Prediction of knot size in uneven-sized Norway spruce stands in Sweden

Fagerberg, Nils; Seifert, Stefan; Seifert, Thomas; Lohmander, Peter; Alissandrakis, Aris; Magnusson, Bill; Bergh, Johan; Αδαμόπουλος, Στέργιος; Bader, Martin K.‐F.

doi:10.1016/j.foreco.2023.121206

Cited by 2 publications

(1 citation statement)

References 33 publications

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“…are simply not known today. Still, efforts are made to predict things such as future log qualities, which is illustrated by Fagerberg et al (2023).…”

Section: Optimization Of Ccsmentioning

confidence: 99%

Sustainable Continuous Cover Forestry Dynamics, Optimal Decisions, and Empirical Estimations

Lohmander

2024

Preprint

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Sustainable continuous cover forestry is defined and analyzed in several ways. The differential equation representing growth of the basal areas of individual trees, motivated by fundamental biological production theory by Lohmander (2017a), is analyzed and extended in different directions. From the solution of the differential equation, the basal area and the tree diameter are obtained as explicit functions of time. The diameter is a strictly increasing function of time. In the absence of competitors, the diameter increment is shown to be a strictly decreasing function of time. Hence, the diameter increment can also be interpreted as a strictly decreasing function of the diameter. Alternative forms of adjustment of the differential equation, with consideration of competition, are defined. If the competition is strong, with large trees in the vicinity of a particular tree, then the basal area increment, and the diameter increment, are reduced. The growth of a large tree is less sensitive than the growth of a small tree, to competition from other trees. Under strong competition, the basal area increment, and the diameter increment, are strictly concave functions of the size of the tree. The unique maximum of the diameter increment occurs at a higher diameter, if the competition increases. In dynamic equilibrium, the tree size frequency distribution is stationary. If natural tree mortality can be avoided via the harvest strategy, the tree size frequency distribution is a function of the size and competition dependent growth function, and the harvest strategy. Empirical tree size frequency data are used to simultaneously estimate parameters of a size and competition dependent growth function and the applied harvest strategy, via nonlinear optimization. The properties of the estimated growth function are consistent with the corresponding properties of the production theoretically motivated hypothetical function, and the properties of the estimated harvest strategy confirm the corresponding hypotheses. The R2 of the nonlinear regression exceeds 0.97. With access to an empirically estimated equilibrium tree size distribution, it is possible to: 1. Estimate size frequency relevant parameters of tree size and competition dependent growth functions for individual trees. 2. Estimate the applied harvest strategy. 3. Explain and reproduce the empirically estimated tree size equilibrium distribution.

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“…are simply not known today. Still, efforts are made to predict things such as future log qualities, which is illustrated by Fagerberg et al (2023).…”

Section: Optimization Of Ccsmentioning

confidence: 99%

Sustainable Continuous Cover Forestry Dynamics, Optimal Decisions, and Empirical Estimations

Lohmander

2024

Preprint

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Wood Properties and Quality

Piispanen,

Pyörälä,

Valkonen

2024

Managing Forest Ecosystems

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Trees in continuous cover forestry (CCF) typically form very narrow rings at young ages in suppressed positions but can grow very quickly at older ages in dominant positions, maintaining long-lived crowns. CCF trees have slightly higher mean wood density in stems than rotation forestry (RF) trees. CCF trees have better fiber properties for pulp than RF trees. CCF trees have a relatively short stem section of small dead knots in sawn timber. CCF trees have a relatively long section of large green knots in sawn timber. Sawn goods produced from spruce logs yielded with the selection system do not differ markedly from those from RF. The application of a shelterwood system with overstorey retention for Scots pine facilitates the production of very high-grade timber.

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Prediction of knot size in uneven-sized Norway spruce stands in Sweden

Cited by 2 publications

References 33 publications

Sustainable Continuous Cover Forestry Dynamics, Optimal Decisions, and Empirical Estimations

Sustainable Continuous Cover Forestry Dynamics, Optimal Decisions, and Empirical Estimations

Wood Properties and Quality

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