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Leaves Online

Leaves are about to emerge on the trees across North America and we're

about to open our mailbox for you to report the occurrence of this spring

event where you live.

Beginning on Monday, February 10th send your reports to:

jn_leafout@informns.k12.mn.us

WHAT TO REPORT:

We will be collecting two kinds of reports. Read on!

1) If you live anywhere in North America from the southern U.S. to

northern Canada and Alaska:

Report when leaves on your trees are the size of a quarter. Please try to

include the name of the species. General reports, such as the one below

that just arrived from Texas, are welcome:

Date: Tue, 7 Feb 1995 17:20:50 -0600 (CST)

From: Judith Keese Leland <joleland@tenet.edu>

Subject: Re: Spring's Journey North

"I just spotted the first redbud trees in bloom near Houston, TX!

Have also seen some other types of flowering fruit(?) trees white

blossoms. Fuzzy buds and pale green leaves are much easier to spot.

We are on the gulf coast so spring often comes earlier for us!"

Remember: Report your observations to: jn_leafout@informns.k12.mn.us

2) If you live where red oak trees are found:

Report when the leaves on RED OAK trees are the size of a quarter.

(Consult map in any field guide to North American trees to see if red

oaks grow in your region.)

Here's why:

As leaves emerge in spring, they're especially tender and rich in protein.

At the same time, there's an explosion of leaf-eating insects. These insects

(in the caterpillar stage of life) arrive on the scene to take advantage of this

food source.

Our question:

How does the oriole's arrival compare with the leafing-out of oak trees

across eastern North America? Do orioles use this insect feast to fuel their

long migration?

We'll test whether these are accurate links of a food chain:

Triggered by spring temperatures and increasing day length,

leaves emerge and forest caterpillars follow. Is this why birds arrive

when they do?

Remember: Report your observations to: jn_leafout@informns.k12.mn.us

Extension:

Make a Leaf-Out Timeline

1) Go outside and see how many different tree species you can find. A

field guide to trees will help you identify species and show you the

characteristics to look for. (For example, bark texture, color and patterns,

bud shapes and their arrangement on twigs, tree silhouette, etc.)

2) Mark each different species with flagging ribbon. Remember, this is

an exercise in observation. The name and exact identification of the

tree is not critical.

3) As the leaves of a species emerge, record the date that they

are the size of a quarter and add the species to your time line. Do leaves

of all tree species emerge at the same time? Can you find the names of

each species more easily now that the leaves are out?

4) Keep temperature records, as described in the Spring Fever project,

and see how temperatures correlate with the emergence of leaves.

5) Do this activity with your class from year to year. Do leaves of each species emerge in the same order from year to year? At the same average temperatures?