SOIL MICROFLORA IN AN AREA WHERE SPRUCE (PICEA-ABIES) WAS KILLED BY SO2 EMISSIONS AND WAS SUCCEEDED BY BIRCH (BETULA-PENDULA) AND MOUNTAIN ASH (SORBUS-AUCUPARIA)
A. Lettl et J. Hysek, SOIL MICROFLORA IN AN AREA WHERE SPRUCE (PICEA-ABIES) WAS KILLED BY SO2 EMISSIONS AND WAS SUCCEEDED BY BIRCH (BETULA-PENDULA) AND MOUNTAIN ASH (SORBUS-AUCUPARIA), Ecological engineering, 3(1), 1994, pp. 27-37
The spruce forests (Picea abies L. Karst.) in North Bohemia, Czech Rep
ublic, died under the influence of SO, emissions. We observed (1988-19
89) that the number of heterotrophic soil bacteria decreased in the de
composition horizons under the dead spruce trees, compared with the si
tuation under healthy spruce forest. The number of micromycetes increa
sed as a result of the influence of acid rain. The biochemical activit
y of soil microbes was reduced. The breakdown of cellulose and the oxi
dation of thiosulphate decreased as did respiration and ammonification
. After the demise of spruce forests the groundflora developed and pio
neer trees like birch (Betula pendula Rath.) and mountain ash (Sorbus
aucuparia L.) took over. The grasses produced enormous amounts of exud
ates and the leaf litter of new vegetation was well decomposed. There
were ample nutrients for soil microflora. The microbial communities (b
acteria plus micromycetes) increased greatly in organic soil horizons
of stands with a grassground cover and mineralization of carbon and ni
trogen compounds was more intensive there than under the dead spruce t
rees. Decomposition and mineralization of the plant titter was also mo
re intensive; the production of enzymes from the sulphur cycle increas
ed in the bacterial component of microbial communities. The microflora
of organic horizons increased under grass and after spruce had been r
eplaced by birch and mountain ash.