NORMAL GROWING STOCK. 187 



Normal Growing Stock. Since the annual valuable 

 increase of wood is in proportion to the amount of leaf surface 

 on trees of the right kind, size and form, it follows that there 

 must always be a certain number of trees of a certain size in 

 order to obtain normal annual growth. This material represents 

 invested capital, and the highest annual income is dependent 

 upon having a normal growing stock upon the land. As a mat- 

 ter of fact, this is an ideal thing, and is seldom, if ever, exactly 

 attained. The amount of normal growing stock which there will 

 be upon one acre will depend upon the species, its age and con- 

 ditions, and must be determined in the working plan of the 

 forest tract after a careful study of its conditions. 



The Normal Income is the crop of wood that a given tract 

 of forest will produce per year under normal conditions. This 

 will, of course, vary with the species and conditions. It may be 

 harvested by selecting only the large trees from all over the area, 

 or by cutting clean over a certain portion of it, as shown in 

 chapter X. It is very plain that, if the increase per year is a 

 given amount, it may be harvested by either method without 

 infringing on the normal growing stock of the whole area. For 

 some conditions the selection method is preferred, while for oth- 

 ers, such as for even stands of Spruce, which are liable to blow 

 down when thinned, it might be better to cut clean, and keep the 

 trees in even age groups. In this latter case the tract should be 

 divided into as many parts as there are years in the rotation, 

 and the timber from one part cut each year. This would mean 

 the planting or seeding of a like amount each year. 



Capital Growing Stock. This represents the actual amount 

 of trees on the land which is producing wood growth of value. 

 The nearer this approaches to the normal growing stock the bet- 

 ter the condition of the forest and the larger its returns. 



Actual Income represents the annual return which a given 

 forest tract is producing. 



Increasing Value of Forests. In countries where forestry 

 has reached a high degree of development a piece of land is 

 regarded as being in forest as soon as it is stocked with trees, 

 even if the seedlings are not yet over two inches high and are 

 hardly to be seen at a short distance. Such a piece of land 

 should have increased value and should be regarded as earning 

 a rate of interest. It is so regarded in many of the European 



