Mistletoe Management Flashcards
What does red flagging refer to?
In the interior squirrels will girdle swelled branches for their sugar and they will die fast, causing red branches to appear.
What are the shortcomings of the 7 point hawksworth system of DMT assessment?
- Hard to see tops of trees when surveying
- No way to state the impact of cumulative bole swelling
What is the acceptable rating of growth loss?
0-2 = 0-5%
What is the 7 point hawksworth system?
A numerical system of assessing the impact of DMT on growth loss. Numbered 0-6 with corresponding growth losses that increase with the numbers.
What would be considered a marginally acceptable growth loss that would depend on land management objectives?
3 - 5-15%
What volume loss at rotation would be indicative of heavy infection?
typically 20-40% in Hw and Pl
What 3 times is DMT assessed in forestry?
- Timber cruising (inventory)
- SP - site plans (silviculture)
- Silviculture surveys (FG and stocking surveys)
What is the most important thing about partial harvesting Dmx infected stands ?
Leave trees must be infection free or the infection will spread to the new crop relatively fast.
What is the general management goal for DMT
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.
List common signs and symptoms of DMT
- Brooms
- Spindle shaped swelling
- Aerial shoots (basal cups)
- Deformed stem (armpits)
- Dead tops (severe)
- Red Flagging (Pl, Fd, Lw interior) - squirrels
What aspects of DMT make it easier for us to manage?
- 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.
What is a basal cup?
A crater indicating past presence of DMT aerial shoots.
What time periods is DMT managed for?
- Harvest/Regen: assessed during silviculture site plan
- Free Growing/ Juvenile spacing: FG survey assesses forest health
What factors decide whether a DMT infected block can be partially harvested?
- Fd, Lw, Hw possible if low enough infection (Pl never partial harvested)
- If less than 50% host, less than 20% of hosts infected.
What cautions would you take if you were to partially harvest a DMT infected block.
- 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.
In general, Clearcutting for DMx is the preferred method of management. What objectives would you follow to try and eliminate DMx from future spread.
- 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
Is DMx a bigger problem in the interior or the coast?
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)
What aspect of DMT could cause a tree to fail FG survey?
- Infected overtopping tree ( tree less than 10m from infected residual)
- Tree has infection present on stem or live branch.
What defines an overtopping tree?
Tree is at least 3x the median height of regen.
What is the difference between signs and symptoms?
Signs (Actual physical proof of pathogen) - Aerial shoots
Symptoms (Indication of possible pathogen) - Spindle shaped swell, brooms, red flagging, deformed stem.
Legally, when does forest health need to be assessed?
At free growing survey
What does sanitation refer to?
The targeting of infected trees during JS. (Might be hard to spot infection on immature trees)
Which Site Index is the deciding factor whether the mistletoes vertical spread will keep up with DMH?
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.
What are the things to remember if you need to JS? (4)
- 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
What is the no acceptance zone?
When edges of cutblock are infected, the no acceptance zone is a 10 m ring of non host species around the edges
What is the ministry perspective on JS in DMP?
- avoid JS if possible (esp. 3+)
- only space if max density exceeded and infection rating 0-2