The purpose of this research was to determine how dendrochronology can be used in an experiential unit to enhance high school students' understanding of environmental change. Dendrochronology, the visual examination of tree ring cross sections provides opportunities to relate environmental change to growth patterns of trees and can be used to show the students both how scientists can investigate the past and how the environment can affect trees. Students engaged in a 10-day unit that employed a variety of constructivist learning activities to investigate environmental change, climate change, and tree growth. The culminating activity was student-created experiments that investigated various aspects of the relationship of trees to their environment.

This research was a mixed method design and was conducted at a small public high school in the Deep South. The school is a Title One school on a four by four block schedule and is located in a rural area where forestry is one of the major industries. Twenty five juniors and seniors who were members of two environmental science classes were the participants in the research.

As evaluated by the Wilcoxon matched-pair signed rank test, students scored significantly higher on the posttest (P < .01) than on the pretest with average scores of 9.52 on the pretest and 18.76 on the posttest. Most of these gains were in questions that evaluated the students understanding of climate change, tree anatomy and statistical analyses of tree growth data. The qualitative components of the research supported that these were the areas of greatest growth and revealed that the students greatly enjoyed participating in investigations of their own.