Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China
Subtropical forests easily suffer anthropogenic disturbance, including deforestation and reforestation management, which both highly affect the carbon pools. This study proposes spatial-temporal tracking of the carbon density dynamics to improve bookkeeping in the carbon model and applied to subtrop...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/3/753 |
| _version_ | 1797484966806814720 |
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| author | Xinyu Wang Runhao Li Hu Ding Yingchun Fu |
| author_facet | Xinyu Wang Runhao Li Hu Ding Yingchun Fu |
| author_sort | Xinyu Wang |
| collection | DOAJ |
| description | Subtropical forests easily suffer anthropogenic disturbance, including deforestation and reforestation management, which both highly affect the carbon pools. This study proposes spatial-temporal tracking of the carbon density dynamics to improve bookkeeping in the carbon model and applied to subtropical forest activities in Guangzhou, southern China, during the period of 1995 to 2014. Based on the overall accuracy of 87.5% ± 1.7% for forest change products using Landsat time series (LTS), we found that this is a typical period of deforestation conversion to reforestation activity accompanied with urbanization. Additionally, linear regression, random forest regression and allometric growth fitting were proposed by using forest field plots to obtain reliable per-pixel carbon density estimations. The cross-validation (CV) of random forest with LTS-derived parameters reached the highest accuracy of R<sup>2</sup> and RMSE of 0.763 and 7.499 Mg ha<sup>−1</sup>. The RMES of the density estimation ranged between 78 and 84% of the mean observed biomass in the study area, which outperformed previous studies. Over the 20-year period, the study results showed that the explicit carbon emissions were (6.82 ± 0.26) × 10<sup>4</sup> Mg C yr<sup>−1</sup> from deforestation; emissions increased to (1.02 ± 0.04) × 10<sup>5</sup> Mg C yr<sup>−1</sup> given the implicit carbon not yet released to the atmosphere in the form of decomposing slash and wood products. In addition, a carbon uptake of about 1.91 ± 0.73 × 10<sup>5</sup> Mg C yr<sup>−1</sup>, presented as the net carbon pool. Based on the continuous detection capability, biennial reforestation activity has increased carbon density by a growth rate of 1.55 Mg ha<sup>−1</sup>, and the emission factors can be identified with LTS-derived parameters. In general, the study realizes the spatiotemporal improvement of carbon density and flux dynamics tracking, including the abrupt and graduate change based on fine-scale forest activity. It can provide more comprehensive and detailed feedback on the carbon source and sink change process of forest activities and disturbances. |
| first_indexed | 2024-03-09T23:12:04Z |
| format | Article |
| id | doaj.art-bce01395420b4016b22f58f3e2b77809 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T23:12:04Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-bce01395420b4016b22f58f3e2b778092023-11-23T17:42:55ZengMDPI AGRemote Sensing2072-42922022-02-0114375310.3390/rs14030753Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern ChinaXinyu Wang0Runhao Li1Hu Ding2Yingchun Fu3School of Geography, South China Normal University, Guangzhou 510631, ChinaSchool of Geography, South China Normal University, Guangzhou 510631, ChinaSchool of Geography, South China Normal University, Guangzhou 510631, ChinaSchool of Geography, South China Normal University, Guangzhou 510631, ChinaSubtropical forests easily suffer anthropogenic disturbance, including deforestation and reforestation management, which both highly affect the carbon pools. This study proposes spatial-temporal tracking of the carbon density dynamics to improve bookkeeping in the carbon model and applied to subtropical forest activities in Guangzhou, southern China, during the period of 1995 to 2014. Based on the overall accuracy of 87.5% ± 1.7% for forest change products using Landsat time series (LTS), we found that this is a typical period of deforestation conversion to reforestation activity accompanied with urbanization. Additionally, linear regression, random forest regression and allometric growth fitting were proposed by using forest field plots to obtain reliable per-pixel carbon density estimations. The cross-validation (CV) of random forest with LTS-derived parameters reached the highest accuracy of R<sup>2</sup> and RMSE of 0.763 and 7.499 Mg ha<sup>−1</sup>. The RMES of the density estimation ranged between 78 and 84% of the mean observed biomass in the study area, which outperformed previous studies. Over the 20-year period, the study results showed that the explicit carbon emissions were (6.82 ± 0.26) × 10<sup>4</sup> Mg C yr<sup>−1</sup> from deforestation; emissions increased to (1.02 ± 0.04) × 10<sup>5</sup> Mg C yr<sup>−1</sup> given the implicit carbon not yet released to the atmosphere in the form of decomposing slash and wood products. In addition, a carbon uptake of about 1.91 ± 0.73 × 10<sup>5</sup> Mg C yr<sup>−1</sup>, presented as the net carbon pool. Based on the continuous detection capability, biennial reforestation activity has increased carbon density by a growth rate of 1.55 Mg ha<sup>−1</sup>, and the emission factors can be identified with LTS-derived parameters. In general, the study realizes the spatiotemporal improvement of carbon density and flux dynamics tracking, including the abrupt and graduate change based on fine-scale forest activity. It can provide more comprehensive and detailed feedback on the carbon source and sink change process of forest activities and disturbances.https://www.mdpi.com/2072-4292/14/3/753carbon emissionssubtropical forestLandsatCCDCtime series |
| spellingShingle | Xinyu Wang Runhao Li Hu Ding Yingchun Fu Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China Remote Sensing carbon emissions subtropical forest Landsat CCDC time series |
| title | Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China |
| title_full | Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China |
| title_fullStr | Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China |
| title_full_unstemmed | Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China |
| title_short | Fine-Scale Improved Carbon Bookkeeping Model Using Landsat Time Series for Subtropical Forest, Southern China |
| title_sort | fine scale improved carbon bookkeeping model using landsat time series for subtropical forest southern china |
| topic | carbon emissions subtropical forest Landsat CCDC time series |
| url | https://www.mdpi.com/2072-4292/14/3/753 |
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