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Collecting Minnesota ash seed: 2009 update

Update: September 2009

Emerald ash borer (EAB), an invasive species, threatens to kill Minnesota’s ash trees. In response, Andrew David, a University of Minnesota forest genetics researcher, and Mike Reichenbach, forestry educator with University of Minnesota Extension, began a project to protect the genetic diversity of ash in Minnesota.

Black ash stand near Cohasset, MN

Black ash stand near Cohasset, MN

Seed collected from wild-grown ash trees will be sent to one of three seed storage facilities in Colorado, Georgia or Iowa depending on the amount of seed collected. This seed collection effort is a proactive response to the presence of EAB in Minnesota and the upper Great Lakes region. This conservation effort will preserve the genetic variation for a future point in time when EAB can be controlled and ash species can be reintroduced to Minnesota using locally adapted seed sources.

How to collect and contribute seed

UMN Assistant Scientist Egon Humenberger with green ash seed collected in 2008.

UMN Assistant Scientist Egon Humenberger with green ash seed collected in 2008.

Ash seed has been ripening all summer and will be ready to pick when the seed cavity is completely filled and the seed coat is brown.  Collection of seed typically begins about September 21st and can continue through much of the fall.  Black ash seed is the hardest to collect because it is difficult to judge ripeness and the seed begins to fall with the leaves.  The best time to collect black ash seed is from 1 week prior to leaf fall to approximately 2 weeks after all leaves have dropped.

In contrast green ash seed will remain on the tree for awhile after the leaves have fallen allowing collections into late fall.  It will be easier to collect from trees before the seed is scattered by winds and rain. Persons wishing to collect seed should watch the ash seed collection webinar found listed under the webinars tab at  The ash seed collection form can also be downloaded here.

Value of ash to Minnesota; ongoing threat of EAB
Minnesota is host to three species of ash: white ash, green ash and black ash. While white ash is an upland species found along the Mississippi River in southeast Minnesota; both black and green ash are common lowland hardwoods found throughout the majority of the state. Ecologically, black and green ash are the most important hardwoods in the lowland forest community. They represent 51 percent of the lowland hardwood cover type in Minnesota. Black ash is very important in native cultures as a source of wood for ash baskets. Both black and green ash provide a source of pallet, saw and veneer logs.  All of Minnesota’s native ash species are threatened by EAB.

EAB was most likely introduced to the region when it was transported on wood packaging of an overseas shipment from Asia in 2002 to the Detroit, Michigan and Windsor, Ontario area. Within the United States the insect is most often transported on firewood. As of August, EAB has been found in Illinois, Indiana, Maryland, Michigan, Missouri, Ontario, Ohio, Pennsylvania and Wisconsin. It has been responsible for the death of over 20 million ash trees despite quarantines on moving nursery stock and firewood out of infected areas.

This conservation effort will preserve the genetic variation for a future point in time when EAB can be controlled and ash species can be reintroduced to Minnesota using locally adapted seed sources.

Click for much more information on emerald ash borer in Minnesota. To get involved in seed collection, contact Mike Reichenbach, (888) 241-0724,; or Gary Wyatt, (888) 241-3214,,  both with University of Minnesota Extension.

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12 Responses to “Collecting Minnesota ash seed: 2009 update”

  1. Lisa says:

    I have green blisters on the leaves of my seedless ash tree that contain small white larvae or little worms. The leaves appear to eventually break open in the blistered area. the size of the blister which appears to be the actual leaf is about one fourth inch long and an oval type shape. I have noticed leaves on the ground that are black curled and dried out lately too. two weeks ago I applied the preventer for the emerald ash borer. thank you! Lisa

  2. esagor says:

    Hi Lisa. Thanks for posting your question! The best place to get an answer to questions like this is the MyMinnesotaWoods discussion board, at If possible, take a picture of one of the blistered leaves and upload that with your question. Good luck and thanks again for the question.

  3. Tony says:

    The reports of the EAB are so disheartening, but this seed collection projects at least gives me some hope.

    Also I was wondering if I could get permission to repost this information on my basketry blog. I am a weaver of black ash baskets and I am sure my readers would be interested in this report.


  4. MIke Reichenbach says:


    The use of black ash for baskets and its potential loss to EAB is disheartening. I would be most interested in continuing a discussion with you and other users of black ash about potential strategies to sustain the species.

    Currently seed collection is the most positive means we have to protect the genetic diversity of ash. However, we need a strategy to either establish outlier populations or replant or breed for trees that might have resistance or some other as yet unknown option. What ideas do you or other basket makers have regarding black ash and the threat posed by EAB?

    Please repost the information in its entirety with the following notes:

    “Reprinted with permission from

    Ash seed ripens in September.


  5. Whitney says:

    Is there any way the public can help with seed collection? Is collection going to continue this fall?

  6. esagor says:

    Hi Whitney. Yes, the public can help with seed collection. In fact my understanding is that public help is an important part of the program’s success. I’ll draw your comment to the attention of the project leads and see if they can give you a more informative answer. Thanks for your interest!

  7. esagor says:

    This comment is from Andy David, University of Minnesota Dept. of Forest Resources, Grand Rapids, MN:

    Whitney, Public collection of ash seed is an important part of the conservation of ash genetic resources. I would encourage you and others to visit

    to learn how to properly identify, collect, store and ship ash seed so it can be saved and used at a later date for species restoration purposes.

    Ship the seed to me at the address below and we will clean it and send it on to one of three places to store it. We will also get your collection up on the Minnesota map at

    Thank you for your help and interest!


    Dr. Andrew David
    1861 Highway 169 East
    Grand Rapids, MN 55744

  8. Linda Hardy says:

    After watching your video on seed collection, you said that you only want seeds from wild trees. Now…I live in what is considered the southern part of Minnesota on approximately 3 acres of land, and have approximately 30 to 35 Ashe trees on our property that are very old. Would it be okay to send seeds from one of these trees? I am hoping the EAB does not infest trees in our area, otherwise I am afraid this property would be worthless, and it’s beauty destroyed forever. Thanks for your reply in advance.

    Best of Luck to your project,

  9. Andy David says:


    If you live in a rural area AND it is likely that your trees are wild, (i.e. not planted), AND your trees are not close to a new housing development where ash trees are likely to have been planted then YES we would like seed from your trees. Please follow the directions in the video and send the seed to the address posted above in question #7.

    Thank you very much for getting clarification. Planted ash trees are typically of a very narrow genetic background that is not necessarily local to Minnesota. That coupled with the fact that in an urban setting all of these genetically similar trees are pollinating each other means that seed collected from urban, planted ash trees does not sample the genetic variation of wild ash trees.

  10. MIke Reichenbach says:


    We are interested in seed from “wild” rather than from trees that were grown in a nursery and planted. This ensures that the collectioned seed captures the genetic variation of Minnesota’s native ash trees. Trees that are purchased at a nursery may or may not be native. Even if they are native they may not reflect the genetic variation from Minnesota. This would be true if the nursery grown trees originated from seed collected in another state.

    I hope this helps.

    Mike Reichenbach Extension Educator

  11. jacob steidl says:

    is it possible to collect and store seeds at home. i understand the “invasion” may last a while.

  12. Andy David says:


    Long-term storage of ash seed is a tricky business as it requires the seed be dried to a relative humidity below 9% and kept at that humidity while frozen at -20 degrees Centigrade (roughly -4 degrees Fahrenheit). Although your common freezer can get this cold the automatic defrost cycle that prevents the buildup of frost and ice actually causes the temperature to fluctuate too much. This constant changing of temperature also impacts the relative humidity of the seed rendering it inviable after about a year. That is one of the reasons we leave the long-term storage of ash seed to the experts (National Seed Laboratory, National Plant Germplasm System, North Central Regional Plant Introduction Station) they have the facilities to dry the seed and store it at a constant temperature and humidity.

    Andy David
    Associate Professor Forest Genetics

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