I have been working on a new, more coherent way to explain when to use 4, 5 or 6ft tree tubes.
The traditional way that tree tube suppliers have explained how to choose the correct tree tube height is by suggesting that tree planters use 4ft tree tubes to protect from “moderate” deer browse, and 5ft tree tubes to protect from “heavy” or “severe” deer browse. Presumably that means that 6ft tree tubes should be used for “super mega wicked bad” deer browse.
When I was talking to a customer on the phone the other day I found myself using some of these phrases, and even as they left my mouth I realized how meaningless and uninformative they are.
The “moderate, heavy, extra heavy” deer browse approach to choosing the right tree tube height is based on the ridiculous assumption that the landowner can actually know in advance how bad the deer browse level is going to be a year or two down the road when the trees emerge from their tree tubes. It’s almost as if tree tube suppliers expect landowners to do a detailed population study of deer in the area, predict future reproductive success balanced against weather conditions and hunting harvest levels, and then assess how much other available plant material will be available for them to browse on… in order to then predict the height to which the local deer will be willing and able to munch.
So while talking to this customer the other day I came up with a different, much more logical and coherent framework for explaining what tree tube height to use. It goes like this:
Basis: All tree tubes provide some level of deer browse protection.
4ft tree tubes provide enough browse protection for successful establishment 75% of the time.
5ft tree tubes provide enough browse protection for successful establishment 90% of the time.
6ft tree tubes provide enough browse protection for successful establishment 100% of the time.
Decision Tree: There are three equally legitimate strategies for using tree tubes to grow trees past the deer browse line:
1) You can save money (or protect more trees within you budget) by using 4ft tubes. There is a 25% chance that the deer will browse emerging trees heavily enough that you will have to either treat them with a deer repellent or add a 2ft “tube extender” to get your trees past the browse line.
Note: I have seen some tree tube suppliers begin claiming that 4ft tree tubes do not protect against deer. That is patently absurd, since 75% of the time 4ft tubes alone provide enough deer browse protection, and the rest of the time a treatment or two of deer repellent or the addition of a tree tube extender (more information coming in a future post) will finish the job the 4ft tube started – while allowing the landowner to spread the cost over a few years.
It’s also strange to claim that 4ft tree tubes don’t protect against deer browse when the majority of tree tubes sold for deer protection are 4ft tall!
2) Spend a little more up front on 5ft tubes. That added 1ft of browse protection is an insurance policy, leaving only a 10% chance that you will need to provide additional protection for your trees after they emerge from the tubes.
3) Go with 6ft tubes and remove all doubt.
It seems like this is a better decision tree framework than making people guess what their deer density is (or, more to the point, what it will be in 2 or 3 years), or how high the local deer will be willing to reach for food.
It provides a more logical framework for decision making: “I can protect more trees with 4ft tree tubes within my current budget, but I might need to go back and provide more protection in the future, or I can protect fewer trees with 5ft or even 6ft tree tubes and reduce the possibility that the trees will need supplemental protection down the road.”
Both are legitimate strategies for successful tree establishment in the face of increasing deer pressure.