Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1111/nph.16742 http://hdl.handle.net/11449/200749 |
Resumo: | Vegetation–fire feedbacks are important for determining the distribution of forest and savanna. To understand how vegetation structure controls these feedbacks, we quantified flammability across gradients of tree density from grassland to forest in the Brazilian Cerrado. We experimentally burned 102 plots, for which we measured vegetation structure, fuels, microclimate, ignition success and fire behavior. Tree density had strong negative effects on ignition success, rate of spread, fire-line intensity and flame height. Declining grass biomass was the principal cause of this decline in flammability as tree density increased, but increasing fuel moisture contributed. Although the response of flammability to tree cover often is portrayed as an abrupt, largely invariant threshold, we found the response to be gradual, with considerable variability driven largely by temporal changes in atmospheric humidity. Even when accounting for humidity, flammability at intermediate tree densities cannot be predicted reliably. Fire spread in savanna–forest mosaics is not as deterministic as often assumed, but may appear so where vegetation boundaries are already sharp. Where transitions are diffuse, fire spread is difficult to predict, but should become increasingly predictable over multiple fire cycles, as boundaries are progressively sharpened until flammability appears to respond in a threshold-like manner. |
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Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitionsfeedbackfire intensityflammabilityignitabilitySavannastructural equation modellingtropical forestVegetation–fire feedbacks are important for determining the distribution of forest and savanna. To understand how vegetation structure controls these feedbacks, we quantified flammability across gradients of tree density from grassland to forest in the Brazilian Cerrado. We experimentally burned 102 plots, for which we measured vegetation structure, fuels, microclimate, ignition success and fire behavior. Tree density had strong negative effects on ignition success, rate of spread, fire-line intensity and flame height. Declining grass biomass was the principal cause of this decline in flammability as tree density increased, but increasing fuel moisture contributed. Although the response of flammability to tree cover often is portrayed as an abrupt, largely invariant threshold, we found the response to be gradual, with considerable variability driven largely by temporal changes in atmospheric humidity. Even when accounting for humidity, flammability at intermediate tree densities cannot be predicted reliably. Fire spread in savanna–forest mosaics is not as deterministic as often assumed, but may appear so where vegetation boundaries are already sharp. Where transitions are diffuse, fire spread is difficult to predict, but should become increasingly predictable over multiple fire cycles, as boundaries are progressively sharpened until flammability appears to respond in a threshold-like manner.Department of Plant and Microbial Biology North Carolina State University, Campus Box 7612Department of Fisheries Wildlife and Conservation Biology North Carolina State UniversityDepartamento de Ciências Ambientais Universidade Federal Rural do Rio de JaneiroLaboratório de Ecologia e Hidrologia Florestal Floresta Estadual de Assis Instituto FlorestalDepartamento de Biologia Universidade Estadual Paulista (UNESP), Campus de JaboticabalDepartamento de Biologia Universidade Estadual Paulista (UNESP), Campus de JaboticabalNorth Carolina State UniversityUniversidade Federal Rural do Rio de JaneiroInstituto FlorestalUniversidade Estadual Paulista (Unesp)Newberry, Brooklynn M.Power, Collin R.Abreu, Rodolfo C. R.Durigan, GiseldaRossatto, Davi R. [UNESP]Hoffmann, William A.2020-12-12T02:15:02Z2020-12-12T02:15:02Z2020-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1111/nph.16742New Phytologist.1469-81370028-646Xhttp://hdl.handle.net/11449/20074910.1111/nph.167422-s2.0-85087859520Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengNew Phytologistinfo:eu-repo/semantics/openAccess2024-06-06T13:04:11Zoai:repositorio.unesp.br:11449/200749Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T15:39:54.851834Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
title |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
spellingShingle |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions Newberry, Brooklynn M. feedback fire intensity flammability ignitability Savanna structural equation modelling tropical forest |
title_short |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
title_full |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
title_fullStr |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
title_full_unstemmed |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
title_sort |
Flammability thresholds or flammability gradients? Determinants of fire across savanna–forest transitions |
author |
Newberry, Brooklynn M. |
author_facet |
Newberry, Brooklynn M. Power, Collin R. Abreu, Rodolfo C. R. Durigan, Giselda Rossatto, Davi R. [UNESP] Hoffmann, William A. |
author_role |
author |
author2 |
Power, Collin R. Abreu, Rodolfo C. R. Durigan, Giselda Rossatto, Davi R. [UNESP] Hoffmann, William A. |
author2_role |
author author author author author |
dc.contributor.none.fl_str_mv |
North Carolina State University Universidade Federal Rural do Rio de Janeiro Instituto Florestal Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Newberry, Brooklynn M. Power, Collin R. Abreu, Rodolfo C. R. Durigan, Giselda Rossatto, Davi R. [UNESP] Hoffmann, William A. |
dc.subject.por.fl_str_mv |
feedback fire intensity flammability ignitability Savanna structural equation modelling tropical forest |
topic |
feedback fire intensity flammability ignitability Savanna structural equation modelling tropical forest |
description |
Vegetation–fire feedbacks are important for determining the distribution of forest and savanna. To understand how vegetation structure controls these feedbacks, we quantified flammability across gradients of tree density from grassland to forest in the Brazilian Cerrado. We experimentally burned 102 plots, for which we measured vegetation structure, fuels, microclimate, ignition success and fire behavior. Tree density had strong negative effects on ignition success, rate of spread, fire-line intensity and flame height. Declining grass biomass was the principal cause of this decline in flammability as tree density increased, but increasing fuel moisture contributed. Although the response of flammability to tree cover often is portrayed as an abrupt, largely invariant threshold, we found the response to be gradual, with considerable variability driven largely by temporal changes in atmospheric humidity. Even when accounting for humidity, flammability at intermediate tree densities cannot be predicted reliably. Fire spread in savanna–forest mosaics is not as deterministic as often assumed, but may appear so where vegetation boundaries are already sharp. Where transitions are diffuse, fire spread is difficult to predict, but should become increasingly predictable over multiple fire cycles, as boundaries are progressively sharpened until flammability appears to respond in a threshold-like manner. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-12-12T02:15:02Z 2020-12-12T02:15:02Z 2020-01-01 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1111/nph.16742 New Phytologist. 1469-8137 0028-646X http://hdl.handle.net/11449/200749 10.1111/nph.16742 2-s2.0-85087859520 |
url |
http://dx.doi.org/10.1111/nph.16742 http://hdl.handle.net/11449/200749 |
identifier_str_mv |
New Phytologist. 1469-8137 0028-646X 10.1111/nph.16742 2-s2.0-85087859520 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
New Phytologist |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1808128547617767424 |