final review: chapter 6 Root Diseases Flashcards
Latin names for: Laminated Root Rot Annosus Root Rot Tea Pot Rot Black Stain Disease Tomentosus Root Rot
Laminated Root Rot:Phellinus weirii Annosus Root Rot: heterobasidion annosum Tea Pot Rot: Rhizina undulata Black Stain Disease: Leptographium wageneri Tomentosus Root Rot:Innonotus tomentosus
General info for Phellinus weirii
Root balls, windthrow chlorosis, thinning and distress cones brown mycelial felts on root surface resupinate conk(upside down-hard to find) red brown stain (incipient stage) laminate decay(advanced stage) Hosts: Fd, Bl, Bg, Hw Spreads radially from root to root via ectotrophic mycelium
Heterobasidion Annosum: General info
HOSTS: pines, true firs, hemlock, spruce Perennial polypore at root collar stringy white decay with black flecks spores colonize wounds bigger problem in coastal BC potential problem in thinned/harvested areas survive for 50+ years in large stumps rare on hardwoods conidia produced but role unknown basidiospores travel many km's hard to detect old infected trees with butt rot Spreads: stumps infected by airborne basidiospores, stem breakage, spread by mycelium from infected stumps to trees thru root grafts or contact
Rhizina undulata general info
- Black tube like apothecium(ascomycete) 6 cm wide, whitish rhizomorphs
- infects regen for few years following fire
- tea pot disease/fungus
- attacks fine root system of seedlings(feeder root disease)
- hard to detect without fruiting bodies
- mycelium disappears following seedling death
- fire acts as soil sterilant eliminating other fungi, more host material for rhizina
- facultative parasitic fungi (mainly saprophytic but also parasitic)
- affects most conifers, old growth stands mainly
- most common on coast and ICH
- delay planting 2 years after burn
Leptographium wageneri general info
- typical crown symptoms
- insect vectors, root contact
- obligate parasite
- black stain in sapwood
- Hosts: Fd type, common on 15-60 yr old Fd. Hw secondary host
- Pl 45-100 years old. Pw and Sx secondary
- blocks vascular tissue
- will predispose Pl to attacks from IBM and IBI
- Often found assoc. with DRA and DRL
Innonotus Tomentosus
Younger trees most affected
-Hosts: Sx(Pl,Hw,Fd,Bl)
-red stain and white pitted rot(honeycomb like-looks like carpenter ants)
-spreads from stumps, spores help initiate new disease
-velvet topped sporophore, annual, quickly eaten/decomposed by invertebrates
-thinning of crown-looks old
-sapwood remains alive and functional, eventually gets to bark
-smaller roots infected
-polypore conk in duff
-common in northern spruce forests and also in ESSF(Northern Climates, high elevations in South)
-infected sx often attacked by IBS
-not a lot of good quality Sx left in s.interior, ESSF remains untouched because lacking high value wood, costs are high
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DRA life cycle
- always a pathogen, can’t live on its own, has to live in root
- fungus exists in root lesions of trees
- lives in stand in balance with natural veg. -for a long time
- DRA takes over when hosts are put under stress(drought, scarring, cut down)
- DRA exploits the weakness of stump and rapidly coloinizes, using it as food base
- Roots of tree remain alive 2 years post cut, during the 2 years fungus spreads throughout entire stump and root system
- Spread limited to parasitic phase, enters saprophytic phase once roots and stump are dead
- uses invaded tissue as food source and produces rhizomorphs
- disease spreads to healthy trees below ground
3 ways DRA spreads to healthy trees below ground
- Mycelial growth across root conacts between infected tissue (most common)
- via rhizomorphs growing through the soil
- by spore infection(rare)
when do trees show above ground symptoms from DRA
hwen >2/3 of root system is colonized by fungus
5 Factors of stump creation affecting severity of DRA spread
- stump size: bigger the infected stump, ore sever the spread potential because:
it means more food, therefore more energy potential for disease;
bigger root systems mean greater potential for root to root contact - stump interval: more uniformly stumps are spaced, greater the potential for sever spread because contact area max’d
- Stump Creation Frequency(# stand entries)
More entries means more potential for severe spread - Stump swarming(# of stumps): more stumps means greater potential for severe spread to live stems
- timing of stump creation: the more time stumps have to decay, the lower the risk of severe attack, because:
- decay decreases size of stumps, meaning less food and less energy provided
- outer tissues decay first reducing risk of root to root contact and leaves less stumps susceptible
Environmental factors affect the inoculum potential of DRA by altering:
- frequency of trees exposure to inoculum
2. quality of inoculum (potential)
3 damage factors that determine level of damage caused by DRA
- stump creation
- species susceptibility
- environmental factors
DRA IN THE ICH:
conditions?
presence?
DRA mortality damage in ICH plantations?
moist climatic conditions in the ICH are more favorable to quantity(amt of exposure) and quality(inoculum potential) of DRA inoculum
DRA universally present in all but driest and wettest sites in ICH
Mortality damage: by age 30, mortality damage varies between 10-30%
Growth loss in trees with non lethal armillaria infections in the ICH?
Fd trees infected at age 9 could show 40% less growth than uninfected tree that had been growing at same rate
Long term productivity loss on medium severity sites determined to be 7.2% in ICH Fd stands
Different responses of DRA in different stands
In the MS, IDF, ESSF, distribution can be patchy and occurs as distinct centers
on the coast, DRA often present, but highly productive sites allow trees to outgrow disease
One trial in Washington state had stand mortality at over 50%, but most of that was Py. Fd is in stands but proven to be more resistant than Py in that area.
What are the two treatment options for DRA chapman is critical of?
- resistant species planting. Points out no highly resistant conifers and those that are tagged as resistant have qualifiers attached
- stumping: points out no hard evidence surrounding viability
what is one of the factors chapman suggests DRA severity depends on
capacity of saprophytes and other organisms to weaken DRA inoculum, not just at a moment in time but continuously throughout the life of a stand.
he says little retention of CWD will decline the saprophyte community and increase root disease incidence
Hypholoma fasciculare
use built upon what hypothesis?
results?
biggest obstacle?
use of the fungus as a DRA treatment built upon hypothesis that some saprophytic organisms may be able to outcompete DRA.
Same technique used in Europe to battle annosus root rot, initial trials show good results
biggest obstacle: expense
What is Chapman suggesting with his treatment?
that the link between timber harvesting and root disease isn’t the creation of stumps, but the lack of CWD that would normally be on the forest floor after a disturbance. The more CWD, the more woody decay fungi and more inoculum potential is there to colonize a site, including roots, taking the energy sources away from DRA.
Trying to play within nature’s rules..a natural-ish treatment
pros and cons of pushover logging
pros: reduces large inoculums sources and exposes roots to dry out
prevents potential for root to root contact
allows reforestation to susceptible host species
CONS: seasonal restrictions
expensive
high levels of soil disturbance
limited by terrain/topo
effectiveness still somewhat contested
address relationship between current funding mechanisms and specific forest health concerns in the context of juveinle spacing in ICH stands. Suggest possible ways to mitigate risks assoc with this issue
-funding limited to pop up spacing and fertilizing
-spacing in areas where it may not be the best management practice, just doing it to keep funding up.
Inneffective because other issues needed to be addressed that spacing wouldn’t affect.
-species sensitive to mechanical damage are affected
-DRA could flush, even if pop-up spacing used
-Creating more area for germination of alt hosts of rusts(ribes)
-Disturbance could give more access to basidiospores of diseases to be windborne
-shade intolerant species could be affected
identify forest health issues related to burton fuel management project and the project’s perceived and/or potential effect on each of these issues
-DRA increase with spacing
-DML thought to be taken care of due to lack of present larch
-white pine blister rust in stand, pruning occurred to decrease susceptibility but was ineffective
-pretty much zero CWD on ground, and if you believe Chapman’s theory then this would have given DRA even more fuel to take over
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