Effects of different methods of site preparation on natural regeneration of Pinus sylvestris in Eastern Poland

Mechanical site preparation (MSP) is commonly used to enable forest regeneration of clear-cuts. Less intense methods may be more suitable from an environmental point of view, but such a method can result in the lack of natural regeneration. We compare the influence of three MSP methods on natural regeneration of Scots pine. The methods differ in their degree of soil disturbance. The effects of MSP by forest plough (FP), active plough (AP), and forest cutter (FC) on density, quality, and biometric parameters of one-year old seedlings were determined. The highest density of seedlings was obtained in the FP treatment (188,000 seedlings ha–1). The seedling density was significantly lower in the AP method (121,000 seedlings ha–1), and in the FC variant (36,000 seedlings ha–1). The best quality seedlings were found in the FC variant, and the worst – in the FP treatment. Most biometric parameters of seedlings did not differ by MSP method, except for the root length and root:shoot ratio. By the end of growing season, in the FP treatment, 1-year old seedlings formed a top bud more than twice as often as the seedlings from the AP and FC treatments. The FP method led to the best Scots pine natural regeneration. The results obtained in the FC variant were not as good as in the FP method, though they were still acceptable from the silvicultural point of view. The FC method was the least intensive method of site preparation, yet it is considered the most appropriate from the environmental (soil protection) point of view.