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Research article2019Peer reviewedOpen access

Effects on stem growth of Scots pine 33 years after thinning and/or fertilization in northern Sweden

Valinger, Erik; Sjogren, Hans; Nord, Gustav; Cedergren, Jonas

Abstract

Thinning and fertilization are two common and important stand treatments in forest management. In terms of area treated, thinning is the single most common form of stand treatment. The extent of forest fertilization on the other hand, has varied widely in recent decades and is currently not very common. Thinning is done primarily to promote stand properties while fertilization is done to increase growth before future final felling. After thinning stands of Scots pine, overall growth decreases, while growth of residual trees increases. An experiment was established outside Vindeln in northern Sweden where the long-term growth effects after thinning and/or fertilization were evaluated after 33 years. Experimental set-up was a randomized block design including 12 replications of four treatments. Treatments were control, fertilization, thinning, and thinning and fertilization combined. Thinning decreased overall and annual volume growth ha(-1), and increased green crown size and diameter growth at breast height (1.3 m, DBH) for the individual trees. No positive growth responses to fertilization could be seen after 33 years. In summary, this study showed that thinning can have long term effects on the growth of a Scots pine stand in northern Sweden. Possible reasons for the lack of positive response following fertilization are discussed.

Keywords

Thinning; fertilization; long-term growth

Published in

Scandinavian Journal of Forest Research
2019, Volume: 34, number: 1, pages: 33-38
Publisher: TAYLOR & FRANCIS AS