Development of spruce (Picea abies [L.] Karst.) target (crop) trees in pole-stage stand with different initial spacing and tending regime

Abstract

This paper presents findings of a twenty-year investigation of silviculture-production in a 40-year-old afforested spruce pole-stage stand located in a mountain region. The stand was established by four different spacing models: (i) 1.5 × 1.0 m, (ii) 2.5 × 1.0 m, (iii) 2.5 × 1.5 m, and (iv) 2.5 × 2.5 m. Three alternatives were studied for each of these spacing models. These were: (i) geometrical (line) thinning, (ii) selective thinning and (iii) no tending. During the period of our research the above-mentioned stand was affected twice by a snow-break disaster. Promising and target trees in the stand were marked and selected at the beginning of the study. The development of the abovementioned categories of trees was analysed in relation to the initial spacing of the stand, as well as to the method of tending. Based on the 20-year research period, we conclude that the most favourable results were obtained on plots that were established at a wider initial spacing and managed by selective thinning as opposed to the denser ones tended by geometrical thinning or without any tending.