Fig. 4

The average difference between mean oak seedling densities (pre treatment versus post treatment) by site at the three oak restoration study sites on the southern Cumberland Plateau, Tennessee, USA (2009 to 2018). The height of the bar is the average difference between means, and the whiskers at the end of each bar represent 1.0 standard error. Scarlet oak was the only oak species to have a significantly higher post-treatment mean compared to its pre-treatment mean (P = 0.001), and there was a significant site effect for scarlet oak and chestnut oak (P ≤ 0.05) using bootstrapped nonparametric comparisons