Comparative Leaf Phenology of White Oak and Northern Red Oak

Abstract

In the landscape, loss of interveinal tissue in developing leaves (leaf tatters) is common for white oak (Quercus alba L.), but not northern red oak (Quercus rubra L.). Previous research identified the cause of leaf tatters, as exposure of unfolding leaves, to low concentrations of chloroacetanilide herbicides. Both white oak and northern red oak were injured by these herbicides at the leaf unfolding stage. Reports from landowners suggest white oak is injured more often than red oak, leading us to theorize that white and northern red oak leaves emerge at different times, and white oaks were more likely to be at the leaf unfolding stage when chloroacetanilide herbicides are applied. A study of comparative leaf phenology of white and northern red oak was done at three sites in Urbana, IL. Identifying oak pairs was challenging, and at each location, four to six paired mature white oak and northern red oak trees were used to observe phenological events. Key development stages (swollen bud, leaf unfolding, or fully expanded leaf stages) were considered to have occurred when reached by greater than 50% of the canopy. Northern red oak expanded leaf stage occurred earlier when compared to white oak. Time between phenological events was similar for both species. Although northern red oak leaves emerged earlier, there was a range of emergence times within short distances. Difference

Phenological responsiveness to climate differs among four species of Quercus in North America

“…Even within a single species and phenophase, there is conflicting evidence as to whether photoperiod is an important driver of bud break. For example, Samtani, Appleby & Masiunas () found a strong correlation between the timing of bud development and photoperiod in Q. rubra , while Laube et al . () reported that this species is insensitive to photoperiod.…”

“…Studies have reported conflicting results, however, concerning the importance of precipitation as a climatic driver in Quercus. Samtani, Appleby & Masiunas (2015) found that increased cumulative precipitation delayed bud break of two North American Quercus species, while Morin et al (2010) found that bud break of three European Quercus species did not respond to variation in precipitation. In California, Fairley & Batchelder (1986) reported that precipitation positively affected the magnitude, rather than the timing, of pollen release from oak species.…”

“…Photoperiod, for which latitude is often used as a proxy, may also influence the phenology of Quercus species. Some studies report that photoperiod is an important driver of bud break (Schaber & Badeck 2003;Samtani, Appleby & Masiunas 2015), while others report that including photoperiod in temperature-based models used to predict bud break does not improve the fit of the models (Hunter & Lechowicz 1992;Kramer 1995). Even within a single species and phenophase, there is conflicting evidence as to whether photoperiod is an important driver of bud break.…”

“…Even within a single species and phenophase, there is conflicting evidence as to whether photoperiod is an important driver of bud break. For example, Samtani, Appleby & Masiunas (2015) found a strong correlation between the timing of bud development and photoperiod in Q. rubra, while Laube et al (2014) reported that this species is insensitive to photoperiod. To our knowledge, no study to date has simultaneously evaluated the roles of geographic location, temperature and precipitation in determining the onset, periodicity, or duration of vegetative and reproductive phenophases in water-limited ecosystems.…”

Biological Flora of the British Isles:Quercus rubra

“…Growth of leaves and relatively rapid vegetative growth of stems lasts from spring (May) to early summer (June; Sander, 1990). In its native range bud swelling occurs in April, leaves unfold in late April and are expanded in May, according to observations from Illinois (Samtani, Appleby, & Masiunas, 2015). In the Great Smoky Mountains, south‐eastern United States, dates were similar: bud break at the middle of March (Julian date 102), and full expansion of leaves at the middle of April (Julian date 130; Lopez, Farris‐Lopez, Montgomery, & Givnish, 2008).…”