A growth and yield model for even-aged Pinus brutia Ten. stands in Syria

Shater, Zuheir; de-Miguel, Sergio; Kraid, Bassel; Pukkala, Timo; Palahí, Marc

doi:10.1007/s13595-011-0016-z

Cited by 30 publications

(23 citation statements)

References 13 publications

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“…Decreasing period factor decreases the prediction for larger diameters associated with later periods, implying that although the fixed part of the mixed-effects model seems unrealistic, the full model may predict realistic growths. This result verifies the conclusion that it may be unwise to use the fixed part of mixed-effects models in growth simulators (e.g., Temesgen et al 2008;Garber et al 2009;Pukkala et al 2009;Shater et al 2011;Groom et al 2012;Heiðarsson and Pukkala 2012;de-Miguel et al 2012;de-Miguel et al 2013). As discussed by Burkhart and Tomé (2012) it would be better to refit the model without random parameters.…”

Section: Diameter Increment and Survival Modelssupporting

confidence: 78%

Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals – a case study for Pinus patula in Kenya

et al. 2014

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Background: The minimum set of sub-models for simulating stand dynamics on an individual-tree basis consists of tree-level models for diameter increment and survival. Ingrowth model is a necessary third component in uneven-aged management. The development of this type of model set needs data from permanent plots, in which all trees have been numbered and measured at regular intervals for diameter and survival. New trees passing the ingrowth limit should also be numbered and measured. Unfortunately, few datasets meet all these requirements. The trees may not have numbers or the length of the measurement interval varies. Ingrowth trees may not have been measured, or the number tags may have disappeared causing errors in tree identification. Methods: This article discussed and demonstrated the use of an optimization-based approach to individual-tree growth modelling, which makes it possible to utilize data sets having one or several of the above deficiencies. The idea is to estimate all parameters of the sub-models of a growth simulator simultaneously in such a way that, when simulation begins from the diameter distribution at the first measurement occasion, it yields a similar ending diameter distribution as measured in the second measurement occasion. The method was applied to Pinus patula permanent sample plot data from Kenya. In this dataset, trees were correctly numbered and identified but measurement interval varied from 1 to 13 years. Two simple regression approaches were used and compared to the optimization-based model recovery approach. Results: The optimization-based approach resulted in far more accurate simulations of stand basal area and number of surviving trees than the equations fitted through regression analysis. Conclusions: The optimization-based modelling approach can be recommended for growth modelling when the modelling data have been collected at irregular measurement intervals.

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Section: Diameter Increment and Survival Modelssupporting

confidence: 78%

Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals – a case study for Pinus patula in Kenya

et al. 2014

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“…Anamorphic curves were extracted from the guide curve, using the maximum height reached at 10 years as the reference age [28] for this study.…”

Section: Site Indexmentioning

confidence: 99%

Growth and Yield Models for Teak Planted as Living Fences in Coastal Ecuador

Cañadas-López

Andrade-Candell

Domínguez-A

et al. 2018

Forests

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Teak plantations cover a total area of about 4.35 million ha worldwide. The species is currently being planted in silvopastoral systems in the coastal lowlands of Ecuador. However, there are no growth and yield models for teak grown in silvopastoral systems, especially as living fences, in this region. The aim of the present study was to develop volume and yield models for teak grown as living fences in silvopastoral systems. For teak planted as living fences, the biological rotation age was estimated to vary between 15 and 26 years. The final yield in the silvopastoral system varied from 49 m 3 ha −1 at 26 years in the least productive sites to 225 m 3 ha −1 at 15 years in the most productive sites in the study area. The mean annual yield for the highest quality site was 15.3 m 3 ha −1 year −1 at age 15 years, for a density of 160 trees ha −1 . For a base age of 10 years, height-based site indexes of nine to 23 m were established. The growth and yield model obtained may be useful to define the biological (optimal) rotation age and estimate the productivity of teak living fences in the coastal lowlands of Ecuador.

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“…Several growth and yield simulators are driven by a model that predicts dominant height as a function of stand age and site index (e.g., Shater et al 2011;Guzmán et al 2012). Use of the dominant height model assumes that dominant height is not reduced in thinning.…”

Section: Introductionmentioning

confidence: 99%

Stand management optimization – the role of simplifications

2014

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Background: Studies on optimal stand management often make simplifications or restrict the choice of treatments. Examples of simplifications are neglecting natural regeneration that appears on a plantation site, omitting advance regeneration in simulations, or restricting thinning treatments to low thinning (thinning from below). Methods: This study analyzed the impacts of simplifications on the optimization results for Fennoscandian boreal forests. Management of pine and spruce plantations was optimized by gradually reducing the number of simplifying assumptions. Results: Forced low thinning, cleaning the plantation from the natural regeneration of mixed species and ignoring advance regeneration all had a major impact on optimization results. High thinning (thinning from above) resulted in higher NPV and longer rotation length than thinning from below. It was profitable to leave a mixed stand in the tending treatment of young plantation. When advance regeneration was taken into account, it was profitable to increase the number of thinnings and postpone final felling. In the optimal management, both pine and spruce plantation was gradually converted into uneven-aged mixture of spruce and birch. Conclusions: The results suggest that, with the current management costs and timber price level, it may be profitable to switch to continuous cover management on medium growing sites of Fennoscandian boreal forests.

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A growth and yield model for even-aged Pinus brutia Ten. stands in Syria

Abstract: International audienc

Cited by 30 publications

References 13 publications

Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals – a case study for Pinus patula in Kenya

Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals – a case study for Pinus patula in Kenya

Growth and Yield Models for Teak Planted as Living Fences in Coastal Ecuador

Stand management optimization – the role of simplifications

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