RESUME

ICP Forests - Results of survey in the CR in 1999
Petr Fabiánek, Jitka Hejdová (pp. 540-541)

Since 1986, the forest quality in the Czech Republic has been assessed by field surveys on monitoring plots of the 1st degree winthin the international co-operative EEC programme - ICP Forests- which deals with monitoring and evaluation of air pollution impact on forests. At present a regular survey is pursued on 100 monitoring plots of the supra-national network 16x16 km and on 200 selected plots of the national network 8x8 km located over the whole Czech territory equally by forest coverage.

In coniferous 60-year and older stands a moderate deterioration compared to the last year’s situation occurred. The defoliation class 2 rose from 57.4 % in 1998 to 62.6 % in 1999. This shift manifested in all surveyed coniferous species mostly uniformly. In the same age category of deciduous species the compariso with the last year’s defoliation is similar. The most noticeable shift can be observed in the class 0, the value of which dropped from 30.1 % in 1998 to 21.0 % in 1999. The greatest participation in this change had the European beech (Fagus sylvatica), whose share in the class dropped from 44.7 % in 1998 to 26.3 % in 1999. A more marked defoliation occurred in younger stands compared to the older ones.

In coniferous stands younger than 59 years the participation in the 2nd defoliation class rose from 7.5 % in 1998 to 20.2 % in 1999. Out of the analysed species the shift was the greatest in Scots pine(Pinus sylvestris); the class rose from 9.3 % in 1998 to 39.4 % in 1999.

In younger deciduous stands the greatest shift occurred in the class 0 from 53.3 % in 1998 to 43.5 % in 1999. In the most frequent deciduous species (Quercus spp., Fagus sylvatica) the change was mutually uniform. Damage by wind (breaks, blowdowns), and leaf-eating insects, and occurrence of epiphytes were recorded about the same like in the last year. The trend of bark-eating insects drops slowly.

The 1999 year was less favourable as for the course of temperatures and precipitation compared to the previous year. The climate irregularity, namely the lack of precipitation in the second half of the vegetation period, represented one of the decisive adverse factors affecting the partial increase in forest species defoliation. The decrease in a total sulphur oxides and solid material emissions continued like in the recent years. The emissions of other polluting materials (NOx, CO, CxHy) have stayed approximately on the same level since 1995. The ozone exposition index value AOT40 for forests was markedly higher in 1998 than in 1997 and this increase probably affected adversely the crown defoliation in 1999.

The development of forest species defoliation in the nineties can be considered a marked divide from the view of long-term forest conditions trend. The growing trend of defoliation culminated approximately in the mid nineties and has been slowly decreasing in the following years.

First verification results of European larch progeny from seed material produced in seed orchards.
Jiří Šindelář, Josef Frýdl (pp. 546-549)

The article summarizes results of the first observations performed at seven permanent sample plots established in order to compare and classify the progeny of European larch seed orchards. In practice, the experiment should result in verification of genetic value of seed orchards and classification of the most valuable units into the category of verified reproduction sources. 37 progenies grown from seed material harvested in 19 seed orchards in different years were involved into the experiment established by general methods. The material was planted in three replications at seven sample plots on plarcels sized 10x10 m with 50 individuals in one parcel. A comparative standard was represented by a progeny of certified seed stand (Opočno provenance). At the age of 5, number of growing individuals and hight growth of progeny were registered at the sample plots. Based on the results two seed orchards were right to register (Znojmo - Tvořihráz, Bučovice - Mouřínov) as units the progeny of which significantly exceed a standard population by their parameters. With regards to the age of evaluated material the results have to be assumed preliminary, eligible to be applied as ongoing observations related to the planned evaluation of plantings in intermediate stages.