After being a definite "niche" product for nearly three decades, known mostly to professional foresters and large-scale tree planters, tree tubes have definitely taken huge strides in the last few years in becoming much more of a mass market product (as those of us who recognized, 25 years ago, their potential to revolutionize the way trees are planted in the USA always thought/hoped they would be).
Here are three signs that tree tubes have become accepted standard practice among the rank & file of tree planters in the USA:
1) Tree tubes are now available on Amazon
2) Tree tubes are a common topic of discussion among sportsmen planting trees for wildlife habitat (and it is truly sportsmen who do the heavy lifting in terms of creating habitat for both game and non-game species) on web discussion boards such as QDMA, Michigan Sportsman, etc. Twenty-five years ago if people were talking about tree tubes at all the discussions centered on questions like,
"What are these things?"
"You mean I can put a 6 inch seedling in a 5 foot tree tube?" (Answer: Yes! But the tree won't be 6 inches tall for long.)
"Won't it burn up in there?" (Answer: No - it will be happy and growing while un-tubed trees are stressed.)
"Why would I spend $3-4 on a tree tube to protect a 50 cent seedling?" (Answer: because if you don't you'll be planting that 50 cents seedling year after year, watching deer eat it, and still have nothing to show for your hard work.)
Now the topics on the discussion boards are more along the lines of,
"Which tree tubes are best?"
"Where can I get the best pricing on tree tubes?"
"When do I take my tree tubes off?" (Answer - not until the tree reaches 3" diameter at the base)
I can't say that the information exchanged on these discussion boards is always accurate or the best advice, but it's awesome that tree planters have moved from if/why use a tree tube to, which tree tube is best and how best to use them.
3) Tree tubes are commonly advertised for sale on Craig's List - with the full expectation on the part of the seller that buyers will a) know what they are, and b) need them.
Oh, and another small indication that tree tubes have gone mainstream: Sales of tree tubes in 2014 have broken all records for total volume, number of orders, and geographic diversity of orders.