Draft Basic Lesson 4
Studying Topography, Orographic Rainfall, and Ecosystems (STORE)
Basic Lesson 4: Vegetation and Climate
Introduction
Two main factors determine local climate: long-term average precipitation and temperature. As
we learned in Basic Lessons 1 through 3, precipitation and temperature are influenced by
topography (i.e., elevation). Building on Basic Lessons 1 through 3, this lesson explores how
local climate affects vegetation. Figure 1, below, shows a generalized view of how temperature
and precipitation are dominant influences controlling the location of ecosystems. Differences in
average annual precipitation and temperature (together with soil type) determine the locations of
biomes (e.g., tropical, temperate, and cold deserts, grasslands, and forests). Students will use the
GIS software to analyze ecosystem data (i.e., predominating vegetation types) obtained from
U.S. Geological Survey (USGS) Land Cover Institute’s National Land Cover Dataset (NLCD).
The USGS is the world leader in acquiring, processing and distributing remotely sensed data to
scientists, policy makers, and educators. Distribution and identification of vegetation
communities in this dataset were determined using Landsat Thematic Mapper Imagery. Students
look at overlaying vegetation zones (grouped by vegetation communities) on maps of
precipitation and temperature, and analyze this data.
Figure 1
(Source: Living in the Environment by G. Tyler Miller)
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Draft Basic Lesson 4
Objective
To challenge students to explore biomes ranges as they relate to precipitation and temperature.
Requirements

Google Earth software

Download “STORE CA Data.kmz” or “STORE Data.kmz”.
Lesson Duration
1/2 class period, 20 to 30 minutes
Part 1: Set-up (ignore if you have already done these steps for a prior STORE lesson)
1. Open Google Earth from your computer. Once Google Earth (GE) is open, click “File” at
the top right corner of the Google Earth window, and click on “Open” from the drop
down menu. In this window, navigate to the “STORE CA Data.kmz” or “STORE
Data.kmz” file downloaded on your computer. Once you have selected the kmz file, click
“Open”. (Note: the file names may also include a date, because revisions have been
made from time to time).
2. Save “STORE Data” file in GE to “My Places” by dragging and dropping the folder into
“My Places” under the “Places” Panel on the right of the screen.
3. Tip before you start: It can get confusing when you have multiple layers selected at once
and multiple folders and subfolders open. To avoid confusion, close layers, folders and
subfolders you are finished with before opening new ones. To start this lesson, if any
layers are open on the map, turn off all of them at once by un-checking the box that is to
the left of the "California Study Area Data" folder in Places Panel.
Part 2: Vegetation and Topography
1. Table 1 shows the elevation ranges in meters and feet for the different predominating
land cover types in the California study area. The table below lists their elevation ranges
in meters and feet.
Table 1:
Land cover
Deciduous forest
Shrub scrub
Mixed forest
GrasslandHerbaceous
Evergreen Forest
Cultivated crops
Elevation ranges
(meters)
100-2800
100-3300
100-1700
100-3300
Elevation ranges
(feet)
328-9186
328-10827
328-5577
328-10827
100-3200
0-1500
328-10499
0-4921
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Emergent
herbaceous
wetlands
Woody wetlands
0-2700
0-8858
0-1900
0-6234
The elevation ranges in meters are also listed in the layer “Elevation Ranges for Land Cover
Types within the California Study Area.”
To see the contents of Table 1 on your screen, click the name of the “Elevation Ranges for
Land Cover Types within the California Study Area” layer.
Question 1: Based on what you now know about the elevation ranges, identify a type that is
likely to have a shrinking habitat in the California Study Area if global warming predictions
come true. Then, explain why, using evidence from the map. Hint: Think about what elevation
ranges support the different vegetation types and about the topography of the Study Area.
Figure 2. USGS NLCD vegetation overlain on a topographic relief map.
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Draft Basic Lesson 4
Part 3: Vegetation and Precipitation
The students will examine the deciduous and evergreen forests in relation to precipitation. For
further investigation, they can also examine other types of predominating land cover in the
STORE California data set. The students will click on and off each of the vegetation types
displaying these feature classes one at a time and compare the vegetation to the underlying
“Precipitation Data Recent Ranges of Values” layer to determine the range of precipitation
associated with that community.
1. Click the box next to the “Recent Average Annual Precipitation Totals” layer to display it
on the map. (Later, as with any layer, you can remove it from your map by clicking the
box again). This layer represents the precipitation per year averaged over a 30 year period
(1961-1990).
2. Then go to the “Recent Predominating Types of Land Cover” folder (and expand “The
Actual Data Showing Recent Predominating Land Cover” and “Broad Predominating
Land Cover Ranges” subfolders. To expand the folder, click the box to the far left of the
label. Depending on what version of Google Earth you have, the box will have either a
“+” sign in it or a carrot ( ) facing right. Checking the “+” sign turns it into a “-“ sign
and checking the carrot makes it appear face down ( ).
3. Also, expand the subfolder “Broad Predominating Land Cover Ranges” in the same way.
Names of layers for all the different type of land cover such as Deciduous Forest will
now be displayed on the Places panel.
4. Turn ‘on’ the “Deciduous Forest” layers in both folders. On the map, the “actual”
Deciduous Forest data will appear as dark blue dots. The broad range of deciduous forest
appears in a polygon surrounded by black lines.
5. If you make the precipitation data layer more transparent, you can see the deciduous
Forest data more clearly. Do this by first clicking the name of the “Recent Average
Annual Precipitation Totals” folder.
Then, select the partially shaded rectangular icon at the bottom of the Places panel, which
opens the “transparency bar.” Google Earth will now know that you want to use the bar
to change the transparency of the layers in that precipitation folder.
The transparency bar has a gauge. Notice how the gauge is set all the way to the right
when you open the precipitation layer. Google Earth does this by default because it
presumes that you want the layer to appear on the map in its most opaque (i.e., thickly
colored) state.
You can make the layer less opaque (i.e. more transparent) by holding down on the gauge
with your mouse, then dragging it to the left as far as you want it to go. Dragging it all the
way to the far left will make it completely transparent (i.e. invisible).
6. Study the relationship between where deciduous trees predominate in relation to the
average annual precipitation levels. Determine the underlying average annual
precipitation ranges for the areas in which the deciduous vegetation type predominate by
examining the legend for the precipitation layer.
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If the legend colors are is not clear enough to help you decipher what the colors
represent, click one of the precipitation ranges on the map. A pop-up table will appear
indicating the precipitation totals for that area. (NOTE: If you do this, make sure that the
map area you click only has one layer on it and that this layer is the one you want to bring
up a popup window about. Otherwise the popup window that appears might be for that
other layer.)
7. Repeat Steps 4-8 for evergreen trees to examine where they predominate in relation to
average annual precipitation levels.
Question 2: What range of precipitation totals is associated with high concentration of deciduous
forests and how does this compare to the range of precipitation totals associated with high
concentrations of evergreen forests?
Part 3: Vegetation and Temperature
Use what you learned in Part 2 of this lesson to explore where deciduous and evergreen trees
predominate in relation to July and January temperatures. But first, here is some background
information about the STORE temperature data that will help you.
BACKGROUND: The STORE data sets for July temperatures include (a) the average highest
July temperature, (b) the average daily highest July temperature, and (c) the average daily July
temperature. This background section of the lesson contains some made-up data that you can
study to understand what these three statistics mean.
Table 2: Highest July temperatures:
Each of the yearly cells in this table shows the highest temperature reached in a particular
location each July over a five-year period from 2005 to 2009. The five-year average is
calculated by adding up each of the individual highest temperatures and dividing them by five
(i.e., 99 + 101 + 95 + 91 + 96 = 482. 482/5= 96.40°)
In contrast, Table 3 shows the average daily highest temperatures across all the months of July
during the same five-year period (2005-2009).
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Table 3: Average daily highest July temperatures:
To calculate the average daily highest July temperature, let us presume that the data collectors
use a thermometer to take a temperature reading each hour, yielding 24 readings (from midnight
to midnight), and that they then identify the highest temperature. Then, to calculate the average
of these highest daily temperatures, they sum them for all 31 days of July, then divide by 31.
Lastly, to determine the “average of the averages” over the five-year span, they sum each July’s
average highest value, then divide by five.
To calculate the daily averages, let us presume that the data collectors do exactly what was
described above for the average daily highest temperatures, except this time the data collectors’
start with the daily average temperature rather than the daily highest temperature. In other
words, they start by adding up each of the hourly readings then divide by 24. Then, they do the
same averaging over the monthly and yearly spans.
Of course, if you compared the average daily highest July temperature to the average daily July
temperature, you would find that the average daily highest temperature would be higher than the
average daily temperature, unless each hour’s temperature was exactly the same (which would be
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Draft Basic Lesson 4
highly unlikely). It would also be the case that the average daily highest temperature would
always be lower than the average monthly highest temperature, unless each daily high was
exactly the same. For example, in Table 3, notice that the highest temperature in July 2009 was
96°, but average daily highest was only 87.90°.
The January data for the California Study Area were calculated in a very similar way as the July
data; the difference being that the January data include the lowest temperatures rather than the
highest temperatures. This is because in California, the highest July temperatures and lowest
January temperatures are good approximations of annual temperature extremes, since January is
often the coldest month and July is often the warmest.
Question 3. Which do you think would be worse for most plants, an intolerably high monthly
peak temperature or a sustained yet slightly lower high temperature? Why? (NOTE: there is not a
simple correct answer for this question.) For more on this topic, read Wahid, A. Gelani, S.,
Ashraf, M, Foolad. M.R. (2007). Heat tolerance in plants: An overview. Environmental and
Experimental Botany 61. 199–223. The article can be read or downloaded at
http://startinternational.org/library/archive/files/heat-tolerance=eeb-2007_fc9bd2df67.pdf.
Question 4. Think of a place in the world where the extremes in July and January would be the
opposite. Why?
Question 5. Now that you understand more about the STORE temperature data, study the
relationship between that data and the ranges of evergreen and deciduous forests. Which of the
two types of trees seem to be more tolerant of temperature extremes, evergreens or deciduous?
Justify your answer with evidence from the data.
Field Demonstration
1. Plan a field trip to a local natural area.
2. What vegetation community do you anticipate to see based on the elevation and average
annual precipitation of this area? Check your map in GE.
3. Test your hypothesis by traveling to this area and conducting a vegetation survey along a
10-meter transect line. Identify and record the types of trees and vegetation present of this
area. Were you right?
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