What is the best way to eliminate green undergrowth of woodsy yard?

The safest way is boiling water. No pollution at all.

Great idea for small areas but I am trying to clear up to two acres so children have a play area. There are too many ticks in the grasses and ferns to be safe.

I've used a rototiller and then pulled the rest.

boiling wate

Mow short starting early in the Spring. Ticks like to hang off taller growth. Mowing not good for fern. We invested in a Weed Wacker to tame our woods. Was a surprise how many more wild flowers bloomed in the early Spring after we tamed the tall grasses by mowing.

A weed whacked is for brush cutting and has 16 inch wheels to Mow tall stuff.