Suggestions for Field Work to Precede Chapter Twelve 



1. A field trip to a greenhouse will help to make clear the im- 

 portant factors of the environment. Observe how the water, 

 light, temperature, soil, animal, and plant factors are taken care 

 of. (Animal factors: scale, aphids, mealy bugs, and white flies. 

 Plant factors: overcrowding, bacterial and fungous diseases.) 



2. In the field, compare the environmental factors in a lake or 

 swamp with those on a hilltop or slope. What are the notable 

 effects of these factors on leaves, stems, and roots? Write the 

 results of your observations in the form of a table. 



3. Examine trees growing in the open to see how the wind 

 affects the shape of the crown. Is the trunk in the center of the 

 crown? What is the direction of the prevailing wind in your 

 locality? In what direction are the branches of trees generally 

 longest in your locality ? Shortest ? What is the relation of this 

 branch development to the direction of the prevailing wind ? 



4. Field trip to a dense wood. Study (i) the environmental 

 conditions of the large trees; (2) of the young trees; (3) of the 

 climbing plants ; (4) of the low herbs ; (5) of the mosses, lichens, 

 or ferns on the tree trunks ; and (6) of the mosses, lichens, or ferns 

 growing on the soil. Write your notes in the form of a table show- 

 ing relative amounts of light, water, and mineral salts available 

 to plants belonging to each of the above groups, and relative dry- 

 ness of air to which they are exposed. 



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