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Learning about Dutch Elm disease and resistant Elms planted on the Green in Plymouth, NH and Katsura and Norway maple trees

Last updated on December 20, 2022

Students reflections on Tree Tour, fall 2022:

I ask students to reflect, so I am adamant about practicing what I preach. The effort is worth the result for me in terms of what I retain, new insights I gain, and questions that emerge that lead to further investigation. Writing my reflections means I can share them with the students and use the information when planning future tree tours.

Guest presenting with the main instructor along has its merits. I am in the role as student and as instructor. I had the opportunity to witness and learn from the structure, resources, and input of the primary instructor. I was also prompted to dig deeper and research more information about trees on our campus to appeal to more types of students.

For this tour, I looked up the economic value of maple syrup for New Hampshire. On the tour, I pointed out the row of sugar maples that line the main walkway on campus in front of the Advancement Office which add so much visual beauty as the leaves turn in the fall. I was surprised to learn NH is not second, third, or even fourth in terms of maple sugar production. We rank sixth,…/us-maple-syrup-production…/

I also found a new cultural story about the always popular Katsura trees, Cercidiphyllum japonicum, ornamentals from Asia. There are two side by side in front of Ellen Reed Hall. Japanese legend indicates the tree provides a path by which gods descend from the heavens, symbolizing the joining of earth and sky. Students noticed one tree is different from the other. The trees are dioecious, meaning there are separate male and female trees. Female flowers are green and male flowers are red, appearing in spring briefly. Fruits from the female trees are small pods, in groups of 2 to 4. If you visit the trees, see if you can determine which is female.

At the beginning of this class, students brainstormed all the benefits of trees. I was surprised to hear a couple of more unusual values, beyond the usual responses like providing oxygen, resources, shade, preventing erosion and providing wildlife habitat:

Responses: Trees

“provide sap,”

“help with our mental health,”

“produce oxygen, but not as much as phytoplankton,”

“ [when they are] dead- provide nutrients,” and related, “food for fungus”,

“are fun to climb and nice to look at,”

“sequester carbon,”

“can communicate subsonically.”

“provide serotonin” (a chemical related to happiness). This last response led me to two new resources:

1. “Why trees can make you happier,”…/why_trees_can_make…, and

2. This scientific study concluded, “Increasing the serotonin level through the meditation-oriented forest therapy program… can contribute to illness prevention and improve quality of life,”

Memorable takeaway messages included similar statements I had heard two days before on a different :tour:

“Learning the history of the dawn redwood.”

“Learning about fascinating trees on campus.”

The following, more specific statements were all written,

“Alaskan cypress looks like something drawn out of Dr. Suess,”

“Trees are used as monuments,”

“Ginko is my favorite tree; we only have one in my hometown of Seabrook, NH… I have kept a Gingko leaf since I was 12 years old… still have it and it was exciting, seeing that tree here (on campus).”

“…tasting the berries (of the Black Tupelo) and looking at the biggest leaves (Big leaf Magnolia)”

“finding a deeper love and enjoyment for trees. I really enjoyed this lab and would love to learn more.” (I need to recruit this student to work on the Tree Campus activities which include giving tours to prospective students on campus.”

“Looking at rare trees was the best.”

“Seeing trees from around the world on campus.”

“Trees give phytoncydes.”

Several students remarked on learning about the great variety of species on campus.

One student related his favorite tree is the American elm. I pointed out that a disease resistant elm has been planted in downtown Plymouth, in the green by local resident, former science teacher, Doug McLane.

American elm trees once lined main street in Plymouth as can be seen in old post cards of the town.

The National Park Service now uses a disease resistant cultivar on the National Mall in Washington D.C. due to their longevity, their appealing shape and the shade they provide.

The Dutch elm fungus came to the US from the Netherlands in 1930 in a shipment of logs. By 1970 most of the elms in New Hampshire were infected and had to be cut down. The USDA Forest Service has created a website for reporting “survivor elms,’ NHPR Protecting New Hampshire’s Trees: Elm, Ash and Chestnut, The Exchange oct. 4, 2017.

I was surprised the student chose and knew this tree because the Dutch Elm Disease mostly wiped out these trees in twenty years, between the late ’60’s and early 80’s, including in my front yard in Denver, CO. The problem fungus is spread by three types of feeding beetles.

Norway maple were planted to replace the Elm as a shade tree only now this species is considered invasive.

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