Tabernacle timbers reveal pioneer-era drought

A Brigham Young University geographer studying timbers from the Salt Lake Tabernacle concludes those old walls can talk, and they tell a new tale of pioneer hardship.

Analysis of the width of the rings in the wood shows that a severe drought began in the years before the first Mormon wagon trains rolled into the Salt Lake Valley the summer of 1847.

"The 1840s were drier than any other decade in this tree-ring history, which spans the years 1702 to 1863," said BYU professor Matthew Bekker, whose findings are published in the current issue of the academic journal Tree-ring Research. "It was a really rough time to establish a settlement based on irrigated agriculture."

During the recent renovation of the Tabernacle, Bekker sampled timbers on the buildings west end underneath the stage that supports seating for the Mormon Tabernacle Choir and the widely-recognized organ. Tree rings that grew in 1846 were much narrower than would be expected with a normal years rainfall, ranking as the sixth narrowest of the 162 years studied. The pioneers first two years of settlement saw little relief with 1847 and 1848 ranked as the 10th and 16th driest seasons in the period.

"The Wasatch Front does not get a lot of rain during the summer, so the settlers depended on snowpack and stream flow," Bekker said. "After several dry years, the first good winter of snowfall may not have brought immediate relief because more of the snowmelt would have been absorbed by the dry soil before it could flow down to the valley where the settlers needed it."

Bekker determined that all 28 trees he sampled were Douglas-fir, which would have been called "red pine" by the pioneers because of the reddish hue in the heartwood.

By comparing the patterns of rings Bekker also established their relative age differences. Up to that point, however, he did not know the exact year any of the trees were cut. For a point of reference, Bekker turned to recently collected samples of very old live trees in northern Utah whose outer rings represented the year they were sampled. These old live trees overlapped the Tabernacle timbers ring history, enabling Bekker to establish dates for the Tabernacle timbers by zeroing in on where they shared similar patterns.

The rings from one timber that supported the organ spanned from 1762 to 1862. The earliest ring goes back to 1702. The distinction of having the oldest ring was shared by seven trees with outer rings grown in 1863, the year the Tabernacles foundation was completed.

Nailing down those dates yielded another surprise: five of the 28 trees died or were cut earlier than 1847, meaning the pioneers harvested trees both live and dead.