METHODS OF TREATMENT 95 



In British woods, where weeds usually abound, it is seldom 

 desirable to await a second seed year if the regeneration fails 

 at the first. It is usually better to plant up the area as soon 

 as it is certain that the regeneration has failed. When there 

 is a very good mast of oak or other light-demanders, it is 

 often possible to cut all the trees at the seeding cut, leaving 

 no shelter. 



When considering the desirability of naturally regenerating 

 woods it is important to take into consideration the age of 

 the existing trees. 



The different species begin to produce good seed at the 

 following ages : 



Birch, white alder, acacia, aspen at 25 to 30 years. 



Pines, larch, Douglas fir, alder at 30 to 40 years. 



Hornbeam, wych-elm, ash, sycamore at 40 to 50 years. 



Spruce at 50 to 60 years. 



Beech at 60 to 70 years. 



Oak, silver fir at 70 to 80 years. 



Gronp method. 



Wherever it is not desirable to have large clearings this 

 method is a good one. Throughout the forest, groups of 

 moderate size and of any shape are cut and are regenerated. 

 In succeeding years other groups are taken in hand, and those 

 first formed are enlarged periodically till in the course of time 

 all merge into one another. The forest is thus continually 

 changing in character, and is uneven aged, patches of all ages 

 and sizes being found. The groups first attacked should be 

 those where the trees are mature or are growing badly ; and 

 wherever patches of natural regeneration are found on the 

 ground the old trees are removed from over them. The new 

 crop can often be obtained by natural regeneration, more 

 especially with shade-bearing species like beech, silver fir, and 

 spruce, but regeneration of oak, ash, and other light-demanders 

 can also be got by making the groups fairly large, so that 



