Relationships between forest tree species, stand production and stand nutrient amount

Data from the literature concerning stand aerial biomass, stand nutrient am ount (i.e. N, P, K, Ca and Mg) of four major forest tree species of the tem perate area were compiled in order to propose simple general relationships to quantify nutrient depletion associated with biomass harvesting. The obje ctives was to identify the tree species effect on nutrient loss through bio mass removal. Mean weighted nutrient concentrations of aerial biomass decre ased rapidly until the maximum current annual increment of stands was reach ed ("adult stands"); the concentration then became more or less constant. F or adult stands, linear relations existed between aerial biomass and their nutrient amount. Using total aerial biomass (TAB) or stem biomass including bark (SBB) as references against the corresponding nutrient amount showed: i) that correlation coefficients were higher in the latter case, ii) that nutrient amount per unit of biomass was lower for SBB than for TAB, and iii ) that these relations were species-dependent. For a same SBB, species were ranked as follows: mean concentration of N and K, European beech > Douglas fir = Norway spruce = Scots pine; Ca, European beech = Norway spruce great er than or equal to Scots pine greater than or equal to Douglas fir; Mg, Eu ropean beech greater than or equal to Scots pine greater than or equal to N orway spruce greater than or equal to Douglas fir. For P, no significant di fference was found for the tested species. The relationships between biomas s and nutrient amount can be easily used by foresters to quantify the nutri ent amount exported from a site during both thinning and harvesting operati ons, as well as the nutrients which remain in the logging residues left on the site and which will slowly yield available elements to the new plantati on or the naturally regenerated stand.