Reintroduction and restoration of Betula pendula var. carelica (Betulaceae) Population in Kizhskii State Nature Sanctuary (Karelia Republic)

The article presents the results of 15 years of reintroduction of curly birch, Betula pendula Roth var. carelica (Mercklin) Hämet-Ahti, which has resulted in a restoration of one of its largest natural populations, formerly found within the State Nature Sanctuary Kizhskii (in the buffer zone of the Kizhi Open-air Museum, which is included in the UNESCO World Heritage List). Our studies revealed the main reasons for its decline (illegal harvesting, critical age of trees, lack of viable advance regeneration), which has become critical for its survival. Seed (derived from free pollination) and vegetative (from clonal micropropagation) progenies of curly birch, single trees of which were found growing naturally on Kizhi Island were used as the source material (planting stock) for this work. A comparative analysis of the survival rates, growth and development of saplings is given for different habitats in the mainland part of the sanctuary and on Kizhi Island itself. A molecular genetic profile of a number the curly birch trees involved in the reintroduction was determined. A conclusion drawn from our study is that when restoring natural populations of curly birch and creating new ones, it is advisable to use progenies of trees of local origin, even if only few of them have survived in their natural habitats. In doing so, seed progeny will help expand the genetic diversity of the population to be restored (or created), while vegetative progeny – to preserve the unique features of the source trees in situ (i.e. in their historically native natural environment).