CHAPTER XXIII 



ELEMENTARY FORESTRY (Continued} 



INFLUENCES OF FORESTS ON SOIL FORMATION, SURFACE 

 WATERS, AND ON CLIMATE.; FOREST FIRES 



ASK the class to observe freshly cut banks, railroad 

 cuts, quarries, excavations, washouts, etc., in forest land 

 to learn two things, not sufficiently appreciated in this 

 country: (i) formation of humus or leaf mould; (2) dis- 

 tribution of roots below the surface. With a sharp tool, 

 when the ground is wet, cut out a square foot of the 

 "forest floor," leaves, dead sticks, leaf mould, down 

 to solid earth ; mount in a box with at least one side 

 glass for study and for experiments to be described below. 

 Beneath this covering the soil is black for some distance, 

 " surface soil " or " loam." Take a pound or so of this 

 also for study and experiment, and, to compare with it, 

 secure a similar specimen of loam from a field long under 

 cultivation. Compare the two as to color, appearance, 

 and consistency. Which seems to be "richest " ? Which 

 would be best to plant seeds in ? 



What makes the loam black and rich ? Suppose we 

 take an equal amount, say 100 grams (one of the chil- 

 dren can get it weighed at the nearest drug store, if there 

 are no scales in the school), of leaf mould, of loam from 

 the forest and of soil from the field. We know that 



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