Two more radical theories about Sukkot
I described the origin of Sukkot, the biblical requirements, the way it was celebrated during the days on Nehemiah around 440 BCE that was startlingly different than the Torah instructions, and the radical view of the origin of Sukkot and the Sukkah by Arnold Ehrlich, in my prior essay. The following are two other radical views of the origin of the sukkah and its cover, the hut that the Torah states Israelites should dwell in for seven days. What does the sukkah recall?
The Book of Jubilees
The Book of Jubilees, composed around the mid-second century BCE, states that angels came to Abraham and told him that the descendants of his son Isaac would “become a kingdom of priests and a holy nation.” Abraham celebrated this announcement with a “festival of joy in this month seven days” by building “booths for himself and his servants and was the first to celebrate the feast of tabernacles on the earth…. Abraham took branches of palm trees, and the fruit of goodly trees, and every day going round the altar [that he built] with branches seven times a day.”
A possible reasonable but contra-Torah explanation
The problem with the traditional explanations mentioned in the prior essay is that they do not seem to have any relevance to the fall festival. If they recall the exodus from Egypt, the requirement of using the Sukkah should be obligated in the spring or associated with Passover when the Israelites left Egypt. Furthermore, neither the two traditional explanations nor Ehrlich’s nor the Book of Jubilees’ explain why the Sukkah is covered with scach, branches. If the Sukkah recalls the dwellings of the Israelites during the forty-year desert wandering, or if it remembers the divine protection during the forty years, or it recalls the temporary dwellings that pilgrims used when they visited the small crowded town of Jerusalem, as Ehrlich contends, the covering should have been solid, protecting the inhabitants from sun and rain.
It is possible that the sukkah recalls the makeshift temporary huts that the farmers used during the fall harvest as shade during the heat of the day and a place to sleep at night rather than returning home each night from the field and losing valuable work time. Tradition demands that our Sukkah today be a temporary dwelling. Why? The Sukkah may be a remembrance of the temporary dwellings of the Israelite harvesters during this season while they were harvesting the fall harvest.
Tradition also requires that the Sukkah be covered by branches. This too, arguably, recalls the ancient harvest practice. The harvesters wanted a covering that would shield them from the beating sun but still allow the wind to enter their temporary hut. A branch covering fit these needs exactly.
Judaism today repeats what the ancient harvesters did but gave it new meaning: it recalls how Israelite ancestors lived during their forty year trek in the desert after leaving Egypt and causes us to think of the divine protection given to the ancient Israelites and to us today.
 The current practice is to circle the synagogue once each day, but on the seventh day, Hoshana Rabba, to circle seven times. It is likely that the holiday of Hoshana Rabba did not exist when the Book of Jubilees was written. See my essay Sympathetic Magic and Sukkot in my book Maimonides: The Exceptional Mind. No explanation is given in the book why Abraham celebrated in this way. The quotes are from the translation of Robert H. Charles (1855-1931).
 This is apparently exactly what Jonah did to protect himself from the heat in the biblical book Jonah 4, and he suffered from the heat when the branches died.
 The two views in BT Sukkah 11b.