HomeMy WebLinkAboutEmerald Ash Borer story for DanbyReport Evaluating Choices For EAB (Emerald Ash Borer) Threat At Sylvan Lane Tract
Prepared for Danby CAC, by G. Adams and J. Zisk… For submission to Danby Town Board
(with significant input from Don Schaufler, Chris Tcimpidis, Jerry Kimmel, and Monika Roth)
The threat: The EAB flies up to 6 miles in a single year, but tends to stay close to the tree from which it
emerged. Spread is farther when infested trees are transported. A reasonable warning would be that if
EAB infestation is within 30 miles of your ash, then yours is in danger.
Prior to infestation it is possible to harvest the un-infested trees for timber sale.
Prior to 60% canopy loss, treatment can save a tree. Treatment currently means either chemicals, or
biological controls. But biological controls are in restricted use (see “Treatment” below).
Choices for the Sylvan Lane stand 59 ash: 1. Entirely logged for profit; 2. Treated with pesticide; 3. Left
entirely alone; or 4. Partly logged, with profits then used to fund treatment of the remaining trees and any
further infestations at other locations.
By selectively cutting, we can gain several secondary outcomes: We can manage for particular wildlife-
habitat and future forest-growth; plan for ease of the logging operation; and minimize the unavoidable
habitat/infrastructure disruptions of logging.
Carbon Sequestration issues: Beyond erosion, groundwater contamination, and the eyesore, badly
managed logging disrupts soil to release sequestered carbon. Unlike the sequestered carbon in trees
themselves— which need not even be released if the timber becomes lumber, and where canopy re-growth
after logging gives a relatively fast re-establishment of photosynthetic carbon sequestration— the soil that
has been disrupted takes much longer to re-establish carbon adsorbing aggregates. The disruption of soil
involving macroscopic habitat, erosion, and groundwater features will also affect sequestration. The
logging BMP's (Best Management Practices—A set of critical rules for how to log responsibly) for those
gross-macroscopic features will also have the same mitigating effects on the microscopic-molecular carbon
sequestration, if (and this is a big question!) those BMP’s are effective.
Logging BMP’s--From “Logging Options to Minimize Soil Disturbance in the Northern Lake States”
Douglas M. Stone et al:
“(1) excluding riparian areas and poorly drained inclusions from cutting units;
(2) dry season harvesting;
(3) plowing snow from (or packing the snow on) skid trails and landings, permitting them to freeze;
(4) felling with delayed skidding until trails and landings have frozen; and
(5) application of best management practices (BMP) recommendations such as progressive (back-to-front)
harvesting.” [ed: Use horses?]
Selective Cutting: Several parts of the Danby stand are wet, steep-slope, pit-and-mound topology, and
densely forested--which makes it difficult to avoid badly disrupting the area in every way; indeed it may be
impossible to log some parts without extensive damage to surroundings. But it may be that by selectively
cutting low-slope and easy-access areas the town profits from a half-logged operation, if that is the choice.
Selective cutting also allows removal of trees which are not growing well, or are interfering with other
more valuable trees, or whose falling in a storm would damage infrastructure or other more valuable trees.
In summary, BMP’s are critical for logging on this fragile tract; perhaps horse-driven logging would work.
Treatment: Options are either chemicals that kill, or the release of biological species that directly or
indirectly cause death of EAB. Regarding biological treatment, the ongoing successful federally funded
parasitoid release program would not be approved for our site, because participation requires a 40-acre
minimum plot. When that research phase is complete we can expect commercial availability. There are
other potentially viable biological treatments in early testing, that we can also consider in the future, if the
choice is ongoing treatment. Currently our treatment choices would be chemical.
Timing: As noted above, ash within 30 miles of known infestation are at risk… But treatments that begin
too early do nothing, will not protect against future infestation, so are wasted money.
Adult onset here is early June; eggs are laid 14 days later… Spring application is most effective.
Problematic Treatment: Imidacloprid and dinotefuran can be effective as a soil-drench, which must be
used in early spring. But this method is not advised on severe slopes—as for much of the Sylvan Lane site.
Slopes and wet soil prohibit soil-drench. Furthermore, the collateral danger to pollinators if chemicals are
used before flowering is devastating to beekeepers, and overall environmental health. One available
formulation of Imidacloprid lists both EAB and woolly adelgid as insects it can control.
A Better Choice: Soil or trunk injection is advised for severe slopes. Trunk spray and/or injection with
emamectin or dinotefuran give faster uptake than soil, so can begin later in the season, after flowering,
which reduces to near zero the risk of harming pollinators. Note--Ash is wind-pollinated, with no bee
pollination involved; it’s the surrounding flowering that should concern us. A location on Tupper road (a
mile from our tract) is frequently used by a local bee keeper for an apiary. It is difficult to rule out others,
possibly closer. Within two miles of a hive is considered typical ranges for honey bees.
There is no microbial poisoning or change in CO2 adsorption and bioactivity in the soil sequestration
processes; the chemicals advised are not detectable at significant levels in groundwater if trunk-injected;
they have a 1-2 year half life in foliage, but the tract has no wildlife that eat ash leaves. The insectivore
issue is new research—EAB larvae die quickly when treated, and birds seek live larva, but data shows
toxicity for ground birds when the poisons are in surface/ground-water; our groundwater will be clear.
Big Questions on Effectiveness: For the most commonly considered pesticides, trunk injection may be
more effective than soil drench—But studies are inconsistent, and as a whole the protocols seem to be more
important than the choice of chemical or technique for application.
Long Term Treatment: Improvement won’t be seen for two years after treatment.
Emamectin works up to 3 years, others for 2—so re-applications every 2-3 years are needed. This is less
expensive than removal to dispose (NB: we have marketable timber, not infested trees today, so it would be
more expensive to treat than to log the whole stand for sale).
Anticipating mixed-use, the four chemicals cited are effective with many other invasive pests.
There is significant hemlock on the Sylvan Lane property. Jim Schuler, who harvests timber extensively in
our area, asserts that once adelgid gets into a stand of hemlock, loss is 100% within 8 years. One NY DEC
link to a non-profit tracking invasives (https://imapinvasives.natureserve.org/) reports infestation on the
attached map below. An inherent limitation to the reports is that volunteers tend to be more accurate for
publicly accessible woodlands, and are probably under-reporting private property, and hence the totals.
The map shows many adelgid sightings in the Danby state forest and two in Lindsay-Parsons, about a mile
from the Sylvan lane parcel. By contrast the nearest EAB sighting is 4 miles north.
It may help to know there are treatments that kill both the EAB and the hemlock wooly adelgid.
Logging only half and then investing in equipment for pesticide application could be used as a defense
against these and future infestations.
Collateral Damage to Biota: Should we expect other wildlife, groundwater/aquifer, agricultural collateral
damage? Groundwater quality has not been measurably affected by any of these treatments when correctly
applied, so amphibians/fish and agricultural quality is unharmed. Woodpeckers (and many other birds)
only feed on mature, living larvae as they emerge from winter dormancy, so consequently they do not
ingest larvae-killing insecticides—although this conclusion has not been definitively confirmed for all
species and time-frames.
Costs: The injector has a 15-20 year steady-use lifetime, costs around $750, and could be kept by the town
for use on other trees. Licensed application is required; see below. Chemical prices are approximately $10-
20 per tree-year, which does not include the amortized cost of the applicator kit— most likely spread over a
decade of use and hundreds of trees. Commercial arborists charge $10-15 per inch, or $150-300 per tree,
per treatment; cost is at the low end when the stand is dense and accessible. Zeb Strickland of Cornell
Botanical Gardens and Forest and Water Solutions (www.forestandwatersolutions.cm) will treat the 59
trees for approximately $7 per inch, which for a 17-inch average diameter prices out to approximately
$7000 for the entire stand, or slightly more (economy of scale) than $3500 for half the stand.
Injector and pesticide use licensing is necessary. According to Jerry Kimmel of the Regional DEC, a
Certified Private Pesticide Technician license is designed for agricultural operations; Sylvan Lane and
Danby’s other silviculture and pest management concerns do not fall under this category because they are
not privately owned, for profit operations. Even considering the nominal profit accrued for the half-logged
Sylvan Lane project, the DEC will not assign this an agricultural designation, and it will require a
Commercial license.
A Commercial license requires a degree in one of several possible fields, plus training, experience, and/or
apprenticeship—all needing several years. Costs for that license are significantly higher. Don Schaufler
has that training, and a prior license. There may be other interested folks in Danby who fit the
qualifications.
If cost were the sole criterion for the choice, logging the entire tract would be advisable, but there are
several other considerations to completely logging the stand that merit concern:
1. Habitat management can be designed by selective cutting.
2. Extensive logging in a fragile area can be habitat destructive, depending on how well managed.
3. Carbon sequestration will be lost or compromised by any logging at Sylvan Lane.
4. Soil erosion and runoff of extensive, unmanaged logging create soil loss and groundwater pollution.
5. Aesthetic-meditative qualities of the woods can become an eyesore with extensive logging.
Long-Term Questions: How many years would treatment be necessary? Is the long-term fight with the
EAB (and other invasives) a losing battle? If chemical treatments are never-ending and dangerous, will
biological methods save us from invasives? The problem with answering these questions is that we have
too little data. The earliest infestations, ravaging the Midwest now, are not entirely complete, so long-term
projections are unclear; treatment of small plots is unproven; and a biological silver bullet does not exist.
Studies in SE Michigan and Ohio, where 99% infestation has been ongoing for over a decade, show no
improvements, no positive “gap effects”, no significant resistance, and major changes to surrounding
habitat. A small number of “lingering ash” seem partially resistant, and are being grafted and studied for
the specific extent and persistence of this resistance. There is guarded hope that the species may survive.
SUMMARY PRO’s and CONS:
Action Pros Cons
Wait for infestation. Infested trees cannot be sold as timber;
no money earned; net higher cost.
Cut all 59 marketable
trees.
Simple; complete infestation
prevention for the tract;
maximum profit.
Maximum disruption; erosion;
maximum release and reduced carbon
sequestration; no management for other
goals.
Treat all with soil
drench…
Easier than injection; no
equipment costs.
Not suitable for our high slope parts;
may not be as effective as injection;
higher risk of aquifer
contamination.
Treat all with trunk
injection emamectin
or dinotefuran; hire a
professional.
May be most effective method for
eradication; no learning curve.
Cost (probably more than an injector);
no equipment to keep for future use;
pollinator care needed.
Treat all with trunk
injection emamectin
or dinotefuran; Danby
doing the work.
May be most effective
eradication; purchased equipment
is reusable.
Licensing issues; learning curve;
delegation; liability issues; pollinator
care needed.
Cut half and treat the
rest.
May be most effective
eradication; purchased equipment
is reusable; logging pays for
equipment.
Licensing issues; learning curve;
delegation; liability issues; pollinator
care needed. This is the most
complicated plan…
Conclusions
To “let nature take its course” here is somewhat analogous to not vaccinating children before sending them
to school—Disease vectors propagate and expand if we let the infestation happen and do nothing.
A majority of the tract has: 1. Susceptibility to water year-round (intruded upon by a wetland); 2. Pit-and-
mound topology; 3. Loose soil structure; 4. Very steep slope. Weak soil and difficult topology for heavy
equipment means it will be extremely difficult to log without major disruption.
Selective cutting in the easier existing access roads will generate some funds. It is not clear how badly the
price of ash is dropping with the current export tariffs, but prices may improve by next year.
The EAB is not infesting the tract yet, and we may have 1-3 years before it would preclude harvest.
Treatment by Zeb Strickland was estimated in the range of $7/inch diameter, around $7,000 for the 59 ash.
Training someone to become Danby’s licensed applicator would only be feasible if a volunteer with prior
experience is available. The cost is in the several-hundred-dollars range; maintaining a license would cost
a few hundred dollars per year; insurance costs are waived for town work. This would be a time
consuming and initially expensive route, but it would save money in the long run if we plan to treat for the
several major pest infestations expected over the next 5-10 years, and it would allow a range of proactive,
tailored solutions, not just calling a tree doctor when infestations occurs.
Doing nothing and then allowing the EAB to infest the 59 trees will cause more physical damage than
logging, when the infested trees fall (out of control), especially where slope or wind exposure are a factor.
Selected Sources:
Frequently Asked Questions Regarding Potential Side Effects of Systemic Insecticides Used To Control
Emerald Ash Borer; Mich/Minn/OSU Extensions
Insecticide Options for Protecting Ash Trees from Emerald Ash Borer; OSU/MSU/Purdue Ext.
Emerald Ash Borer Management Options—Iowa State Extension
Emerald Ash Borer Biological Control Release and Recovery Guidelines; USDeptAg et al 2019
The Role Of Biocontrol Of Emerald Ash Borer In Protecting Ash Regeneration After Invasion;
Jian J. Duan1 et al 2019
Mechanisms of Carbon Sequestration in Soil Aggregates; H. Blanco-Canqui∗ and R. Lal, 2010
Severe slope
saturated soil hemlock wooly adelgid in Danby
pit and mound topology