Spatiotemporal trends of rubber defoliation and refoliation and their responses to abiotic factors in the northern edge of the Asian tropics
Bibliographic record
Abstract
Hevea brasiliensis, a species native to evergreen broadleaf forest in Amazon tropical regions, exhibits a concentrated period of defoliation and refoliation after introduced to the northern edge of Asian tropics. However, up to date, spatiotemporal patterns of rubber phenology and the underlying mechanism remain unclear. In this study, we first investigated the optimal vegetation indices in monitoring four key rubber phenology metrics (i.e., Start of Defoliation (SOD), End of Defoliation (EOD), Start of Refoliation (SOR), and End of Refoliation (EOR)). Then the trends of the four phenology metrics from 2003 to 2022 in the northern edge of Asian tropics were explored. Finally, the phenological responses to climatic and topographical factors were also investigated. Results indicated that the kernel normalized difference vegetation index performed best in extracting SOD and EOD while the near-infrared reflectance of vegetation performed best for SOR and EOR. SOD exhibited an annual delay of 0.14 days, whereas EOD, SOR, and EOR showed significantly advance by 0.11, 0.27, and 0.52 days, respectively. The four phenological metrics generally delayed with increasing elevation and slope, with 0.13 days/50 m and 0.21 days/° for SOD, 0.43 days/50 m and 0.24 days/° for EOD, 1.10 days/50 m and 0.31 days/° for SOR, and 0.94 days/50 m and 0.36 days/° for EOR. Temperature and humidity were found to jointly regulate SOD and SOR, while humidity predominantly influenced EOD and EOR. This study contributes to a deeper understanding of the mechanism underlying rubber phenology and its response to future climate change. Trends of rubber defoliation and refoliation and their responses to abiotic factors ● Four rubber phenological dates are spatiotemporally mapped using four rebuilt VIs. ● NIRv performs best for refoliation while kNDVI performs best for defoliation dates. ● Refoliation is significantly advanced while trend of defoliation is not significant. ● Four phenological dates show delayed trend with arising elevation and slope. ● Temperature and humidity co-control start dates while humidity controls end dates.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".