Student Lesson

Lesson Title: Oak Savanna Ecology

Lessons Summary: Students will study the oak Savannas in Oregon to determine the environmental conditions that support this specific ecosystem. Students will gather data for the Willamette River Basin, including current species prevalence and rain fall, as well as historic data from the original plats of cadastral surveys to determine optimum and historic oak distribution.

Lesson Objectives: Students will analyze patterns of oak disbursement in the Willamette Basin, determining patterns of distribution and correlations between rainfall and species prevalence.

Extension: Students will compare historic records to current GIS vegetation maps and student-conducted vegetation field reports.

Before you begin using this module, you will need to know about using a Web-based GIS viewer. You can do this by watching the tutorial video or working through the tutorial. The tutorial video, student activity, and Web-based GIS Tutorial Viewer can be found at http://gis.lanecc.edu à “Modules” tab à “Tutorial” link. The activity works best with a high speed Internet connection.

Prior Skills: You will need to know how to turn layers on and off, use the ID tool and, zoom in and out of the map, toggle from layers to the legend, and perform a search (Boolean) query.

Remember, computer steps are indicated by a symbol and questions you need to answer are numbered.

The Body of the Lesson:

  • Open the web browser and go to http://arcgis.lanecc.edu/website/orall
  • Click on both the “Visible” and “Active” buttons next to the ‘Basin Outline,’ then hit

Q1) What are the names of the four basins bordering the Willamette Basin?

  • Locate the “Willamette” Basin, and, using the enlarge tool , drag a box around the entire basin.

(If you make a mistake and want to move backwards, hit the button.)

  • To view the key for the map, hit the “legend” button from the toolbar .

The amount of precipitation should be highlighted.

Q2) Describe the pattern of precipitation in the Willamette Basin.

  • Zoom out to the entire state

Q3) Is the precipitation evenly distributed or are there differences across the state? If there are differences, discuss where they are using location terms such as: north, south, east, west, central…

How would you compare the amount of precipitation found on the valley floor and the surrounding hills/mountains?

The total size of the Willamette Basin is approximately 11,460 square miles. To locate the stands of oak in the Willamette Valley, we can create a query.

  • Toggle back to the “layer” list by clicking
  • Unclick the “Visible” Precipitation layer.
  • Click both the “Visible” and “Active” layer of “Vegetation” à
  • Toggle back to the “legend” by clicking

This gives you an overview of the vegetation in the Willamette Basin. To locate all oak stands ONLY in the Willamette Basin:

  • Hit the ‘Query’ Button , and at the bottom of the page you will see:
  • Under the “Field” drop-down menu, select “VEG_NAME”
  • In the “Operator” drop-down menu, select “=”
  • Then click the button à select “Oak” à

IF you were to execute this Query, all the “Oak” in the state would be highlighted. To limit your search to the Willamette Basin, we must use the “And” function:

  • Click the à Field = “NAME” à àChoose “Willamette”
  • à

The oak will now be highlighted in a neon blue color.

  • Toggle back to the “key” to identify the oak by clicking in the upper left corner of the map.

Q4) Looking at the Willamette Basin as a whole, how would you describe the distribution pattern of the oak? Again, it is evenly distributed or is the clustered in specific areas? If it is clustered describe where that occurs.

You can use the “Zoom” button to explore the patterns of oak growth in the Willamette Basin.

Q5) Using the zoom tool, what patterns of oak distribution emerge when you zoom in?

Q6) What are the predominant vegetation types adjacent to the oak?

Q7) What other patterns do you see or wonder about?

To find the total area of the oak in the Willamette Basin we can capture the “squaremile” data from the chart at the bottom of the page:

  • Highlight THE ENTIRE CHART (including the title ‘precipitation’) à right click à “Copy”
  • Open Microsoft Excel à right click à “Paste”
  • Click in an empty cell (box) at the bottom of the squaremile column and, using the summation button , highlight the entire squaremiles column only.

Q8) How many square miles of oak exist in the Willamette Basin? (round to the nearest mile)

Correlations help look for relationships. A positive correlation occurs when things occur together such as high rainfall and high moss growth. A negative correlation occurs when one value is high and the other is low for example high precipitation and low solar radiation rates.

To explore the correlation between oak and rainfall in the Willamette Basin you can measure the area of oaks that occur in areas of rainfall in A) less than (<) 50 inches per year, and B) > 50 inches per year AND < 75 inches per year.

A) To find oak in the Willamette Basin AND < 50 inches per year, you need to complete a three-step Query:

  • Under the “Field” drop-down menu, select “VEG_NAME”
  • In the “Operator” drop-down menu, select “=”
  • Then click the button à select “Oak” à

The bottom of your screen should look like this.

  • Click the
  • Field = “NAME” à àChoose “Willamette” à .
  • Click the
  • Under the “Field” drop-down menu, select “RANGE”
  • ** In the “Operator” drop-down menu, select “<” **
  • Then click the button à select “50” àà

(Note: You will not see this field added to the query unless you highlight the entire query)

  • .

All of the oak, in the Willamette Basin, and growing in less that 50” of rain per year should be highlighted.

Q9) Using the same cut and paste method into excel, calculate the number of square miles of oak in the Willamette Basin that occurs in less than 50 inches of rain per year (rounded to the nearest mile):

Using what you have learned, create a query that calculates the Oak in (AND) the Willamette Basin AND a Range 50 AND Range 75.

Q10) Using the same cut and paste method into excel, calculate the number of square miles of oak in the Willamette Basin that occurs in more than 50 inches of rain per year AND less than 75 inches per year (rounded to the nearest mile):

Q11) How many square miles of oak are there in the Willamette Basin that receive more than 50 AND less than 75 inches of rain per year?

Q12) What generalization (or hypothesis) could you make about the correlation between oak and rainfall in the Willamette Basin?

Q13) What other patterns or correlations could you look for (using all the species types and other data available in the map? (Create at least three correlations or pattern questions that you could explore. Use complete sentences.)

Q14) (Bonus/Extra Credit) Scaling back to a map of the entire state, find the area that has significant oak growing in areas of rainfall greater than 75 inches per year. What part of the state would you find most of these oaks growing?

Career Extension

  • Go to the website http://esri.com/industries.html
  • Find a career from the list that is of interest to you. For example: In the Natural Resources list, there is a link to forestry. In the forestry link, there are several job descriptions.
  • List four ways GIS is used in the career you choose.
  • Conduct an internet search to find information about salary ranges and possible job locations.

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GEOSTAC NSF-ATE # 0903330