Terms and definitions:

• Growing space

  • The space which each plant has available to develop to grow
  • Not only resources (light, water, nutrients), but also physical space
  • Sum of all resources available to an individual tree (the local environment)

• Age class

  • A distinct group of trees or portion of the stand categorized on the basis of chronological age
    • Important stand types defined based on age class:
      • Even-aged: One age class
      • Two-aged: Two age classes
      • Uneven-aged: Three or more age classes
  • Fieldwork typically uses codes

• Cohort

  • An aggregation of trees that have established due to the same disturbance
  • Distinction between age class and cohortL
    • Cohort can include advance regeneration that was present in the understory before the disturbance, so the chronological age of cohorts can vary widely

• Crown class:

  • Describes the relative size and position of a tree's crown within the canopy of a stand
    1. Dominant (D): Large crowns above the rest
    2. Co-Dominant (C): Large crowns but not the tallet; Have a steeper angle getting light
    3. Intermediate (I): Still get direct light from above, very narrow crowns; very squished between Dominant and Co-Dominant
    4. Opressed (O) (Suppressed): Very little light; on their way out

• Stratification:

  • Different species develop complex multi-species and uneven-aged stands seperated into different strata.

Disturbances are the driver of natural stand dynamics:

• Both the end and the beginning
• Drivers of natural stand dynamics