Stem volume equations and basic density for grey alder and common alder in Sweden

Abstract

The objective was to determine stem volume models for grey and common alders and, based on the models, stand volume for naturally regenerated grey and common alder stands was summarized. Basic density for grey and common alders and mean annual growth for stands was estimated. Net volume accretion data were collected from 24 stands of grey alder (Alnus incana (L.) Moench) and 31 stands of common alder (Alnus glutinosa (L.) Gaertner) in Sweden. The stands ranged in latitude from 58 to 64° N and from 56 to 62° N for grey and common alder, respectively. The mean age of grey and common alder stands was 41 years and 48 years, respectively, the mean stand density 1726 stems ha−1 and 1078 stems ha−1, and the mean diameter at breast height (over bark) was 20 cm and 21 cm. Stem volume equations were developed for grey and common alders. The adopted model for grey alder was based on diameter at breast height and height. For common alder, crown height was added to diameter and height. Mean standing volume (over bark) for grey and common alder stands was 428 and 374 m3 ha−1. Mean annual growth for grey and common alder stands was 12.0 m3 and 8.4 m3 a−1 ha−1, respectively. Basic density (under bark), for grey and common alder stems was 359 and 427 kg m−3, respectively. The basic density (under bark) for the lowest twigs in the crown and in the lateral part of the crown was 415 and 421 kg m−3 for grey alder and 423 and 423 kg m−3 for common alder.