GERMAN FOREST MANAGEMENT REGULATING A FOREST. 



243 



nently based, is named first, and the average age of the growth with special reference to the 

 dominating timber is ascertained for the purpose of ranging the parcel into an "age class," which 

 comprises usually twenty years, so that the growth of ] to 20, 21 to 40, 41 to <0 years, etc., form 

 each an age class or period. The density of the growth and larger openings devoid of tree growth 

 are specially noted. The valuator at the same time is expected to form, from general appearances, 

 :ri opinion as to the best treatment of each parcel in the near future, and note it, and especially 

 whether the growth is to be cut during an earlier or later period than its age would warrant, 

 considering the likelihood of its thrifty or its unsatisfactory growth. He also estimates the amounts 

 to be taken out in thinnings for the next twenty years. 



With this information established a table maybe constructed, in which the area of each parcel 

 is entered, according to its average age or "age class," modified by considerations of productive 

 capacity, and from this a "timber map" is made, showing the present conditions of the forest, 

 the kind of dominating timber in each parcel being denoted by a color, intermixed timbers by 

 signs, and the age by the shade of the color in 4, 5, or (5 gradations, according to the number of age 

 classes, as shown in the accompanying ideal map. 



ARRANGEMENT OP AGE CLASSES. 



Now follows the determination of the future arrangement of age classes, the object of which 

 is to have, when the forest is regulated, in each period of the rotation an approximately equal or 

 equally producing area to be cut. It therefore becomes necessary to shift the distribution, of age 

 classes, in order to attain the equality of the sum of areas in each period. In addition to the mere 

 equalization of areas, there are several other considerations guiding the valuator in arranging the 

 age classes. The oldest timber, as well as that which for some reason has ceased to make 

 satisfactory growth, is of course to be cut first; hence the conditions of these areas are more 

 specially examined regarding health, density of cover, soil, vigor, etc. In coniferous growths, 

 especially in the plain, the danger from windfalls, if one parcel is cut and thereby the other 

 exposed to the prevailing storms, necessitates snch an arrangement in the location of the fellings 

 (or age classes) that the removal of an old growth will leave behind it a young growth which is 

 less liable to be thrown. This local distribution of the age classes by which, in the direction of 

 the prevailing winds, no two neighboring growths are assigned to the same period is also desirable 

 from other considerations. By avoiding a series of extensive fellings side by side the danger from 

 fires is lessened and liability to spread of diseases and insect attacks, danger from frost, and 

 drought to young growths is confined or reduced. Hence an arrangement of the age classes as 

 near as possible after the following scheme has been generally adopted, in which the Roman figures 

 denote the age classes, I standing for the oldest growth, containing, if the rotation -has been set 

 at 100 years, timber of 80 to 100 years, to be felled within the first twenty years; II for that to be 

 felled within twenty-one to forty years from the present, and so on; V to be felled in from eighty 

 to one hundred years. 



l'tr\ ailing \\intU- 



FIG. 23. Diagram showing arrangement of age classes. 



Ill mountainous districts, where the topography influences the expense of transportation, 

 fellings are often more concentrated and the higher parcels used and reproduced before the lower, 

 in order to avoid injury to the young growth by a reversed condition when the material from above 

 would have to pass through the young growth below. Various minor points may also dictate 

 exceptional arrangement. In coppice growth, needed protection of the stocks against cold north 



