170 FARM AND SCHOOL PROBLEMS. 



Decay of wood is caused by low forms of plant life, known 

 as fungus organisms. Various experiments have been made to 

 determine whether these fungi can be prevented from develop- 

 ing by use of some preservative treatment. 



The methods of prolonging the life of posts are given in the 

 order of their efficiency, and cost as follows: 



1. Peeling and seasoning. 



2. Charring. 



3. Painting. 



4. Dipping. 



Creosoting. 



Creosote is a derivative of coal tar and has come into ex- 

 tensive use for treating ties, posts and other timbers which on 

 account of quality and exposure are subject to rapid decay. 



Send for Farmers' Bulletin No. 377, The Preservative Treat- 

 ment of Farm Timbers. U. S. Dept. of Agriculture. 



Purposes of Forestry. 



The principles of forestry are founded upon some of the 

 important truths stated in the following paragraphs : 



1. Tree planting should come under either one of two heads: 



(a) Planting for ornaments, windbreaks, shade, parks, groves, 

 and wood-lots. 



(b) Planting trees for forests to produce wood, posts, lumber 

 and other commercial products. 



Forest Uses. 



1. Trees conserve moisture, modify climate and purify the air. 



2. Forests serve often as a protection against floods and tornadoes. 



3. Forests render a service in the protection of streams, for 

 fishing, birds, and game preserves. 



Propagation. 



In the propagation of trees it will be of importance to ob- 

 serve some of the following facts: 



1. To get a model for forest planting, visit an ideal forest noted 

 for its commercial value and note the varieties that grow suc- 

 cessfully, and observe the distances between trees, the height 

 of trees, the arrangement of limbs. Compare trees growing to 

 a great height in the forest with a tree or trees of the same 

 variety growing in fields or open places. 



