One thing I find irritating about these dryers is the suggestion that the use of the dryer will save trees. In fact, the website of the company has this tagline: "Push button, Save trees." The trouble is that such an assertion is misleading at best, and downright dishonest at worst. The belief that trees will be saved is the result of some rather naive assumptions, and a failure to understand the basic economic concepts of supply and demand.
The incorrect assumptions are that paper companies indiscriminately harvest trees, that these trees belong to no one in particular, and that trees are non-renewable. In fact, trees are simply another agricultural commodity. Though they take longer than other products (such as corn) to come to maturity, tree production is nevertheless subject to the same laws of supply and demand. Paper companies, rather than indiscriminately cutting down "public" trees, purchase trees from a third party or they own land where they grow trees for the express purpose of making paper.
Now lets assume, for the moment, that a large number of people switch to using the World Dryer, enough to result in a substantial decrease in the demand for paper towels. As the demand for towels slips, so will the demand for trees. With the drop in demand for trees, the price of the trees will also decrease. The lower price for trees means growers will find it less profitable to grow trees, making it less likely they will plant new trees.
The end result of all this is that, rather than "saving" trees, as is suggested, there will be a net loss of trees. If the World Dryer company truly wants to see more trees, they should encourage the use of paper towels.