ESTABLISHMENT OF TREES ON MIXTURES OF PULVERIZED FUEL ASH AND GYPSUM .1. TREE PERFORMANCE

Experiments that investigated the performance of nine tree species pla nted in pulverized fuel ash (PFA) and gypsum power station wastes are described. Lombardy and white poplars, common alder and false acacia w ere the most successful in gypsum and PFA-gypsum mixtures, but tree gr owth in pure PFA was unsatisfactory. Co-disposal of gypsum and PFA is the best means of promoting the growth of tolerant species planted in power station wastes. Tree performance is improved if these materials are covered by a soil layer, which promotes tree rooting into the unde rlying wastes.