A customer in Florida planting a bunch of sawtooth oak seedlings in spring, 2013. They were about 24 inches tall at planting. The vast majority of them came screaming out the tops of the tubes last year, most of them with measurable daily growth increments of an inch or more during the peak of the growing season.
All too often I either see (or read about in online discussion groups about wildlife habitat and tree planting) people take the trees tubes off at this point, or complain that the trees are too tall and thin.
It’s difficult to get across to people that tree tubes have three distinct functions – or phases – during the establishment of a tree. The first phase is protection from deer browse and rapid height growth, all with a goal of getting the terminal bud of the tree safely past the deer browse line as quickly as possible. Yes, the tree will have a fairly thin stem relative to its height (although this disparity is much less pronounced since the advent of vented tubes and flexible pvc tree tube stakes). Tree tube makers know this and take this into account when designing tree tubes.
The second phase, after the tree emerges from the tube, is the support phase. The tree tube is meant to stay in place (do not remove!) to provide support while the crown of the tree sways in the wind. This swaying, shaking motion triggers hormonal responses in the tree that cause it to allocate more growth energy into stem thickness and root development, and less energy into height growth.
It’s amazing how quickly the trees gain stem thickness in that first year after emerging from the tubes. And right on cue my customer in Florida sent me photos of a couple of his sawtooth oaks that emerged from their tree tubes last summer, with the text message, “Trees are putting on a lot of girth now!”
The only thing is, these trees apparently didn’t get the memo about slowing down in height growth while putting on girth; many of these trees are now 10 feet tall!
The third and final phase of tree tubes is trunk protection. It would be an absolute tragedy to remove the tree tube at this point, only to have the trunks shredded or broken by rutting bucks, or girdled by gnawing rodents. The tubes should stay on until the trees reach about 3 inches in diameter at the base… which won’t be long now!