Mistletoe Management

Question 1

What does red flagging refer to?

Answer 1

In the interior squirrels will girdle swelled branches for their sugar and they will die fast, causing red branches to appear.

Question 2

What are the shortcomings of the 7 point hawksworth system of DMT assessment?

Answer 2

• Hard to see tops of trees when surveying

- No way to state the impact of cumulative bole swelling

Question 3

What is the acceptable rating of growth loss?

Answer 3

0-2 = 0-5%

Question 4

What is the 7 point hawksworth system?

Answer 4

A numerical system of assessing the impact of DMT on growth loss. Numbered 0-6 with corresponding growth losses that increase with the numbers.

Question 5

What would be considered a marginally acceptable growth loss that would depend on land management objectives?

Answer 5

3 - 5-15%

Question 6

What volume loss at rotation would be indicative of heavy infection?

Answer 6

typically 20-40% in Hw and Pl

Question 7

What 3 times is DMT assessed in forestry?

Answer 7

• Timber cruising (inventory)
• SP - site plans (silviculture)
• Silviculture surveys (FG and stocking surveys)

Question 8

What is the most important thing about partial harvesting Dmx infected stands ?

Answer 8

Leave trees must be infection free or the infection will spread to the new crop relatively fast.

Question 9

What is the general management goal for DMT

Answer 9

Goal is to achieve a hawksworth value of 2 or less on crop trees. Basically less than 5% growth loss of crop trees in a stand.

Question 10

List common signs and symptoms of DMT

Answer 10

• Brooms
• Spindle shaped swelling
• Aerial shoots (basal cups)
• Deformed stem (armpits)
• Dead tops (severe)
• Red Flagging (Pl, Fd, Lw interior) - squirrels

Question 11

What aspects of DMT make it easier for us to manage?

Answer 11

• Obligate
• Species specific - By mixing species we can slow or stop development with non host species barriers.
• Slow development
• Obvious signs and symptoms - on mature trees
• Trees outgrow and shade it out on good sites.

Question 12

What is a basal cup?

Answer 12

A crater indicating past presence of DMT aerial shoots.

Question 13

What time periods is DMT managed for?

Answer 13

• Harvest/Regen: assessed during silviculture site plan

- Free Growing/ Juvenile spacing: FG survey assesses forest health

Question 14

What factors decide whether a DMT infected block can be partially harvested?

Answer 14

• Fd, Lw, Hw possible if low enough infection (Pl never partial harvested)
• If less than 50% host, less than 20% of hosts infected.

Question 15

What cautions would you take if you were to partially harvest a DMT infected block.

Answer 15

• Target severe and moderate trees
• Short cutting cycles (10-15 years) to keep up with potential spread.
• Favour non host or alternate species when selecting leave trees.

Question 16

In general, Clearcutting for DMx is the preferred method of management. What objectives would you follow to try and eliminate DMx from future spread.

Answer 16

• Create disease free boundaries if possible by cutting out diseased areas.
• Irregular shaped blocks are more likely to have infection in edges. (Minimize perimeter to area ratio)
• Eliminate residual trees (3.0m knock down clause on coast)
• Reforest any infected edge with non host or alternate spp.
• Mix spp throughout block.
• Dense stand is favourable

Question 17

Is DMx a bigger problem in the interior or the coast?

Answer 17

Interior due to poor quality sites that produce slow growing trees which allows for DMP to keep up with tree growth. (0.5m knockdown clause in effect)

Question 18

What aspect of DMT could cause a tree to fail FG survey?

Answer 18

• Infected overtopping tree ( tree less than 10m from infected residual)
• Tree has infection present on stem or live branch.

Question 19

What defines an overtopping tree?

Answer 19

Tree is at least 3x the median height of regen.

Question 20

What is the difference between signs and symptoms?

Answer 20

Signs (Actual physical proof of pathogen) - Aerial shoots

Symptoms (Indication of possible pathogen) - Spindle shaped swell, brooms, red flagging, deformed stem.

Question 21

Legally, when does forest health need to be assessed?

Answer 21

At free growing survey

Question 22

What does sanitation refer to?

Answer 22

The targeting of infected trees during JS. (Might be hard to spot infection on immature trees)

Question 23

Which Site Index is the deciding factor whether the mistletoes vertical spread will keep up with DMH?

Answer 23

SI 22 (rich)
22 DMH will remain in lower crown
(If ground is steep, vertical spread can be increased since lower crown DMH can spread into upper crown of trees downslope.

Question 24

What are the things to remember if you need to JS? (4)

Answer 24

• Only feasible if SI>22 @ 50years.
• Sanitation
• if void too big, leave trees with least crown infection. (Still cut stem infection)
• Hard to assess infection at juvenile age

Question 25

What is the no acceptance zone?

Answer 25

When edges of cutblock are infected, the no acceptance zone is a 10 m ring of non host species around the edges

Question 26

What is the ministry perspective on JS in DMP?

Answer 26

• avoid JS if possible (esp. 3+)

- only space if max density exceeded and infection rating 0-2