Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings

Low growth rates of atmospheric CO_2 were observed following the 1991 Pinatubo (Luzon) volcanic eruption. One hypothesis for this CO_2 anomaly is that since diffuse light is more efficiently used by forests than direct light, the increase in the diffuse fraction of sunlight due to scattering by volc...

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Bibliographic Details
Published in:Global Biogeochemical Cycles
Main Authors: Krakauer, Nir Y., Randerson, James T.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Geophysical Union 2003
Subjects:
NPP
Online Access:https://doi.org/10.1029/2003gb002076
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spelling ftcaltechauth:oai:authors.library.caltech.edu:wnxy2-rpz61 2024-10-13T14:08:04+00:00 Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings Krakauer, Nir Y. Randerson, James T. 2003-12 https://doi.org/10.1029/2003gb002076 unknown American Geophysical Union https://doi.org/10.1029/2003gb002076 eprintid:91300 info:eu-repo/semantics/openAccess Other Global Biogeochemical Cycles, 17(4), Art. No. 1118, (2003-12) NPP Pinatubo tree rings carbon sink diffuse light boreal forest info:eu-repo/semantics/article 2003 ftcaltechauth https://doi.org/10.1029/2003gb002076 2024-09-25T18:46:39Z Low growth rates of atmospheric CO_2 were observed following the 1991 Pinatubo (Luzon) volcanic eruption. One hypothesis for this CO_2 anomaly is that since diffuse light is more efficiently used by forests than direct light, the increase in the diffuse fraction of sunlight due to scattering by volcanic sulfur aerosol in the years following the eruption substantially increased forest net primary production (NPP). However, other observations suggest a decrease in northern forest NPP because of the cooler conditions following the eruption. Here we used a global database of dated tree ring widths (which correlate with forest NPP) to test this hypothesis. Ice core records of sulfur deposition allowed us to identify the timing and magnitude of 23 Pinatuboâ€scale eruptions since 1000 CE. We found a significant decrease in ring width for trees in middle to high northern latitudes (north of 45°N) following eruption sulfur peaks. Decreases in tree ring widths were in the range of 2–8% and persisted for ∼8 years following sulfur peaks, with minima at around 4–6 years. Ring width changes at lower latitudes in the Northern Hemisphere (30°N to 45°N) and in the Southern Hemisphere (30°S to 56°S) were not significant. In the tropics (30°N to 30°S) the paucity of tree ring records did not permit the evaluation of NPP changes. Given that elevated aerosol levels and summer cooling last only ∼2–3 years after an eruption, the persistence of declines in northern tree growth for up to 8 years after eruptions implies some additional mechanism that links these shorterâ€lived global eruption effects to sustained changes in tree physiology, biogeochemistry, or microclimate. At least for this sample of trees, the beneficial effect of aerosol light scattering appears to be entirely offset by the deleterious effect of eruptionâ€induced climate change. © 2003 American Geophysical Union. Received 1 April 2003; revised 28 July 2003; accepted 8 August 2003; published 16 December 2003. N. Y. K. thanks the Betty and Gordon ... Article in Journal/Newspaper ice core Caltech Authors (California Institute of Technology) Global Biogeochemical Cycles 17 4
institution Open Polar
collection Caltech Authors (California Institute of Technology)
op_collection_id ftcaltechauth
language unknown
topic NPP
Pinatubo
tree rings
carbon sink
diffuse light
boreal forest
spellingShingle NPP
Pinatubo
tree rings
carbon sink
diffuse light
boreal forest
Krakauer, Nir Y.
Randerson, James T.
Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
topic_facet NPP
Pinatubo
tree rings
carbon sink
diffuse light
boreal forest
description Low growth rates of atmospheric CO_2 were observed following the 1991 Pinatubo (Luzon) volcanic eruption. One hypothesis for this CO_2 anomaly is that since diffuse light is more efficiently used by forests than direct light, the increase in the diffuse fraction of sunlight due to scattering by volcanic sulfur aerosol in the years following the eruption substantially increased forest net primary production (NPP). However, other observations suggest a decrease in northern forest NPP because of the cooler conditions following the eruption. Here we used a global database of dated tree ring widths (which correlate with forest NPP) to test this hypothesis. Ice core records of sulfur deposition allowed us to identify the timing and magnitude of 23 Pinatuboâ€scale eruptions since 1000 CE. We found a significant decrease in ring width for trees in middle to high northern latitudes (north of 45°N) following eruption sulfur peaks. Decreases in tree ring widths were in the range of 2–8% and persisted for ∼8 years following sulfur peaks, with minima at around 4–6 years. Ring width changes at lower latitudes in the Northern Hemisphere (30°N to 45°N) and in the Southern Hemisphere (30°S to 56°S) were not significant. In the tropics (30°N to 30°S) the paucity of tree ring records did not permit the evaluation of NPP changes. Given that elevated aerosol levels and summer cooling last only ∼2–3 years after an eruption, the persistence of declines in northern tree growth for up to 8 years after eruptions implies some additional mechanism that links these shorterâ€lived global eruption effects to sustained changes in tree physiology, biogeochemistry, or microclimate. At least for this sample of trees, the beneficial effect of aerosol light scattering appears to be entirely offset by the deleterious effect of eruptionâ€induced climate change. © 2003 American Geophysical Union. Received 1 April 2003; revised 28 July 2003; accepted 8 August 2003; published 16 December 2003. N. Y. K. thanks the Betty and Gordon ...
format Article in Journal/Newspaper
author Krakauer, Nir Y.
Randerson, James T.
author_facet Krakauer, Nir Y.
Randerson, James T.
author_sort Krakauer, Nir Y.
title Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
title_short Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
title_full Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
title_fullStr Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
title_full_unstemmed Do volcanic eruptions enhance or diminish net primary production? Evidence from tree rings
title_sort do volcanic eruptions enhance or diminish net primary production? evidence from tree rings
publisher American Geophysical Union
publishDate 2003
url https://doi.org/10.1029/2003gb002076
genre ice core
genre_facet ice core
op_source Global Biogeochemical Cycles, 17(4), Art. No. 1118, (2003-12)
op_relation https://doi.org/10.1029/2003gb002076
eprintid:91300
op_rights info:eu-repo/semantics/openAccess
Other
op_doi https://doi.org/10.1029/2003gb002076
container_title Global Biogeochemical Cycles
container_volume 17
container_issue 4
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