28 College of Forestry 
rain entirely destitute of organic food supply and there ‘‘set 
up its machinery ” and start a process of food making, which 
food being first built up into living plant protoplasm becomes 
ultimately the source of food for the animal kingdom. Thus 
not only is the ground gaining capacity of vegetation linked 
up with the static character and nutrition habits of the green 
plant, but its invasion of the land makes possible also a cor- 
responding development of the animal kingdom. 
Now, in the case of forest trees, the plant may go on de- 
veloping on the one spot for perhaps hundreds (in maximum 
cases thousands) of years. Not only is the soil pierced by its 
roots and built up about it, the ground is shaded by the 
crown, the movement of air is impeded, its drying out power 
checked and, if we have many such trees growing close 
together, an all-round transformation of the environment 
oceurs. 
Menacing the future welfare of this static community is 
the fact that all the accumulation of poisonous and waste 
products, all the sloughed off dead material of bark, branch, 
leaves, flower parts and fruits, ultimately even each whole 
organism, dead from disease or accident or old age, falls 
among the living and, by the mere volume of debris as well as 
by the menace of an unsanitary soil, threaten the existence 
of the remaining living members. More than this, and in the 
long run of more fundamental consequence, the renewal of 
the community by the development of young from the em- 
bryo of the seed (another important item in the economy of 
these static organisms) would be prevented if this menace of 
accumulating dead were continuous. As a matter of fact, in 
a normal, healthy climax forest 1t does not exist. On the con- 
trary, the dead members are stored up energy * which being 
1 Wood and coal are commonly spoken of as stored up or potential 
energy which becomes by burning available, working energy in the form 
of heat which may be transformed into steam energy, electric energy, 
etc. In the case of soils, as pointed out by Russell, ‘‘ Soil Conditions 
and Plant Growth,” pages 53 and 66, the potential energy of dead or- 
ganic stuff is liberated by bacterial activity and becomes available, 
productive energy in the form of nitrates, etc., which goes into the 
building up of new generations of living organisms. 
