RELATIONS OF TREES TO TEMPERATURE 207 



years ago, was a well- wooded country, and all the fruits 

 of the sub-tropical climates were raised there to perfec- 

 tion by its ancient inhabitants. The date-palm, the fig- 

 tree, and the olive grew there and bore fruit abundantly. 

 Palestine is now a treeless country, and the same fruits 

 are incapable of enduring its climate ; yet recent obser- 

 vations have demonstrated that its climate is not colder 

 than it was in the days of the kings of Israel. But as 

 the country has been despoiled of its forests, these sub- 

 tropical fruits are deprived of their natural conservatories, 

 and cannot be raised without great labor and expense in 

 preparing artificial protection for them. Let the forests 

 be restored to the hills and mountains of Palestine, and, 

 though the temperature of its summers were not increased, 

 the fields would be protected by these forests from the 

 winds, and the tender -fruits, thriving under their protec- 

 tion, would again become abundant. 



The principles involved in these and similar facts form 

 a distinct branch of meteorological science, and would re- 

 quire a volume for their illustration. I have only hinted 

 at some of the general conclusions. It is evident, in- 

 deed, that the same objects that serve to protect us from 

 cold may in an equal degree protect us from heat. The 

 woodcutters will continue their labor in a deep forest 

 without discomfort on a winter's day, when they could not 

 endure the intense cold of the open country. The earliest 

 flowers of spring, however, are found neither in a wood nor 

 in an open meadow, but under the protection of a wood 

 on its southern border, in little openings that are exposed 

 to the beams of the sun. 



