Defoliation of American Hornbeam Forest
This Carpinus caroliniana forest was made in the Spring of 2013 and this year it was defoliated for the first time. Owen Reich told me that American Hornbeam respond well to defoliation (maximum once per year) and indeed the results were positive. One issue I noticed is that as the second flush was coming in, some very vigorous leaves grew back at an accelerated pace and became very large. These were periodically removed to allow the smaller, less vigorous leaves to fill in at a more uniform pace.
The tree was defoliated May 31st, just after the new growth had hardened off. One month later, the second flush had filled in and hardened off.
May 20th, ten days before defoliation (I forgot to take a picture right before defoliating the tree). The leaves here are not quite hardened off.
May 31st immediately following defoliation.
The tree today, just over one month after defoliation. One major effect of defoliation was that the smaller interior shoots were allowed to open up. Many did not open up at all in the spring as all of the vigour went to the shoots of the exterior canopy. After defoliation, the density of the tree is much more uniform.
The new leaves are about 50% the size of the old ones. Very nice!