Tolerance Flashcards
What is the main driving factor in tree tolerance?
Moisture
-Ex. Fd is tolerant in dry soil conditions and less tolerant in moist soil conditions.
What is meant by “Total Site”
Combination of root space and crown space
Define succession
The change in composition of plant communities over time as a result of competition.
What are some factors that slow down succession?
- Dry sites
- Wet sites
- Cold sites
What aspect of harvesting in the ESSF can really mess up succession? How do forresters manage for this issue?
Harvesting too aggressively causes the water table to rise, creating unfavourable conditions for the regeneration of the original community.
This can be managed for by trenching, to create drainage ditches.
On what sites is the speed of succession the fastest?
Mesic Sites
What is the importance of “expression of dominance”
- Responsible for developing stand structure in forests.
- Is reflected in crown classes (Dominant/Co-dominant/Intermediate/Suppressed)
What is tolerance?
A term used by foresters to indicate a trees capacity to develop and grow in competition for light, water and nutrients with other trees.
When does competition start with forest trees? where does tolerance fit in?
When there is full crown and or root closure. Tolerance concerns the trees ability to compete after crown or root closure.
How does succession relate to tolerance on a temporal scale?
Succession basically progresses from very intolerant to very tolerant species over time. Very intolerant species are usually first to colonize, followed by intolerant species, followed by intermediate species, tolerant species, and lastly very tolerant species.
What are some factors that cause variance in the tolerance of tree species?
give an ex. of how tolerance varies with age in specific species
Age, Region, Site richness.
- white pine more tolerant in seedling and sapling stages
- black spruce intolerant as a seedling but gains tolerance with age
What are some key features of tolerant species?
- Deeper crowns
- Tapered crowns
- higher stand densities
- slow to mature, long lived
What are some key features of intolerant species?
- shallow crowns
- cylindrical crowns
- low stand densities
- early to mature, generally shorter lived
List the very tolerant species in our region
- Western Hemlock
- Amabilis fir
- Sub alpine fir
- Red cedar
- Redwood
- Pacific Yew
- Vine maple
List the tolerant species in our region
- Engelmann spruce
- Sitka spruce
- Yellow cedar
- Mountain hemlock
- Grand fir
- Big leaf maple
