"Jean B." wrote
Why the yard workers just spent all day burying the bases of trees
and their roots in a foot of mulch (which I now have to dig off of
them)?

Because your "yard workers" are not horticulturists. Or not in the
employ of a firm that will give its workers precise instructions. Nor
did you give them (the workers) precise instructions about what you
wanted to be done and how.

And while you are at it, could someone tell me why they had to
blow out the pine needles (which I always say I want left alone)
and put mulch under the pine trees instead?

Because you didn't supervise the 'yard workers' and make this clear,
or make it *luminously* clear (and perhaps written into a contract)
with whatever supervisory personnel was involved.

These are mostly rhetorical questions. I just need to vent among
people who do know that trees do not want to have their roots
buried, nor do they want mulch going a foot up their trunks....

Good news. Mulch around tree trunks is harmful to only a few species.
Bad news. If you paid for a foot of mulch to be deposited in all
mulchable areas, you probably wasted a lot of money. 3-4 inches is a
common depth. Unless, of course, you have no plants at all, and simply
want tidy areas of mulch.

Unsupervised landscape projects often result in nasty surprises. In
spite of "they *should* know...", they don't. The landlord of my
cottage employed a gardener who liked me. One day he said he'd brought
some carnation plants for me as a special treat. How nice. Except that
there wasn't really a planting area with enough sun... Too late I
recalled the one sunny spot where I'd been nurturing a flowering
ginger, then in hopeful and plentiful bud. Gone, gone, gone. Replaced
by straggly ol' carnations that never produced a bloom.