172 FARM AND SCHOOL PROBLEMS. 



2. Low-growing trees may be planted among high-growing trees. 

 This will afford shade, help to conserve moisture and hasten 

 the growth of all the trees. Trees that grow rapidly are usually 

 short-lived and may temporarily fill areas while trees of slower 

 and more permanent growth are coming to the proper size. 

 There should be a sufficient number of trees and denseness of 

 foliage to furnish annually a leaf mulch for helping to retain 

 moisture in the soil. 



3. Variety will also check -drouth, disease and insect ravages; 

 gives beauty and increases interest; insures marketable products; 

 produces greater variety of food and shelter for birds and other 

 animals. 



PROBLEMS. 



How TO MEASURE A TREE. 



1. To guess at the height of a tree, take a stick five or ten feet 

 long; set it up at the side of the trunk; then at some distance from the 

 tree estimate how many times the length of this stick would be required 

 to reach to the top of the tree. 



2. On a bright sunny day either before noon or afternoon place 

 a stick by the side of the tree. Measure the length of the shadow 

 of the stick and the length of the shadow of the tree. If the stick is 

 6 feet long and its shadow is 8 feet and the shadow of the tree is 80 

 feet then the solution is: 8 : 6 : : 80 : (?) 



3. Measure with a tapeline, from the foot of the tree to a point 

 from which a line can be drawn to the top of the tree at an angle of 

 45. The distance from the foot of the tree to this point will be the 

 height of the tree. 



4. Let the horizontal distance between two perpendicular sticks 

 be 6 feet. Let the outside stick be 6 feet high, and the inside stick of 

 sufficient height, that the tops of the two sticks shall be in line with the 

 top of the tree. 



Draw a horizontal line from the top of the outside stick to the 

 trunk of the tree. From these measurements, drawings may be made 

 showing that we have two similar right angled triangles from which we 

 can easily compute the height of the tree. 



5. To find the diameter of the trunk divide the circumference 

 by 3.1416. 



6. To find the number of feet of lumber in a log or tree, see 

 "Board Measure and Lumber Problems" in Chapter 28. 



Questions. 



1. Should a wood-lot be used as a pasture? 



2. How does a forest effect soil moisture and soil temperature?' 



