In 1994 an interdisciplinary project was set оп two windthrow test sites of 10 to 20 ha of size each in the Central Ural. The study sites are located in the forest enterprises of Novaja Ljalja (Shajtanka) and Nishnije Sergi (Sergi). As part of an Russian-Swiss research project а longterm experiment with three different silvicultural treatments was initiated : one third of the experimental area was left untouched without any timber removal and plantation. Another third was logged roughly and the last third was logged and replanted afterwards. One important goal of the experiment was to compare reforestation dynamics in uncleared areas with both undamaged stands and windthrow areas which were partly afforested or regenerated naturally after timber removal. The natural regeneration of the first three years after the storm was studied in all described treatments and in the neighbouring stand, undamaged by the storm.
Natural regeneration of 5 conifer species and 6 broadleaved species in Shajtanka, 3 conifer and 5 broadleaved species in Sergi was registered. Тhе total amount of regenerated trees in each treatment varies from 3758 to 4249 trees per 1 ha in Shajtanka and from 3831 to 5514 trees per 1 ha in Sergi.
On both sites natural regeneration reacted to the changes of ecological factors in а similar way. Three years after the storm the share of broadleaved trees increased to 86,4-90,6 % in Shajtanka and to 58,1-77,5 % in Sergi, reaching its maximum in cleared treatments. In the neighbouring stand in Shajtanka the share of broadleaved trees is 34,7% and in Sergi-59,9%. The most frequent broadleaved species in Sergi are Populus tremula and Sorbus aucuparia, in Shajtanka - Populus tгemula.
Conifer regeneration is presented mainly by preliminary generation. Most of the regenerated conifer trees are in uncleared treatments. Among the conifer species in all experimental treatments in Shajtanka Picea obovata prevails, in Sergi Abies sibiгica and Picea obovata are most frequent.
А certain connection between the type of experimental treatment and the structure of regeneration was noticed. In Sergi one similar coпelation of regenerated species was registered in uncleared treatments and in the neighbouring stand, the other similar coпelation - in cleared treatments. In Shajtanka these results are similar in all experimental windthrow treatments, but they differ very much from the neighbouring stand.