Csontos et al. (2012) Applied Ecology and Environmental Research

Csontos, P., Halbritter, A., Tamás, J., Szili-Kovács. T., Kalapos, T., Uzinger, N., Anton, A. (2012): Afforestation of dolomite rock grasslands with non-native Pinus nigra, and its effect on soil trace elements. Applied Ecology and Environmental Research 10: 405-415.

Abstract

The non-native  Pinus nigra has been widely planted on natural dolomite grasslands in Hungary, yet little is known on its influence on soil properties. We compared soil micro-element concentrations in rock grassland (RG) and under P. nigra plantation (PP), both grown on north facing slopes of dolomite bedrock. At PP sites, the original vegetation was RG prior to afforestation. For both vegetation types, five sampling sites were selected, and at each site soil samples were taken from three depths (0-5, 5-10 and 10-15 cm). Micro-element concentrations of corresponding soil layers in the two vegetation types were compared. Under the pine plantation, the concentration of a number of soil trace elements was altered compared to the original rock  grassland soil, and this effect increased with soil depth.  At the deepest layer, significant differences were found for 10 microelements (Al, Fe, Mn, Ba, Cd, Co, Ni, Pb, Sr, Zn), and in each case the concentration was higher in PP than in RG soil. In contrast, the concentration of Cr, Cu, Hg, Mo and Se was not different between the two habitats throughout the soil layers sampled. Values exceeding the Hungarian environmental limits of background concentrations were detected for lead and cadmium. In the RG soil, concentrations of Pb and Cd were highest in the topmost layer, while for the PP sites these elements showed concentrations higher in the 10-15 cm layer than in the 5-10 cm depth. Concentrations of some other micro-elements showed similar inversion at PP sites. The depth inversion of these, often airborne pollutant trace elements was explained as a consequence of afforestation with P. nigra and such phytostabilization effect of the pine stands is assumed to increase with stand age.

Keywords

dolomite, heavy metals, Pinus nigra, rock grassland, soil pollution

Cseresnyés & Csontos (2012) Acta Botanica Croatica

Imre Cseresnyés, Péter Csontos (2012): Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands. Acta Botanica Croatica 71 (2): 249–260.


Abstract
Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, howeverR. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resproutingand recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cmsoil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands.


Keywords
Afforestation, dormancy, Pinus nigra, plantation, Robinia pseudoacacia, seed germination, soil seed bank