I had already indicated this when writing about woodland patterns – there is a new version of the jsdotpattern pattern generator available. In this I completely redesigned the symbol selector. This now allows combining arbitrary symbols into sets to be randomly used in the pattern for which previously i used pre-defined sets (which are kept for backwards compatibility).
I added quite a few additional symbols, in particular for trees. Here a few examples – click on the images to generate the pattern in the pattern generator where you can adjust the parameters or save it as SVG.
You can find the program with the latest changes on github.