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TEN! Talks

Tree-of-heaven Control

11/10/2016

2 Comments

 
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This article is part 2 of 2 on Tree-of-heaven describing why Tree of Heaven is considered invasive and potential control methods. Please see part 1: How to ID Tree-of-heaven for identification tips.

Why invasive?
While numerous exotic plants have little or no impact on the ecological systems into which they’ve been introduced, over two centuries of Tree-of-heaven’s presence in the United States’ has taught us it’s worth making a stink about – and not just because it stinks (both its crushed leaves and male flowers are known for their acrid odor). Some call it Chinese sumac or, you guessed it, ‘Stink Tree,’ but the botanical name for Tree-of-heaven is Ailanthus altissima, implying its preternatural ability to put on height rapidly – 6 to 10 ft in a single growing season.1 Of course, this is part of the problem.
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According to Matthew Kassan of Virginia Tech (PhD Penn State), Tree-of-heaven originally spread from the gardens of 18th century Philadelphia botanists via new railroad systems extending beyond city limits. The disturbed soils along the tracks served as highways for this quick growing tree to take-off, and urban environments across the states have since supplied prime territory for Tree-of-heaven’s continued outbreak. Kassan claims, "It's the number one cause of native regeneration failure in clearcuts in Pennsylvania." Natural or urban environment, it doesn’t matter, the tree simply outcompetes.2 

The Bureau of Environmental Services’ The Problem with Invasive Plants claims “invasive plants are a leading cause of declines in native plant and animal numbers, and are a factor in Endangered Species Act listings.” They go on to address the how invasive plants negatively impact water quality, tree cover, and even act as conduits for wild fires. They state the $120 billion dollars that the U.S. economy spends annually on invasive species control get passed on to consumers through many avenues, and reduces Oregon personal incomes by $83 million dollars per year.

The Threat
Once established, Tree-of-heaven has its way of sticking around. Firstly, it’s allelopathic. Its roots release a toxin that prevents other plants from establishing nearby. The root structure itself concentrates near the surface, and sends vertical shoots that lead to clonal colonies, like the thicket (below) on Columbia Blvd near NE 63rd Ave, and the means by which it easily spread across Pennsylvania. The shoots have been found up to 50 feet away from the main trunk. Female trees are extremely fecund, producing about 350,000 viable seeds per year. 






​Once the trees are full grown, which doesn’t take long, they become a danger to the neighborhood. Their wood is brittle, making major limb failures almost inevitable in Portland’s stormy winters. 
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Control
Quick disclaimer: please see the part 1: How to ID Tree-of-heaven before implementing any of the following control tactics.

As discussed, Tree-of-heaven is a mighty foe. Its complete eradication from urban areas has been unsuccessful to date, and largely unattempted. To do so will require coordination between tree care professionals, government agencies, and resident stewards, which one group in Portland fully intends on pursuing... Contact Tree-of-Heaven Eradication Now! (TEN!) for further information, and see how you can help the cause. But to get a better idea of what it’ll take, here are some considerations and tactics split into two divisions based on tree size.

Young Trees (<3” DBH) 
    The process:
  •  Go after the leaves
  •  Remove (with a specialized tool)
  •  Monitor the sprouts
  •  Repeat step 1
Eliminating the problem before it begins is the best way to stay ahead of tree-of-heaven’s spread. So it’s crucial to identify saplings before they get to big. Anything above 3 inches in diameter at breast height (DBH = 4.5’ above the ground) is going to give you a much harder time, and likely require professionals.

Mechanical means
  • Persistent Defoliation: Continually pull all the leaves from young sprouts. This cuts off the food source to the tree, stunting further growth and eventually starving the sapling until its demise. At this point, simply pull out by the roots.
  • Weed-puller: These can be found at your nearest tool library. The tool locks onto the trunk and rips from the base. It’ll take some muscle, and the bigger the sapling, well, the more muscle. You’ll need to be extra vigilant if your goal is to avoid the use of herbicides.
Chemical means
With so many rather expensive herbicides on the market that fall under a Restricted-Use Pesticide appellation, choosing an appropriate product for your yard can be daunting if not impossible without an applicator license. 
So here are two DIY options:
  •  Roundup Concentrate – This can be found at most hardware and garden supply stores. Wait for the sapling to show about 5 leaves. The idea here is that leaves will absorb the poison and transmit it backward through the cambium to the branch, trunk, and bark as it would starch. Spray the leaves and let the transmission commence!  

Adult Trees (>3" DBH)
The process changes for large trees since spraying or pulling the leaves would hardly make a dent.
  • Remove the tree*
  • Immediately treat the stump
  • Grind the stump
  • Monitor for the next 3+ years
  • Treat the suckers when they sprout (per the young tree process)
  • Pull the suckers after they’ve died
*Removing the tree: View the list of Urban Forestry-approved tree care companies in Portland to narrow the search. Ask if they’ve got an Herbicide applicator’s license to ensure they can finish the job the way Tree-of-heaven often necessitates --
have the arborists (or you if it's non-chemical)  immediately treat the stump with one of the following options:
  • Garlon 4 (triclopyr)
  • Picloram
  • Roundup Concentrate (glyphosate)
  • Salt (and Oil; in this context, not really a chemical means)
Choices 1 and 2 are serious herbicides that require applicator licenses, while Choice 3 does not, yet has been shown work. Ensure that any herbicide product or agent you use is applied safely (protect yourself and non-target plants!). Check the table below, and the Environmental Protection Agency’s Restricted-Use Pesticide list here to see if an applicator license is required. No literature has been found on the oil and salt method, but professional rumblings warrant giving it a shot.

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​The stump and roots will react to the canopy’s removal, which cuts off the tree’s food source; i.e. foliage. Naturally, the remaining live material will produce many sprouts as the tree tries to compensate – hence the necessity to apply products effectively. 

Each of these stump-treatment methods requires the agent be absorbed through the tree’s vascular tissue, particularly the phloem. Find this thin, darker ring just the inside of the bark, and outside of the cambium. Apply the agent to the freshly cut stump and don’t hold back. The agent will be transmitted down to the roots, where it has the best chance of killing off clonal suckers before they sprout. ​
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​Wait about a month for the agent to run its course in the roots before grinding the stump. Arrange for this stump-grinding with your arborist during the removal. Once this is done, stay vigilant – now the process becomes a project, albeit one that requires little effort. Keep an eye on the surrounding area for a good 3 years - and don't neglect your neighbors' role in this! They'll have to keep on top of the shoots as well. This tree has the complete invasive package, so root suckers will happen. When they do, you all be ready. 

Total Control
Extrapolating from data compiled across the nation, the Oregon Department of Agriculture has recognized the economic impact that Tree-of-heaven could have on urban areas like Portland. Although only listing this potential impact threat as 5 out of 10, repairs to sidewalks, house foundations, and property damage from limb failures are associated with significant costs at the individual level. The report notes, “Eastern Oregon [Tree-of-heaven] populations are expanding but currently are not located in areas where they create economic problems. Lateral rooting can push up pavement and sidewalks, and has been noted to ruin septic tank drain fields in its search for moisture.” Importantly, this report comes from 2012. Take a drive along I-5 in north Portland today, or I-84 east toward The Dalles, and it’s easy to see how quickly Tree-of-heaven can expand. The report continues, “On the west coast, tree of heaven creates problems in natural systems by forming large thickets via root suckering. Riparian areas are especially affected.” So just imagine the threat it imposes on the Sandy River or Johnson Creek watersheds -- an invasion of either would essentially render control attempts futile. 

We see that critical to the eradication of Tree-of-heaven isn’t only the cooperation amongst government agencies and experts, but also homeowners and community groups – those people who are likely directly affected. It falls on each one of us at the local level to attack the problem before it’s a much larger, costlier issue. As we like to say in the tree world, make that 25 cent cut now and avoid the $2,500 cut down the line. Or in this case, just pull those sprouts when you see them! 
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... and Further Research
Some research is being conducted into two bio-controls with larger, wide-spreading implications for Tree-of-heaven. The first is a weevil (Eucryptorrhynchus brandti), and the second is a fungus (Verticillium nonalfalfae). Each of their applications is being studied intensely before use could be approved. Ensuring these bio-controls don’t unexpectedly affect non-target species is of utmost concern. If one or both prove effective, the whole eradication game could shift, but eyes on the local level will always be necessary. Be sure to contact TEN! for information on what to do when you see Tree-of-heaven in your neighborhood! 

References
  • Southeast Exotic Pest Plant Council. 2016. http://www.se-eppc.org/manual/ailanthus.html
  • University of Pennsylvania. 2016. http://news.psu.edu/story/280078/2013/06/24/research/ailanthus-trees-status-invasive-species-offers-lesson-human 
  • The Problem with Invasive Plants. 2016. https://www.portlandoregon.gov/bes/article/330681 
  • GoogleMaps.2015.https://www.google.com/maps/@45.5683609,-122.5979266,3a,75y,198.56h,110.54t/data=!3m6!1e1!3m4!1s69Ifh9U-sDQWsLg27GTuOQ!2e0!7i13312!8i6656    
  • Tree-of-heaven Eradication Now. 2016. http://www.tenpdx.org/ 
  • The Wood Database. 2016. http://www.wood-database.com/lumber-identification/hardwoods/ailanthus/ 
  • Portland Trees. 2016. https://www.portlandoregon.gov/trees/article/424016? 
  • EPA. 2016. https://www.epa.gov/sites/production/files/2016-02/documents/rupreport-sec3-update-jan2016.pdf
  • Odell Engineering. 2016. http://www.odellengineering.com/newsletters/2014-06/2014-06.html
  • Yoder Farm. 2016. http://www.yoderfarm.com/sugar/assetssugar/trunkxs1.jpg
  • Oregon Department of Agriculture. Plant Pest Risk Assessment: Tree of Heaven. 2012.
  • National Center for Biotechnology Information. 2012. http://www.ncbi.nlm.nih.gov/pubmed/22525066
  • USDA. 2015. http://www.nrs.fs.fed.us/disturbance/invasive_species/ailanthus_and_Vn/ 
2 Comments
Amy Whitworth link
2/25/2018 12:54:37 pm

I have had good luck with the removal of my old tree of heaven without any suckering. I had the tree removed in mid summer, after flowering had begun - around mid-July. It seems the tree had expended all of its energy in its spring flush of leaves and then flowering. The stump was ground a short time after removal. Perhaps timing is everything. Mine was a male tree.

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top resume review link
12/10/2019 03:09:38 pm

This is not something that I believe in, but it amuses me that there is a legend like this. I mean, a tree that grants immortality? That is just wacky in my opinion. I am not here to criticize the people who believe in it, and I am sorry if my tone sounds offensive. I have no real reason to not believe in it, but then again, there is no real reason to believe in it either, so it is all the same for me.

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