Comparison of stem taper equations for eight major tree species in the Spanish Plateau

Abstract

<p class="Articulo"><em>Aim of study:</em><strong> </strong>A stem taper function and a compatible merchantable volume system are compared to evaluate which provides a better description of the stem profile for the main species in central Spain.</p><p class="Articulo"><em>Area of study:</em><strong> </strong>This research was carried out in the region of Castile-Leon, located in Central Spain.<strong></strong></p><p class="Articulo"><em>Material and Methods:</em> A total of 6,357 trees were selected for destructive sampling. All models were fitted using a first-order continuous autoregressive error structure to address the problem of autocorrelation.<strong></strong></p><p class="Articulo"><em>Main results:</em> In terms of accuracy, the root mean square error (RMSE) in both models ranged from 0.75 to 2.72 depending on the species analyzed, presenting values similar to those reported in other studies. Small differences in the goodness-of-fit for both procedures were also found, and the Stud model provided better accuracy for 6 of the 8 species studied, with RMSE reductions of 0.5% to 8.6%. The RMSE obtained in the cross-validation phase was on average 1.22 times higher than what was obtained in the fitting phase.<strong></strong></p><p class="Articulo"><em>Research highlights:</em><strong> </strong>The non-linear extra sum of squares method indicated that the stem taper differs among the five softwood species and three hardwood species. In hardwoods, the first inflection point is lower than in softwoods (at around 5%) and the second inflection point is higher (at around 85%) than those of softwoods.</p><p class="Articulo"><strong>Keywords</strong>: taper function; volume system; Central Spain; softwoods; hardwoods.</p>

Using Tree Detection Based on Airborne Laser Scanning to Improve Forest Inventory Considering Edge Effects and the Co-Registration Factor

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Het effect van houtoogst op nutriëntenbalansen in bossen op zandgronden : onderbouwing van een adviessysteem

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Innovation in the Value Chain of Wood Products: Data, Equations and Life-Cycle Analysis

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