Several Journey North classrooms are lucky enough to have leaves on their trees already! Their "Leaf-Out" reports are provided below. When the leaves on your trees are the size of a U.S. quarter, please send a report to Journey North. Simply fill out a Field Data Form by selecting the blue button below labeled, "Report Field Observations". We're ready and waiting to hear from you!
In our last report, we asked how warm you thought it must be for leaves to emerge on deciduous trees. Students had different ideas about this. Mrs. Tingley's and Mrs. Flynn-Browns students in at Tri- Valley Central School Grahamsville, NY said it should be 70 degrees F. A student in Owenwood, Ontario looked in an atlas and decided 15 C (60 F) was warm enough. Elizabeth Bergkamp of Valley Heights High School in Blue Valley, Kansas arrived at the same conclusion: "I figure 60 degrees F will be warm enough for a deciduous tree to leaf-out. If the temperature gets too low it will freeze." Katie Carter's class at Pemetic Elementary School in Southwest Harbor, Maine thinks it should be between 45 and 50 degrees.
While students didn't agree on the exact temperature needed, they do share the idea that heat is required. In fact, you can measure exactly how much heat it takes for leaves to grow by conducting the attached "Spring Fever" experiment. After you look closely at the "Growing Degree Day" equation see if you can answer this question:
Challenge Question # 29
"According to the Growing Degree Day equation, at what minimum temperature do leaves on deciduous grow?"
If you're tired of waiting for buds, blossoms and leaves to emerge on your trees, try this! Bring a small twig from a tree or bush inside and fool it into thinking it's spring. Place the twig in water and watch what happens. This is called "forcing" and you'll soon have a close-up view of each stage of the bud's growth. You can sketch this process each day and see how growth relates to temperature. Many different species of plants can be forced-- forsythia, pussy willows, dogwoods and maples for example. You may be surprised to see the intricate flowers that emerge from these apparently life-less branches.
Leaf-out Observations Through March 7, 1996
Date............Place.................(Comments)
02/19-23/96.....San Antonio, TX.......("The plants think it's spring.")
02/26/96........Orchard, TX...........("Small buds, should leaf-out soon.")
02/27/96........College Station, TX...("Many leaves now full size")
03/04/96........Lexington, SC.........("Our Bradford Pear tree has leafed
out!")
03/5/96.........East of Orlando, FL...("Leaves remained the size of a
quarter.")
03/07/96........New Orleans, LA.......("Many leaves are starting to bud.")
From: TEXAS
February 19-23, 1996
"Howdy from San Antonio, Texas! The weather is very unusual for us right now. Last week, Feb.19-23, we were registering above the 90's with one day reaching 100. The plants think it's spring. The redbud trees are beautiful. The other tree that's leafing is the Arizona Ash. The peach trees also are blooming. The end of this week will bring some cold weather. Hope not a freeze or frost. I will keep in touch." Sincerely, Carol Ann waltca@tenet.edu
From: TEXAS
February 26, 1996
"We are watching our trees for the leaf-out project and as yet only have seen the small buds. It has been so warm here lately (in the 80's every day), so they should really begin to open up soon.
We have spotted a few robins in our area. Maybe spring is finally here. Also, the geese are beginning to make their way north. Our resident bird watcher (the science teacher) wants to know if the geese have made it to Oklahoma yet." Twyla Reinecker, Orchard Elementary/Brazos Middle School Orchard, Texas reinecke@tenet.edu
From: TEXAS
February 27, 1996
"With the warm (actually HOT - upper 90s with lows in the 60s) weather here in College Station, the Arizona Ash trees have finally leafed out - and many leaves are full-size (longer than a quarter but narrow). The Elm trees are also beginning to leaf out. The redbuds are continuing to bloom, but haven't leafed yet. The Live Oaks are starting to drop their old leaves, and the Water Oaks (which dropped their leaves last fall) are budding. No sign of life on the Post Oaks yet.
Spring is slow this year. A new cold front is headed our way - and if the temps get as cold as predicted, it may freeze the new leaves. We're all hoping for some RAIN as we're still VERY dry with no rain for several months. The relative humidity has risen, and there are clouds in the sky again, so we're hopeful." K Kothmann kwk@tenet.edu
From: SOUTH CAROLINA
March 4, 1996
"Mrs. Alexander's third grade class are excited to report that their Bradford Pear tree has leafed out! There are still many white flowers on the tree, but several leaves have begun to appear. The temperatures were in the 80s two weeks ago and have remained in the 60s and 70s. It is certainly beginning to look like spring around our school." Teresa Alexander Oak Grove Elementary oge@scsn.net
From: FLORIDA
March 5, 1996
"Down south at latitude 28 degrees, 10 minutes 33 sec, and longitude is 80 degrees 35 minutes and 25 seconds most leaves on trees do not drop during the winter. Our oaks have remained the size of a quarter. While it did get close to freezing in our area we did not have a heavy freeze this year (meaning that on the beach we did not have frost damage)." Carol Robitschek ROBITSC@mail.firn.edu
From LOUISIANA
March 7, 1996
"Many of the leaves are starting to bud. On one of my walks I noticed that the sweetgums had leaves on them larger than a quarter. However, the tulip poplars, the pecans, and hackberries have not leafed out as yet. My husband's grandmother said you could be sure that spring was finally here when the pecan trees budded. We are having sandwich weather (cold and warm weather). Sometimes trees get frozen when they bud out too early . We had a Japanese plum that frequently froze its flowers. I'll keep you up to date." Janice Catledge MAWSE@jazz.ucc.uno.edu
How to Report Leaf-Out
When the leaves on trees in your area are the size of a quarter, please let us know! Simply fill out a Field Data Form by selecting the button below labeled, "Report Field Observations".
Remember, the leaves you report must be on trees not on bushes or other leafy plants. In the comments section of your Field Data Form, please tell us the kind of tree you are reporting. If you are unsure, please check in a Field Guide to Trees of North America or ask a local naturalist to help you.
How to Respond to Challenge Question #29:
1. Address an e-mail message to: jn-challenge@learner.org
2. In the Subject Line of the message write: Challenge Question #29.
3. In the body of the message, answer the question!
Please include your school name and the state/province in which you live.We'll share your ideas and those of other students in future reports. You can also see students' answers to Challenge Questions on Journey North's WWW site.
The Next Leaf-Out Update Will be Posted on March 22, 1996
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