Police and security present at Adams farm in force. Tree cutting started near barns. Protestors present in growing numbers. Trees are being occupied. Please get along to help if you possibly can!

Why don't you just spike the trees? Cheap and simple method to cause huge delays to their attempts to cut them down.

spiking the trees only makes it harder to fell them with chainsaws/ process the timber afterwards. it has been used as a tactic in places where the forests are being commercially logged, as the companies involved need to cut/ prepare the timber for sale in order to make money. and the nails can cause problems at the sawmill.
but this is 'clearance work', for a road to be constructed. for all we know, they might just be ripping these trees down with bulldozers, in which case the nails won't make any difference at all. as for selling the wood, it's more likely it'll end up getting burnt.

anyway, it sounds like the people involved in this campaign are actually sitting up trees right now, and may not find it so easy to get online/ get to the ironmongers. maybe you could visit them, and take the nails with you, and find out if they're useful or not?

hammering nails into trees im tryna save doesnt sound like my cup of eco-tea. but thanks all the same.