Near-complete Loss of Fire-resistant Primary Tropical Forest Cover in Sumatra and Kalimantan

Near-complete Loss of Fire-resistant Primary Tropical Forest Cover in Sumatra and Kalimantan | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Near-complete Loss of Fire-resistant Primary Tropical Forest Cover in Sumatra and Kalimantan Tadas Nikonovas, Allan Spessa, Stefan Doerr, Gareth Clay, Symon Mezbahuddin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-75720/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Deforestation in Sumatra and Kalimantan in recent decades has made increasingly large parts of the region vulnerable to fires. Burning is particularly widespread in deforested peatlands, leading to globally significant carbon emissions. Here we assess primary forest cover loss and fragmentation combined with active fire observations between 2001 and 2019 for the entire region. We find that fires did not penetrate undisturbed primary forest areas deeper than two kilometres from the forest edge irrespective of drought conditions, highlighting the resistance of such forests to burning. However, only 10% of primary forest on peatland and 13% on non-peatlands remain in this category, with the rest being severely fragmented or degraded due to proximity to the forest edge. Fire-resistant forests now cover only 3% of peatlands and 4.5% of non-peatlands in Sumatra and Kalimantan. We also show that 15% and 17% of burning during the 2015 and 2019 fire episodes respectively occurred on land cleared since 2001. Our work demonstrates that protection and regeneration of the remaining contiguous primary forest blocks, as well as peatland restoration, are an urgent necessity for mitigating the impacts of potentially more frequent fire events under future global warming in Indonesia. Environmental Policy deforested peatlands Deforestation non-peatlands Indonesia Figures Figure 1 Figure 2 Figure 3 Figure 4 Full Text Additional Declarations There is NO Competing Interest. Supplementary Files FigS1.jpg Primary forest cover in the region at the beginning of 2002. Monthly precipitation anomalies, changes in primary forest cover and fire regimes over the study period for the delineated sub-regions are shown in figures S2 – S4. FigS2.jpg a) Monthly precipitation anomalies for the study period (Methods). b, c) Change in extent and % of fireaffected grid cells showing only (b) peatland and (c) non-peatland areas in Central Sumatra sub-region (Fig. S1). Showing only areas which were undisturbed primary forest (grid cells having 99% or more primary forest cover) at the beginning of year 2002. Solid lines indicate the primary forest cover percentage thresholds. Dashed lines represent distance from the forest edge thresholds for the undisturbed forest category. Note different colour scales for peatland (b) and non-peatland (c) plots. FigS3.jpg Same as Fig. S2, but for the West Kalimantan sub-region. FigS4.jpg Same as Fig. S2, but for the South Kalimantan sub-region. Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-75720","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":2422262,"identity":"cf5927d4-952a-49e3-a7da-a70df8b27fe7","order_by":0,"name":"Tadas Nikonovas","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYHACAxDBI8HeAGJbEFbPA9fCcwCkRYJ4LQwSEglgirAWe/bDGz/+YLgjIznz+dUNPwokGPjbuxPw28KTVizNw/CMR1o6p+xmD9BhEmfObiDgsBwDaQaGwzxy0jlpN3iAWgwkcglo4X9j/PMHSIvkmbSbf4jSIpFjJsED1CItwX7sNnG23HhWZs1jcJhHsieH7baMgQQPQb+w9ydvvvmj4rC9xPHjz26++WMjx9/ei18LBEBiE0ISoRxh4QNSVI+CUTAKRsEIAgDjjj7//i+0VwAAAABJRU5ErkJggg==","orcid":"","institution":"Swansea University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Tadas","middleName":"","lastName":"Nikonovas","suffix":""},{"id":2422263,"identity":"9733755c-f316-4cd7-847b-d73d315b91e9","order_by":1,"name":"Allan Spessa","email":"","orcid":"","institution":"Swansea University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Allan","middleName":"","lastName":"Spessa","suffix":""},{"id":2422264,"identity":"b2a0aa18-989e-4c8d-b507-066dbbd2ff01","order_by":2,"name":"Stefan Doerr","email":"","orcid":"https://orcid.org/0000-0002-8700-9002","institution":"Swansea University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Stefan","middleName":"","lastName":"Doerr","suffix":""},{"id":2422265,"identity":"91003dc3-c94b-4c58-b541-5965159bc20a","order_by":3,"name":"Gareth Clay","email":"","orcid":"","institution":"University of Manchester","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Gareth","middleName":"","lastName":"Clay","suffix":""},{"id":2422266,"identity":"5c247cbc-a8a9-4fa1-bc55-9f2e860a6f19","order_by":4,"name":"Symon Mezbahuddin","email":"","orcid":"https://orcid.org/0000-0001-9341-4023","institution":"University of Alberta","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Symon","middleName":"","lastName":"Mezbahuddin","suffix":""}],"badges":[],"createdAt":"2020-09-10 15:35:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-75720/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-75720/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":2480379,"identity":"965694f8-35e6-43f5-811d-1bd29f4ee9a4","added_by":"auto","created_at":"2020-09-18 16:03:57","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":305344,"visible":true,"origin":"","legend":"The remaining fire-resilient primary forests in the region at the beginning of 2019. The categories shown\nare \u003c99% primary forest cover, primary forest cover \u003e99% but within 2 km from the forest edge, and primary\nforests cover \u003e99% and further from the forest edge than 2 km.","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/Fig1.jpg"},{"id":2480380,"identity":"01f830d4-97cc-4406-9e58-2ed2e7315118","added_by":"auto","created_at":"2020-09-18 16:03:57","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":207073,"visible":true,"origin":"","legend":"(a) Annual primary forest cover loss in the region; and total primary forest cover at the beginning of\n2001 and 2019 shown against total area of (b) peatlands and (c) non-peatlands.","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/Fig2.jpg"},{"id":2480381,"identity":"bf7e7458-6739-44db-a307-26b3973fc1b0","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":310378,"visible":true,"origin":"","legend":"a) Monthly precipitation anomalies in the region for the study period (Methods). b, c) Change in extent\nand % of fire-affected grid cells for different primary forest cover percent categories in peatlands (b) and nonpeatlands\n(c) of Sumatra and Kalimantan. The lines represent primary forest cover thresholds and indicate year\nto year changes in extent of areas covered by 1 km grid cells having primary forest cover of more than 99%\n(area to the left from the 99% threshold line), 99% to 50%, 50% to 1% and less than 1%. Colour indicates % of\nfire-affected grid cells. Primary forest cover estimates for each year represent the state at the beginning of the\nyear. Forest loss estimate for that year is accounted for in the figure for the following year.","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/Fig3.jpg"},{"id":2480382,"identity":"4006de06-876e-4545-96cd-8cbd4193122e","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":353679,"visible":true,"origin":"","legend":"a) Monthly precipitation anomalies in the region for the study period (Methods). b, c) Change in extent\nand % of fire-affected grid cells. In contrast to Fig. 3, this Figure only shows (b) peatland and (c) non-peatland\nareas which were undisturbed primary forest (grid cells having 99% or more primary forest cover) at the\nbeginning of year 2002. Solid lines indicate the primary forest cover percentage thresholds as in Fig. 3. Dashed\nlines represent distance from the forest edge thresholds for the undisturbed forest category. Note different\ncolour scales for peatland (b) and non-peatland (c) plots. See figures S1 – S4 (Supplement figures) showing the\nsame analysis split into different sub-regions of Sumatra and Kalimantan.","description":"","filename":"Fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/Fig4.jpg"},{"id":13532820,"identity":"454f8e10-bbae-4248-86a8-9fda970c8f15","added_by":"auto","created_at":"2021-09-17 01:18:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1843262,"visible":true,"origin":"","legend":"","description":"","filename":"NikonovasetallossoffireresistantprimaryforestSumatraKalimantanrevised.pdf","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1_covered.pdf"},{"id":2480388,"identity":"7f92d910-0aae-4d0f-a454-b0c940b267a1","added_by":"auto","created_at":"2020-09-18 16:04:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2246279,"visible":true,"origin":"","legend":"","description":"","filename":"NikonovasetallossoffireresistantprimaryforestSumatraKalimantanrevised.pdf","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1_stamped.pdf"},{"id":2480383,"identity":"38a47109-2459-4949-b367-13efda6cb980","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2216977,"visible":true,"origin":"","legend":"","description":"","filename":"NikonovasetallossoffireresistantprimaryforestSumatraKalimantanrevised.pdf","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/NikonovasetallossoffireresistantprimaryforestSumatraKalimantanrevised.pdf"},{"id":2480384,"identity":"5b407546-6d7a-474d-bd6a-7a8f00791327","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":406169,"visible":true,"origin":"","legend":"Primary forest cover in the region at the beginning of 2002. Monthly precipitation anomalies, changes in\nprimary forest cover and fire regimes over the study period for the delineated sub-regions are shown in figures\nS2 – S4.","description":"","filename":"FigS1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/FigS1.jpg"},{"id":2480385,"identity":"978f3b08-1370-4163-941b-c72bfacf503c","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":408461,"visible":true,"origin":"","legend":"a) Monthly precipitation anomalies for the study period (Methods). b, c) Change in extent and % of fireaffected\ngrid cells showing only (b) peatland and (c) non-peatland areas in Central Sumatra sub-region (Fig. S1).\nShowing only areas which were undisturbed primary forest (grid cells having 99% or more primary forest cover)\nat the beginning of year 2002. Solid lines indicate the primary forest cover percentage thresholds. Dashed lines\nrepresent distance from the forest edge thresholds for the undisturbed forest category. Note different colour\nscales for peatland (b) and non-peatland (c) plots.","description":"","filename":"FigS2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/FigS2.jpg"},{"id":2480386,"identity":"b1a3291a-27d6-4ddd-8b83-1fd53a07a31a","added_by":"auto","created_at":"2020-09-18 16:03:58","extension":"jpg","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":393892,"visible":true,"origin":"","legend":"Same as Fig. S2, but for the West Kalimantan sub-region.","description":"","filename":"FigS3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/FigS3.jpg"},{"id":2480387,"identity":"57267fa1-5ff0-411e-a16c-eef54b7d59d5","added_by":"auto","created_at":"2020-09-18 16:03:59","extension":"jpg","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":393228,"visible":true,"origin":"","legend":"Same as Fig. S2, but for the South Kalimantan sub-region.","description":"","filename":"FigS4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-75720/v1/FigS4.jpg"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"\u003cp\u003eNear-complete Loss of Fire-resistant Primary Tropical Forest Cover in Sumatra and Kalimantan\u003c/p\u003e","fulltext":[{"header":"Full Text","content":"\u003cp\u003eThis preprint is available for \u003ca href='/article/rs-75720/latest.pdf' target='_blank'\u003edownload as a PDF\u003c/a\u003e.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"deforested peatlands, Deforestation, non-peatlands, Indonesia","lastPublishedDoi":"10.21203/rs.3.rs-75720/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-75720/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDeforestation in Sumatra and Kalimantan in recent decades has made increasingly large parts of the region vulnerable to fires. Burning is particularly widespread in deforested peatlands, leading to globally significant carbon emissions. Here we assess primary forest cover loss and fragmentation combined with active fire observations between 2001 and 2019 for the entire region. We find that fires did not penetrate undisturbed primary forest areas deeper than two kilometres from the forest edge irrespective of drought conditions, highlighting the resistance of such forests to burning. However, only 10% of primary forest on peatland and 13% on non-peatlands remain in this category, with the rest being severely fragmented or degraded due to proximity to the forest edge. Fire-resistant forests now cover only 3% of peatlands and 4.5% of non-peatlands in Sumatra and Kalimantan. We also show that 15% and 17% of burning during the 2015 and 2019 fire episodes respectively occurred on land cleared since 2001. Our work demonstrates that protection and regeneration of the remaining contiguous primary forest blocks, as well as peatland restoration, are an urgent necessity for mitigating the impacts of potentially more frequent fire events under future global warming in Indonesia.\u003c/p\u003e","manuscriptTitle":"Near-complete Loss of Fire-resistant Primary Tropical Forest Cover in Sumatra and Kalimantan","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2020-09-18 16:03:56","doi":"10.21203/rs.3.rs-75720/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"communications-earth-and-environment","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"commsenv","sideBox":"Learn more about [Communications Earth and Environment](https://www.nature.com/commsenv/)","snPcode":"","submissionUrl":"","title":"Communications Earth \u0026 Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Communications Series","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"84e0e1d9-e479-4957-8281-f1c0dfd05b4d","owner":[],"postedDate":"September 18th, 2020","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":551098,"name":"Environmental Policy"}],"tags":[],"updatedAt":"2020-10-22T18:35:34+00:00","versionOfRecord":[],"versionCreatedAt":"2020-09-18 16:03:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-75720","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-75720","identity":"rs-75720","version":["v1"]},"buildId":"-HB7Z8yhvgn0wM9Nzuekk","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}