physiographic - terraces - hollows exposed areas perennials - quick growing (short growing annuals - grow on at least most season) successful on bare ground. secondary succession pioneer community - lichens lichens. 1. organic acids 2. physiological or mechanical bug contraction. community = any society of plants - nothing specific. waspale - windup or bleaks south west exposure. gumperies communis form bed for spuce in certain areas - answer? to the ? why do spunces invade open areas? south west slope populus erigeron Rites cereum succession in red flow along starts with bare rock - lichens mosses - grener & herbs populus pine pined - abies.