Figure 6. Mean vessel density (\(\pm\)SE) of Q. alba andL. tulipifera and samples across chronosequences (Panel (a)) and
age (Panel (c)). Groups of bars not sharing the same uppercase letters
denote significant differences (p ≤ 0.05) between species, while
bars within groups not sharing letters denote differences within species
among ages or chronosequences from a two-way ANOVA with species and age
as fixed factors and region as a blocking factor (Table 2). Panel (b)
and (d) show the relationship between mean lumen area and mean specific
embolism threshold of individual trees assessed by linear regression.
Lines are best fit from linear regression when slope is significant
(p ≤ 0.05). Solid lines are best fit across species and dashed
line is at the species-level.