As there are more ways to make trees than there are rulesets to play in 28mm...
I did some research, as always, and finally decided that these two videos were what I wanted to replicate. The first is by an Aussie (?) who is clearly a master woodworker and into making terrain "on the cheap". The second is a more conventional project.
I made the jig from the first video for pines, and hand-twisted wire trees to replicate the second. I hope to have something to show soon.
As mentioned, there are so many other worthwhile tutorials out there - here are a few more.
This is a great option for Wargaming trees, as opposed to some of the more complex "train terrain" versions out there:
This is a neat series about one modeler's attempt at trees
A simpler blog:
This link has a really cool way of making trees from aquarium plants - he wrote it for 15mm:
This gent in the UK models for 28mm, but his scenery is gorgeous:
These guys do a cool series of How-To's - the 6mm version is featured further down:
A really good option that uses steel wool (I tracked this one down after reading the one above...)
This is more for dioramas, but the concepts are the same - and since I'm currently working on a diorama for my wife, well...
And for realism over usefulness:
Some articles scaled specifically for 6mm, or for "Canpoy"-style groves: