Selecting tree species for reclamation of coal mine tailings based on physiological parameters

Abstract

In the present study we compared the physiological performances of Prunus avium L., Robinia pseudoacacia L., Juglans nigra L., and Populus x euramericana cl. Pannonia, planted at the coal mine tailings of the Mining Basin "Kolubara" (Serbia), to assess the potential of different tree species for land reclamation. The measurements were conducted during three consecutive years characterized by contrasting climatic conditions (wet and drought). The results showed that the rate of net photosynthesis (A), stomatal conductance (gs) and transpiration rate (E) sharply declined in two dry years in all tree species. These trends were particularly evident for R. pseudoacacia and J. nigra, in which A, gs and E were twice as low during the dry years. On the other hand, R. pseudoacacia and P. x euramericana cl. Pannonia seedlings were characterized by the highest water-use efficiency and intrinsic water-use efficiency during the dry years, indicating that these species are more efficient responders to drought, due to their ability to maintain a balance between the loss of water and the CO2 assimilation rates. The survival rate of the examined tree species was high (>86%) and increased in the following order: P. avium < J. nigra < R. pseudoacacia < P. x euramericana cl. Pannonia. Based on the obtained results we recommend R. pseudoacacia and P. x euramericana cl. Pannonia as a good solution for afforestation and revitalization of degraded habitats, such as coal mine tailings, although high survival rate, observed in P. avium and J. nigra, makes these two species a candidate for planting during degraded sites reclamation, as well.