Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause

Steep decline in forest fires about a century ago occurred in coniferous forests over large areas in North America and Fennoscandia. This poorly understood phenomenon has been explained by different factors in different regions. The objective of this study is to evaluate the validity of the four mos...

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Published in:Silva Fennica
Main Author: Wallenius, Tuomo
Format: Article in Journal/Newspaper
Language:English
Published: Finnish Society of Forest Science 2011
Subjects:
Online Access:https://doi.org/10.14214/sf.36
https://doaj.org/article/27349965eabb4555b0681eb5e3a01048
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spelling ftdoajarticles:oai:doaj.org/article:27349965eabb4555b0681eb5e3a01048 2023-05-15T16:11:36+02:00 Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause Wallenius, Tuomo 2011-01-01T00:00:00Z https://doi.org/10.14214/sf.36 https://doaj.org/article/27349965eabb4555b0681eb5e3a01048 EN eng Finnish Society of Forest Science https://www.silvafennica.fi/article/36 https://doaj.org/toc/2242-4075 2242-4075 doi:10.14214/sf.36 https://doaj.org/article/27349965eabb4555b0681eb5e3a01048 Silva Fennica, Vol 45, Iss 1 (2011) Forestry SD1-669.5 article 2011 ftdoajarticles https://doi.org/10.14214/sf.36 2022-12-30T21:38:22Z Steep decline in forest fires about a century ago occurred in coniferous forests over large areas in North America and Fennoscandia. This poorly understood phenomenon has been explained by different factors in different regions. The objective of this study is to evaluate the validity of the four most commonly suggested causes of the decrease in forest fires: fire fighting, over-grazing, climate change and human influence. I compiled the available dendrochronological data and estimated the annually burned proportions of Pinus-dominated forests in four subcontinental regions during the past 500 years. These data were compared to the development of fire suppression, grazing pressure, climate and human livelihoods. The annually burned proportions declined over 90% in all studied regions. In three out of the four regions fires decreased decades before fire suppression began. Available drought data are annually well correlated with fires but could not explain the decrease of the level in annually burned areas. A rapid increase in the number of livestock occurred at the same time with the decrease in fires in the Western US but not in Fennoscandia. Hence, fire suppression in Central Fennoscandia and over-grazing in the Western US may have locally contributed to the reduction of burned areas. More general explanation is offered by human influence hypothesis: the majority of the past forest fires were probably caused by humans and the decrease in the annually burned areas was because of a decrease in human caused fires. This is in accordance with the old written records and forest fire statistics. The decrease in annually burned areas, both in Fennoscandia and the United States coincides with an economic and cultural transition from traditional livelihoods that are associated with high fire use to modern agriculture and forestry. Article in Journal/Newspaper Fennoscandia Directory of Open Access Journals: DOAJ Articles Silva Fennica 45 1
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Forestry
SD1-669.5
spellingShingle Forestry
SD1-669.5
Wallenius, Tuomo
Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
topic_facet Forestry
SD1-669.5
description Steep decline in forest fires about a century ago occurred in coniferous forests over large areas in North America and Fennoscandia. This poorly understood phenomenon has been explained by different factors in different regions. The objective of this study is to evaluate the validity of the four most commonly suggested causes of the decrease in forest fires: fire fighting, over-grazing, climate change and human influence. I compiled the available dendrochronological data and estimated the annually burned proportions of Pinus-dominated forests in four subcontinental regions during the past 500 years. These data were compared to the development of fire suppression, grazing pressure, climate and human livelihoods. The annually burned proportions declined over 90% in all studied regions. In three out of the four regions fires decreased decades before fire suppression began. Available drought data are annually well correlated with fires but could not explain the decrease of the level in annually burned areas. A rapid increase in the number of livestock occurred at the same time with the decrease in fires in the Western US but not in Fennoscandia. Hence, fire suppression in Central Fennoscandia and over-grazing in the Western US may have locally contributed to the reduction of burned areas. More general explanation is offered by human influence hypothesis: the majority of the past forest fires were probably caused by humans and the decrease in the annually burned areas was because of a decrease in human caused fires. This is in accordance with the old written records and forest fire statistics. The decrease in annually burned areas, both in Fennoscandia and the United States coincides with an economic and cultural transition from traditional livelihoods that are associated with high fire use to modern agriculture and forestry.
format Article in Journal/Newspaper
author Wallenius, Tuomo
author_facet Wallenius, Tuomo
author_sort Wallenius, Tuomo
title Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
title_short Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
title_full Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
title_fullStr Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
title_full_unstemmed Major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
title_sort major decline in fires in coniferous forests – reconstructing the phenomenon and seeking for the cause
publisher Finnish Society of Forest Science
publishDate 2011
url https://doi.org/10.14214/sf.36
https://doaj.org/article/27349965eabb4555b0681eb5e3a01048
genre Fennoscandia
genre_facet Fennoscandia
op_source Silva Fennica, Vol 45, Iss 1 (2011)
op_relation https://www.silvafennica.fi/article/36
https://doaj.org/toc/2242-4075
2242-4075
doi:10.14214/sf.36
https://doaj.org/article/27349965eabb4555b0681eb5e3a01048
op_doi https://doi.org/10.14214/sf.36
container_title Silva Fennica
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