Yair . . .
CM1995
Scrub I doubt that D3B would push over that tree no matter what kind of tree pusher is fitted without a fair amount of digging around the stump.
For sure mate, that's a big lump of wood which makes the O/P methods all the more frightening.
And of course there are ways and means of digging . . . can't say I have ever seen anyone reduce the ground level around a tree to that extent though. (big grin)
From where I sit typing this I can see a tree larger than the tree in question that I have no doubt could be pushed by a D3 with a pusher . . . another fifty feet away not so much.
If it ever rains again I am going to put a wire rope around that second tree about thirty feet from the ground and I have every expectation I can pull it with a fifty horse wheel tractor. I have never been shy to put a rope up a tree, it is mostly easier on the gear and can save a lot of time.
Digging can be a bit of a mixed blessing, if you dig a single trench you are still standing on the roots . . . that is another advantage of a tree pusher of course, it puts the tractor back a little from the trunk.
If a very large tree has to come out and no rope is available I mostly cut two trenches intersecting at an angle leaving just enough ground to stand on. I leave the dirt piled so that as the tree falls the heft and weight of the trunk and branches will to some extent lift the root ball clear of the hole . . . it is easy with big timber to get into the situation where you get the tree down okay but it's a struggle to get it out of the hole.
Another thing to watch is getting jacked up by the root ball. As soon as the tree starts to fall back out of there quick as a big root can get up behind the blade and pull the tractor forward sit it on its arse.
Cheers.