THE WILLOWS AND POPLARS 95 



the so-called Robenhausian culture of the Swiss lake dwellers 

 (7000-5000 B.C.), the remains of whose dwellings, built on piles 

 and found so abundantly throughout the region of the Alps and 

 the valley of the Danube, record the time when early man ceased 

 being merely a nomadic hunter and came to occupy fixed abodes 

 and garnered some crops. And when the race passed from lake 

 dwellings to fortified and moated habitations in the swamps and 

 along the rivers of southern Europe, the willows must have been 

 one of the familiar and useful plants in their immediate environ- 

 ment, during what is called the Terramara period, so that they should 

 have at least a sentimental interest for the modern race. Unlike 

 more useful trees to the lumber industry the willows and poplars, 

 because of their efficient seeding habits and rapid growth, do not 

 appear to be in danger of extermination, despite the enormous 

 toll that the pulp mills and forest fires take every year. 



