Mycorrhizal status of a Scots pine (Pinus sylvestris L.) plantation affected by pollution from a phosphate fertilizer plant

Ectomycorrhizas are an integral, functioning part of many conifer tree species root systems and often considered a link in the causal chain leading to forest decline. In our experiment 12-year-old Scots pine trees grown for 10 years on a polluted acid soil with high aluminium content were compared to a control stand in western Poland. Soil at the polluted site had lower pH than the control site, increased aluminium availability and very low microbial activity. Roots analysed over two years showed lower number of mycorrhizal tips at the polluted site, but only when calculated per soil volume. Differences between sites were not significant when number of mycorrhizal tips was expressed per root mass. There was no significant reduction in the occurrence of any mycorrhizal morphotype. The number of mycorrhizas on trees from the polluted stand was negatively correlated with aluminium content in the needles. Our results showed no clear pollution effect on mycorrhizas in a young stand of Scots pine.