WILL IT SHARE THE FATE OF THE AMERICAN CHESTNUT? 



THE FUTURE OF BUTTERNUT 



Mary Torcello 



TRADITIONALLV, 



BUTTERNUT 



WAS PLANTED ON 



it 



FARMS & IN 



YARDS... 



THE NUTS WERE 



USED FOR FOOD, 



THE HUSKS FOR 



CLOTH DYES, 



& THE WOOD 



FOR FURNITURE & 



CABINETRY... 



time to fight it was a favorite 



MATERIAL OF 



WOOD CARVERS & 



PROVIDES 



EXCELLENT 



WILDLIFE FOOD... 



I remember when..." is a phase often heard 

 when talking with people about trees such 

 as American chestnut and American elm, two 

 species devastated by disease. Recently, 1 have 

 heard that same phase used for butternut. It 

 sent a chill down my spine. A disease is attack- 

 ing butternut throughout its native range. 

 Records have shown that tree numbers have 

 been declining over the last 25 years, but many 

 people believe that there is st 

 back. 



Butternut (\uglans cinerea], a cousin to black 

 walnut, is not a common species. In the forest, 

 butternut trees almost never grow in pure 

 stands. Since it cannot grow in shaded condi- 

 tions, it requires openings in the forest canopy 

 to naturally regenerate. Most often, butternut 

 can easily be found growing in bottomlands 

 along stream banks and fields of rich loamy soils 



Traditionally, butternut was planted on farms 

 and in yards because of its usefulness. The nuts 

 were used for food, the husks for cloth dyes, 

 and the wood for furniture and cabinetry. Also, 

 it was a favorite material of wood carvers. In ad- 

 dition to being a valuable commodity, butternut 

 provides excellent wildlife food and is an impor- 

 tant biological component of our forest. 



What is this culprit that is placing our native 

 butternut in jeopardy? It is a non-native fungus 

 {Sirococcus clavigignenti-juglandacearum) called the "But- 

 ternut Canker" whose exact origin is unknown. It was first 

 reported in Wisconsin in the 1960s. Today, infected trees 

 are found from Maine to Minnesota, and south to the 

 Carolinas and Arkansas. 



The fungus causes multiple branch and stem cankers 

 that eventually girdle the tree. Canker infections start 

 through leaf scars and buds, open bark fissures, and 

 wounds. Cankers on branches cause sunken discolored 

 areas that are usually elliptical in shape. On the tree 

 stem, the canker can cause a patch of black liquid ooze 

 in springtime that later becomes sooty in appearance. 

 Under the stained bark is the dark ellipsoid canker It's 

 common to find cankers at the base of trees and on ex- 

 posed roots. In some cases, infections can weaken the 

 tree enough to make it susceptible to other problems, 

 which in turn add to the demise of the tree. Sections of 

 the tree crown can die back (however, this symptom can 

 be caused by other factors). 



There is no known control for this disease. However 



in landscape settings, actions can be taken to 

 help an infected tree. Watering the tree in 

 times of drought and preventing wounds with 

 yard equipment can decrease stressful situa- 

 tions for the tree. Removing dead trees is rec- 

 ommended (they act as reservoirs for the fun- 

 gus), especially if the trees pose a hazard to 

 life and/or property. 



The visual impact of losing butternut 

 trees is not as impressive as that caused by 

 the decline of the American chestnut from the 

 chestnut blight fungus. American chestnut was 

 found in great numbers in hardwood stands 

 across the East, while butternut is typically an 

 uncommon species across its range. Unlike the 

 infectioned American chestnut, infected butter- 

 nut trees may take a number of years to die — 

 and some trees can survive infections. How- 

 ever, given naturally low populations of butter- 

 nut in the forest, there is concern about main- 

 taining a genetically viable population. Wiscon- 

 sin and Michigan report significant numbers of 

 live butternut are decreasing. 

 Currently butternut is listed as a Federal Cat- 

 egory 2 Candidate on the Endangered and Threat- 

 ened Plants list. In this category, species in question 

 have some evidence of vulnerability. Collecting 

 more information on the status of butternut 

 would help to determine if it is truly a threat- 

 ened species under the Endangered Species Act. 

 A 'Butternut Coalition" of state and federal govern- 

 ment agencies, conservation organizations and concerned 

 individuals now meet to discuss the conservation of but- 

 ternut. These groups bring together the most current 

 knowledge about butternut and the disease. Current ef- 

 forts focus on conservation and the propagation of ge- 

 netically disease-resistant trees. 



But it is difficult to tell genetically resistant trees 

 from ones that are not Timber harvesting guidelines are 

 available which target salvaging dead and heavily in- 

 fected trees (non-resistant to the fungus), and saving 

 possible disease-resistant butternut in the forest. In 

 1992, Minnesota placed a moratorium on the harvest of 

 healthy butternut within the state. In 1993, the USDA 

 Forest Service placed a similar harvesting restriction on 

 the National Forests. The trees that remain may then be 

 candidates for collection of their genetic material 



Candidate trees for retention need to be healthy in 

 appearance and free of cankers or have been able to 



October & November 1995 



