Ald4o Leopold 
nemt is                           partiular plants or animals by keeing the

Biotic landuse is t       &s~4land by keeping the plants and animals

favorable. 
The biotic iea is thu s an extension of theiAea  f m    emt, and it   sserts

the cnr      of the management theorem. 
Both stem from ecolog. The biotic idea merely translates ecolog     for puroses

of guiding lanuse. 
The term land includes soils, wter systnem, Mnd wild and tame plants and

animals. 
Ction is the attempt to understand4.d..              the interactions of
these 
components of land, and 1&ir collective behavior                    human.

LaM-yue problems are of two orders. 
We hear most about those problems which hinge on questions of empp1y    a
demand 
Timber famine, agricultural adjustment, and attempts to husband the supply
of wte 
and game are fui ar examples. This order is, for present p             not
very im- 
portant, becse it deals with visible forces which are amenable to social
controls. 
Sol~tions are possible and ways and means are kown. 
Te hear least about another order which is very important because ws and
men 
are not kwn,    *t              a e -a' rs.  Th.4it consists of dislocations
of land 
which present no visible cse. Thus some species irrupt as weeds or pests,
while 
others disappear, both without visible reason.