainable activities in recreation and sports.