Those would be my second choice cybball but they work! Look back at previous pages in this thread and you'll see many pics of ProTex tubes I've used. I would highly recommend using small zip ties to keep them together. I actually used the "holes" that are already there from the tabs and zip tied them together that way. I used a zip tie at every tab, the tubes I tried to be cheap and skimp on zip ties ended up not having enough back bone and getting mangled later on. I did use T-post on all of our plantings and have removed a few dozen post from trees, I do it during the dormant time and have had zero issues with root damage. We also didn't drive the post super deep, we didn't go beyond the T on the post so roots would be limited on what they would grow over/around. I like the t-post because they provide the most support for the tube and tree. We have not noticed an issue with our oaks or walnuts being over supported and not growing a strong enough back bone to ultimately support themselves. I have used 3/8" rebar, 1/2" metal or PVC conduit to stake trees. I like metal vs PVC. With the trees in my yard I tried something new this year and I placed the stake inside the tube and attached it to the stake yet. I did this vs the normal way of having the post on the outside of the tube because I was having issues of animals chewing on zip tie ends and also zip ties breaking as tubes would be pulled away from them, from both wind and wildlife. So place the stake inside the tube seemed to cure two things, the zip tie could be more hidden and also was subject to less stress now that the stake would absorb some of the pulling force vs all of it being on the zip ties. If that makes sense? I did notice when using metal conduit or rebar post that they don't have the holding power a T-post does so when trees got larger in higher winds those post would wiggle loose and if a tree wasn't ready to support itself it'd lean over and get into the deer browse line or grow tilted. I could come up with a 100 different things that could go "wrong" or what to watch for when it comes to planting trees and using trees tubes. But honestly, it is my favorite habitat project, I love it! Things will go "wrong", I'm just trying to give you a heads up on what we've had go "wrong" and how we fixed them and what you can do to help prepare for those situations.
Here's some pros and cons to those tubes:
Pros:
-cheap
-mice seem to stay out of them vs the Miracle ProTubes, possibly because they move around more in the wind? This is huge IMO
-trees do grow extremely very well in these
Cons
-they are more flimsy and can get torn apart and wind blow them around more. When trees are young they can be blown off the small tree. This can be addressed by putting a short second stake on the opposite side to really support
-the top edge is sharp, when trees get large enough it can damage the bark, we haven't had any trees die because of this but I keep an eye on it and assess the situation as needed, tape on the top edge is a good solution to this as needed, you wouldn't want to do all of them IMO
-when trees get larger and catch wind these tubes get put under even more stress, if they break away they crumble if the tree isn't able to hold it's self up. At least the Miracle Tubes are rigid enough the tree can still stand somewhat. There isn't anything you can really do about this, it's not like it happens to every single tree, just some. I guess what I've done is put a piece of electrical fencing wire around the tube and post to help keep it attached to the post, this is one advantage I can see to putting the post inside the tube.
-these need put together, takes a couple extra hours, not a huge deal
-holes should be drilled in a stack of flat tubes to allow for air flow when the tube is assembled, not a huge deal but something I'd highly recommend doing