Landscape history of the riverside alder forests in Sopron Mountains (W Hungary)

Abstract

The authors aimed to examine the development and changes of riverside alder forests of Sopron Mountains during the last 230 years. Various historical map series, six archive and actual aerial photo series were analyzed using GIS and historical forestry data as well as all the extant forestry management plans of the Mountains were evaluated.
The territory of the present riverside alder forests of Sopron Mountains (except for the narrowest valleys) was undoubtedly covered by grass vegetation in the 1780’s and presumably also during the former centuries. These grasslands could have been hay meadows with shrubs, tall herb fringe communities or seldom mixtures of fen meadows and sedge meadows with narrow riverside row of trees or their small patches. The extension of the grasslands was the same until the beginning of the 20^th century; they covered all the broad valleys, regularly reaching the hill-sides as well. Their extension reduced drastically during the 20^th century. Although few specimens of black alder occurred along all the streams of the Mountains before the beginning of the 20^th century, the extension of the riverside alder forests could have been inconsiderable. They were restricted only to narrow stripes in the streamside areas or bordered the grasslands of the bottoms of the wide and plain valleys.
In addition to these, in the narrow and steep valleys being forested centuries-long there were young and small alder stands (only some rows of trees), which were mainly coppice forests due to the constant clear cutting. At the beginning of the forest management according to management plans, the area covered by black alder reduced permanently due to the extensive coniferous plantations and at the same time, the spontaneous forestation of grasslands started because of the termination of grazing. Between 1884-1925, the area occupied by black alder was almost unchanged. The extension of alder forests in the narrow valleys of the Mountains didn’t change during the 20^th century, while in the wide and flat valleys it increased significantly, especially in the 1960-80’s. Today’s wide alder stands developed partly by spontaneous forestation of abandoned grasslands and partly by the forest planting launched at the end of the 19^th century, implemented mainly in the second half of the 20^th century. At present, riverside alder forests occur along all the streams of the Sopron Mountains, there are considerable stands in the areas of former grasslands, while in the narrow valleys they are restricted to narrow stripes.