Wk 3 Alternative: Tree identification & iNaturalist

Overview

Today you will be using different methods to identify tree species in natural areas that have not been landscaped. You will use a traditional dichotomous key and the INaturalist app to identify dicot trees. Then you will compare results between these methods.

Begin by reading "Instructions for Tree Identification" in todays folder

Overview

Use a traditional dichotomous key to identify 4 broadleafed trees and compare the results with the identification results from a digital app. We will skip gymnosperms (skip trees with needle-like leaves) here because you key out gymnosperms in a different exercise. This lab will teach you how to use a dichotomous key for identifying species and introduce you to an identification app.

Background:

There are now several apps that facilitate plant identification. Because tree leaves have distinctive shapes, these apps usually guess identifications based on leaf shape. Traditional dichotomous keys can require more work, but have the advantage of allowing the user to provide additional information besides leaf shape. Reliance on leaf shape alone can be problematic because there is leaf-shape variation within species, and some different species have similar shapes.

The goal of this exercise is to compare the effectiveness of a traditional key in tree identification with that of an app. For the traditional key, we will use a key to common trees of South Carolina (if you are not completing this exercise in the Carolinas, Georgia, or Virginia, let the instructor know so a suitable alternative key can be identified).

For this exercise we will use the INaturalist app. (Leafsnap from Columbia University is another good free app to know about.)

Steps:

1. Find at least 4 different living dicot trees (not gymnosperms) in a natural area (not a yard or a park). It can be on the edge of a yard, if the trees are native trees, not planted. Do not use trees in an arboretum, at a nursery, or that are already identified. Make sure you can reach the leaves. You will identify them one at a time.

2. Take Photographs of the tree for your assignment.

Include at least one photo of entire plant (or an entire branch) and at least one photo of individual leaf with entire leaf flat on a plain surface (e.g. a sheet of paper), with your identification sticker in the photograph. If it is a compound leaf, include the whole leaf, not just 1 leaflet.

3. First read ‘How to Use a Dichotomous Key’ here (1 page), then identify the tree using this link: Dichotomous Key of Familiar Trees of S.C. You will record all of the steps taken to arrive at the tree’s common name, then record the common and scientific names.

Below a branch from a tree in the woods near my house. I will show the steps taken to arrive at this tree's common name using the key provided. You may not choose a tree of this species as one of your 4 to identify. You will show the steps in the key that you took in the same way for 4 definitely different trees in a natural area.

On page 20 of the Dichotomous Key of Familiar Trees of S.C., you’ll find the key to follow along with me.

We are doing broadleaved trees in this lab, therefore begin with the statement below for the first couplet:

1. Trees with broad flat leaves of many shapes and patterns (broadleaves) (go to) 11

My example below, shows the choices I made for each couplet in the key based on my plant above:

1. Trees with broad flat leaves of many shapes and patterns (broadleaves) ….. 11

(Go to 11, read this couplet as “Leaves fan-shaped, 2 or more feet across OR Leaves otherwise and make a choice, continue the process until you get to a common tree name)

11. Leaves otherwise… (go to) 12

12. Leaves alternate…. 17 (Tip: Check down the branch to determine leaf arrangement because leaves grow very close together near the tip of the branch)

17. Leaves simple…. 23

23. Leaves deciduous, thin and papery …. 27

27. Leaves unlobed or with occasional small shallow lobes …. 41

41. Leaves with smooth margins (or occasionally with shallow teeth)….42

42. Leaves heart-shaped ….. eastern redbud (this is the common name)

Scientific Name: Cercis canadensis

To find the scientific name, use the index on page 2 to find your plant, then check to see if the image on the referenced page looks correct. If so, write the scientific name (my example is on p. 12). If it does not look correct, you will need to start at the beginning of the key and try again. You have made a mistake, but you don’t know where.

Record the common name as well as scientific name (remember to capitalize the genus and leave the species name lowercase; italicize both: for example, Cercis canadensis).

4. Photograph the tree according to the instructions provided by the app

5. Upload the photographs to INaturalist. (Directions for using the INaturalist app are in the folder for today.) Remember that photographs are geolocated, so you may choose to avoid photographing trees in your yard if you want your home's location to be private.

Use the ‘Suggest ID’ function to identify the tree. If the app indicates that it is "confident" about an identification, then choose that species. If it is not confident, then you can select among the choices it gives you.

6. Compare and record identification methods. Include all of the following (A-C) for the first tree in a Word document saved to your computer. Then, repeat steps A-C for a total of 4 trees.

A. Label Tree #1 photos: Resize and crop your photos, then copy photos to your document. Label photos using Tree #1a, Tree #1b, etc.

B. Type all the steps taken in Dichotomous Key to arrive at the common name under Tree #1s photos in your document. Include the Scientific name.

C. Compare:

1. Indicate what you identified the tree to be using the dichotomous key:

"Dichotomous key ID:____________________".

2. Indicate the tree's identity according to INaturalist:

"INaturalist ID:______________________".

3. Your username on INaturalist is ­­­­­­­­­­­­­­­­___________________. This will allow me to view the date, time and location of your photographs.

1. Using the species name(s) from 1 and 2 above, check the Species Accounts for trees at Carolina Nature (linked here). (if the species is not on Carolina Nature, find another website with which to compare). Scroll down on the page and click on the species' name(s) you identified to see images of various plant parts.
   • a. If the dichotomous key and the app gave the same species name, indicate whether the answer appears to be correct and why you think so according to Carolina Nature. If the answer appears to not match the description at Carolina Nature, explain what trait or traits do not match. Begin your comparison with the following statement: "My evaluation according to Carolina Nature:"...
   • OR
   • b. If the dichotomous key and the app gave different species names, indicate which you think is correct (dichotomous key or app), and why. Begin your comparison with the following statement: "My evaluation according to Carolina Nature:"....

7. Repeat Everything for #6. A-C above for a total of 4 different tree species.

8. Finally, give INaturalist a final score (percent correct) for the number of leaves that you think the app got right.

Final App score __________________% (hint: Number correct/4) - see example below

Example of what to include in your Word document for one tree (you may not use the tree species in this example as one of your 4 different tree species)

6. A. Photos of tree #1

Tree 1a. leaf

Tree 1b. branch

(Make sure one photo clearly shows one entire leaf and they are all large enough for viewing)

6. B. List ALL Steps taken in the dichotomous key:

1. Trees with broad flat leaves of many shapes and patterns (broadleaves) ….. 11

11. Leaves otherwise… (go to) 12

12. Leaves alternate…. 17

17. Leaves simple…. 23

23. Leaves deciduous, thin and papery …. 27

27. Leaves unlobed or with occasional small shallow lobes …. 41

41. Leaves with smooth margins (or occasionally with shallow teeth)….42

42. Leaves heart-shaped ….. eastern redbud

Scientific Name: Cercis canadensis

6. C. Compare:

1. Indicate what you identified the tree to be using the dichotomous key:

"Dichotomous key ID:___Eastern redbud (or scientific name)______".

2. INaturalist ID:____Basswood (or scientific name)_________".

3. Your username on INaturalist is ­­­­­­­­­­­­­­­­__Add your username___________. This will allow me to view the date, time and location of your photographs.

4. My evaluation according to Carolina Nature: the key identified this tree correctly, but the app did not. I think that because the shape of the leaf shown on Carolina Nature for Eastern redbud resembled the tree’s heart-shaped leaves more closely. The leaf images for Basswood, show leaves that are also heart-shaped, but have a strongly toothed margin and the leaf on the tree I observed is entire (smooth).

**Repeat ALL of these steps for 3 more different tree species.

**Then type in the accuracy of the app for your 4 trees. 1/4 =25%, 2/4 =50%, etc.

Directions for INaturalist

1. Download the INaturalist app on your phone. This app allows you to identify wild plants based on photographs. It also uses social media to allow others to verify your identifications or correct identifications.

• The locations of images you post is public and linked to a map, so if you are concerned about privacy avoid photographing plants in your yard.
• Create an account. I suggest using your first name as part of your username but not your full first and last name if you want to maintain privacy.
• Find a natural area (nature park, stream bank, wood lot, etc.) and photograph plants

These trees should be wild, not planted in landscaping, a garden, or at a nursery.

Photograph the plants. Take high quality photographs like you practiced in the first week. It is best to take at least 2 - 3 photographs per tree. More than 1 photo at a time can be uploaded to the app.

• Upload photographs to INaturalist.
• Then, use the "Suggest ID" feature on the app. This will usually generate a list of 10 suggested species. Compare your photo to the images they provide. Also, consider that plants that are labeled as "Seen nearby" are usually better guesses than ones without this label. Select whichever ID seems best.