Fig. 3
From: Variable retention forestry in European boreal forests in Russia
Successional stages (age groups [gruppy vozrasta in Russian]) of forests in different regions of NW Russia (Regional 2017, 2018). Young—0–40 (0–20) years for coniferous (deciduous) stands; mature—101–140 years and older for coniferous (deciduous) stands depending on vegetation zone, site index, and forest category; over-mature—all stands older than mature; pre-mature—20 years before the age of maturity; middle-aged—all stands between young and pre-mature. The figures show the share of forests in each successional stage from total forested area. Red lines denote the borders between the countries. Gray lines denote the borders between vegetation zones (Bonh et al. 2000, 2003). NB northern boreal zone, MB middle boreal zone, SB southern boreal zone, HB hemiboreal zone. Dashed red lines denote the borders between the regions. A Arkhangelsk region, K the Republic of Karelia, Ko Komi Republic, L Leningrad region, M Murmansk region, N Novgorod region, P Pskov region, V Vologda region