RIVER SUMMER CURRICULUM: Natural Sciences Biological...

Environmental Consortium of Hudson Valley Colleges & Universities 1

RIVER SUMMER CURRICULUM: Natural Sciences Biological Sciences – Hudson River Watershed Forest Ecology Comparing Forest Communities in Close Proximity ABSTRACT: Forest communities in close proximity can vary considerably with respect to species composition. The composition of these communities is a factor of soil, light, moisture, aspect and other ecological factors. This project utilizes the Point-Center Quarter Method to analyze two closely situated forest communities. The communities to be compared can be located along an altitudinal gradient, north vs. south facing slopes, or areas with markedly different ecological habitats. Data collected will be entered into a spreadsheet and an Importance Value will be calculated based on how common the species is across the community (density), the total amount of area the species occupies (dominance), and the total number of the species in the community (frequency). Importance values are then plotted using both column and pie charts. This curriculum can be combined with RIVER SUMMER CURRICULUM: Geographic Information Systems (GIS) CampusBlitz: An Introduction to the Use of GPS and GIS for Data Collection and Display which can be downloaded from the River Summer website. PROJECT DEVELOPER: Tom Sarro, Ph.D., Biology Department, Mt. St. Mary College, 330 Powell Ave., Newburgh, New York, 12550 LEARNING GOALS: Skills

• Use of a compass to set up a transect line • Utilize a transect line to execute the Point-Center Quarter Method for

collecting data in a forest community • Identify common forest trees • Analyze the data to observe differences between two forest communities and

propose possible explanations for the differences observed • Use of excel as a tool for charting, graphing and analyzing data

Insights • Propose situations where the Point-Center Quarter Method can be used


• See the importance of the effects of both biotic and abiotic factors on community composition

• Recognize the difference between ‘density’, ‘dominance’ and ‘frequency’ MATERIALS & PREPARATION NEEDED:

Supplies and materials:

Basic orienteering compasses (from Forestry Suppliers) • 50 meter fiberglass tape measure(s) graduated in meters (from Forestry Suppliers) • A wooden dowel cut to 130 cm (used to measure D130, the diameter at 130 cm height) • Fiberglass diameter tape(s) graduated in centimeters (from Forestry Suppliers) • Field guides for forest tree identification see Watt references below for an affordable entry level option) • Clip board(s) • Data sheets and pen(s) or pencil(s) • Access to a computer with a spreadsheet program such as Excel installed on it

Safety issues: • Wear appropriate footwear for the terrain • Practice appropriate precautions against ticks and other biting insects (light colored clothing, tucking pants into socks, and the use of insect repellents)

Sites: • East/West running roads that provide a cut through a valley or depression

provide excellent opportunities to study north and south facing slopes • Altitudinal differences can be studied along many of the trails used for hiking

Catskill summits • Any area with trees and varying habitats (parks, state forests, etc.)

Time of year: this exercise can be performed virtually any time of year. However, it is more easily performed when trees are in leaf since identification is considerably less difficult than in winter and early spring when leaves are absent.

SKILLS AND UNDERSTANDING NEEDED:

• Use of an orienteering compass • Tree identification and the use of keys • Familiarity with a computer spreadsheet. An excellent primer can be

downloaded for free from http://www.uvm.edu/envnr/vtcfwru/spreadsheets/. Although a slightly dated version of Excel is used the basics are presented with worked out exercises in chapters 0-3.


• An understanding of how abiotic and biotic factors influence community structure. This information can be found in most introductory level ecology texts such as those listed under readings.

Readings

• Adams, D.L. and Barrett, G.W. 1977. Species Importance in a virgin and timbered beech-maple forest ecosystem. Ohio Journal of Science. 77(2):84-87.

• Bryant, J. R. and Curtis, J.T. 1957. An ordination of the upland forest communities of southern Wisconsin. Ecological Monographs. 27(4):325-349.

• Cain, M.L., Bowman, W.D., and Hacker, S.D. 2008. Ecology. Sinauer Associates, Inc. Sunderland, Massachusetts.

• Cantlon, J.E. 1953. Vegetation and microclimates on north and south facing slopes of Cushetunk Mountain, New Jersey. Ecological Monographs. 23:241-270.

• Cottam, G. and Curtis, J.T. 1956. The use of distance measures in phocociological sampling. Ecology. 37(3): 451-460.

• Gurevitch, J., Scheiner, S.M., and Fox, G.A. 2002. The ecology of plants. Sinauer Associates. Sunderland, Massachusetts

• Molles, M.C. 2010. Ecology concepts and applications, 5th Ed. McGraw-Hill Companies, Inc. New York, New York

• Odum, E.P. and Barrett, G.W. Fundamentals of Ecology, 5th Ed. Thompson Brooks/Cole. Belmont, California

• Smith, R.L. and Smith, T.M. 2001. Ecology and field biology, 6th Ed. Benjamin Cummings

Resources

• Harlow, W.H. 1959. Fruit key and twig key: to trees and shrubs. Dover Publications, Inc. New York

• Kricher, J.C., and Morrison, G. 1988. Peterson field guides: Eastern forests. Houghton Mifflin Co. Boston, Massachusets

• Petrides, G.A. 1973. Peterson Field Guide: A field guide to trees and shrubs: northeaster and north-central United States and southeaster and south-central Canada, 2nd ed. Houghton Mifflin Harcourt. Boston, Massachusetts

• Petrides, G.A. 1988. Peterson Field Guide: A field guide to eastern trees: Eastern United States and Canada. Houghton Mifflin Harcourt. Boston, Massachusetts

• Silvics of North America. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm

• Watts, M.T. 1998. Tree finder: A manual for the identification of trees by their leaves. Nature Study Guide Publishers. Rochester, New York

• Williams, M.D. 2007. Identifying Trees: an all-season guide to eastern North America. Stackpole Books. Mechanicsville, Pennsylvania


DEVELOPMENT OF ACTIVITY Time to be allocated: 2-4 hours excluding travel time Overview: The student groups will be laying out two transects run along a specific compass bearings (N/S or E/W depending on your study design) in order to compare the tree data along two areas of forests. Measurements will be made along each transect at intervals determined by a random number generator. At each measure site 4 trees will be evaluated, one in each quadrant, before moving on to the next measuring site. Once the data has been collected in the field it can be analyzed using an excel spreadsheet. Step by step instructions: FIELD COMPONENT:

1. The purpose of this activity is to compare two different ecological habitats. Once you have selected the two areas for study begin by selecting a compass bearing that relates to the habitat being studied so you can lay out your transects. Note you will probably want to divide your students into two groups to collect data on the two different transects (further dividing into smaller groups to collect portions of the transect is also advisable if enough supplies are available). Doing one sample station all together is recommended to avoid confusion.

STEP 1: Compass Bearing STEP 2: Lay Out Transect

2. Securing one end of the 50 m tape measure and following the compass

bearing selected above, walk straight laying out your transect.

3. Using a calculator with a random number generator OR a random number chart (see attached) select the number of meters to travel to locate the first


point to be studied. (If you are using the attached number chart mark the first number you use. For each successive station you will use the number immediately to the right of the first number you select.)

4. At point One, find a relatively straight stick and position it perpendicular

to the line of transect this will divide the point into four quadrants (Fig. 1 and photo below)

STEP 4: Divide into 4 quadrants STEP 6: Measure D130 of the tree

Figure 1


5. Within each of the quadrants locate the nearest tree with a D130 (diameter at 130 cm) of 10 cm or greater and identify it species. Record this in the appropriate space on the data sheet

6. Measure the D130 of the tree and record in cms on your data sheet. 7. Measure the distance from cross mark at point One to the tree and record

on data sheet. BE sure to record this in meters not feet. 8. Repeat for the remaining three quadrants (Fig.2)

Figure 2

9. Using your next random number following your 50 meter tape walk that

number of meters along the original compass bearing. If a previously sampled tree is in one of the new quadrants, skip this quadrant entirely and select the next random number of meters and move to the next location following the prescribed bearing. Each quadrant you measure should have all unique trees recorded.

10. Continue to do this until at least 50 points have been recorded. For the sake of time this number can be abbreviated but realize that it may not truly represent your sample.

BACK IN THE CLASSROOM

11. Once all of the data has been collected it must be entered into a spread sheet for analysis back in your class. You will be setting up a multitab


spreadsheet. Set up the first page (raw data tab) of the spreadsheet in the same format as your data sheet. (Fig. 3)

Figure 3

12. The basal area for each tree must be calculated using the formula (note r =

diatmeter/2) area = π r2

Create a column headed Basal Area and compute the areas of each tree.

13. Next take the mean of the Point to Tree distances and square them. Create a formula that takes the average of the Point to Tree distances and square it. This is the average area in which one tree is found.

14. With the data entered and the calculations completed Importance Values (IV) for each species of tree can now be determined. An IV is calculated using the following formula: ____________1____________

Density (all species) = (mean point to tree distance)2


To determine the density of trees/hectare (100 x 100 m) divide the density obtained in the previous equation into 10,000 m2.

IV = Relative Density + Relative Dominance + Relative Frequency

# of individuals of a species X 100 Relative Density = Total # individuals (all species) total basal area of a species X 100 Relative Dominance = total basal area of all species

Frequency of a species X 100

Relative Frequency = sum of frequencies of all species A set of sample data with a completed calculations can be downloaded as an excel file as part of this activity but as a separate file to assist with your calculations (see activity website).

15. Once the Importance Values have been calculated plot their values as both column and pie charts.

16. Discuss your findings. Were there differences between the two sites you

evaluated? What might have caused these differences?

=============================================================== To aid in performing these calculations in Excel you will find detailed instructions in the attached Appendix. These instructions correspond to the downloadable Excel workbook that contains a sample set of data with annotated cells to aid with understanding the calculations. Comments as to the contents of a particular cell can be found in those cells with a red triangle in their upper right corner.


APPENDIX

TOTAL DENSITY CALCULATIONS 1. Copy raw data to a new sheet 2. Delete columns A&C (Point # and D130) 3. Obtain the average point to tree distance for all trees (cell B42) 4. Square the average point to tree distance (cell B43). This represents the average area

occupied by one tree. 5. Typically when using the metric system density is represented as trees/hectare (ha).

To calculate this divide the average area for one tree into 10,000 m2, this is one hectare (cell B44)

RELATIVE DENSITY CALCULATIONS 1. Copy raw data to a new sheet 2. Delete columns A&D 3. Obtain a total number of trees sampled by using the count function (cell B42) 4. Sort all data, excluding cell 42 5. Using a separate area on the spreadsheet, determine the number of trees of each

species (cells E3:E7) 6. Check your calculations to be sure your total number of trees is accurate. It should

equal the number in cell B42 (cell E8) 7. Calculate the relative density for each species by dividing the total number of trees of

each species by the total number of trees sampled and multiplying this number times 100 (cells F2:F7)

8. Do a calculation check by summing all of the relative densities to be sure they total 100 (cell F8)

RELATIVE DOMINANCE CALCULATIONS 1. Copy raw data to a new sheet 2. Delete both Point # and Point to Tree Columns (columns A&D) 3. Sort the two remaining columns by species 4. Calculate the basal area for each species (see comments in cells)

4.1. Determine each tree’s radius by dividing the diameter by 2, D130/2 (cell C2) 4.2. Square each radius (cell D2) 4.3. Calculate the basal area using the formula below (cell E2)

Basal area = π r2 5. Calculate the sum of all the basal areas (cell E42) 6. Create a column for each species sampled (cells H2:H7) 7. Using the sum function, calculate the total basal area for each species (cells I2:I7) 8. Do a calculation check by summing all of the total basal areas to be sure they equal

the total for all tress (cell E42 = I8)


9. Calculate the relative dominance for each species by dividing the total basal area of each species by the total basal area for all species and multiplying by 100 (cells J2:J7)

10. Do a calculation check by summing all of the relative dominances to be sure they total 100 (cell J8)

RELATIVE FREQUENCY CALCULATIONS Unfortunately I have yet to figure out a way to do these calculations easily using Excel (sometimes the old paper and pencil method is still the best). If anyone has an insight as to how these calculations can be done using Excel please contact me with the method and I will be glad to include it in the methodology. Until then you will find the paper and pencil method described below and the actual calculations performed in the workbook provided. 1. Print out a copy of the raw data 2. Make a list of each of the species sampled 3. Looking at each point separately, put a single slash below the species if that species

is located at that particular point

4. For this particular data set the results above were obtained see sheet labeled Relative Frequency

5. In a separate spreadsheet, make a list of all of the species sampled


6. To calculate frequency divide the total number of points each species was found in by the total number of points sampled (cells C2:C7)

7. Total the frequencies for all of the species (cell C8) 8. Calculate relative frequency by dividing the frequency of each species by the total of

all frequencies and multiplying by 100 (cells D2:D7) 9. Do a calculation check by summing all of the relative frequencies to be sure they

total 100 (cell D8) IMPORTANCE VALUES 1. Copy the relative density, relative dominance, and relative frequency values for each

species to a new spreadsheet. You should use the paste special (values) feature for this operation.

2. Determine the importance value for each species by summing each of the relative values (cells E2:E7)

3. Using the calculated importance values produce bar and pie charts to represent the data.

This Project has been funded in part by a grant from the New York State Environmental Protection Fund through the Hudson River Estuary Program of the New York State Department of Environmental Conservation


Point-Quarter Raw Data Sheet

Point-Tree Point No. Quadarant Species Diameter Distance I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV


1000 Random Numbers

9 6 1 7 9 1 1 3 6 8 9 1 2 6 6 2 2 8 9 3 4 3 8 7 7 7 8 5 7 8 2 6

6 9 7 8 6 2 7 3 3 8 6 1 8 7 9 2 8 8 6 6 1 3 5 1 4 1 5 8 1 8 8 7

1 9 4 1 3 4 3 6 8 9 3 4 5 9 6 2 5 1 3 6 7 5 2 1 1 1 2 8 7 8 4 9

7 9 1 2 9 4 9 6 3 2 9 4 2 1 3 5 2 2 8 6 2 6 8 1 7 1 8 8 4 2 1 9

4 3 7 2 6 7 6 8 9 2 6 6 8 1 9 5 8 2 5 9 8 6 2 4 4 4 5 2 1 2 7 1

9 3 4 4 3 7 1 9 6 3 3 7 3 3 6 8 2 5 2 9 5 9 8 4 1 4 2 2 7 2 4 3

6 6 1 5 9 7 7 9 3 5 9 7 9 4 3 8 8 5 8 9 2 9 5 7 7 7 7 3 4 5 1 3

3 6 7 7 6 1 4 2 9 6 6 1 5 6 9 8 5 7 3 3 8 9 2 7 1 7 2 5 1 5 7 6

9 6 1 7 9 1 1 3 6 8 9 1 2 6 6 2 2 8 9 3 4 3 8 7 7 7 8 5 7 8 2 6

6 9 7 8 6 2 7 3 3 8 6 1 8 7 9 2 8 8 6 6 1 3 5 1 4 1 5 8 1 8 8 7

1 9 4 1 3 4 3 6 8 9 3 4 5 9 6 2 5 1 3 6 7 5 2 1 1 1 2 8 7 8 4 9

7 9 1 2 9 4 9 6 3 2 9 4 2 1 3 5 2 2 8 6 2 6 8 1 7 1 8 8 4 2 1 9

4 3 7 2 6 7 6 8 9 2 6 6 8 1 9 5 8 2 5 9 8 6 2 4 4 4 5 2 1 2 7 1

9 3 4 4 3 7 1 9 6 3 3 7 3 3 6 8 2 5 2 9 5 9 8 4 1 4 2 2 7 2 4 3

6 6 1 5 9 7 7 9 3 5 9 7 9 4 3 8 8 5 8 9 2 9 5 7 7 7 7 3 4 5 1 3

3 6 7 7 6 1 4 2 9 6 6 1 5 6 9 8 5 7 3 3 8 9 2 7 1 7 2 5 1 5 7 6

9 6 1 7 9 1 1 3 6 8 9 1 2 6 6 2 2 8 9 3 4 3 8 7 7 7 8 5 7 8 2 6

6 9 7 8 6 2 7 3 3 8 6 1 8 7 9 2 8 8 6 6 1 3 5 1 4 1 5 8 1 8 8 7

1 9 4 1 3 4 3 6 8 9 3 4 5 9 6 2 5 1 3 6 7 5 2 1 1 1 2 8 7 8 4 9

7 9 1 2 9 4 9 6 3 2 9 4 2 1 3 5 2 2 8 6 2 6 8 1 7 1 8 8 4 2 1 9

4 3 7 2 6 7 6 8 9 2 6 6 8 1 9 5 8 2 5 9 8 6 2 4 4 4 5 2 1 2 7 1

9 3 4 4 3 7 1 9 6 3 3 7 3 3 6 8 2 5 2 9 5 9 8 4 1 4 2 2 7 2 4 3

6 6 1 5 9 7 7 9 3 5 9 7 9 4 3 8 8 5 8 9 2 9 5 7 7 7 7 3 4 5 1 3

3 6 7 7 6 1 4 2 9 6 6 1 5 6 9 8 5 7 3 3 8 9 2 7 1 7 2 5 1 5 7 6

9 6 1 7 9 1 1 3 6 8 9 1 2 6 6 2 2 8 9 3 4 3 8 7 7 7 8 5 7 8 2 6

6 9 7 8 6 2 7 3 3 8 6 1 8 7 9 2 8 8 6 6 1 3 5 1 4 1 5 8 1 8 8 7

1 9 4 1 3 4 3 6 8 9 3 4 5 9 6 2 5 1 3 6 7 5 2 1 1 1 2 8 7 8 4 9

7 9 1 2 9 4 9 6 3 2 9 4 2 1 3 5 2 2 8 6 2 6 8 1 7 1 8 8 4 2 1 9

4 3 7 2 6 7 6 8 9 2 6 6 8 1 9 5 8 2 5 9 8 6 2 4 4 4 5 2 1 2 7 1

9 3 4 4 3 7 1 9 6 3 3 7 3 3 6 8 2 5 2 9 5 9 8 4 1 4 2 2 7 2 4 3

6 6 1 5 9 7 7 9 3 5 9 7 9 4 3 8 8 5 8 9 2 9 5 7 7 7 7 3 4 5 1 3

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