11.  LAW OF SUCCESSION

The same site will not be indefinitely held by the same plant community, because the physiographic agents and the plants themselves induce changes in the whole environment, and these allow other plants heretofore unable to invade, but now more efficient, to displace the present occupants.

12.  LAW OF REGIONAL CLIMAX

The processes of succession go through a shift of controls but are not indefinite, for they tend to an equilibrium that allows no further relay; the climatic-topographic-edaphic-biological balance of forces results in an ultimate pattern which shifts from region to region.

Tenants of any locality
Just by holding their own,
Even without intending to
May greatly transform their zone.
They may foster its betterment
Or make it deteriorate.
By making it suited to newcomers
They may be sealing their fate.
A string of successions proceeds over time,
Ends up reaching a peak,
Or a balance point it will seek.