Until quite recently the notion about the peculiar pedogenesis of mountain-taiga soils in continental North-East Asia based upon the permanent transformation of the parent rock into zonal soil was assumed without consideration of the active pyrogenesis impact, i.e. not taking into account the whole complex of processes and phenomena in natural landscapes as related to fire effect.

To our opinion, first of all it deals with the existing concept of fires as a primarily anthropogenic factor, which is mostly connected with human activity. Yet forest fires for millenia accompanied soil forming on the continental part of North-East Asia and exerted decisive influence on the trend of soil-building processes.

The pyrogenesis impact becomes apparent in the period when zonal vegetation was eradicated and successional stages of regeneration are formed by means of temporary forms of phytocoenoses. It leads to interruption in pedogenesis which is continued on a new cover of the latest deluvium deposits, washed off from the watershed surface and covering partially or completely the cut surface humus horizons of the primary soils.

Thus, in place without cover glaciation automorphic soils with a polycyclic profile are formed, composed by two or sometimes three buried degraded humus horizons with plenty of black charcoal. It shows that the soils pass 2-3 stages of zonal pedogenesis within the period of their development (usually 2-2.5 thousand years).

The range, high frequency and recurrence of the pyrogenesis influence allow us to consider it as a soil forming subfactor especially in humid continental regions of permafrost zone.

Dr. Aleksandr P. Chevichelov
Senior Scientist
Institute of Biology SO RAN
Lenina pr. 41
Yakutsk, RUSSIA
Tel. 35244