We have heard that bigfoot will climb a tree but it is rare as these animals like their cover. So what is also odd here is this behavior. It could well be curiosity at work. Anyway we have way too much leg for a bear and i suspect way too much leg for a Bigfoot. The leanness is also suspect.
I think that we can safely add in the Giant Sloth as a prospect. In fact the color matches another suspected case in California.
I wish that the observer had simply set up to observe until the creature moved out of the tree. That would have separated the two. He had the safety of his car at hand in order to do this safely. It would be way too dangerous otherwise. Do not do this if you lack a secure refuge like a car. Houses are vulnerable as a Giant Sloth can tear its way through.
A Bigfoot is safe to be around, but a giant sloth is not at all and i suspect any number of missing hunters have fallen victim over the years...
The next day: After thinking about this picture, i woke up to what was completely wrong. No primate will hold his legs in the manner shown while up a tree. In fact this is how a giant sloth would position itself because it is gripping the trunk with its claws. This allows the animal to throw itself out horizontally to grasp an adjacent trunk or limb ten feet away, or to rotate downward to drop quickly from the tree in an ambush.
This is the picture of a giant sloth and it is also consistent with the other Californian example reported. The coloration is jet black in contrast to the Eastern version which runs from black through light brown. Again this is one scary and seriously dangerous creature that will tear you apart.