Forest Preserve District of Cook County, Illinois
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Tree Diaries
Nature Bulletin No. 406-A   February 13, 1971
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

We know a man whose life, as a civil engineer on construction projects, had been spent mostly out-of-doors but he knew very little about the plants and animals he saw. In 1945, after a long severe winter, March was usually warm and sunny. The birds came back north, the wildflowers bloomed, and the trees leafed out much earlier than in any year he could remember. So he spent every morning, from daybreak until time to go to work, walking through a forest preserve near his home, and he kept a diary of everything he saw.

He had been doing that every year since 1945. He not only has some very valuable records but, in the meantime, by observing them carefully and studying about them in books, he has come to know more than most people about wildflowers, weeds, trees, birds, insects and other animals, and has had a lot of fun. Phenology, as it is called, can be an absorbing hobby and one of the best teachers. You also learn what an important factor weather is. For instance, there may be a difference of as much as a month in the earliest date of blooming of the skunk cabbage.

Recently, we heard of two boys, next-door neighbors, who are doing the same thing in a different way. A year ago, in winter, each "adopted" a tree on-the route they travel to and from school. Pete chose a silver maple (he calls it a "soft" maple) and "Butch" picked a big elm. Each keeps a diary of what happens to his tree what birds visit it: what insects; when the buds swell in spring; when it blooms and puts on leaves; when it bears seeds and when they drop to the ground. A robin built a nest in the maple and a Baltimore oriole built its hanging nest far up in the elm. In late summer and autumn they watched when the leaves began to change color, drop off, and the trees became entirely bare. The maple still had some yellowish-green leaves in late October. One of its big branches was broken off during a bad storm in September.

Now Pete and Butch want to see what happens to their trees this year and how events compare with those of last year. Each has quite a collection of insects, pressed leaves, seeds, twigs with buds on them, drawings and photographs.

The same thing can be done as a school project, with half the class adopting one tree in or near the school yard, and the other half adopting a tree of a different kind. It can develop into a friendly competition to see which tree has more insects and bird visitors upon it, which pupil sees something before the others do, who sees the most, and who can draw the best colored pictures.

A Boy Scout Troop in one of the suburbs has a similar contest. In the troop headquarters they have tacked two big sheets of paper on the wall. On each sheet is drawn a circle about 3 feet in diameter, divided into twelve pie-shaped segments by radial lines -- one for each month in the year. As each scout discovers something on or about his group's tree, the Scoutmaster records it in the space for that month, with the date and the boy's name. If something new and strange is seen, they look it up and study about it in a book. That has helped those Scouts earn an unusual number of merit badges.

Tree diaries interest children in learning about nature. They find that trees bloom, just like wildflowers, and each kind of tree has its own kind of flowers -- some very early in spring: some in June. Each has its own kinds of bark on the trunk and on the branches, its own kind and arrangement of twigs and of winter buds on those twigs. They learn what kinds of insects damage a tree, and why. They learn how a tree grows, and how much each year.

When is the best time to start a tree diary? Any time.

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