^fruitful Grees. 137 



give temporary shelter to the incoming throngs with 

 frame houses first. The development of the great 

 West would never have been possible but for the 

 mighty forests of Maine, of Michigan, of Wisconsin, 

 of Minnesota, of the States on the Pacific Slope. 

 The waving branches of the trees of our woods have 

 beckoned a welcome to every immigrant upon our 

 shores. 



But there is a closer relation yet between our 

 prosperity and our trees. The forests as they stand, 

 the trees growing and working, the trees as they ex- 

 ercise their natural functions, are more valuable friends 

 than in their post-mortem estate. They have a most 

 vital relation to the fertility of our soil, to the state 

 of our climate, to the perpetuation of our streams. 

 For nature has made the tree one of the great con- 

 servators of the soil. Out of the deeper layers of 

 surface soil, out of the circulating air, the trees imbibe 

 rich chemic gases, which they build into solids and 

 deposit in leaf, twig, and trunk. So that when 

 these fall and moulder they lay upon the top of the 

 ground new harvests of nutrition which they have 

 reaped in the fields above and the fields below. So 

 that all the trees in the valleys are heaping up enrich- 

 ment of the soil where they stand ; and all the trees 

 on the hillsides are doing the same thing and more. 



For every rill which flows down a hillside bears 

 some of the earthy salts which feed the soil with 

 new life into the vales below. When our steep 

 mountainsides and hillsides are covered with forests 



