comparison of nutrition, nutrient return and nutrient retranslocation between stands of alnus subcordata and taxodium distichum in tashbandan, amol (mazandaran)

in this study, nutrition, nutrient return and nutrient retranslocation were compared between two stands of alnus subcordata (n-fixing tree) and taxodium distichum (coniferous deciduous tree), planted on a weak drained soil in north of iran (tashbandan, amol). in each tree stand, n, p, k, ca and mg concentration of fresh and senescent leaves and soil were measured. the concentrations of n and mg in fresh leaves and n, k and mg in senescent leaves of alnus were significantly greater than those of taxodium but ca was less. c/n ratio in senescent leaves and n retranslocation of alnus were lower than those of taxodium. the concentrations of n and k in soil of alnus were greater than those of taxodium but p, mg and c/n ratio were less. the results indicated that alnus stand, compared to taxodium stand, can gradually promote quality and fertility of the site, due to greater storage of nutrients in litter, higher nitrogen return to soil and lower c/n ratio.