Plate 52. A (Upper left). The trees gradually prune themselves and the tightly 

 closed canopy prevents any germination of ground cover. It is this stage, lasting 

 from twenty to thirty years, that is sometimes referred to as a "biological desert." 

 B (Upper right). At around the forty-to-fifty-year age period, the crown begins to 

 open and the return of herbs and hardwoods begins on the woodland floor. 

 C (Lower). At maturity we find a top crown of pine, partially broken, with a com- 

 plete hardwood-shrub-herb stand underneath. The shelter is out of reach, but 

 iood has now returned. 



