Effect of first thinning type and age on growth, stem quality and financial performance of a Scots pine stand in Finland

Abstract

Highlights• Early commercial first thinning at the top height of 11 m with tree selection targeting high quality of remaining stems was more profitable in a Scots pine stand than thinning from below at similar time or delayed thinning 10 years later.• After early first thinning only one intermediate thinning was needed, but a late thinning at age of 60 years was feasible in connection with increased amount of high quality butt logs after artificial pruning.• The optimal rotation period for a Scots pine stand using a lower interest rate of 1% was 80-85 years depending on the thinning pattern. With a higher rate of 4%, the optimal rotation took only 60 years. AbstractThe objective of the study was to ascertain the effects of tree selection (thinning from below, from above and according to stem quality) and timing of first commercial thinning (early and delayed) on the growth, yield and quality of trees in a Scots pine (Pinus sylvestris L.) stand. A long-term field experiment (25 years) was measured in 5-year periods and the further development was simulated with growth and yield models to final cuttings using alternative rotation periods of 55-85 years. The measurements included also the exact location and type of technical defects detected on all trees in the experimental plots. The measured volume increment per unit area during the study period, 25 years after the early thinning stage was the lowest in the plots thinned from below, and the highest in the plots thinned from above or in the delayed thinning plots. However, the largest volume of saw logs during the whole rotation of 80 years was yielded after early first thinning according to the quality. The largest volume of very high-quality butt logs was produced by pruning connected with early thinning from above, and a smaller volume after early thinning according to stem quality but no after thinning from below or delayed first thinning. Without pruning an early quality thinning with one intermediate thinning was the most profitable thinning treatment in the Scots pine stand regardless the rotation length or the interest rate used. By interest rates of 1% and 2%, the optimal rotations were 80-85 years and 70 years respectively. A late thinning at the age of 60 year with long rotation was profitable only for the pruned pine stands with a low interest rate.

CRECIMIENTO RADIAL Y CONICIDAD DEL FUSTE EN PLANTACIONES CON ACLAREO DE Pinus patula SCHIEDE ex SCHLECHTENDAL & CHAMISSO

“…El impacto reducido de los aclareos sobre las características de los anillos de crecimiento en Pinus patula se puede deber a que éstos se aplicaron demasiado tarde (Niemistö et al, 2018), si se considera la densidad inicial de la plantación y el elevado nivel de competencia desde su establecimiento. Las parcelas presentaron 3600 o más árboles ha -1 antes del aclareo de 2004, lo que se Cuadro 2.…”

Harvendusraiete tasuvuse analüüs ja pikaajalise mõju simulatsioonid Järvselja õppe- ja katsemetskonnas

“…Nimetatud ökonoomilised tegurid toetavad harvendusraiete tegemist. Üldiselt ollakse seisukohal, et harvendusraietega on võimalik tõsta metsa pikaajalise majandamise tasuvust (Niemistö et al, 2018). Samas on avaldatud uurimusi, mille kohaselt harvendusraie tähendab kulusid (Soucy, 2010).…”

“…Uuringus jõuti järeldusele, et harvendusraiete tulemusena vähenes puistus puude looduslik suremus ning puude diameetri juurdekasv suurenes, kui suurendati raiekraadi. Niemistö et al (2018) uurimuses analüüsiti keskmise viljakusega kasvukoha männipuistus erinevas vanuses tehtud harvendusraiete tulu ja tulusust ning tõdeti, et esimese harvendusraie tulu 30aastases puistus jäi vahemikku 400-440 eurot ha kohta, hilisem harvendusraie 40aastases puistus aga andis ligikaudu neli korda suurema tulu. Muiste (1988)…”

“…Raiet kavandades juba arvestatakse sellega, et puidutulu ületaks metsavarumiskulusid. Keskmine puhastulu 344 €/ha kohta jääb samasse suurusjärku Soomes tehtavate esimese harvendusraie tuludega (Niemistö et al, 2018). Kuna Soomes on paberipuidu hinnad kõrgemad kui Eestis, on sealne harvendusraietelt saadav tulu arusaadavalt suurem kui Eestis.…”

Effect of Breeding on Income at First Commercial Thinning in Silver Birch Plantations

“…In northern Europe, the internal rate of return for improved Norway spruce was 5.3%, but for Scots pine from a third round of seed orchards was 7% [7,8]. Such rates were notably higher than in stands regenerated from unimproved material [9]. It demonstrates the economic gains possible for forest owners and the potential to reduce the rotation period, thus ensuring higher wood supply for processing [10,11].…”