Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries
Accurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood density as predictors are currently used in most tropical forest carbon studies. In particular, a pantropical biomass model has been widely used...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/1571/2016/bg-13-1571-2016.pdf |
| _version_ | 1818057497839140864 |
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| author | P. Ploton N. Barbier S. Takoudjou Momo M. Réjou-Méchain F. Boyemba Bosela G. Chuyong G. Dauby V. Droissart A. Fayolle R. C. Goodman M. Henry N. G. Kamdem J. K. Mukirania D. Kenfack M. Libalah A. Ngomanda V. Rossi B. Sonké N. Texier D. Thomas D. Zebaze P. Couteron U. Berger R. Pélissier |
| author_facet | P. Ploton N. Barbier S. Takoudjou Momo M. Réjou-Méchain F. Boyemba Bosela G. Chuyong G. Dauby V. Droissart A. Fayolle R. C. Goodman M. Henry N. G. Kamdem J. K. Mukirania D. Kenfack M. Libalah A. Ngomanda V. Rossi B. Sonké N. Texier D. Thomas D. Zebaze P. Couteron U. Berger R. Pélissier |
| author_sort | P. Ploton |
| collection | DOAJ |
| description | Accurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood
density as predictors are currently used in most tropical forest carbon
studies. In particular, a pantropical biomass model has been widely used for
approximately a decade, and its most recent version will certainly
constitute a reference model in the coming years. However, this reference model
shows a systematic bias towards the largest trees. Because large trees are key
drivers of forest carbon stocks and dynamics, understanding the origin and
the consequences of this bias is of utmost concern. In this study, we
compiled a unique tree mass data set of 673 trees destructively sampled in
five tropical countries (101 trees > 100 cm in diameter) and an
original data set of 130 forest plots (1 ha) from central Africa to quantify
the prediction error of biomass allometric models at the individual and plot
levels when explicitly taking crown mass variations into account or not doing so. We first
showed that the proportion of crown to total tree aboveground biomass is
highly variable among trees, ranging from 3 to 88 %. This proportion was
constant on average for trees < 10 Mg (mean of 34 %) but, above
this threshold, increased sharply with tree mass and exceeded 50 % on
average for trees ≥ 45 Mg. This increase coincided with a progressive
deviation between the pantropical biomass model estimations and actual tree
mass. Taking a crown mass proxy into account in a newly developed model
consistently removed the bias observed for large trees (> 1 Mg)
and reduced the range of plot-level error (in %) from [−23; 16] to [0; 10].
The disproportionally higher allocation of large trees to crown mass may
thus explain the bias observed recently in the reference pantropical model.
This bias leads to far-from-negligible, but often overlooked, systematic
errors at the plot level and may be easily corrected by taking a
crown mass proxy for the largest trees in a stand into account, thus suggesting that the
accuracy of forest carbon estimates can be significantly improved at a
minimal cost. |
| first_indexed | 2024-12-10T12:45:41Z |
| format | Article |
| id | doaj.art-a64c82e04bc34a02a47dbd41f09343e1 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-10T12:45:41Z |
| publishDate | 2016-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-a64c82e04bc34a02a47dbd41f09343e12022-12-22T01:48:24ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-03-011351571158510.5194/bg-13-1571-2016Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometriesP. Ploton0N. Barbier1S. Takoudjou Momo2M. Réjou-Méchain3F. Boyemba Bosela4G. Chuyong5G. Dauby6V. Droissart7A. Fayolle8R. C. Goodman9M. Henry10N. G. Kamdem11J. K. Mukirania12D. Kenfack13M. Libalah14A. Ngomanda15V. Rossi16B. Sonké17N. Texier18D. Thomas19D. Zebaze20P. Couteron21U. Berger22R. Pélissier23Institut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceFaculté des Sciences, Université de Kisangani, Kisangani, Democratic Republic of CongoDepartment of Botany and Plant Physiology, University of Buea, Buea, CameroonInstitut de Recherche pour le Développement, UMR-DIADE, Montpellier, FranceInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceResearch axis on Forest Resource Management of the Biosystem engineering (BIOSE), Gembloux Agro-Bio Tech, Université de Liège, Gembloux, BelgiumYale School of Forestry and Environmental Studies, New Haven, USAFood and Agriculture Organization of the United Nations, Rome, ItalyLaboratoire de Botanique systématique et d'Ecologie, Département des Sciences Biologiques, Ecole Normale Supérieure, Université de Yaoundé I, Yaoundé, CameroonFaculté des Sciences, Université de Kisangani, Kisangani, Democratic Republic of CongoCenter for Tropical Forest Science, Harvard University, Cambridge, USALaboratoire de Botanique systématique et d'Ecologie, Département des Sciences Biologiques, Ecole Normale Supérieure, Université de Yaoundé I, Yaoundé, CameroonInstitut de Recherche en Ecologie Tropicale, Libreville, GabonCentre de coopération internationale en recherche agronomique pour le développement, Montpellier, FranceLaboratoire de Botanique systématique et d'Ecologie, Département des Sciences Biologiques, Ecole Normale Supérieure, Université de Yaoundé I, Yaoundé, CameroonInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceDepartment of Botany and Plant Pathology, Oregon State University, Corvallis, USALaboratoire de Botanique systématique et d'Ecologie, Département des Sciences Biologiques, Ecole Normale Supérieure, Université de Yaoundé I, Yaoundé, CameroonInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceTechnische Universität Dresden, Faculty of Environmental Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt, GermanyInstitut de Recherche pour le Développement, UMR-AMAP, Montpellier, FranceAccurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood density as predictors are currently used in most tropical forest carbon studies. In particular, a pantropical biomass model has been widely used for approximately a decade, and its most recent version will certainly constitute a reference model in the coming years. However, this reference model shows a systematic bias towards the largest trees. Because large trees are key drivers of forest carbon stocks and dynamics, understanding the origin and the consequences of this bias is of utmost concern. In this study, we compiled a unique tree mass data set of 673 trees destructively sampled in five tropical countries (101 trees > 100 cm in diameter) and an original data set of 130 forest plots (1 ha) from central Africa to quantify the prediction error of biomass allometric models at the individual and plot levels when explicitly taking crown mass variations into account or not doing so. We first showed that the proportion of crown to total tree aboveground biomass is highly variable among trees, ranging from 3 to 88 %. This proportion was constant on average for trees < 10 Mg (mean of 34 %) but, above this threshold, increased sharply with tree mass and exceeded 50 % on average for trees ≥ 45 Mg. This increase coincided with a progressive deviation between the pantropical biomass model estimations and actual tree mass. Taking a crown mass proxy into account in a newly developed model consistently removed the bias observed for large trees (> 1 Mg) and reduced the range of plot-level error (in %) from [−23; 16] to [0; 10]. The disproportionally higher allocation of large trees to crown mass may thus explain the bias observed recently in the reference pantropical model. This bias leads to far-from-negligible, but often overlooked, systematic errors at the plot level and may be easily corrected by taking a crown mass proxy for the largest trees in a stand into account, thus suggesting that the accuracy of forest carbon estimates can be significantly improved at a minimal cost.http://www.biogeosciences.net/13/1571/2016/bg-13-1571-2016.pdf |
| spellingShingle | P. Ploton N. Barbier S. Takoudjou Momo M. Réjou-Méchain F. Boyemba Bosela G. Chuyong G. Dauby V. Droissart A. Fayolle R. C. Goodman M. Henry N. G. Kamdem J. K. Mukirania D. Kenfack M. Libalah A. Ngomanda V. Rossi B. Sonké N. Texier D. Thomas D. Zebaze P. Couteron U. Berger R. Pélissier Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries Biogeosciences |
| title | Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries |
| title_full | Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries |
| title_fullStr | Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries |
| title_full_unstemmed | Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries |
| title_short | Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries |
| title_sort | closing a gap in tropical forest biomass estimation taking crown mass variation into account in pantropical allometries |
| url | http://www.biogeosciences.net/13/1571/2016/bg-13-1571-2016.pdf |
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