Shared knowledge case: Historical and modern Forest disturbances data & studies from Bulgarian mountain coniferous forests
We have collected data for disturbances in mountain coniferous forests in Bulgaria from historical sources and recent records + case studies. The data shows that historically the most important disturbances were fires and windthrows. Biggest fire (end of 19th century) was about 9000 ha affecting spruce and Scots pine forests; Biggest windthrow was the 1961 in the Rhodopes (3000 ha). Insect outbreaks were occurring mostly after snow-damages, but also we had one recent Ips typographus (>200 ha) after windthrow (60 ha) in the Bistrishko branishte reserve. Our studies in the Parangalitsa reserve (Norway spruce) showed, that windthrows were the most important factor shaping the landscape in the last 2 centuries.
Studies on the natural regeneration after large windthrows (Parangalista reserve, 1962 and 1983 windthrows) and Bistrishko branishte reserve (2001 windthrow) showed continuous regeneration process with duration of more than 30-40 years and distinct peaks in intensity. The most important species for regeneration were Norway spruce (higher altitudes), fir (lower altitudes). Pioneers played less than expected role.
Our data can serve as reference and long-term example of natural dynamics.