good quality green lasers seem hard to come by in aus, though there's plenty of the $2 garbage variety.
I've got a red laser that I carry with me to all quotes as part of my quote package which has a diameter tape, quote book, book of all the rules for different councils, couple of pens, tree marking tape and the laser. We have very specific laws for different council areas in aus that state what percentage of a tree can be pruned, and what the maximum branch diameter is. A lot of times clients want to do a removal but aren't permitted to, so the next thing they want is to remove as much as possible. You have to be very specific when quoting trims or it leads to disputes later.
The laser has been great, but a little hard to see in bright sunlight, especially on taller trees. A higher powered one with a bigger dot would be great.
Shaun