Chestnuts – Celebrating Castanea, part two

December 18, 2013

Castanea mollissima

Chestnuts – Celebrating Castanea, part two

In our last post we learned about the chestnut and its great value for food and timber. This time around we’ll see what happens to a species, in this case the American chestnut (Castanea dentata), in the face of introduced disease.

Chestnut Blight and the Pennsylvania Chestnut Tree Blight Commission

Chestnut bark blight fungus (Cryphonectria parasitica, formerly Diaporthe parasitica and Endothia parasitica) first arrived in North America from Asia in the last quarter of the 19th century, probably hitching a ride on infected Japanese nursery material in the days before quarantine regulations. The disease spread rapidly to the domestic species of chestnut which had no natural resistance. In 1904, trees at the Bronx Zoological Park were observed with cankers in their bark and the next year C. parasitica was identified as the cause.

Concern over the disease, which was killing large numbers of trees, prompted the Pennsylvania legislature to form a “Commission for the Investigation and Control of the Chestnut Tree Blight Disease” in 1911. It met first in February 1912 but opinion was divided among the participants as to whether the disease was foreign, having come in on infected plant material, or of domestic origin and caused by poor husbandry. Under the Commission’s auspices, programs for diseased tree identification and destruction were implemented in hopes of stopping or at least slowing the progress of the disease. It was believed that 1913 would be a turning point; however the fungus continued its advance. The Commission ceased operations that year having removed over 30,000 trees. Its work might have ultimately seemed futile; however it raised official awareness of plant disease which led to quarantine regulations for plant material later in the decade, as well as proving the disease had wind-borne transmission.

Frank Meyer and Chestnut Blight

Frank Meyer collected ornamental woody plants in China for the Arnold Arboretum from 1905-1918. His primary employer however was the United States Department of Agriculture, in the person of David Fairchild of the USDA Bureau of Plant Industry. Meyer traveled widely throughout the country collecting plants of possible economic use; he photographed what he saw and wrote detailed descriptions of the uses the indigenous people made of the plants.

In late 1912, Fairchild was alerted to the fact that the chestnut bark blight which was ravaging trees in eastern North America might have come from Asia. He tasked Frank Meyer in 1913 to seek out chestnut trees in China and observe any that might be infected with the disease. In May, Meyer headed out to an area in Hebei Province and immediately found infected trees. In a letter to Fairchild in early June he reported that while he saw a number of trees exhibiting evidence of infection, he could not see any that had actually succumbed to the disease. He added however, that those trees might have “been removed by the ever active and economic Chinese farmers,” who attempted to manage the disease, which they attributed to insect pests, by scraping clean the bark. He observed that in general, trees growing in good, well-drained areas were less susceptible to attack by the fungus than those growing in more stressful conditions. We have copies in the Archives of the photographs Meyer took in China for the USDA at the time, as well as further field observations in 1914 and in 1915 in Japan.

Whither Chestnuts?

The American Chestnut Foundation is working to breed American chestnut trees containing enough Chinese chestnut DNA to impart blight-resistance but which will retain as much of their original genetic material as possible. The program is especially keen to breed disease resistant trees which have the stature of pre-blight American chestnut populations, rather than producing small spreading trees which reflect their Chinese chestnut genes. Experiments continue apace but it takes time, five to six years, for the backcrosses and intercrosses to mature. We’ll have to stay tuned for more developments.

The Library has books about chestnuts and the Archives has a collection on chestnut blight and the Chestnut Blight Commission. In addition we have many historical photographs of these magnificent trees in their heyday. Please pay us a visit to learn more.

FURTHER READING

Freinkel, Susan. American chestnut : the life, death, and rebirth of a perfect tree. Berkeley : University of California Press, 2007.

Pennsylvania Chestnut Tree Blight Commission. Report of the Pennsylvania Chestnut Tree Blight Commission.
Harrisburg, C.E. Aughinbaugh, 1913-1914.

Pennsylvania Chestnut Blight Conference (1912 : Harrisburg, Pa.). The conference called by the governor of Pennsylvania to consider ways and means for preventing the spread of the chestnut tree bark disease : The Capitol, chamber of the House of representatives, Harrisburg, Pennsylvania, February 20 and 21, 1912. Stenographic report of proceedings of the conference. Harrisburg : C. E. Aughinbaugh, printer to the State of Pennsylvania, 1912. Available to view online.

Lisa Pearson, Head of Library and Archives

One thought on “Chestnuts – Celebrating Castanea, part two

  1. I have been cross breeding the American Chestnut from Mass and NH native trees for the pass 20 years. I have a number of hopeful mother trees that exhibit both tall growth and resistance. I would like to donate some offsprings to the Arnold Arboretum for future expansion. If interest, please email me. Thanks Ron Squillacioti

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