TREE SURGERY 



587 



antiseptic and coated with a waterproof covering. Not infre- 

 quently large limbs are wired or in other ways supported so as 

 to relieve stress during storms. Such care often lengthens the life 

 of a tree many years. 



Practical Exercise 6. In what southern states are there coniferous forests ? 

 In what northern states are such forests found? The supply of hardwoods 

 comes from the deciduous and mixed forests. Where are most of our decid- 

 uous forests ? 



In repairing a tree which is decayed, the affected portions are first cut out. Then the cavity 

 is treated with an antiseptic to prevent any further decay, and is filled with cement. 



Self-Testing Exercise 



Man is responsible for a (1) per cent of the forest fires 



each year. The chestnut (2) has killed most of the chestnut 



trees in the (3). We (4) trees four times as fast 



as we (5) them. Trees in a city have an (6) value. 



(7) (8) is used to protect trees. Our forests are 



conserved by (9) old areas, (10) new areas, 



(11) unnecessary wastes (12) of cut areas is under the super- 

 vision of (13) and (14) forestry stations. 



PROBLEM III. WHAT IS BEING DONE FOR THE CONSERVA- 

 TION OF FISH AND OTHER AQUATIC ANIMALS? 

 The conservation of fresh-water fishes. We have learned that 

 the food supply of many of our fishes depends upon plankton, 

 tiny plants and animals living in the water. In many parts of the 

 United States these little organisms have been exterminated, and 

 theiood fish with them, by the pollution of our streams and lakes. 



