When plastic tree tubes made the leap "across the pond" from the UK and became commercially available in the USA in 1989, many of the first customers were black walnut growers.
It made perfect sense: Eastern black walnut produces extremely high value veneer lumber, but can suffer from low initial survival rates and its seedlings are a favorite of deer. Black walnut growers often paid premium prices for planting stock with known superior genetics; all the more reason to protect their investment with tree tubes.
And while only the most unrealistic of these planters ever hoped to live to see these trees grow large enough to harvest in their lifetime, they all hoped to see those trees well established and on their way to maturity before leaving them as a legacy to their descendants.
There was only one problem: Growers quickly realized that from Missouri on north, black walnut seedlings did not harden off properly for winter inside the unvented tree tubes sold at that time. We learned over time that if the tree emerged from the tube by about August 1st it would generally have enough exposure to ambient conditions to harden off for winter. If it didn't emerge from the tube until after that date, or didn't emerge from the tube at all the first year, it stayed active and growing too deep into the autumn and would suffer die back after the first hard frost. It didn't kill the tree; it would resprout from close to the ground the following year and very quickly grow up through the tube. Ultimately the tree would emerge from the tube early enough in the season to harden off properly for winter.
Unfortunately, by that time many black walnut growers had grown frustrated with tree tubes and stopped using them.
A short term "fix" was discovered through trial and error. It was learned that if you elevate the base of the tube an inch or two off the ground on Labor Day the air flow through the tube would induce dormancy and would prevent die back. Of course it would also expose the base of the tree to rodents, at a time of year when rodents are actively seeking food and shelter. This solution was more like a "patch" software designers come up with while truly fixing the problem in the next version of the software.
Well, the next version of tree tubes - Tree Tubes 2.0 - is here: Vented Tree Tubes. Vented tree tubes have solved the die back problem with black walnut, chestnut and all other trees where it was a problem.
Black walnut growers were correct to view treeshelters as the ideal solution to their problems. It just took a little while for tree tube technology to catch up, and for tree tube designers to introduce version 2.0 instead of simply offering a patch.
So if you are planting black walnut seedlings, grafts, or direct seeded nuts, don't plant without our Tubex Combitube Treeshelters. Your trees - your legacy - deserves nothing less.