Stability of height positions in young naturally regenerated stands of Scots pine

Abstract

The stability of height positions of saplings in young stands of Scots pine ( Pinus sylvestris L.) was examined by comparing the height order of trees at successive measurements. The data consisted of six naturally regenerated stands and one planted stand for comparison. The length of the examination period was approximately 20 years, covering the mean height development of stands from 0.5 to 5.5 m. For each stand, a structural equation model was fitted by which the covariance structure occurring in the data could be described. In terms of the stability coefficients between the variables produced by the model, the height position of the saplings was very stable. The height positions had mainly been established during the first 5–10 years of age and at a mean height of less than 0.5–1 m. In the naturally regenerated stands, stability was virtually complete from the stage of 15–20 years and 1.5–2 m onwards. In the planted stand, stability became complete slightly later than in the naturally regenerated stands. According to the results, the height of the sapling can be emphasized as a selection criterion in precommercial thinning.