Float test data for Oregon white oak (Quercus garryana Douglas ex Hook.)

This study used acorns from Oregon white oaks (Quercus garryana Douglas ex Hook.) collected in both masting (2019, 2023) and non-masting (2021) years to examine the biological basis and accuracy of the "float test" in quickly distinguishing between viable and damaged acorns. Acorns were float tested in all years, examined for damage and for presence of filbert worms and filbert weevils in 2019, and germinated to determine whether the test could detect insect damage and acorn viability in 2021 and 2023. The test accurately predicted 84-89% of germination in both masting (2023) and non-masting (2021) years based on linear regression with the proportion of a site’s (2021) or a tree’s (2023) acorns that sank as the explanatory variable, and the proportion of that site’s or tree’s acorns that germinated as the response variable. External and internal examinations for damage yielded significant associations between damage and float test results (Chi-squared), damage and acorn density (ANOVA), and insect infestation and float (Chi-squared) test results.