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- Bai, M. W., et al.
(författare)
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Different responses of the radial growth of the planted and natural forests to climate change in humid subtropical China
- 2020
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Ingår i: Geografiska Annaler Series a-Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 102:3, s. 235-246
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Tidskriftsartikel (refereegranskat)abstract
- China holds the world's largest area of planted forests, which play a crucial role in mitigating climate change. Knowledge gaps remain on the responses of the growth of planted forests to climate changes in China, particularly for their long-term changes. This study compared the long-term tree-ring growth patterns and their responses to climate between planted and natural forests. We developed four chronologies from two typical conifer species ofPinus massonianaandCunninghamia lanceolatafrom planted and natural forests in humid subtropical China. One chronology is to our knowledge the longest chronology from planted forests in China spanning since 1944. Tree growths of both natural and planted forests are generally limited by summer drought due to the hot and dry summer in this area. In general, tree rings of the natural forests are more sensitive to climate than planted forests as indicated by higher inter-series correlations, which agree with previous studies. The natural forests are more drought sensitive wheareas the planted forests are relatively more limited by temperature. TheC. lanceolataforests showed more significant correlations with the accumulated drought thanP. massonianafor both the natural and planted forests.
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| 3. |
- Chen, D., et al.
(författare)
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A tree-ring delta O-18 based reconstruction of East Asia summer monsoon over the past two centuries
- 2020
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:6
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Tidskriftsartikel (refereegranskat)abstract
- The East Asian summer monsoon (EASM) exhibits considerable decadal variations since the late 20th century. Efforts to examine long-term behaviors and dynamics of the EASM are impeded largely due to the shortness of instrumental meteorological records. So far, reconstructions of the EASM with annual resolution from its core regions remain limited. We conduct the first 200-year robust EASM reconstruction based on tree-ring cellulose delta O-18 records derived from Pinus massoniana trees growing in the middle Yangtze River basin, one of the core EASM areas. The delta O-18 chronology accounts for 46.2% of the actual variation in an index of the EASM from 1948 to 2014. The reconstructed EASM indicates that the monsoon intensity was below average before the 1950s, peaked in the 1950s-1970s, and then began to decline. The reconstructed EASM is negatively correlated with the El Nino-Southern Oscillation (ENSO), but this teleconnection is dynamic through time, i.e. enhanced (reduced) ENSO variability coheres with strong (weak) EASM-ENSO connections. In addition, despite high ENSO variability since the 1980s, the EASM-ENSO relationship weakened possibly due to anthropogenic impact, particularly aerosol emissions.
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| 5. |
- Li, D. W., et al.
(författare)
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Climate, intrinsic water-use efficiency and tree growth over the past 150 years in humid subtropical China
- 2017
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:2
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Tidskriftsartikel (refereegranskat)abstract
- Influence of long-term changes in climate and CO2 concentration on intrinsic water-use efficiency (iWUE), defined as the ratio between net photosynthesis (A) and leaf conductance (g), and tree growth remain not fully revealed in humid subtropical China, which is distinct from other arid subtropical areas with dense coverage of broadleaf forests. This study presented the first tree-ring stable carbon isotope (delta C-13) and iWUE series of Pinus massoniana from 1865 to 2013 in Fujian province, humid subtropical China, and the first tree-ring width standard chronology during the period of 1836-2013 for the Niumulin Nature Reserve (NML). Tree-ring width growth was limited by precipitation in July-August (r = 0.40, p < 0.01). The tree-ring carbon isotope discrimination (Delta C-13) was mainly controlled by the sunshine hours (r = -0.66, p < 0.001) and relative humidity (r = 0.58, p < 0.001) in September-October, a season with rapid latewood formation in this area. The iWUE increased by 42.6% and the atmospheric CO2 concentration (c(a)) explained 92.6% of the iWUE variance over the last 150 years. The steady increase in iWUE suggests an active response with a proportional increase in intercellular CO2 concentration (c(i)) in response to increase in c(a). The contribution of iWUE to tree growth in the study region is not conspicuous, which points to influences of other factors such as climate.
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| 6. |
- Zhao, Z., et al.
(författare)
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Responses of the radial growth of the endangered species Keteleeria fortunei to climate change in southeastern China
- 2019
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Ingår i: Trees-Structure and Function. - : Springer Science and Business Media LLC. - 0931-1890. ; 33:4, s. 977-985
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge on the responses of endangered species to current global changes can highlight the necessity and importance of protecting these species. Tree-ring-based studies provide a longer term perspective than monitoring studies on the responses and adaptations of the growth of endangered species to climate change and forest disturbances. Therefore, this study conducted a tree-ring case study on Keteleeria fortunei, an endangered and endemic species in southern China, and presents the first tree-ring chronology of K. fortunei from 1850 to 2013 in the Fuzhou area, which is located west of the Taiwan Strait. K. fortunei trees tend to grow in moister locations in closed forests and are more sensitive to forest disturbances and sunshine than Pinus massoniana. Our study shows that missing rings are more frequent for K. fortunei than for P. massoniana in the same area, which agrees with previous findings that wedging and missing rings tend to occur in trees experiencing growth suppression in closed forests.
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