but the tree was over two metres high and 5 foot in diameter. Broke the suspension, the rear tyres, bent the tray and the chassis too

I can believe that... that's about 130 cubic feet of wood. Figure the tree at about 75% the density of water and that would be, ummm... 130x62.5x.75 a bit over 6,000 pounds dropping into that truck. Probably more than half again the weight of the truck itself.

tanstaafl.