FINE-ROOT BIOMASS AND NUTRIENT CONTENT IN A BLACK SPRUCE NEAT SOIL WITH AND WITHOUT ALDER

Vertical distribution of fine root biomass and nutrient content was ex amined within a black spruce (Picea mariana) stand growing on a boreal peat soil in northeastern Ontario. The influence of site physical and chemical properties on fine root biomass production was assessed. Mor e then 80% of the fine roots were present in moss plus the top 10 cm o f peat where nutrients and aeration are most favourable. The fine root biomass (W/V) was significantly higher with alder (5.9 kg m(-3)) (Aln us rugosa) as understory vegetation compared to non-alder locations (2 .9 kg m(-3)). Total nutrient content in fine roots was 54, 3.2, 5.4, 6 3 and 5.7 kg ha(-1) on the alder site and 20, 1.4, 2.3, 28 and 4.2 kg ha(-1) of N, P, K, Ca, and Mg on the non-alder site, respectively. The mass (W/V) of nutrients in fine roots was strongly dependent upon the availability of nutrients in the peat. Fine root content had a strong positive relationship with peat available P and exchangeable K conten ts suggesting that P and K may be limiting nutrients for black spruce in this peat soil.