Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations

The mild climate and, in recent decades, the increased demand for timber have favoured the establishment of extensive plantations of fast-growing species such as <i>Pinus radiata</i> in Galicia (a fire-prone region in northwestern Spain). This species is characterised by very poor self-p...

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Main Authors: Cecilia Alonso-Rego, Paulo Fernandes, Juan Gabriel Álvarez-González, Stefano Arellano-Pérez, Ana Daría Ruiz-González
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Forests
Subjects:
Online Access:https://www.mdpi.com/1999-4907/13/10/1697
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author Cecilia Alonso-Rego
Paulo Fernandes
Juan Gabriel Álvarez-González
Stefano Arellano-Pérez
Ana Daría Ruiz-González
author_facet Cecilia Alonso-Rego
Paulo Fernandes
Juan Gabriel Álvarez-González
Stefano Arellano-Pérez
Ana Daría Ruiz-González
author_sort Cecilia Alonso-Rego
collection DOAJ
description The mild climate and, in recent decades, the increased demand for timber have favoured the establishment of extensive plantations of fast-growing species such as <i>Pinus radiata</i> in Galicia (a fire-prone region in northwestern Spain). This species is characterised by very poor self-pruning; unmanaged pine stands have a worrying vertical continuity of fuels after crown closure because the dead lower branches accumulate large amounts of fine dead biomass including twigs and suspended needles. Despite the important contribution of these dead ladder fuels to the overall canopy biomass and to crown-fire hazards, equations for estimating these fuels have not yet been developed. In this study, two systems of equations for estimating dead ladder fuel according to size class and the vertical distribution in the first 6 m of the crown were fitted: a tree-level system based on individual tree and stand variables and a stand-level system based only on stand variables. The goodness-of-fit statistics for both model systems indicated that the estimates were robust and accurate. At the tree level, fuel biomass models explained between 35% and 59% of the observed variability, whereas cumulative fuel biomass models explained between 62% and 81% of the observed variability. On the other hand, at the stand level, fuel-load models explained between 88% and 98% of the observed variability, whereas cumulative fuel-load models explained more than 98% of the total observed variability. These systems will therefore allow managers to adequately quantify the dead ladder fuels in pure <i>Pinus radiata</i> stands and to identify the treatments required to reduce crown-fire hazard.
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spelling doaj.art-b2e480b19f2940c5a330f3922d00bce82023-11-24T00:10:23ZengMDPI AGForests1999-49072022-10-011310169710.3390/f13101697Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> PlantationsCecilia Alonso-Rego0Paulo Fernandes1Juan Gabriel Álvarez-González2Stefano Arellano-Pérez3Ana Daría Ruiz-González4Unidad de Gestión Ambiental y Forestal Sostenible (UXAFORES), Departamento de Ingeniería Agroforestal, Escuela Politécnica Superior de Ingeniería, Universidad de Santiago de Compostela, Rua Beningno Ledo s/n, 27002 Lugo, SpainCITAB—Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, PortugalUnidad de Gestión Ambiental y Forestal Sostenible (UXAFORES), Departamento de Ingeniería Agroforestal, Escuela Politécnica Superior de Ingeniería, Universidad de Santiago de Compostela, Rua Beningno Ledo s/n, 27002 Lugo, SpainUnidad de Gestión Ambiental y Forestal Sostenible (UXAFORES), Departamento de Ingeniería Agroforestal, Escuela Politécnica Superior de Ingeniería, Universidad de Santiago de Compostela, Rua Beningno Ledo s/n, 27002 Lugo, SpainUnidad de Gestión Ambiental y Forestal Sostenible (UXAFORES), Departamento de Ingeniería Agroforestal, Escuela Politécnica Superior de Ingeniería, Universidad de Santiago de Compostela, Rua Beningno Ledo s/n, 27002 Lugo, SpainThe mild climate and, in recent decades, the increased demand for timber have favoured the establishment of extensive plantations of fast-growing species such as <i>Pinus radiata</i> in Galicia (a fire-prone region in northwestern Spain). This species is characterised by very poor self-pruning; unmanaged pine stands have a worrying vertical continuity of fuels after crown closure because the dead lower branches accumulate large amounts of fine dead biomass including twigs and suspended needles. Despite the important contribution of these dead ladder fuels to the overall canopy biomass and to crown-fire hazards, equations for estimating these fuels have not yet been developed. In this study, two systems of equations for estimating dead ladder fuel according to size class and the vertical distribution in the first 6 m of the crown were fitted: a tree-level system based on individual tree and stand variables and a stand-level system based only on stand variables. The goodness-of-fit statistics for both model systems indicated that the estimates were robust and accurate. At the tree level, fuel biomass models explained between 35% and 59% of the observed variability, whereas cumulative fuel biomass models explained between 62% and 81% of the observed variability. On the other hand, at the stand level, fuel-load models explained between 88% and 98% of the observed variability, whereas cumulative fuel-load models explained more than 98% of the total observed variability. These systems will therefore allow managers to adequately quantify the dead ladder fuels in pure <i>Pinus radiata</i> stands and to identify the treatments required to reduce crown-fire hazard.https://www.mdpi.com/1999-4907/13/10/1697canopy base heightcanopy fuel loadcanopy bulk densitycrown-fire hazardpure even-aged standsforest management
spellingShingle Cecilia Alonso-Rego
Paulo Fernandes
Juan Gabriel Álvarez-González
Stefano Arellano-Pérez
Ana Daría Ruiz-González
Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
Forests
canopy base height
canopy fuel load
canopy bulk density
crown-fire hazard
pure even-aged stands
forest management
title Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
title_full Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
title_fullStr Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
title_full_unstemmed Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
title_short Individual-Tree and Stand-Level Models for Estimating Ladder Fuel Biomass Fractions in Unpruned <i>Pinus radiata</i> Plantations
title_sort individual tree and stand level models for estimating ladder fuel biomass fractions in unpruned i pinus radiata i plantations
topic canopy base height
canopy fuel load
canopy bulk density
crown-fire hazard
pure even-aged stands
forest management
url https://www.mdpi.com/1999-4907/13/10/1697
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