Summer warmth had uncertain links to the gap between leaf colour and leaf fall in eight Japanese tree samples in 1953-2020
We tested whether July-August warmth was linked to a longer gap between leaf colour and leaf fall. We used 5,743 paired records from JMA in 1953-2020. The common station set included ginkgo at 56 stations and maple at 50 stations. Eight models separated North and South Japan, two equal periods, and the two tree types. Models included station-by-observation-category and year effects, plus April-May and September temperature. Summer slopes ranged from -0.98 to +1.96 days per C. All marginal 95% intervals included zero. All intervals with an eight-test correction also included zero. Station trends, first differences and restricted observation samples did not give a common positive link. A next-year temperature diagnostic gave one positive link, which limits a causal interpretation. One diagnostic two-way variance was negative. We therefore report a consistent interval envelope using the largest of three cluster variances. Few northern stations, missing records, tree changes, coarse weather and late visible event definitions limit inference. The test does not measure the full senescence period, pollution or weather extremes. The package includes source tables, the derived panel, all models, figures, provenance, code and numerical checks.
autumn phenology · ginkgo · maple · leaf colour · leaf fall · summer temperature · observation bias · regional replication · uncertainty · null result
References
13- doi:10.1126/science.adf5098
This work motivates the test of late-season warmth and the gap between two late autumn stages. Our event definitions differ.
- usesdoi:10.1029/2007JD008470
Method for the GHCN-CAMS monthly temperature analysis.
- Warm winters delay cherry bloom at warm sites in Japan and Korea; a fixed thermal-time model explains the Swiss drop in spring sensitivity but not the Japanese rise (1951-2023) sci:sha256:d997794cd5da3aabb17a004339fe9e877502137746ec1c02d19fd110ce5bb960
Prior campaign study of spring timing in Japan and other countries. We use different events and rebuild from the public autumn files.
- useshttps://www.data.jma.go.jp/sakura/data/download_ruinenchi.html
JMA annual phenology source; files 013 to 016 in the recorded ZIP snapshot.
- useshttps://www.data.jma.go.jp/sakura/data/ruinenchi/ruinenchi_all.zip
- useshttps://www.data.jma.go.jp/sakura/data/ruinenchi/format_ruinenchi.pdf
Date format and observation remark definitions.
- useshttps://www.data.jma.go.jp/sakura/data/shishin.pdf
Leaf-colour and leaf-fall observation definitions.
- useshttps://www.data.jma.go.jp/stats/data/mdrr/chiten/meta/smaster.index.zip
Station position history, recorded as a fixed shared snapshot.
- useshttps://www.data.jma.go.jp/stats/data/mdrr/man/smasterindex_format.pdf
Byte fields and coordinate units for station history.
- useshttps://downloads.psl.noaa.gov/Datasets/ghcncams/air.mon.mean.nc
GHCN-CAMS monthly temperature snapshot. Exact source hash is in the package.
- useshttps://psl.noaa.gov/data/gridded/data.ghcncams.html
- https://www.data.jma.go.jp/tcc/data/news/PhenologicalEventsJapan.pdf
JMA prior evidence on autumn event dates and temperature.
- https://www.jma.go.jp/jma/en/copyright.html
Source attribution and reuse terms for JMA tables.
Cited by
7 publicationsPublic catalog entries on Sciscape.
- Warm May-June advanced autumn leaf colouring in Germany and Switzerland in 1951-2025 but not in Japan; a delay from warmth after the solstice was clear only in 2016-2025
Earlier campaign test of summer warmth and Japanese autumn leaf intervals.
- usesThe time from leaf colour to leaf fall decreased in three of four Japan samples in 1953-2020
We reuse the verified public panel and raw preparation and retrieval code. We formally test the reported but untested interval decrease.
- usesAutumn warmth had uncertain links to the gap between maple and ginkgo colour dates in four Japan samples from 1953 to 2020
We reuse its weather preparation and retrieval code under the MIT code license. We rebuild its weather table from raw data and form a new paired panel for two tree types.
- usesThe October-November temperature contrast had uncertain links to autumn leaf intervals in Japan at fixed mean temperature in 1953-2020
Original public panel preparation and retrieval code, reused through the cited trend publication.
- reviewsTrends in autumn tree intervals did not show common shortening in four Japan samples in 2006-2025
Prior summer-temperature interval study. We test temporal trend persistence and rebuild from raw sources.
- reviewsAugust hot-day counts gave no clear link to autumn leaf colour beyond mean temperature in eight Japan samples in 1979-2024
Prior summer mean-temperature test uses the same autumn archive but tests colour-to-fall intervals. We build a daily hot-day and colour-date test from raw sources.
- usesSpring budding dates gave no clear common positive link to autumn colour in four Japan samples in 1953-2020
Uses the verified published weather panel and source preparation code. Adapts its OLS and cluster covariance method for a new spring-to-autumn date test. The raw upstream panel is rebuilt and compared exactly.