Melanie Moore and Mike Ostry, USDA Forest Service, Northern Research Station, St. Paul, MN Paul Berrang, USDA Forest Service Region 9, Milwaukee, WI Butternut: The most famous tree no one’s heard of Juglans cinerea Butternut Oil nut White walnut Lemon nut Paul Berrang The Butternut treetopics.com Ecological importance • Riparian species • Soil stabilization • Mast (wildlife food) • Northernmost large mast • Biodiversity na.fs.fed.us nativeplantwildlifegarden.com The Butternut Human Uses: Hawkridge Furniture • Furniture • Paneling • Carving James F. Frechette • Nuts • Syrup epitkezes-kert.vatera.hu • Dye • Medicine • Fish toxin • Historical significance springvalleyherbs.com The Butternut L’ans aux Meadows: Viking settlement site Faculty.cua.edu D. Gordon E. Robertson JonnyU Wikipedia.org Cultural History George Bush: First American settlers of the Olympic Peninsula Henderson House Museum Henderson House Museum bushprairiefarm.com Olympia Historical Society Cultural History Butternut Soldiers: Confederates in homespun uniforms Jessica Hack garyhendershott.net fiveprime.org Cultural History Problems • Short-lived • Regeneration poor • Needs full sunlight and disturbed soil • Several pests and diseases • Butternut canker Butternut Canker Butternut Canker The Fungus: Ophiognomonia clavigignenti-juglandacearum “OCJ” Formerly Sirococcus clavigignenti-juglandacearum uvm.edu uvm.edu Mike Ostry Closely related to Walnut Anthracnose Ophiognomonia (Gnomonia) leptostyla, Marssonina juglandis Butternut Canker Probably an introduced pathogen from Asia • Recent appearance (since 1960’s) • Rapid spread • Only asexual spores found, no sexual stage • Resistant Japanese “heartnuts” planted widely 100 yrs ago • DNA studies show 3 genetic clusters, several introductions • DNA a close match to an endophyte on Chinese maples Base map by Andrew Clarke Butternut Canker The Threatened/Endangered Butternut • Listed endangered in Canada • US Forest Service “Regional Forester sensitive plant” • Listed endangered in Minnesota US Forest Service FIA Surveys • Decline in butternut numbers in nearly every size class and every recent state surveyed (5 years, 2007-2012) • Top losses • Iowa 92% • Michigan 73% • Missouri 52% Butternut Canker Current Research Findings • Conidia can survive 2 weeks or more on a surface over a range of temperatures and humidities (vector, seed, scion, etc.) • Host range studies- Artificial inoculations Fungus Recovered Fungus Recovered Canker Stem Wounded Leaf Butternut Red Oak Butternut Bur Oak Black Walnut White Oak Black Walnut Red Oak Heartnut Black Oak Heartnut White Oak Persian Walnut Black Cherry Manchurian Walnut Sugar Maple Shagbark Hickory Hazel Chinese Walnut Yellow Birch Bitternut Hickory Chestnut Shagbark Hickory Sweet Birch Pecan Bitternut Hickory American Beech Pecan = Natural infection documented Current Research Is There Hope? Healthy Cankered • Bark phenotype: Dark/deep versus light/shallow • Structural differences: Thickness of periderm • Chemical differences: Natural defenses such as juglone Current Research: Resistance Testing for Resistance: Inoculations Drawbacks • Time consuming • Inconsistent results • Bypass bark defenses Goal: Develop a rapid screening technique… Current Research: Resistance Juglans species and Juglone: a possible resistance mechanism • Allelopathy • Antibiotic properties • Traditional and herbal medicines Rosemount (UMore Park): • Selected grafted butternuts, non- selected butternuts, black walnut, heartnut, and hybrids • Bark sampled monthly, three years Current Research: Bark Extracts Butternut Bark Bioassay • Collect branch samples and peel inner bark • Dry and grind • Extract in 95% ethanol • Evaporate ethanol • Apply to filter discs • Place on Petri dish seeded with OCJ spores • Measure inhibition zone in 3 days Current Research: Bark Extracts Bioassay Results 2010 Inhibition Zone by Month 22 20 Selected Butternut 18 B S 16 H W Unselected Butternut Y Meaninhibition zone,mm 14 12 Apr May Jun Jul Aug Sep Oct Month 2010 Inhibition Zone by Accession 20 19 18 17 16 15 14 13 12 Mean inhibition zone, mm zone, inhibitionMean 11 10 B16 B03 S01 H133 B10 W01 B11 S54 B04 Y128 S67 S60 S22 S148 S20 Accession Current Research: Bark Extracts Chemical Characterization • Same crude extracts as those used in bioassay • Ultra high performance liquid chromatography • Juglone and plumbagin (both naphthoquinones) • Quantity varied by accession and month • Juglone data correlates with bioassay data for butternuts (r2 > 0.53) for 5 of 9 months • Juglone and probable other chemical substances may have a role in resistance Current Research: Bark Extracts The Hybrid Dilemma Butternut “Buart” Juglans cinerea J. x bixbyi • Vigorous and faster growing • More resistant to butternut canker • Difficult to distinguish from pure butternut • Areas of high hybrid incidence— urban, farms, etc. • Unknown ecological consequences X Japanese walnut (Heartnut) Juglans ailantifolia var. cordiformis Often “resistant” butternuts turn out to be hybrids! Current Research: Hybrids Hybrid Resistance Studies Forest Service unit at Purdue Canker incidence in half-sib families of seed from selected parents Preliminary Results of long-term study: Butternuts Hybrids • Very few in resistant categories • Resistant to susceptible • Resistance heritability low • Resistance heritability higher Hybrids may have usefulness in breeding if pure species selections fail Current Research: Hybrids Identify healthy trees in forests; Collect scion Graft to Manage remaining (twigs) rootstock stands Overview of Forest Establish clone Service (Region 9) banks Butternut Conservation Preserve copies of Restore butternut Produce seed; original trees; to forests Test for resistance Test for resistance Conservation Program Clone Banks being established: Key locations • UMore Park, Rosemount, MN • Oconto River Seed Orchard, Nicolet NF, WI • Hardwood Tree Improvement and Regeneration Center, Purdue University, IN • Ontario Ministry of Natural Resources (several locations) Recent federal and state locations • Green Mountain NF, VT • Mark Twain NF, MO • Wayne NF, OH • Allegheny NF, PA • PA Bureau of Forestry • VT Dept. of Forests and Middlebury College Some locations are also starting seed banks Conservation Program Additional Disease Research Questions • Site influence • Stress vs. canker severity • Tree age Restoration Research Questions • Seed regeneration “how-to’s” • Planting “how to’s” • Reducing competition • Reducing damage from deer Future study Summary • Clone and seed banks preserve potentially resistant material • Bark extract research could be useful in early screening • Hybrid testing encouraging • Host range studies, stem and leaf • Spore viability and movement • One of many North American trees being threatened by introduced diseases The Bush Butternut Tree bushprairiefarm.com Will future generations be able to connect with this tree? Summary Thanks to our cooperators: • Jim McKenna, FS • County, state and federal foresters • University of Minnesota • UMore Park Experiment Station • Dr. Adrian Hegeman, Dept. of Horticulture • A. Cece Martin, Dept. of Horticulture • Dr. Bob Blanchette.