Post-fire succession in blueberry pine forests of the Voronezh nature reserve

Annual monitoring of the vegetation cover in a blueberry ( Vaccinium myrtillus L.) pine forest has been carried out on a permanent plot (area of 0.25 ha) in the Voronezh State Nature Reserve. The study is based on data from 1993 through 2022, including data for 14 years after the 2008 fire. Before the fire, the phytocenosis belonged to the boreal ecological-coenotic type, characteristic of humid conditions with medium nutrient content (B3). We described the initial stages of post-pyrogenic succession after an intense sustained fire that led to the death of the tree layer. The following stages were identified: 1) pioneer post-pyrogenic assemblages (the first year after the fire), 2) plant community development (years 2-6), and 3) stabilization of the floristic and ecological-coenotic composition of the phytocenosis (years 7-13). There were described changes in the species composition, ecological and cenotic structure of the vegetation cover and environmental conditions, calculated according to the indicator tables by L.G. Ramensky, D.N. Tsyganov, and E. Landolt. Later stages of post-fire succession (26-29 and 46 years post-fire) were described in 1998-2001 and 2018 at the site of a blueberry pine forest growing under similar conditions and disturbed by a 1972 fire. We conclude that in blueberry pine forests in humid medium-rich environments, post-fire succession after the death of adult trees due to fire leads to a change in forest formation: birch forests with aspen are formed. There is an increase in diversity of vegetation: boreal, nemoral-boreal, and meadow-pine ecological-coenotic types have replaced boreal pine forests. The fires led to reduction of area covered by blueberry, loss of rare boreal vascular plant species ( Lycopodium clavatum L.). Restoration of the moss layer of Dicranum polysetum Sw. and Pleurozium schreberi (Brid.) Mitt. is not observed both immediately after the fire and dozens (up to 50) years later.