Mod 2 Readings

Question 1

What management values are best achieved through the normal forest concept?

Answer 1

• Timber supply

- Economic returns for the timber value

Question 2

What are some downfalls of forest managed under the normal forest concept?

Answer 2

• Vulnerable to natural disturbance events that could result in significant mortality
• Very limited resilience (recovery potential)
• Lack complexity

Question 3

What is a natural forest?

Answer 3

• Composed of stands that were created in response to natural disturbance, with a variety of species and structure.

Question 4

What are some pro’s and cons of a natural forest from a management perspective?

Answer 4

Cons
- less timber production
Pros
- Heightened complexity and Greater resilience
- Increased biodiversity
- Tend not to collapse as a result of disturbance events
- offers a greater guarantee of timber supply following a timber destroying event.

Question 5

In a complex ecosystem, what type of relationship is more likely between organisms? linear or non linear?

Answer 5

Non linear (Meaning what happens to one species is not necessarily in response to another species)

Question 6

What is a practice that balances normal and natural forest concepts? What are the pros and cons?

Answer 6

(Promoting diverse structure in a stand) comes at the cost of reducing yield, but will produce healthier, more resilient and biodiverse stands and forests that take into account a wider range of management values than just timber production.

Question 7

What is the most basic management unit in a forest?

Answer 7

Stand level

Question 8

What are the two patterns that dictate forest management?

Answer 8

Succession: The natural growth and development of an existing forest or stand.

Disturbance: The partial or complete destruction of an existing forest or stand by natural or manmade events.

Question 9

What are some advantages and disadvantages of uneven over even aged silviculture?

Answer 9

Uneven aged silviculture
- emulates later stages of succession
- leads to increased structure, complexity and biodiversity
- is far more resilient and resistant to timber destroying events.
Even aged however
- is more productive in the short term with much higher yield (higher value).

Question 10

In general, what are the temporal characteristics of succession?

Answer 10

Early stages characterized by rapid changes in vegetation while later stages are characterized by slow changes.

Question 11

What is a normal forest?

Answer 11

A Completely controlled forest composed of even aged, fully stocked stands through the rotation that will produce the greatest yield.

Question 12

What are the four stages of succession that typically follow a stand initiating disturbance?

Answer 12

1. Stand Initiation - Site colonization and establishment lead to a forest canopy dominated by an even aged cohort of trees. Rapid establishment of herb strata.
2. Stem exclusion - Space and resources become limiting factors and canopy closes. Competition is intense and the shrub and herb strata are limited due to low light. Stratification of tree height results from inter species competition for light.
3. Understory Re-initiation - Mortality of some over-story trees leads to canopy openings that allow regeneration of the herb strata and release of shade tolerant species in understory. (gap phase regeneration dynamics).
4. OG stage - accumulation of CWD, horizontal and vertical diversification of canopy, increased biomass/diversity of understory. Most shade tolerant species in overstory. More or less static except for gap phase regeneration.

Question 13

Why is natural disturbance of ecological importance?

Answer 13

They establish ecological conditions for new plant communities to establish themselves.

Question 14

What are the 3 dimensions of disturbance?

Answer 14

Frequency: the rate at which existing disturbances recur. Frequent every few years, Infrequent every few centuries.

Predictability: The regularity of the occurrence of disturbances. (how predictable it is.)

Magnitude: duration of disturbance. (ex. short:fire long:drought.)

Question 15

How are ecological regions classified in BC?

Answer 15

According to the Frequency, Predictability and Magnitude of the dominant disturbance events in that region.

Question 16

What is the relationship between disturbance frequency and severity?

Answer 16

Inverse. The more frequent the disturbance, typically the less severe it will be.

Question 17

What are the most common disturbances on the coast?

Answer 17

Small disturbances affecting one to a few trees. Windthrow, lightning, Snow etc.

Question 18

What dictates regeneration in OG stands?

Answer 18

The duration of time that the canopy remains open for following the creation of a gap by a single or group mortality event. (will understory make it to overstory before it closes.)

Question 19

Understory trees are more likely to reach the overstory following the creation of a gap if:

Answer 19

1: The gap is large
2: The trees adjacent to the gap to not respond with vigorous lateral crown growth.
3: Gap is enlarged by the death of trees that border it.

Question 20

During which phase is expression of dominance the strongest?

What else influences expression of dominance?

Answer 20

Stem exclusion phase.
-expression of dominance is more pronounced in rich sites and can also be related to better genes, earlier establishment and better microsite conditions.

Question 21

What is the normal forest concept?

Answer 21

• For a specified rotation period, one age class could be harvested per year. At the end of the time cycle, the first stands harvested would be ready for harvesting again.