Overview

You will read three papers that use FIA data to investigate whether eastern North American tree species are shifting their geographic ranges in response to climate change. Each paper approaches this question from a different angle. All three rely on the same FIA database you have been working with in our lab exercises.

Due date: [TBD]

Papers

  1. Murphy, H.T., VanDerWal, J., and Lovett-Doust, J. (2010). Signatures of range expansion and erosion in eastern North American trees. Ecology Letters, 13: 1233–1244.

  2. Zhu, K., Woodall, C.W., and Clark, J.S. (2012). Failure to migrate: lack of tree range expansion in response to climate change. Global Change Biology, 18: 1042–1052.

  3. Woodall, C.W., Oswalt, C.M., Westfall, J.A., Perry, C.H., Nelson, M.D., and Finley, A.O. (2009). An indicator of tree migration in forests of the eastern United States. Forest Ecology and Management, 257: 1434–1444.

Part 1: Summary (one half-page per paper)

For each paper, write a half-page summary (~250 words) in your own words. Your summary should address:

Important: Do not copy phrases from the abstract or text. Imagine you are explaining the paper to a classmate who has not read it. Use plain language and show that you understand the logic, not just the vocabulary.

Part 2: Figure Interpretation

For each paper, select one figure (or table) and provide a detailed interpretation. Your write-up for each figure should include:

Paper 1 — Murphy et al. (2010)

Choose one of the following: Figure 1a, Figure 1b, or Figure 2.

  • Describe what the axes represent and how the plot is organized.
  • What pattern do most species show? Where do they cluster in the plot?
  • Pick two specific species labeled in the figure. Look up their SPCD in the REF_SPECIES table from our lab data. Describe what the figure tells us about those species’ range dynamics.
  • What does this pattern suggest about whether trees are expanding northward, eroding from the south, or both?

Paper 2 — Zhu et al. (2012)

Choose one of the following: Figure 2, Figure 4, or Figure 5.

  • Explain the four-quadrant framework (what does each quadrant represent?).
  • If you chose Figure 4: compare the two example species. What do the seedling vs. tree distributions tell us about whether each species is expanding or contracting?
  • If you chose Figure 5: what proportion of species fall into each quadrant? What is the dominant pattern, and why is this surprising given climate change predictions?
  • Connect the results to our Lab 3 Importance Value analysis: how does the way these authors measure “abundance” relate to IV?

Paper 3 — Woodall et al. (2009)

Choose one of the following: Figure 2, Table 2, or Table 3.

  • If you chose Figure 2: select two species maps (one northern, one southern). Describe the spatial pattern of seedlings (red/blue) vs. tree biomass. Is the seedling distribution shifted northward relative to biomass?
  • If you chose Table 2: compare Little’s historical range limits with current FIA data for three species of your choice. Are seedlings appearing at higher latitudes than biomass?
  • Explain the “outer range ratio” (ORR) concept. Why did the authors use ratios rather than raw counts?

Part 3: Synthesis (one paragraph)

Write one paragraph (~150 words) that connects the three papers to each other and to our lab exercises. Consider:

Academic Integrity