Tamsin, Paco John, et al.,
Thanks for mentioning Tree Trust. One of our Ramsey County(MN) Master Gardeners is an employee of Tree Trust, and she is now gathering native tree seeds and putting together "Tree Trunks", which are boxes of labelled tree seeds to be used in schools to demonstrate how trees start out, and is a "hook" to further conservation(as we used to call it in the dark ages) education. Again, that website is www.nationaltreetrust.org .
And John, you are so right about using native plants--in Minnesota we have a number of projects going to rid our state of exotics that are destroying the ability of native plants to preserve the landscape(and in so doing preserve and restore water quality, nesting areas for migrating and nesting native birds and animals,etc., and to control erosion--in other words, to attempt to bring some semblance of balance back to our Ma, the Earth. Among those projects are "Buckthorn Busting(also including Mulberry and non-native Honeysuckle species)", and the horribly invasive and wetland destroying Purple Loosestrife, which is actually OUTLAWED here in Minnesota(pull that one out of Clinton CG, Adam, the hybrids have pollen, too, and your honeybees can go up to 5 miles in their search for nectar--and I'm going to send the picture I took of that specimen to Laura to post--for educational purposes only, of course!), and there is a state funded biocontrol project to get rid of that beautiful and wonderful smelling(AWFUL) invasive plant.
End of sermon.
Diane Dodge, Ramsey County Master Gardener St. Paul, Mn