Kdjykuj

Death occurs in extremely high humidity and an average temperature of 23 C (~75 F), both of which continue for six weeks.

At that time, temperature begins to fall over the course of eight weeks to an average of 5 C (~40 F). At the beginning of these weeks humidity decreases sharply, though the air is still quite humid.

The next three months are cold, averaging 0 C (32 F) and with moderate levels of humidity.

This is followed by eight weeks of warming and then a hot, humid summer of two months with temperatures as high as 40 C (~105 F).

A dry season follows for six weeks and then the cycle repeats.

All this time the body is clothed (clothing composed primarily of cotton), open to the environment and can be accessed by insects and scavengers.

In this weather cycle, about how long would it take for the body to be skeletonized?

Also, how long would it take for the bones to separate from each other and fall from the tree assuming it starts securely wedged between two branches?

I don't need exact amounts, just ballpark figures would be useful.

You can have it stay up there as long as your story needs it to stay up there.

People sometimes climb up into trees and kill themselves. I remember reading about one such that winter hikers spotted. The body had been up there for years. I could not find that one again but here are others.

1. https://www.dailymail.co.uk/news/article-2100499/Melissa-Joy-Dietzel-Decomposing-body-woman-30ft-tree-Sydney-missing-US-tourist.html

Her body was up in the tree for 2 weeks. It was a populated area and people smelled it.

2: https://www.bournemouthecho.co.uk/news/11404359.suicide-verdict-for-missing-21-year-old-found-in-tree-at-meyrick-park-golf-club/

This body was in the tree for three years. In a park!

3: https://www.telegraph.co.uk/news/worldnews/europe/germany/5098610/Skeleton-found-in-tree-29-years-after-suicide.html

This body was a skeleton, found after 29 years.

Summary - if you want it to fall out after 3 days, fine. But decomposition is a lot slower up off the ground. Ants, worms and beetles access the body from the ground and a body on the ground will also stay moist which facilitates decomposition. Coyotes, armadillos and the like will not be able to get a body in a tree and depending how deep in the branches it is, vultures might not either. It is those big animals that pull a corpse apart.

What is left is insects and they will leave the skeleton intact. In your scenario, I suspect fly maggots will eliminate the soft parts while it is summer; that will also eliminate much of the ability of the corpse to hang on to moisture. Once the weather cools the insects die off and then what is left will desiccate in the dry cool winter. The desiccated sinews and muscles will hold the skeleton together and are not very attractive to scavengers. If you need it to stay up there lodged in the branches for decades, that can happen.

It won't last a week.

You are basically providing an ideal environment for normal decay. It takes less than 7 days for insects to basically skeletonize a human body (not counting some stringy bits), with the presence of larger scavengers it is unlikely to last even that long. On a normal tree it is unlikely to still be on the tree within a day or two, scavengers even insects can move a body around a lot. Without knowing hte exact environment it is hard to say exactly beyond this.