Mesh Tree Generators
SnappyTree Online Mesh Tree Generator
At the time of this writing, the official version on SnappyTree's website has an error in one of the js source files which has not been corrected, causing an export failure. The workaround is to download the source and run the application locally or on your own remote server, after making a simple correction as outlined here: https://github.com/supereggbert/SnappyTree/issues/2 . The SnappyTree application source is freely available to download and use on a PC or remote webserver, anywhere that a browser such as Chrome or Firefox can access. You can simply grab the zip package from here: https://github.com/supereggbert/SnappyTree
Just click on the ZIP tab near the top to download the package, unzip, then open /js/export.js in a text editor to make the simple correction. Next, open index.html with your favorite browser and the rest is fairly self-explanatory. When the Export window appears, the file name is always saved as "tree.dae" into your browser's default download location unless you right-click and rename it to your choice and location.
If you don't want to bother with that workaround, Nebadon Izumi has put SnappyTree on his webserver for anyone to use at: http://snappytree.onikenkon.com/
You can also visit Nebadon's region Topiary where he has dozens of pre-made mesh trees available for copy.