In this lab, students examine tree communities found on the north and south slopes of a local mountain (in the Holyoke Range,
near Amherst, MA). Student-generated questions include: are the tree species different on the two slopes? are there density and
size differences? are these differences due to climate and adaptation to cold and drought? are there other important factors that
help us understand the types and sizes of trees that we find there?
Students spend four three-hour lab sessions on this project. During the first field trip they make observations about the study
site, ask and focus questions, develop hypotheses from these, and design a sampling regime to address their hypotheses.
On the second trip, they collect data on tree types and other variables of interest to them (e.g., tree size). We use an array
of recording thermometers to obtain temperature data over a week. During the third and fourth lab periods, they work in task
teams to enter the data on spreadsheets and generate figures and tables for everyone's use. Students then work alone and
write a research-style paper with references that I make available (e.g., including similar studies elsewhere).
At the conclusion of this multiweek lab, students will:
- understand some of the basics of asking and attempting to answer ecological questions (beginning with observations in the field, focusing
broad questions towards narrower answerable ones, developing hypotheses, designing a project to answer these questions, and actually
conducting that project),
- design and conduct a research inquiry including using skills in experimental design and data analysis (use of spreadsheets, simple statistics,
data reduction, developing clear figures and tables that address specific questions),
- advance their scientific critical thinking skills by revising their initial questions and hypotheses due to their findings as well as findings by
others in published literature,
- advance their skills in working in collaboration with their peers in conducting a scientific study,
- advance their skills in communicating scientific findings to peers (written and oral presentation of research results and using primary
literature relevant to each group's research project),
- advance their skills at thinking about the abiotic factors that affect the distribution and abundance of plant species across a sharp climatic gradient, and thereby better understand the associated issues of individual organismal adaptation to environment,
- advance their appreciation that other factors, particularly past disturbance (in this case hurricanes and tree cutting for firewood), can also greatly affect vegetation distribution and types; also that disturbance, light, temperature, moisture, and soils interact to influence the modern day plant community, and
- learn how to identify trees in the study plots.
Equipment/ Logistics Required:
* field clothing (which will include raingear if it is raining),
* this handout and data sheets,
* OnSet recording thermometers, Li-COR solar sensor, DBH tapes, meter tapes,
* transportation for two 3 hour blocks for field work,
* use of a computer facility for 2 three hour blocks for data analysis.
Summary of What is Due:
From this multiweek lab, students submit an original research paper written individually based on the data
their group collected and the literature that they consulted.
Principal Ecological Question Addressed:
Are tree communities different on the north and south slopes of a mountain, and if so, what important factors could account for any differences observed?
Ecological Topic Keywords:
plant ecology, autecology, environmental adaptation, population ecology, community ecology, biogeography.
Science Methodological Skills Developed:
field observations especially in ecological situations where habitat contrasts are obvious, experimental design and quantifying observations,
correlation of physical factors (such as light and temperature) with community composition and biodiversity, hypothesis testing, use of
spreadsheets and graphing programs; use of primary literature, oral communication, writing primary research paper.
Pedagogical Methods Used:
student-directed inquiry, cooperative learning,