26 The Natural Regeneration of Forests. 



one. Squirrels and mice consume large quantities of tree seeds. 

 Rooks and wood pigeons account for large quantities of acorns 

 and beech mast, while smaller birds eat the seeds of conifers. Of 

 insect enemies, Megastigmus spermotrophus, which lays its eggs 

 and passes the larval stage in the seeds of Douglas and silver fir, 

 may be given as an example. 



Of the many systems of natural regeneration, I mean to 

 speak only of four. 



I. — The nearest approach to the before-mentioned process 

 which goes on in natural forests is the Selection system. 

 A wood managed under this system would contain trees 

 of all ages from 1 year up to 80 or more years, 

 according to the length of rotation. Selection fellings 

 are made every ten years or so, and the oldest, largest, mis- 

 shapen, and diseased stems removed. The effect of this opening 

 up of the canopy is to reduce the leaf mould on the surface of the 

 soil, and to make it suitable for the reception of the seed. The 

 canopy, too, is stimulated to more prolific seed production. Later, 

 seed falls on the spaces cleared, and these soon become stocked 

 with a crop of young seedlings. When the area under regenera- 

 tion is a large one, it may be divided into, say, 10 compartments, 

 and a compartment dealt with annually. Thus, selection fellings 

 will be carried out in each compartment every tenth year. If 

 the rotation were a 100 years, 1-1 0th of the increment on each 

 compartment would be removed at each selection felling. This 

 would give a regular annual yield. This system is employed in 

 the beech woods of Buckinghamshire, and in the mixed oak and 

 beech forests of the Spessart in Bavaria. Its chief advantage lies 

 in the protection it affords to the soil against the deteriorating 

 influences of sun and wind. Its great drawback, however, is the 

 with-holding of light from the young crops. The system may be 

 used to advantage on steep, rocky mountain slopes, where the 

 soil is liable to be washed away by rain. It is better suited for 

 shade-bearing species. Where the light demanding oak is grown 

 with beech as a soil improver, as in the Spessart, the oak, when 

 young, requires protection against the beech, which springs up 

 much more readily. 



II. — The second .system to be considered is the Group 

 system, which somewhat closely resembles the first. There 

 are many modifications of this system, one of which, known as 



