Growth and mycorrhizal colonisation of naturally regenerating Scots pine Pinus sylvestris (L.) in relation to microsite conditions created by different site preparation methods

Abstract

Mechanical site preparation (MSP) is recommended for natural regeneration of the Scots pine (Pinus sylvestris L.). The study aimed at comparing the effects of three MSP methods [LPz 75 double-mouldboard forest plough (FP), single-mouldboard U-162 active plough (AP) and FAO-FAR FV 4088 forest cutter (FC)] which in different ways interfere with the soil environment and influence the growth of naturally regenerating Scots pine seedlings and their mycorrhizal colonisation in the first year after self sowing. Pine seedlings growing within and outside strips prepared with FC did not have different growth parameters and mycorrhizal colonisation, but those from ridges were bigger and less mycorrhized than seedlings growing in furrows. This difference was bigger in FP than in AP and was probably caused by more favourable trophic conditions and presence of polyphenols in ridges. Removal of the organic layer in furrows did not limit a degree of mycorrhizal colonisation. Ploughing direction had no significant impact on pine features analysed. The trend towards improved growth in furrows formed with FP can be noticed in NW-SE variant. Higher mycorrhizal colonisation was found in seedlings growing in all microsites in the NW-SE variant. However, these differences were not confirmed statisti cally. Growth parameters of pines located within the area the edge and in the centre of the experimental clear-cut were to a great measure influenced by light conditions; seedlings from the edge were higher, had less lateral shoots, and shorter roots than those growing in the middle of the clear-cut.