Even vs Uneven aged stands Flashcards
When managing uneven aged stands, how would you harvest them?
Not by clearcut, but by other methods suck as shelterwood, single stem selection etc.
Where would you expect to find large diameter Fd? Why?
In old growth forests on good sites.
In normal forest conditions Fd typically do not grow as big due to short rotations for maximum yield.
What are are some pros and cons to normal forests.
Pros -increased timber production -lower harvest cost Cons -Decreased resilience -Decreased biodiversity -Decreased resistance to timber destroying events
When managing even aged stands, what seral stages are you targeting?
- Stand initiation and
- Stem exclusion
What tree species has the shortest stand initiation phase
Pl, due to high seed periodicity (normalized seed production)
What kind of soil do early serial species prefer?
What about late?
Early: Mineral soil
Late: organic soil (duff)
Differentiate between stocking and density.
Density: SPH
Stocking: Relative # of SPH compared to density requirements.
ex. If density requirement for site is 1000 sph and you have 800, then you have 80% stocking.
Why do we do stocking surveys in BC?
To relieve us of the liability of not meeting legal stocking standards defined in the forest stewardship plans.
What is a factor that could reduce stocking on a site?
Intraspecific competition (smaller trees get left behind in the understory where they lose the ability to compete.)
What determines seed germination?
Genetics and site conditions
What causes stand differentiation ?
Expression of dominance
What is an important thing to remember regarding competition and tree size?
Trees typically only compete with trees that are relatively similar in size.
State the temporal relationship between serial stage and diameter spread.
At stand initiation diameter spread starts small, as stand advances through the sere, diameter spread increases.
What would cause a decline in SPH in a normal stand?
Thinning
What is complete site occupancy
when you have as many stems per hectare as required at a given time to maximize yield.
What is pre commercial thinning
a.k.a thinning to waste ( thinning before timber meets TMS )
Do you pay stumpage for commercial thinning?
yes
What shape is the DBH vs SPH distribution curve for a natural even age stand? Why?
bell shaped due to infraspecific competition resulting in a wider range of DBH classes
What is the optimum crown to generate the highest yield?
1/3 - 1/2 of tree height is crown
What is the period of greatest growth referred to? What is it called when that period is finished? What happens to volume after.
Grand period of growth
- referred to as culmination when it stops putting on fast growth.
- After culmination, volume still increases at a decreasing rate.
What 2 factors regulate culmination?
Species and site
Why do uneven aged systems generate more fiber supply flexibility?
Because you have to option to make multiple entries and if the block is small you won’t have to spend big money on roads.
What kind of stand would you want on sensitive, dry or wet sites?
Uneven aged because it offers more site protection.
How would you know what the required stocking is for a site?
Reinekes stand density index. SPH x (Dq/25)^1.605
