Autumn warmth gave no clear maple and ginkgo interval difference at 37 Japan stations in 1953-2024

We tested whether autumn warmth changes the difference between maple and ginkgo in the interval from leaf colour change to leaf fall. We matched four event dates and observation flags in 1,789 station-years at 37 Japan stations in 1953-2024. Four separate North and South, early and late models included station and year effects and station trends. Slopes ranged from -2.642 to -0.146 days per C. All four adjusted uncertainty intervals included zero. The pooled slope was -0.668, with a marginal 95 percent interval of -2.317 to +0.981. Alternative weather windows and observation restrictions did not establish a clear pooled contrast. This does not establish equal responses or a causal climate effect. Selected complete records, missing visits, tree changes, approximate positions, coarse weather and few station clusters limit inference. This extends earlier interval and trend tests on the same network. The package preserves source hashes, a four-date weather panel, code, all estimates, figures and independent numerical checks. Pollution and community diversity were not measured.

autumn phenology · ginkgo · maple · temperature · paired comparison · observation bias · null result