Leaf-out Update: February 7, 1997

On this very day two years ago, teacher Jo Leland of Houston, Texas reported, "I just saw my first redbud leaves. We are on the Gulf Coast so spring comes earlier for us!"

What a contrast to the cool spring of '96, when no new spring leaves had been spotted as late as February 23rd.

How will this year compare to the springs of 1996 and 1995? We hope you'll help us measure spring's northward journey by reporting when leaves emerge on your trees. Simply adopt a local tree and let us know when its leaves are the size of a U.S. quarter. That's our definition of "leaf-out".

Remember, the leaves you report must be growing on trees--not on bushes or other leafy plants. The trees must also be "deciduous".

How to Report Leaf-Out:
Simply press the blue owl button on the left and a Field Data Form will appear.

A Race So Sweet!

Vermont's Tree (44.15 N, - 72.34 W)

Minnesota's Tree (44.55 N, -93.31 W)

In northern regions, where trees still look drab and gray, amazing changes are about to occur on the inside. Before leaf-out each spring, maple trees produce a tasty reward and students in Vermont and Minnesota are standing by.

Minnesota's "Chanhassen Chiefs", a 4-H Club near Minneapolis ( 44.55 N, -93.31 W) and 5th graders at Vermont's Union Elementary School in Montpelier (44.15 N, - 72.34 W) will each tap a maple tree this spring. Then they'll race to see whose tree produces ONE FULL BUCKET of sap first. The two groups will watch the weather at both sites carefully, since experts say maple sap runs best when:

• The temperature drops below freezing at night

• Daytime temperatures go above freezing

Whose bucket do you think will fill first? Visit this page regularly. When the sap begins to drip into the buckets you'll know spring has begun--and the race is on. (Thanks to Andy Rolling for these great drawings!)

Challenge Question #1

"Why do you think sap flows in the spring?"

To respond to this Challenge Question, please follow the instructions at the end of this report.

Try This!

• Before the leaves emerge in the spring, go outside and see how many different tree species you can find on your school grounds. A Field Guide to Trees of North America will help you identify trees by name. Such a guide will also show you what to look for. You may be surprised how much variety there is between trees: For example, you can identify trees by comparing their silhouettes, the shapes of their buds, and even the texture, color and patterns of their bark.

• Divide the class into three groups. Have each group try to find a different tree species. Have them mark one small branch of their tree with yarn or flagging ribbon. (For now, this is an exercise in observation. The exact name and identification of the trees is not important at this point.)

• Have students visit their adopted tree on a regular basis. They should sketch the buds on the same small branch each time they visit. Students will watch the bud open, the tree bloom and the leaves emerge.

• This would be a good time to start the Spring Fever activity. (Also see Page 111 of your Teacher's Manual.) Students can begin to collect daily temperature readings and compare the rate of leaf growth vs. temperature.

• Connect with another Journey North classroom. Your students can make predictions, exchange data and compare results from different geographical regions. Use the Teacher-Teacher Feature to locate another participating class. You can do so by sending a message to: jn-talk@learner.org

Suggested Resource

Since your students will be receiving reports from other geographical regions, we recommend "A Guide to Field Identification of Trees of North America". (Golden Press, 1986). This guide has maps showing where different tree species grow.

The maps will lend to discussions about the effect of climate on the range of tree species.

How to Respond to Leaf-Out Challenge Question #1

1. Address an e-mail message to: jn-challenge-leaf@learner.org

2. In the Subject Line of your message write: Challenge Question #1

3. In the body of the message, answer this question:

   "Why do you think sap flows in the spring?"

   Please give as many facts and details as you can. We'll share your ideas and those of other students in future reports.

   The Next Leaf-Out Update Will be Posted on Friday, February 21, 1997.