Even vs Uneven aged stands

Question 1

When managing uneven aged stands, how would you harvest them?

Answer 1

Not by clearcut, but by other methods suck as shelterwood, single stem selection etc.

Question 2

Where would you expect to find large diameter Fd? Why?

Answer 2

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.

Question 3

What are are some pros and cons to normal forests.

Answer 3

Pros
-increased timber production 
-lower harvest cost
Cons
-Decreased resilience
-Decreased biodiversity
-Decreased resistance to timber destroying events

Question 4

When managing even aged stands, what seral stages are you targeting?

Answer 4

• Stand initiation and

- Stem exclusion

Question 5

What tree species has the shortest stand initiation phase

Answer 5

Pl, due to high seed periodicity (normalized seed production)

Question 6

What kind of soil do early serial species prefer?

What about late?

Answer 6

Early: Mineral soil
Late: organic soil (duff)

Question 7

Differentiate between stocking and density.

Answer 7

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.

Question 8

Why do we do stocking surveys in BC?

Answer 8

To relieve us of the liability of not meeting legal stocking standards defined in the forest stewardship plans.

Question 9

What is a factor that could reduce stocking on a site?

Answer 9

Intraspecific competition (smaller trees get left behind in the understory where they lose the ability to compete.)

Question 10

What determines seed germination?

Answer 10

Genetics and site conditions

Question 11

What causes stand differentiation ?

Answer 11

Expression of dominance

Question 12

What is an important thing to remember regarding competition and tree size?

Answer 12

Trees typically only compete with trees that are relatively similar in size.

Question 13

State the temporal relationship between serial stage and diameter spread.

Answer 13

At stand initiation diameter spread starts small, as stand advances through the sere, diameter spread increases.

Question 14

What would cause a decline in SPH in a normal stand?

Answer 14

Thinning

Question 15

What is complete site occupancy

Answer 15

when you have as many stems per hectare as required at a given time to maximize yield.

Question 16

What is pre commercial thinning

Answer 16

a.k.a thinning to waste ( thinning before timber meets TMS )

Question 17

Do you pay stumpage for commercial thinning?

Answer 17

yes

Question 18

What shape is the DBH vs SPH distribution curve for a natural even age stand? Why?

Answer 18

bell shaped due to infraspecific competition resulting in a wider range of DBH classes

Question 19

What is the optimum crown to generate the highest yield?

Answer 19

1/3 - 1/2 of tree height is crown

Question 20

What is the period of greatest growth referred to? What is it called when that period is finished? What happens to volume after.

Answer 20

Grand period of growth

• referred to as culmination when it stops putting on fast growth.
• After culmination, volume still increases at a decreasing rate.

Question 21

What 2 factors regulate culmination?

Answer 21

Species and site

Question 22

Why do uneven aged systems generate more fiber supply flexibility?

Answer 22

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.

Question 23

What kind of stand would you want on sensitive, dry or wet sites?

Answer 23

Uneven aged because it offers more site protection.

Question 24

How would you know what the required stocking is for a site?

Answer 24

Reinekes stand density index. SPH x (Dq/25)^1.605

Question 25

What is harvesting referred to in even vs uneven age stands?

Answer 25

even: rotation. stand is removed
uneven: harvest over multiple entries. Time between called ENTRY PERIOD