Stem Decay and Cruickshank Flashcards
1
Q
Benefits and limitations of stumping trials as told by Cruickshank
A
BENEFITS:
- works for all impacted tree species
- reduces incidence of root disease, creates more stable stands-esp. after drought
- removes barriers to site productivity therefore allowing more trees without loss in individual size, resulting in higher density gives higher crown and fewer knots(knots are big downgrade)
LIMITATIONS:
- site limited
- expensive
2
Q
describe white rot
A
- tends to follow hardwoods
- fibrous because cellulose remains intact until very late stages
- typically less fibrous in hardwoods than in softwoods because of shorter fibers in hardwoods
- turns whitish because of bleaching by oxidation and loss of lignin
3
Q
describe brown rot
A
- brown because carbohydrates are removed, leaving brownish, oxidized lignin.
- no fibrous texture because cellulose is broken up early
- tends to follow softwoods
4
Q
Characteristics of spore dispersal
A
- spores may be released for a few days(mushrooms) or for six months or more per year(perennial conks)
- up to 300 billion spores per day are produced by some conks
- spores are wind dispersed. they are in suspension in air and can travel many miles even in a light breeze
- some decay fungi have a conidial stage in culture but those are rarely found in nature and their importance s unknown
5
Q
Define and describe infection courts for stem decays
A
- Fire scars: early studies say these are most important, both in hardwoods of SE and in conifers in the west. Unsure if still true today
- wounds: broken tops, treefall scars, animal damage, logging scards, carving and hatchet marks. Logging injuries are an important infection court we can manage to reduce heart rot.
- Branch stubs: Diameters only a few mm in size can be infection courts.
- Roots
- Cankers, Mistletoe infections, necrotic galls: may eventually become infected by decay fungi, which may lead to stem breakage
6
Q
what is the first line of defense against decay fungi?
A
Bark. No stem decay fungi can infect through intact bark.
7
Q
Characteristics of sapwood resistance to stem decay
A
- capable of active response to invasion
- parenchyma cells in sapwood sense presence of fungus and initiate doomsday response
- killed by terminal metabolism, resulting in unfavorable conditions for fungi
- Chemicals limit progress of fungi, resin piped in to seal off area, cambium responds to trauma by producing effective wall in xylem that restricts invader to wood laid down previously.
8
Q
Characteristics of heartwood resistance to stem decay
A
- heartwood is dead, so no active resistance.
- Chemicals are deposited in heartwood as it forms by dying parenchyma, rendering it more or less inhospitable to fungi.
- species vary greatly: cedars are high, aspen and birch very low.
9
Q
Rate of fungal growth in trees
A
- Two approaches to finding out:
- inoculate, wait five years, then cut and measure
OR - find trees with infection courts that can be aged, then cut and measure.
- results variable, from 0-60 cm/yr. Average about 6-8cm.
- Initial growth could be faster due to aeration, which leads to overestimation
10
Q
factors affecting stem decay in stands
A
AGE OF STAND:
- stem decay increases with age of a stand
- more infection courts in older trees(stubs, breaks, wounds, etc)
- more heartwood in older trees
- wounds heal more slowly in older trees so more likely to be infected
- older trees grow more slowly ,fungus grows faster relative to the tree
STAND HISTORY:
- fire: basal scars
- ice and snow storms: top breakage, top rot
- Logging: felling wounds, basal scards from skidders and logs
- Density: Assuming fungus gets in via larger branch stubs…Open stand=larger stems, but some fungi use smaller twigs, so dense young stand may favor them
- Animals: animal damage to young stand
STAND COMPOSITION:
- different species hit by decay differently
SITE
- relationships of stem decay to site are not consistent, no generalizations can be made
INOCULUM:
- we assume spores will be there, no hard evidence for this.
11
Q
Mgmt strategies to prevent wounding of trees
A
- clear cutting
- plan logging roads carefully to avoid damage to residual stand. use trees to be harvested as bumper trees, then harvest them last
- keep stand entries at a minimum, avoid frequent light cuts
- keep vehicles away from trees
- prune early, when branches are less than a few inches in diameter
12
Q
compartmentalization and Phellinus pini
A
- 2-3 feet above
- 3-5 feet below each conk or blind conk
- several conks or punk knots indicate complete cull
13
Q
Compartmentalization and Phaelous schweinitzii
A
- extends roughly 3m up tree stem
- seriously damages roots and butts of trees
14
Q
compartmentalization and echinodontium tinctorium
A
- decays cross section of tree around 4-6m above and 2-4m below location of fruiting body
15
Q
compartmentalization and fomitopsis pinicola
A
- no exact numbers
- most of the time it comes in after something has already killed the tree
- causes a lot of rot, but at a point when it’s already too late for the tree anyways
