Environmental History of the Southwest

Study Guide for Exam #3 (our Final Exam)–Modern Issues

NOTE: In 2022, this exam will be take-home, open-book, and open-notes. For each content lecture of Part III, summarize key points and why they are important for study of environmental history of the American Southwest. Include representative images in your answer and refer to them specifically in your writing; screen captures would be fine. Each answer should be no more than one page, including the images.

Anglo Settlement of the SW

  1. Describe the history and impacts of livestock grazing on ecosystems of the Southwest.
  2. Explain arguments for and against the notion that early Anglo livestock overgrazing contributed to the late 1800s episode of arroyo cutting in the Southwest.
  3. Explain arguments for and against the notion that climatic variation contributed to the late 1800s episode of arroyo cutting in the Southwest.

Forest Fire

  1. Show and intepret a dendro fire history graph and how can it be used to understand fire history?
  2. Distinguish typical fire frequency and intensity in southwestern ponderosa pine forests before and after the late 1800s-early 1900s.
  3. What might have caused this big change in forest fire behavior?
  4. Discuss forest fire management strategies to return wildfire to a more natural role in forests. Give pros and cons.

Forest Health

  1. What does "forest health" mean? Describe two components of forest health.
  2. How do different species of trees serve as a "control group" in the study of insect outbreaks in the tree-ring record? How can outbreaks be distinguished from background climatic variation?
  3. Contrast spruce budworm outbreaks of the 20th Century versus those prior to 1900.
  4. Describe multiple lines of evidence of changes in fire occurrence, changes in tree recruitment, repeat photography, and the PDSI time series of Southwest ponderosa pine forests.


  1. Be familiar with reading a flood hydrograph. Discuss environmental and human factors that influence whether SW flooding tends to be flashy or sluggish.
  2. Describe recent changes in the occurrence of floods in the Santa Cruz River; don't forget skew.
  3. Distinguish between the mean and median of a distribution (show a histogram). Which of these values is immune to effects of outlying values?


  1. Describe drought in terms of duration, magnitude, and spatial extent.
  2. Put the 1950s SW drought in perspective spatially and temporally.
  3. Put the current SW drought in perspective spatially and temporally.
  4. Be able to name droughts in SW history (last 1000 years) that impacted human systems somehow; describe their impacts (name specific societies discussed in earlier classes).

Global Change

  1. Explain and compare the two main human contributions to CO2 flux into the atmosphere. Ramifications?
  2. How might vegetation of the Southwest migrate with the climate change projected for the future? Desert and/or mountain ecosystems? Modern homework and uniformitarianism?
  3. What does "ecosystem goods and services" mean? What are some examples?
  4. How do you personally affect the grand carbon equation of life (i.e., which direction)?

Water: Groundwater, Colorado River, and Water Demand

  1. What is an aquifer? The importance of aquifers in supply-demand of water?
  2. What are some consequences of overdraft of groundwater?
  3. When, what, and where of the Colorado River Compact?
  4. How might the Colorado River compact negotiators have used tree-ring data in their decision making, if only those data had existed at that time? Show that time series of Colorado River annual discharge back in time.
  5. In terms of the state-wide water budget, how does Arizona use water? Ramifications?

An extra question
For an 8th question/answer for this exam, consider the concept of how modern Southwesterners might live with the following environmental situations, i.e., avoiding the bad aspects while taking advantage of the good aspects. Pick three from this list to discuss:

  1. Top predators (like the wolf) and grazing
  2. Forest fire OR forest insects
  3. Flooding
Include an image for each topic, but pick data graphics, not just pretty pictures. Refer to the data graphics in your text (e.g., what is being shown and how does it relate to your point).