The article provides a brief overview of the almost century-long history of the largest natural populations of curly, aka Karelian, birch, Betula pendulaRothvar. carelica (Mercklin) Hämet-Ahti, which were discovered in Karelia in the 1930s and were in 1984 giventhe official status of state botanical reserves (BRs), not found elsewhere in our country.The current state of each of the four operating curly birch BRs (Anisimovshchina, Kakkorovsky, Spasogubsky, and Curly Birch Near the Village of Tsarevichi) is described. Thearticle reveals the principal reasons for the changes taking place in the BRs (lack of regular tending, critical age of trees, illegal logging), which entail negative consequences, ofthem being a marked decline in tree numbers. The more than 15-year-long experienceof restoration activities in the Kakkorovsky and Spasogubsky reserves is analyzed. It isemphasized that despite the obviously insufficient scope of protection and tending activities, the curly birch BRs established in Karelia have contributed greatly to the preservationof its gene pool and genetic diversity and continue to play the pivotal role in this matter.Currently, they comprise the greatest and the most valuable part of the gene pool of thisunique tree variety, which is an essential element of the natural heritage of Karelia, as wellas Russia in general.