T ree ring width Trees grow faster and form wider rings in warm years and grow more slowly and form narrower rings in cooler years. The figure shows ring widths of a Siberian pine from 1500 to 2000.

(a) What is the range of the ring width function?

(b) What does the graph tend to say about the temperature of the earth? Does the graph reflect the volcanic eruptions of the mid-19th century?

Ring width (mm) R+ 1.6+ 1.4+ 1.2 0.8 1- 0.6+ 0.4+ 0.2 0 1500 1600 1700 1800 1900 2000 Year