Forestry Literature. 17 
umes by Theophrastus (390-286 B. C.), a pupil of 
Aristotle and Plato. 
Among the Romans, besides a number of historians, 
at least three writers before Christ discussed in detail 
agriculture and, in connection with it, tree culture; 
namely, Cato (234-149 B. C.) who wrote an excellent 
work De re rustica, in 162 chapters; Varro (116-26 
B. C.), also De re rustica, in three books; and Vergilius 
Maro (70-19 B. C.), who in his Georgica records in six 
books the state of knowledge at that time. Of the 
many writers on these subjects after Christ there are 
also three to be mentioned, namely, Cajus Plinius Major 
(23-79 A. D.), who in his Historia naturalis, in 3% 
books, discusses also the technique of silviculture; 
Lucius Junius Moderatus Columella (about 50 A. D.), 
with 12 books, De re rustica, and one book De arboribus, 
the former being the best work of the ancients on the 
subject; and Palladius, writing about 350 A. D., 13 
books, De re rustica, which in the original and in trans- 
lations was read until past the middle ages. 
Only a few references which exhibit the state of 
knowledge on arboricultural subjects among the Romans 
may be cited, and some of this knowledge was also de- 
veloped in Greece and found application, more or less, 
through the Roman empire from India to Spain. 
Nursery practice was already well known to Cato, 
while Varro knew, besides sowing and planting, the art 
of grafting and layering, and Columella discusses in 
addition pruning and pollarding (which latter was prac- 
ticed for securing fuelwood), and the propriety of leav- 
