|Punakoivun (Betula pubescens f. rubra) lehdet alkavat punertua.|
Betula pubescens f. rubra is a mutant form of Betula pubescens, which exhibits a special springtime phenology: the young leaves are green but turn to red soon after leaf burst because of anthocyanin accumulation. During the summer, as the amount of chlorophyll increases, the content of anthocyanins also increases further, deepening the red colour of the leaves. (For more information, see Kauppi A. & Ulvinen T. 1989. Two new forms of Betula pubescens from Finland. Memoranda Soc. Fauna Flora Fenn. 65: 133–136.)
For the month of May 2021, I'll try to post a photo every day. You can find an open comment section in my post of the first of May.
Stay safe and well!