We studied pyrogenic succession during four years on the Olenij island (Kandalaksha gulf, White sea). We discovered that plant renewal on hard burned area is slow and goes mainly via seeds. Plant renewal on the light burned area is quick and goes by vegetative mean.
Island Olenij burned at the end of July---the beginning of August, 2000. This island has area about 2,7 sq. km and located in Chupa bay (Kandalaksha bay, White sea) on the territory of Keretskij national park. More then 30% of forest was burned mostly on the north-eastern part of island.
We have chosen two experimental sites 10 m x 10 m in size in more and less damaged by fire parts of the island. We estimated the projective covering of all plant species according to Brawn-Blanquet scale and their abundance according to seven-points visual scale. This estimation was done once a year within four years (2001 - 2004) in the second half of July during White sea expeditions of Moscow South-West High School (N 1543).
On the less damaged experimental site plants with ligniscent stems (Vaccinium myrtillus, V. vitis-idaea), that were less damaged by fire, or plants with beared in the ground diaspores (Equisetum sylvaticum, Ledum palustre and Melampyrum pratense), that germinated actively after the fire, recovered in the first turn. Fast renewal of these plant species can be connected with the reduction of competition after the fire. Fire has not damaged roots of aspens and birches which allowed these trees form young root growth in the next year after the fire.
On the more damaged experimental site all vegetation was burnt almost completely, and only seed renewal was performed. The only exception was made for Vaccinium vitis-idaea, which restored in the next year after the fire, because its rhizomes have not suffered, perhaps. It is interesting, that total projective covering of the moss layer of the more damaged site exceeds those for less damaged site. It can be explained by decreasing the pressure of plants from other layers after their burning.
Our data clearly show, that less damaged by fire vegetative cover actively renews (mostly in vegetative way), whereas more damaged vegetative cover renews with difficulties (mostly in generative way).
Rabotnov T.A. Phytocenology. M., 1983. [In Russian]
Amihanov A.M., Kolosov A.M. Flora and fauna of islands in nature reserves // Collection of proceedings of TsNIL Glavohoty RSFSR. Ì., 1989. [In Russian]