478 TIMBER BONDS 



money returns from forestry. Three great systems of 

 forest management are distinguished: The seed sys- 

 tem, the sprout system and the composite system. The 

 seed system includes the stand method, group method, 

 strip method, patch method, strip stand method, group 

 seed method, scattered seed method, single tree meth- 

 od, reserve seed method, clean cutting method. The 

 sprout system includes the sprout method. The com- 

 posite system includes the reserve sprout method. 



Forest Policy. The principles which govern the ad- 

 ministration of a forest for its best permanent use. 



Forest Products. All usable material yielded by the 

 forest. Major products include all wood harvested 

 for any purpose. Minor products include all forest 

 products except wood. 



Forest Protection. The safeguarding of the forest 

 against any damage not caused by its own growth. 



Forestry. The science and art of making the best per- 

 manent use of the forest. The main branches of 

 forestry are forest policy, silviculture, forest manage- 

 ment, forest protection and forest utilization. 



Forest Type. A forest or a part of a forest possessing 

 distinctive characteristics of composition or habits of 

 growth. 



Form Class. All trees in a stand so similar in form 

 that the same form factor is applicable in determin- 

 ing their actual volume. 



Form Factor. The ratio expressed decimally between 

 the volume of a tree, or portion of a tree, and of a 

 cylinder of the same height and diameter. The vol- 

 ume of this cylinder multiplied by the form factor 

 gives the actual volume of the tree or portion of the 

 tree. Three kinds of form factors are distinguished, 

 according to the portion of the tree to which they 

 refer: A tree form factor is used for determining the 

 actual volume of the whole tree; a stem form factor 

 for determining the volume of the stem, and a timber 

 form factor for determining the merchantable contents 

 of stem, crown or both. A form factor is called ab- 

 solute, when the diameter of the tree is measured at 

 any convenient height, the form factor referring only 

 to that portion of the tree above the point at which 

 the diameter is measured; normal, when the diameter 

 is measured at a height in constant ratio to the total 

 height of the tree; and artificial, when the breasthigh 

 diameter is measured. 



Four Paws. See double couplers. 



Frog. 1. The junction of two branches of a flume. 



