PETERSON1, PAUL M.*, MONES ABU-ASAB2, STANWYN G. SHETLER1, AND SYLVIA STONE ORLI1. 1Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0166 and 2Section of Ultrastructural Pathology, Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20894. - Earlier plant flowering as a response to global warming in the Washington, DC, area.
Evidence for global warming is inferred from the onset of earlier
flowering times in plants from the Washington, DC, area.
First-flowering times over a 29 year period were examined for 100
plant species representing 43 families of angiosperms. The trend of
average first-flowering times for all plants/year for 100 species
shows a significant decrease of -2.4 days over the 29-year period.
When 11 species that exhibited later first-flowering times were
excluded from the data set, the remaining 89 showed a significant
decrease of -4.5 days. Trends for earlier-flowering species ranged
from -0.2 to -46 days, while those for later-flowering species ranged
from +0.3 to +10.4 days. Onset of earlier flowering in these 89
species is inversely correlated with local changes in minimum
temperature (TMIN). Our results are concordant with
other studies where warmer air temperatures and higher CO2
levels have lead to advancement of the average annual growing season.
Key words: climate change, earlier plant flowering, global warming, growing season