Why do this to healthy Oaks?

 Judging from the cuts, I imagine a "tree worker" or the owners professional landscapers told the owner the trees might fall if they dont remove a few branches.

Not their trees

 Pruning trees that are not theirs to increase their view.

Pink Robinia ignored by homeowner during million dollar home and landscape remodel.

House remodel $$$$ over a 2 year period, and they leave this sad tree in the middle of a new landscape.

Staking a Birch for long term stability

 Yep, keep the stake, even when it rots at the base. The trees will eventually hold up the post.

Grade changes are fun (Pittosporum eugeniodes)

Trees were buried. They are likely to survive longer than you would think, but really?

Same owners attacked their oaks. 

Japanese maple - 2 nice cuts

 A contractor no less...

Bit of extra soil for my Redwoods (Sequoia sempervirens)

 I had to put the soil somewhere.....