The Făgăraş and Retezat ranges are the highest ranges in the South Carpathians (the highest peak in the Făgăraş range is Moldoveanu 2543 m, in the Retezat range - Peleaga 2509 m). They very much resemble the High Tatras, were however less glaciated. Glaciers formed there only the upper reaches of valleys or remained only in cirques. The glacial relief does not cause any considerable variation in the course of the upper forest line, as is the case in the High Tatras. Fundamental factors influencing the altitude of the forest line are: the climate, the massiveness and the height of the ranges. Both above-mentioned ranges are only slightly lower than the High Tatras. On the other hand, the highest-situated localities of the original forest line in the Retezat range reach the altitude of at least 2850 m, which is approximately 200 m higher than in the High Tatras. The most important factor - which causes the difference in the altitude - is the continental climate, i. e. higher temperatures in summer in the area of the South Carpathians. The average July temperature of air in the mountains areas in the South Carpathians is circa 2,5 °C higher than temperatures at the same altitudes in he Carpathians. Small occurence of the stone fields in the area of the forest line in the Retezat and Făgăraş ranges most favourably influence its course and its tendency to steadiness, which is not the case in the High Tatras or the Ďumbier Group in the Low Tatras. In the Retezat range in the area of the upper forest line and above in the occurrence of any typical "flag-like" forms of trees is scarce. The typicality of forms is more subdued here than in our ranges although the altitude of the forest line in the South Carpathians lies much higher. The main reason for these differences is given by the fact that due to the increasing distance from the Atlantic Ocean the influence of winds strongly decreases so that mechanical and physiological effects upon trees in the area of the forest line in the South Carpathians are considerably smaller than in the Tatras. The upper forest line in the Retezat and Făgăraş ranges is formed by spruce (Picea excelsa Link) together with Pinus cembra L. which retains the form of a tree almost up to the altitude of 2000 m. At the present it frequently occurs in the National Parc Retezat. In some places, however, where cattle are grazing intensively it has retreated partly or completely. The present course of the upper forest line has been strongly influenced by man grazing large herds of cattle in these areas. In South Carpathians it is a common phenomenon at the present that forests as well as the mountain pine (Pinus mugo TURRA) are removed by fire. Over large distances the upper forest line has been lowered almost by 300-400 m. Most intensive deforestation takes place in the Făgăraş range in the area of the upper forest line and above it.
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