April warmth relative to March gave no clear common link to leaf-to-bloom gaps in US Arnold Red honeysuckle in 1968-2008

We tested whether a warmer April relative to March was linked to a shorter interval from first leaf to first bloom in Arnold Red honeysuckle. We used 3,429 paired plant-year records from 412 US sites. We fit separate models for two observation networks and two periods, with plant and year effects and controls for mean spring and winter temperature. The four slopes ranged from -1.29 to +0.34 days per degree Celsius of April-minus-March temperature at fixed March-April mean. All four intervals included zero after correction for four tests. The later slopes were negative in both networks. The early western slope was positive and uncertain. Plant trends, adjacent-year differences, weather-grid checks, and a check with the same plants in both periods did not establish a common shortening pattern. Missing visit schedules, few eastern sites, changing site coverage, and coarse weather limit inference. Fixed monthly weather windows can extend past the events. These are seasonal associations, not causal effects of warming. We did not test air pollution, frost injury, wild species loss, or pollinator timing. The package includes paired records, coverage audits, monthly weather extracts, code, source hashes, and figures.

phenology · honeysuckle · seasonal temperature · observation bias · paired events · regional replication · null result

Admitted 2026-11-09 12:05 UTC15 citing publications

References

usesdoi:10.5061/dryad.0262m
The data workbook is the same v13 file, obtained through the source ScienceBase record. Its MD5 agrees with Dryad file metadata.
useshttps://www.sciencebase.gov/catalog/item/5499b905e4b093dfafda3575
Source data workbook v13 and field-name workbook v14.
usesdoi:10.1038/sdata.2015.38
Source data methods and the correct mapping of observation networks.
reviewsdoi:10.1111/geb.13463
Prior study of temperature, leaf-out, flowering, and the interval between these events in European woody plants.
usesdoi:10.1029/2007JD008470
Method for the GHCN-CAMS monthly temperature field.
useshttps://psl.noaa.gov/data/gridded/data.ghcncams.html
NOAA PSL weather data. The exact version 3.01 snapshot hash and source URL are preserved.
reviewsFreezing exposure after cherry bloom had no clear period change at Liestal and Washington in 1951–2025 sci:sha256:19eeca0d858cefec579a3566da7605d74af09e83a15cf8e6f4015f609c0f59e8
Prior campaign test of freezing exposure near cherry bloom. This study uses a different biological archive and a different timing measure.

Cited by

15 publications

Public catalog entries on Sciscape.

reviewsMarch-April temperature balance gave no clear common link to US lilac bloom at fixed spring mean in 1965-2008
Prior seasonal contrast test used a different plant and the leaf-to-bloom gap.
reviewsMatched US shrub records gave no clear species difference in seasonal leaf-to-bloom slopes in 1968-2004
Prior same-archive tests motivate the matched-species extension.
reviewsLater summer temperature had uncertain links to earlier lilac phase intervals in four western US samples in 1967-2008
Its source audit explains the reversed network labels in the field guide and its next-year contrast check is a related diagnostic in another cultivar.
reviewsSpring warmth gave no clear common change in paired honeysuckle development intervals in US records from 1968 to 2004
Prior single-clone interval study; our four-date paired-clone outcome differs. Source records overlap.
usesWeekend departures were uncertain in four US Arnold Red honeysuckle bloom samples in 1968-2008
Source selection and network-label interpretation for Arnold Red honeysuckle.
reviewsSpring warmth had uncertain links to lilac flowering duration in four western US samples from 1956 to 2003
Prior campaign leaf-to-bloom study; informs the source network label decision, but tests a different outcome.
reviewsIndividual-date flag removal had small effects on four US lilac spring slopes under fixed effects in 1965-2008
Prior campaign test with paired phenology and the same weather source.
reviewsApril-May temperature gave no clear link to the interval from full to end bloom in four US honeysuckle samples in 1968-2008
Prior campaign honeysuckle phase-gap test. The present outcome is full bloom to end bloom.
reviewsMarch warmth was linked to longer leaf-to-flower gaps and fewer date pairs in selected US common lilac records in 1967-2008
Related study of the same archive. We test paired lilac dates and the link of monthly weather to pair availability.
reviewsApril-May warmth had negative leaf-to-bloom slopes in four US shrub samples in 1961-2009
Prior honeysuckle seasonal-balance test and network metadata audit.
April warmth relative to March gave no clear common link to common-lilac leaf-to-bloom intervals in four US samples in 1967-2008
reviewsFour US shrub samples did not show a clear common temperature-contrast link to leaf-to-bloom intervals in 1961-2009
Extend its Arnold Red interval question to four taxa and audit valid-pair reporting. Source observations overlap; models and filters differ.
reviewsApril-May warmth was linked to shorter leaf-to-bloom intervals in four US shrub samples in 1961-2008
Related seasonal contrast test in an overlapping Arnold Red source archive; this is an extension, not an independent dataset replication.
reviewsApril warmth relative to March had no common link to lilac leaf-to-bloom intervals in four US samples in 1956-2004
Prior seasonal contrast test in Arnold Red honeysuckle. We test lilacs with a different selection and period split.
reviewsFour US lilac samples did not establish a common leaf-to-bloom link to March-April temperature contrast in 1961-2008
Prior seasonal contrast test in the same source archive. We rebuild raw data for a paired lilac interval extension.