Whole-tree harvesting at clear-felling: Impact on soil chemistry, needle nutrient concentrations and growth of Scots pine

The effects of logging residue removal on soil chemical properties and the needle nutrient concentrations and growth of Scots pine (Pinus sylvestris L.) were studied after clear-felling on two sites of different fertility in eastern Finland. Harvesting was carried out either conventionally, i.e. harvesting only the stems [conventional harvesting (CH)], or totally, i.e. harvesting all of the above-ground tree biomass [whole-tree harvesting (WTH)]. The seedlings were planted in ploughing tilts on 50 x 50 m sample plots. The number of replications was 24 on the more fertile site and 12 on the less fertile site. Compared with CH, WTH had no effects on either the survival or growth of Scots pine trees during the first 22 years. Apart from the statistically significant increase in needle nitrogen concentration in the WTH treatment on the less fertile site, the needle concentrations were not affected by the harvesting intensity. On the more fertile site, the total amounts of carbon, nitrogen and calcium, as well as exchangeable calcium and extractable phosphorus in the organic layer, were significantly lower on the WTH than on the CH plots. Although the pH remained unchanged, the exchangeable aluminium concentrations increased on the more fertile site, and on both sites the calcium/aluminium ratio was significantly lower on the WTH plots than on the CH plots.