Lesson 3: Species in the environmental complex

Billings: Groups of factors in a terrestrial plant environment:
– Climate
– Edaphic
– Geographic
– Topographic
– Pyric
– Biotic
Groups were subdivided into: factors subfactors and aspects.
Examples:
Climate was divided into the factors Radiation, Temperature, Water, Atmospheric gases.
Edaphic was divided into Parent material, Soil;
Geographic was divided into Gravity, Rotational Effects, Geographic Position,
Vulcanism, Ditrophism (folding, faulting), Erosion and Deposition, Topography, etc.
The factor Radiation was divided into the subfactors: Solar radiation, cosmic radiation, and
terrestrial radiation.
The subfactor Solar radiation was subdivided in the aspects, wavelenths, intensity,
photoperiod and other cycles.
Billings identified a total of 64 environmental aspects, but this was by no means a
comprehensive list. It only served to illustrate how complex the plant environment is and
how the aspects interact among themselves and the plant.