On Sun, 24 Oct 2010 19:55:08 +0100, Lawrence wrote:

This summer I've been trying to get rid of nettles and thistles prior to
planting trees on my 1.5 acre field.

Nettles don't like being topped do it two or three times a year for a
couple of years and they'll be gone. Thistles don't come back from
being dug up, provided you get most of the tap root and they are in
full flower but not gone to seed. Shove a fork full depth around the
plant, waggle, lift and pull the plant. Best to do it when it after
it has rained and the soil is soft.

1.5 acres with thistle plants every couple of feet would be a lot of
thistle plants to get rid of and take a day or two.

--
Cheers
Dave.