Practical Sylviculture. 599 



by tlie removal of the old trees as they become fit for economic pur- 

 poses. As different forests and species growing therein required 

 different treatment, so the management has had to be altered and the 

 following systems introduced. But then again, these chiefly allude 

 to mixed and not pure forests, though their adaptability to eucalyptus 

 forests is permissible, and may in some cases be found advan- 

 tageous. 



The Selection System. — Under this method of treatment the regene- 

 ration goes on by the removal of old, diseased, or defective and 

 large trees. The operation is not necessarily restricted to certain 

 areas, but can go on all over the forest, advantage being taken of 

 good seed years to remove the greatest number of these trees. Even 

 where gaps have been caused, it is often found expedient in a few years 

 to cut away some of the adjoining trees to enable the seedlings to obtain 

 more light, but other than this no assistance is deemed necessary 

 under this system. Where, however, a large area of forest is worked 

 under this method, it is found best to divide it into blocks, one being cut 

 over each year. This makes the cuttings take place at regular intervals 

 in each block. In the Burmese teak forests the cuttings take place 

 at intervals from 10 to 20 years. In Bengal the sal {Shorea rohusta) 

 forests are cut over every 30 or 40 years. The cuttings under this 

 divisional system are naturally heavier than if a yearly catting were 

 undertaken. 



This system is useful in protecting th ■ soil, as the leaf canopy is 

 only interrupted in small patches, hence rain cannot disturb the 

 surface soil and humus is encouraged. It is the best system to 

 adopt in a forest that has not been systematically managed or has 

 been severely over felled. It is also good for small forests. But it is 

 a bad system where the demand for produce is greater than the 

 supply ; and it has a tendency to withhold light from the young 

 growing stock and draw them up somewhat sickly, where the species 

 is light demanding 



The Group System. — This, as its name indicates, is the cutting of 

 the forest in patches, the resulting growth of seedlings comes up in 

 these and forms groups. These patches, each succeeding year, are 

 made wider, till the whole forest is gone over. The result is an 

 uneven growth. This system is best adapted to mixed forests such 

 as are found in Europe, but is least suitable to Australia as it is most 

 expensive owing to its operations being scattered over a large area 

 rendering supervision and transport of material difficult and costly. 



The Compartment System. — The forest in this case is divided into 

 compartments, each of which is cut over in turn, i.e., all the trees on 

 that area are felled ; the seedlings which will then spring up to 

 take the place of the felled trees will all be of one age, or what 

 is known as of even growth or even aged. This, it is hardly neces- 

 sary to point out, greatly facilitates future working, more especially 

 when the trees having arrived at maturity, the fellings can be on a 

 wholesale scale if a demand exists for the produce, instead of picking 

 a tree here and there as would be the case in an uneven agfed forest. 



