Introduction

Dendrochronology, the science of tree ring analysis, offers much more than just counting rings to reveal a tree's age. We can begin to unlock a detailed record of past growing conditions by measuring the width of each ring. For certain North Dakota tree species, such as ponderosa pine and bur oak, these rings even tell stories of ecological disturbances, like fire and flooding. By studying multiple trees across various sites, we can piece together a rich climate history for the entire region. Despite North Dakota’s prairie-dominated landscape, dendrochronology holds untapped scientific potential, offering insights into our environment.

In North Dakota, we have used dendrochronology to peer into the past, working with historians, ecologists and others to reconstruct earlier climates, corroborate historical documents, and provide evidence to land managers to help inform their current-day decision making. A few of our studies are listed below, while more can be found here: A History of Dendrochronology Studies in North Dakota

Under the right circumstances, a tree can record certain ecological disturbances within its rings. Flooding that occurs in spring, when the trees have just broken out of dormancy, shows up in the rings of both oak and ash trees. On the Red River of the North, we are finding evidence of the flood of 1826 recorded in bur oak trees. The flood was immense in the downstream community of Winnipeg, Manitoba, Canada. However, questions remain as to how widespread the flood was along the U.S. portion of the Red River. Through dendrochronology, we’ve found evidence of the flood as far south (upstream) as Fargo, ND. However, it appears that flooding was not quite so intense in this area. Further north (downstream), towards Shelly, MN, flooding appears to have been much more widespread and may have occurred to a greater depth.