Recent carbon-14 tests on the beams confirm their antiquity. Some predate Herod’s Temple Mount: One beam dates to the ninth century B.C.E.—the First Temple period! The exact history of the beams is hard to pin down. They were likely used in two or more different constructions, and poor storage has led to the ever-quickening degradation of the beams.And just as I was finishing this post I found this Times of Israel article by Matti Friedman, which has much more information: Did ancient beams discarded in Old City come from first and second temples? A collection of neglected wooden beams from the Al-Aqsa mosque offer a glimpse at ancient Jerusalem — and possibly at the biblical temples themselves. Excerpt:
In 1984, a scholar from Tel Aviv University, Nili Liphschitz, published a brief scientific paper looking at 140 of the beams in a Hebrew journal, Eretz Yisrael, along with two other scholars.Some of the beams are also inscribed in Greek or Arabic.
Liphschitz, a dendochronologist — a specialist in determining the age of trees — found that most of the beams she examined were of Turkish oak, with a smaller number of Lebanese cedars. There were also beams of cypress and several other types of wood.
By analyzing the tree rings and using carbon-14 dating, she found, unsurprisingly, that some of the wood was from the early Muslim period. One of the cedars, for example, was about 1,340 years old, or roughly the same age as Al-Aqsa. (The margin of error for the rather inexact dating process was 250 years.)
But others were older, dating to Byzantine times, and still others dated to Roman times, around the era of the Second Temple in Jerusalem.
Even more striking were her findings regarding one of the cypress beams. The age of the beam “was found to be 2,600 years,” she wrote, with a margin of error of 180 years. That placed it near 630 B.C.E. — around 50 years before the destruction of the First Temple.
And one of the oak beams was even older: 2,860 years. That meant the tree had been cut down around 880 B.C.E, early in the First Temple period.