Competition and silvics
Stronger competition causes lower crown rations
- crown recession and branch mortality
- Reduced crown width, less crown volume
Differentiation
The process of the seperation by vigor in each stratum
- Vigor can be described with crown classes
Occurs seperated in each stratum
Why does it happen?
- Small age differences
- Microsite
- Distance to neighbors
- Competition by other vegetation
- Herbivory/browsing
- Pathogens
- Difference in genetics
- Weather events
Self-thinning
Definition: Natural mortality through competition
- Growing space is limited
- Growing space is repartitioned
- Trees must grow larger to survive
Either of these scenarios is possible:
- large number of small trees
- small number of large trees
- Small number of small trees - space left over, but only temporarily
- (MISSING OPTIONS)
Characteristics of tree species contributing to competitive profile
- branch and limb stiffness
- Initial growth rate
- Repro capacity
- Crown spatial requirements
- Rooting depth
- shade tolerance
- Drough or waterloggin endurance
- nutrient requirements
- Phenological differences
Generalists
- Wide Ecological amplitude
- Climatic amplitude
- Edaphic amplitude
- Within-species variation
Key takeaways
- Crown recession sets in with crown closure
- Growing space is repartitioned through competition
- Self-thinning occurs through differentiation after crown closure
- Ecological and silvical characteristics determine stand development