Reflections on Four Decades of the Study of American Chestnut Ecology

Frederick Paillet University of Arkansas

Years Ago 0

12,000

Readily recognized wood texture TYPICAL CHESTNUT SPROUT HOW SLOW CAN CHESTNUT GROW? 1987 field sketch 15 YEARS LATER 25 years later 2012 photo NATURAL BONSAI

50 growth rings

1-inch diameter

HEMLOCK HOLLOW at Harvard Forest Hemlock woodlot at Harvard Forest BLIGHT ARRIVES IN NE MASS 1922 Chestnut study plot in NE Massachusetts Uncut logs pull roots out when they fall Chestnut sprouts from big stumps only with difficulty SEEDLING CYCLE Sprouting mechanism designed for eternal youth RED OAK PHOTO Conventional stump sprouts have weakened trunks Hypovirulence appears in the wild Large Virginia survivor (2013) Trunk is one continuous canker Chestnut reproduction questions Why chestnut seedlings were not under mature trees??? • Halo of abundance around Hemlocks at Harvard Forest • Henry Thoreau found few seedlings in chestnut groves • Immortality and palatability go together • Foragers plow ground under mature trees • Trees want long distance dispersal to disturbed areas • The ultimate in opportunistic tree

Visions of Naturalized American Chestnut in West Salem, WI West Salem more than 500 miles from natural range of chestnut Stand Background

• Nine trees established in old meadow after 1890 • Originated as seed brought from Western PA • Invasion into adjacent oak-hickory stand after 1940 • Selectively logged about 1980 for oak & chestnut • 1st TACF visit spring 1987 & initial blight discovery • Hypovirulence treatment starting 1992 • Gilland et al document chestnut mast production Journal of the Torrey Botanical Society, 2012, v 139, p. 283-289 Growth form of Forest Grown American Chestnut Examples of West Salem trees Paillet field notes 1987 Compare trunk form of Chestnut Open grown Naturalized in forest

Virgin chestnut forests of the Russian Caucasus Virgin old-growth chestnut Visions of a magnificent tree in its prime • European chestnut – Castanea sativa • The Caucasus – eastern extension of the Alps • Steep slopes with mostly deciduous forests • Main associates – beech, oak and hornbeam • Other species – maple, elm, linden, ash • Unblighted as of last TACF visit in July 2002 • Blight reported in eastern (Caspian shore) edge of range as of 2008. Deciduous forests of the Russian Caucasus Russian chestnut expert Mikhail Pridnya

General forest view

Chestnut in foreground

Leaves and immature burs in mid July European chestnut - Castanea sativa Typical European chestnut beside oriental beech One of the largest Russian trees Chestnut bark Seedlings chestnut oak CHESTNUT IN CHINA Chinese Chestnut - Further questions about blight and its host • How resistant are the three Chinese species? • Are there differences in levels of resistance? • Are there differences within cultivars? • Are there timber-form Chinese trees? • How does blight interact with Chinese trees? • Are there other strains of blight we haven’t seen yet? • Can we set up a cooperative program to conduct experiments with our cultivars?

Mountain chestnut Castanea henryi Largest of the three Chinese species Seguin chestnut Castanea seguinii Chinese chestnut

Castanea mollissima

Growing in a natural forest setting Castanea mollissima (blighted) Blight verified in the lab

Chestnut vs Allegheny Chinquapin

Virginia and North Carolina Ozark Chinquapin Ghosts in the Ozark forest Blight appears in NY 1904 arrives in NW Arkansas 1957

Growth history of oaks near chinquapin logs

TB white oak Wed black oak snag Blight arrival Hobbs white oak Ring width in mm in width Ring

0 1920 1940 1960 1980 2000 Calendar year REPRESENTATIVE SAMPLES More than 70% of original blight kill had single main trunk Scale in feet Old growth chinquapin THE MIRACLE OF A SEEDLING Hemlock crisis Questions?