Conner’s aspen phenology study wins third place in the 2014 Wyoming State Science Fair

Conner Whitman, an 8th grader in Laramie Junior High School, monitored leaf color changes in 3 aspen trees for 29 weeks (May – Oct 2013) by measuring their spectral reflectance values every week.

His research focused on how age and health status of these aspen clones influenced the changes in their leaf pigments. Every week starting in the spring, he collected leaves from 2 healthy (young and old), and 1 stressed (young) aspen trees and measured the amount of light reflected in eleven different wavelengths.

For comparison he also measured light reflected by an Engelmann spruce. Most conifer trees like Engelmann spruce do not exhibit prominent leaf color changes.

Using the amount of light reflected in infrared and red portions of the spectrum he calculated the different index which can be related to the amount of leaf chlorophyll content in each tree.

His results (figure above) indicated that the rate of chlorophyll change was influenced by health status of individual aspen trees within a clone. However there was no difference between the young and old healthy aspen trees. The light reflected by Engelmann spruce steadily increased throughout the year and did not show the declining trend in fall season.

Conner presented his research findings in the 2014 Wyoming State Science Fair in Laramie on 3/4/2014 and won the third place in the Plant Sciences category.