tree ID & context

The purpose of this lab is to do some basic tree ID as well as understand a bit about the conditions in which certain trees tend to grow. We’ll look at how a few key environmental patterns (soils, aspect, & moisture) affect the spatial distribution of tree species. We’ll also pick out one tree in a nearby location to our homes and survey the area for offspring of that tree, testing our hypotheses for what might be driving that distribution. Of course, these same patterns affect smaller woody, herbaceous and even non-vascular plants as well, but this is simply a great time of year to be looking closely at trees, as so much interesting biology is happening day by day, week by week.

the lab activity

Habitat Activity - Part 1: Start out by watching the first video below in the "Background" section. Identify a place near your home that has wild trees (i.e. those not directly maintained by people), if at all possible. This could be in a park, the edges of a schoolyard, scrubby trees growing along a stream or drainage ditch, the back of your family’s property, etc. Wherever you find your trees, define an area of about 15m in length (width can vary depending on where you found these trees; no need to consider an area wider than 15m). If you know your pace in meters, or have a measuring tape, great; go ahead and use those. You can also make a good estimate by assuming that each step you take is about 85cm in length, so 18 steps will usually be fairly close to 15m for most people. Make some initial observations about the habitat and the trees you find there:

• Describe the habitat generally.

  • • Sketch a basic map of your habitat, including any prominent features, indicating slope (flat, steep, etc.) and direction (N,S,E,W) and noting surrounding land covers.

    • Is this an upland or a lowland habitat relative to other nearby parts of the landscape?

    • How would water move across this part of the landscape (is it flowing from somewhere else into here, and where would it flow from here)?

    • By hand or with a small hand shovel, dig a couple of shallow soil pits. How would you characterize the upper layers of the soil?

      • • Rich or poor in organic matter?

        • Sandy or more dominated by clays?

• Do these trees seem to be old or relatively young judging by their diameters?

• Tree ID: How many different species of trees can you find in your habitat?

  • • • ID at least 7 tree species - make sure you include images of structures that helped you ID them - links to keys can be found below in the Background section

      • What features of the trees are you finding the most useful for telling them apart?

      • Which tree species are flowering right now? Can you get a photo of the tree flowers? Check out the second video in the "Background" section if you want to see black oak flowers as an example.

      • Are these species native to your region of the world, or have they been introduced elsewhere?

      • Do the descriptions (found in your key(s) or online) for suitable habitat for these species match fairly well your habitat, or do you see any mismatches in that?

Habitat Activity - Part 2: Start out by watching the third video below in the "Background" section. Locate a mature tree in your habitat that a) you believe you can identify the seedlings of (maples usually are easy and prolific this time of year) and b) if possible, is the only one of its kind in the immediate area. Now you’re going to complete a simple belt transect survey for seedlings of your tree along four ~10m transects radiating out from the trunk.

• First, hypothesize where you expect to find the greatest number of seedlings:

  • • Do you expect that they will be evenly distributed, highest density further from the trunk, closer, etc?

    • Do you expect to see more along one or two transects than the others?

• Give the rationale for your hypothesis. Why do you expect to see that pattern or patterns?

• Second, walk slowly along four transects radiating out from your tree’s trunk, such that the transects are at 90° to each other around the tree. Each should run for 10m (or again, about 12 steps for the typical person). Along each transect:

  • • Survey 50cm on either side of the line you walk for the presence of seedlings of your tree, and count each one. Make a table like the one below for your data. Enter the count into the data table below, with a total for each 50cm increment of each transect.

• Finally, discuss your findings:

  • • How did your results compare to your hypothesis?

    • Were there any clear differences in seedling counts between the transects? Why so?

    • How about along each transect; did seedlings appear to be evenly distributed or clustered at certain distances from the parent tree?

what to hand in on your website

• Description of the habitat (containing trees) that you are choosing to focus on as indicated above (slope, aspect, soils, sketched map as jpg, etc.) [10 points]

• Tree IDs (at least 7) with pictures and descriptions as indicated above [35 points]

• Seedling transect activity

  • • hypothesis [5 points]

    • data table [5 points]

    • discussion of results [5 points]

background

Here is a list of Tree ID websites in addition to the apps you already are familiar with. There is some jargon and nomenclature to learn to use these keys but many of them have great pictures and diagrams to help you sort it out. If you need some additional help here is a slideshow from Merry Lea's Bill Minter. This is not an exhaustive list, just some I have found (no particular order):

• Urban Tree Key

• North Carolina State Tree Key

• Iowa State University Tree Key

• Oregon State University Tree Key

• Multiple resources from Wisconsin to ID trees

• What Tree?

Some characteristics you may want to pay attention to are as follows:

• leaf characteristics

• twig characteristics

• bark characteristics

• tree form

• growing habit

other resources

Trees found at Merry Lea around MLSF:

1. Black Walnut

• chambered pith

• dark pith

• dark nuts

• chocolate bark when hit

2. White Ash

3. Green Ash

   1. • • green half moon leaf scar

        • wetted area

4. Blue Ash

   1. • • square stem

5. Eastern Cottonwood

6. Sandbar Willow

7. Sugar Maple

8. Kentucky Coffee Tree

9. White Elm

10. Red Elm

11. Bitternut Hickory

12. Northern Red Oak

13. Black Oak

14. Eastern White Oak

15. Eastern Redbud