Functional response of Betula species to edaphic and nutrient stress during restoration of fly ash deposits in the Middle Urals (Russia).

We studied the impact of fly ash produced by the thermal power station in the Middle Urals (Russia) on functional traits of two Betula species naturally colonizing ash dump lagoons. The main limiting factors for tree growth on fly ash deposits were nitrogen deficiency, high alkalinity, and unfavorable mechanical composition of substrate. Leaf area ratio (LAR) and leaf mass ratio (LMR) per tree, leaf area (LA), leaf shape coefficient (LSh), leaf thickness (LT), leaf mass per area (LMA), photosynthesis (A) and transpiration rates, chlorophyll (Chl), carotenoid (Car), and nitrogen (N) content were measured in Betula pendula Roth and Betula pubescens Ehrh.