Lesson CCII

The Pine

Leading thought—The pines are among our most ancient trees. Their foliage is evergreen but is shed gradually. The pollen-bearing and the seed-bearing flowers are separate on the tree. The seeds are winged and are developed in cones.

Method—At least one pine tree should be studied in the field. Any species will do but the white pine is the most interesting. The Austrian pine which is commonly planted in parks is a good subject. The leaves and cones may be studied in the schoolroom, each pupil having a specimen.

Observations—1. What is the general shape of the pine tree? Is there one central stem running straight up through the center of the tree to the top. Do you find any trees where this stem is divided into two or three near the top? Describe how the pine tree grows. What is the “leader?” What happens if the leader is injured? How do the topmost branches of the young pine look? Do they all come off from the same part of the stem? How many are there in a whorl?

2. What color is the bark? Is it ridged or in scales?

3. Do the branches come off the main stem at right angles or do they lift up or droop down? Where is the foliage borne on the branches? What is the color of the foliage? Is the pine foliage ever shed or does the pine leaf, when it comes, stay on as long as the tree lives?

4. Study the pine leaves. Why are they called needles? Note that they grow several together in what we call a bundle. How many in one bundle? Is the bundle enclosed in a little sheath at the base? Are the bundles grouped to make distinct tassels? Study one of the needles. How long is it? Is it straight or curved? Flexible or coarse and stiff? Cut it across and examine it with a lens. What is the outline in cross section? Why does the wind make a moaning sound in the pines?

5. Study a pine cone. Does it grow near the tip of the branch or along the sides? Does it hang down or stand out stiffly? What is its length? Sketch or describe its general shape. Note that it is made up of short, over-lapping scales. What pattern do the scales make as they are set together? Describe or sketch one scale; has it a thickened tip? Is there a spine at the tip of the scale?

6. Where in the cone are the seeds? Describe or sketch a pine seed. How long is its wing? How is it carried and planted? When the cone opens, how are the seeds scattered? What creatures feed upon the pine seed?

7. Study the pine when in blossom, which is likely to occur in June. This time is easily determined because the air around the tree is then filled with the yellow pollen dust. Study the pollen-bearing flower. Is it conelike in form? Does it produce a great deal of pollen? If you have a microscope, look at the pollen through a high objective and describe it. How many of the pollen catkins are clustered together? On what part of the twigs are they borne? Where are the pistillate flowers which are to form the young cones? How large are they and how do they look at the time the pollen is flying? Do they point upward or droop downward? Why? Look beneath the scales of a little cone with a lens and see if you can find the flowers. What carries the pine pollen to the flowers in the cone?

8. Name all the uses for pine lumber that you know. Write an English theme on how turpentine is produced from pines and the effect of this industry upon pine forests. Where does resin appear on the pine? Of what use is it to the tree? Do you think it is pine sap? What is the difference between resin and rosin?

9. How long do the pine trees live? Write a story of all that has happened to your neighborhood since the pine tree which you have been studying was planted.

10. Make the following drawings: A bundle of pine needles showing the sheath and its attachment to the twig; the cone; the cone scale; the seed. Sketch a pine tree.

Supplementary reading—Trees in Prose and Poetry, pp. 32, 151, 152; The Spirit of the Pine, Bayard Taylor; To a Pine Tree, Lowell; Nature in Verse, pp. 15, 288.