FOREST EXPLOITATION. 183 



' Natural reproduction is effeoted by a gradual removal 

 of the existing older stock. If a forest track be suddenly 

 cleared, there will ordinarily spring up a mass of coarse 

 herbage and undergrowth, through which seedlings of the 

 forest growth will rarely be able to struggle. In the case 

 of mountain forests being suddenly laid low, we have also 

 to fear not only the sudden appearance of an undergrowth 

 prejudicial to tree reproduction, but the total loss of the 

 soil from exposure to the full violence of the rain when it 

 is no longer bound together by the tree roots. This soil 

 is then washed away into the valleys below, leaving a 

 bare or rocky hillside bearing nothing but the scantiest 

 herbage. We must therefore note how Nature acts in the 

 reproduction of forest trees, and follow in her footsteps. 

 As Pope writes — 



First follow Nature, and your judgment frame 

 By her just standard, which remains the same, 

 Unerring. .... 



Acting on this principle, foresters have arrived at a system- 

 atic method of treatment, under which large tracts of 

 forest in Germany and France are now managed. The 

 forests of a division, working circle, or district, are divided 

 according to the description of the timber and the prevail- 

 ing age of the trees, and it is the aim of the forester 

 gradually to equalise the annual yield, and ensure its per- 

 manency. With this object, he divides the total number 

 of years which are found necessary to enable a tree to 

 reach maturity into a certain number of periods, and 

 divides his forest into blocks corresponding with each 

 period or state of growth. Thus, the beech having a 

 rotation of 120 years, beech forests would be divided into 

 six periods of 20 years each — that is to say, when the 

 forest has been brought into proper order, there should be 

 as nearly as possible equal areas under crop in each of the 

 six periods, viz., from 1 year to 20, from 20 to 40, and 

 so on. It is not necessary that the total extent in each 

 period should be together, but it is advisable to group 

 them as much as possible, and work each tract regularly 



