at a wildlife refuge complex where we deal with a lot of non-native invasive plants (reed canarygrass, Himalayan blackberry, English ivy, false indigobush, japanese knotweed, yellow flag iris, canada thistle, etc. etc. etc.). I am not aware of anyone who has attempted to "harvest" these plants for some other purpose. It is usually kind of tough just to get to them, much less bundling them up and hauling them off.
The one exception at our refuge is hay
fields. The main purpose of the refuge is to provide space & food for wintering waterfowl, mainly geese. So there needs to be large areas of short grass in the winter. They achieve this by finding a "cooperator" (farmer) to come hay the fields in the summer. The farmer gets to keep the hay in return for mowing the fields. In previous years they have achieved the same result by allowing a rancher to run their cows in the fields in the summer. However that requires a lot of fencing (& fence
maintenance) which is a pain and is also counter to the open/wild feel that a refuge should
When possible, we try to cut/mow the plant while it is blooming (i.e. most of its energy
is above ground), then when/if it resprouts, we spray
just the resprouts with herbicide. Assuming that goes as planned, we come through and plant native plants
(the refuge only allows plants that are native). If we don't plant something else, the bare ground just turns back into one of the invasives.
I am trying to get the refuge manager to let me try some more "permie
" methods for conversion from non-native invasive plants to native ones, and I am beginning to wear him down but I still have a ways to go. Since I am just a volunteer, not an "expert", my ideas/opinions don't carry as much weight as others. But I have built up quite a bit of credibility over the years so I am optimistic that I will at least be able to do some experimental plots. I think
my experiments are in line with your point #6.
There is an investigation into using Arundo donax (giant reed grass) as a biofuel at a coal-fired electric generation plant east of here: http://oregoninvasivespecies.blogspot.com/2011/10/arundo-power-part-2.html
The plant is super invasive in most of the country, but not here - yet. However as our climate warms I have a feeling that it will become invasive here.