Growth is from left to right. Note the difference in growth patterns between the four younger rings to the left and the older rings to the right. During the year in which the fourth ring from the left formed, some disturbance occurred which greatly reduced the growth rate of this tree. Perhaps a wind storm damaged the crown of the tree, thus reducing its ability to photosynthesize and produce more wood. This chronology is providing scientists new insights on climate over the past 10,000 years, especially at the end of the last Glacial Maximum.
Growth is from the left to the right.
The large vessels in the earlywood indicate this is a ring-porous angiosperm tree species. The large earlywood vessels are formed early in the spring during the initial flush of growth that occurs when the tree breaks dormancy after the winter. The vessels help transport water and nutrients up to the crown of the tree. Because ring-porous species almost always begin annual growth with this initial flush, missing rings are rare in such species as oak and elm. In fact, the only recorded instance of a missing ring in oak trees occurred in the year 1816, also known as the Year Without a Summer.