In Hungary the growth trend of forests has been variable, but generally increasing over the last century. After and between the two World Wars the forest area changed considerably, especially due to numerous afforestations which increased the forest areas in the country. In 1920 the forest cover amounted to 11.7 % which had increased by 1992 to 18.5 %.
In 1950 the proportion of conifers was 6.3 %, and that of broad-leaved species was 93.7 %, while by 1990 the proportion was 15.7 % conifer and 84.3 % broad-leaved species. The growing stock and current annual increment have increased as well as the annual cut, which in most cases was less than the annual increment. The species composition of the forests has also changed in favour of conifers and fast-growing species.
The growing stock (m3/ha) increased during the period 19801990 for oak: from 202 to 219, for beech: from 350 to 358, for Turkey oak: from 204 to 217, for poplars: from 106 to 122, for black locust: from 125 to 119, for conifers: from 172 to 186. The species age group distribution is uneven, and in particular conifers are found in the younger age groups (140 years). Forest growth has been controlled for at least 35 years in a thousand long term research plots. For the last seven decades, since a 1920 forest-survey, data has been available, but the accuracy varies. The periods from 1950 to 1970 and from 1970 to 1980 are the periods for which increasingly accurate data is available concerning growing stock and increment.
The forest cover in Slovenia increased in the last century from 36 % in 1870 to 53 % in 1990. The growing stock per ha increased from 129 m3/ha in 1947 to 207 m3/ha in 1990 and the current annual increment also rose from 3.2 m3/ha/year to 5.3 m3/ha/year.
The tree species composition in Slovenie forests is as follows: spruce, 34 %; silver fir, 13 %; larch, 1 %; other conifers, 6 %; beech, 30 %; oaks, 8 %; other broad-leaved species, 8 %. The assumption that site productivity has changed during the last three decades in Slovenie forests is more than likely and has been validated by an extensive analysis of beech stands. However, this increase needs to be contrasted with a noticeable silver fir die-back, which has diminished forest growth.
The first forest survey was carried out in 1950, and systematically repeated every 10 years.
Key words: forest cover, trees composition, growing stock, current increment.
Correspondence: Marijan Kotar, University of Ljubljana, Biotechnical Faculty, Department of Forestry, Vecna pot 83, p.p. 95, 61111 Ljubljana, Slovenia
Fax: +386 61 271-169
E-mail: bf.gozdarstvo@uni-lj.si