What was done
The authors developed two reconstructions of spring (May-June) precipitation for southwestern Turkey from tree-ring width measurements, one of them (1776-1998) based on nine chronologies of Cedrus libani, Juniperus excelsa, Pinus brutia and Pinus nigra, and the other one (1339-1998) based on three chronologies of Juniperus excelsa.

What was learned
The reconstructions, in the words of the authors, "show clear evidence of multi-year to decadal variations in spring precipitation."  Nevertheless, they report that "dry periods of 1-2 years were well distributed throughout the record" and that the same was largely true of similar wet periods.  With respect to more extreme events, the period preceding the Industrial Revolution stood out.  They say, for example, that "all of the wettest 5-year periods occurred prior to 1756."  Likewise, the longest period of reconstructed spring drought was the four-year period 1476-79, while the single driest spring was 1746.

What it means
Climate alarmists claim that (1) global warming produces both more frequent and more severe periods of wetness and dryness and (2) the global warming of the past century was the most dramatic of the past millennium.  However, 660 years of reconstructed spring precipitation from southwestern Turkey provide no evidence for the validity of either of these contentions, suggesting that at least one of them is wrong.  In fact, the real-world data actually hint at an opposite effect of global warming on precipitation.