Biomass distribution in a subarctic Piceamariana – Cladoniaalpestris woodland

Abstract

A study of 15 lichen woodlands in the subarctic of eastern Canada indicated a stron dominance by P. mariana and C. alpestris. Mean tree density was 556 trees/h. Over 75% of all tree stems were P. mariana. P. glauca and Larix laricina were only minor components. Total shrub and ground cover was 120%. Lichen covered 97% of the surface area. G. alpestris alone represented 78% of total lichen cover. Shrubs covered 17% of the surface area. Moss and club moss species (6% cover) were minor. Total live biomass on a representative site was 46,291 kg .cntdot. ha-1. P. mariana and C. alpestris formed 75% of the total. The only other significant species was Betula glandulosa (12% of total). Biomass was distributed between tree, shrub and ground layer species in the approximate ratio of 3:1:1. Lichen and leaf tissue represented 1/3 (31%) of the total biomass. Stem and roots constituted 40% and 28% of total biomass, respectively. P. mariana contained 76% of all stem tissue. Shrub root mass (39%) of shrub dry weight) was high in comparison with tree root mass (34% of P. mariana dry weight). Evergreen vascular species had 3 times more shoot mass relative to root mass than deciduous forms. Comparison of biomass levels and tissue distribution indicated the lichen woodland studied was similar to others in the immediate area and to Larix woodlands in the USSR. Lichen woodland had much lower total biomass, had high root-shoot ratios and high shrub and ground layer biomass compared with boreal conifer and temperate deciduous forest.