Grass cover on forest clear-cut areas ameliorates some soil chemical properties.

Clear-cut areas formed after forest decline due to acid deposition, pest attacks, or wind-breaks in temperate mountainous regions are often populated by grass (mainly Calamagrostis villosa). This study focused on the changes of soil chemical characteristics under the grass cover replacing the forest, focusing mainly on aluminium (Al) speciation. Clear-cut area due to strong acid deposition in the Jizera Mountains (Northern Bohemia) was studied. The soils under grass cover exhibit higher pH values and lower exchangeable Al content compared to adjacent surviving forest. Mobile Al species under the grass have larger proportion of non-toxic organic complexes. The content of exchangeable base cations is slightly higher under the grass. The positive effect of grass on soil chemistry was enhanced by liming. The temporary grass cover can therefore improve soil chemical quality for following reforestation. However, the differences are generally limited to surface organic horizons. Similar results were found also on a bark-beetle clear-cut area in the Bohemian Forest (Southern Bohemia) with smaller acid deposition; nevertheless, most differences were not significant there.