Biography of Durham’s Finest Tree* No. 3: White Ash (Fraxinus Americana)

by Wendy Diaz

A White Ash tree in Parkwood is the 2015 Durham’s Finest Trees¹ winner in the ‘large category’ for its species.  On March 6, 2016, four Durham trees located across the city and county were recognized for their size and significance during Durham’s Arbor Day ceremony at the Museum of Life and Science.  The White Ash (Fraxinus Americana) is located near the corner of Timmons Drive and McCormick Road in the Parkwood Neighborhood of South Durham.

2016ParkAsh

ParwoodashDescription

It has a trunk circumference of 123 inches and it is at least 90 feet in height with an average canopy spread of 85 feet.  The white ash dominates the overstory of this small woodland and towers over understory hardwoods that surround it in this dense forest situated along a small tributary to Northeast Creek.  In fact, the height of the Parkwood Ash is close to the current North Carolina Champion Tree of the same species located in Forsyth County (height 100 feet, circumference 206 inches and 102 feet crown spread)¹.

The White Ash is the only southeast native of four ash species that is not a wetland species:  Green Ash-Fraxinus pennsylvanica; Carolina Ash- F. caroliniana; Pumpkin Ash-F. profunda².  A noteworthy characteristic of mature White Ash trees is the diamond-shaped ridging of the gray bark³.  On the west side of the Parkwood White Ash trunk is an area of the ridging that has been worn smooth; most probably from a large animal rubbing on the bark of the lower tree trunk who needed a good scratch.  An interesting bit of trivia for the Durham baseball fans out there—White Ash wood is used for the Louisville Slugger baseball bats.  Ash trees also support at least 150 pollinator species of moths and butterflies including the Eastern Tiger Swallowtail².

PWhiteAshVertical

History

The tree is located in the undeveloped natural area of the Parkwood subdivision, which up until its development in the early 1960’s was a very remote wooded area of Durham County4.  The first home was occupied in August, 19604 and the grand opening of the nearby Parkwood Shopping Center occurred on December 11, 19625).  The award-winning Parkwood neighborhood was linked to the development of the Research Triangle Park (RTP) to provide housing for RTP employees and Parkwood HOA was one of the first homeowners associations formed in North Carolina on September 25th, 19606.

PWhiteAshDiamondRidgeBrk

Characteristic White Ash Bark

PWhiteAshrubbedbark

This bark has been rubbed by an animal.

A Serious Threat to Ash Trees

This grand old occupant of Southern Durham County is in danger of the southerly migration of the Emerald Ash Borer (EAB) from northern states.  The tiny iridescent green EAB, is a native of Asia, and was first discovered in southeastern Michigan in 2002.  It has taken just over a decade to reach North Carolina in 2013 by way of Virginia3.  Typically, the EAB will kill an ash tree within 3 to 5 years after the tree is infested3. It has already killed almost every ash tree species in Ontario and Quebec, Canada and is present in most states east of the Mississippi River.2  Female EABs lay eggs in bark crevasses and when the tiny larvae hatch they chew through the outer bark and then the inner bark.  The EAB bores into the sapwood and feeds on this tissue under the bark resulting in the tree loosing its ability to transfer food and water between the roots and leaves2.  The feeding larvae disrupt the transport systems of the tree by creating winding tunnels (galleries) in the sapwood2.  This time of year in late spring, the EAB has begun to emerge from the ash wood as a mature beetle and will feed on the leaves and reproduce.  To track the pest, The City of Durham is placing sticky traps at known stands of ash7.  These traps mimic the attractive scent that the distressed ash trees emit that is irresistible to the EAB.  If the presence of EAB is confirmed then the City of Durham is eligible to receive parasitoid wasps from the N.C Forest Service, which will eat the EAB larvae and slow the spread of EAB.  In 2014, the pest was found in Durham County but has not been trapped within the city limits, yet7.

The Parkwood White Ash may well be a rarity in our county, if it survives.  It is no longer recommended that ash trees be planted as shade or street trees in our North American cities.  Unlike in the Northeast, Ash trees were rarely planted as street trees in Durham and it is estimated that only six per cent of Durham trees are ash and most are located in floodplains and along streams7.  Please protect the Parkwood White Ash and our existing ash trees by remembering to only use local firewood.  This will prevent unintentional transport of these pests to other stands and please report dying ash trees (initially the top of crown thins and partially dies) to the North Carolina Forest Service: http://www.ncforestservice.gov/forest_health/fh_eabfaq.htm.

PWhiteAshCrown 2015ParkAshCrown

Photo Credits: Wendy Diaz

References:

  1. http://ncforestservice.gov/Urban/big_species_results.asp
  2. Invasive Exotic Insects Threatening Our Native Forests, Emerald Ash Borer in North Carolina by Catherine Bollinger  North Carolina Botanical Garden Conservation Gardener Magazine; Spring & Summer 2016
  3. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=282936&isprofile=1&basic=White%20Ash
  4. http://www.newsobserver.com/living/livcolumnsblogs/pasttimes/article27115885.html)
  5. http://www.opendurham.org
  6. http://www.parkwoodnc.org
  7. Durham Now Monitoring for New Invasive Tree Pest, by Alex Johnson, Urban Forestry Manager, General Services Department, City of Durham. Herald-Sun Newspaper, Sunday, May 8, 2016

* Durham’s Finest Trees program recognizes significant trees in Durham County, promotes discovery and ability to identify trees, and helps preserve the best examples of specific tree species, particularly native and those trees well adapted to Durham County. The program also promotes awareness of trees in our community and hopes to catalog fine examples of magnificent specimens of trees due to their size, setting, historical importance, or significant feature.

Durham naturalists and tree lovers of all ages are invited to submit their nominations for significant trees in Durham County now through October 1, 2016. Trees on private or public property can be nominated in each of the three categories: largest, historical, or meritorious. Preference will be given to native North Carolina tree species. Non-native trees may be considered if they are of a species, subspecies, variety or cultivar proven to be relatively long-lived and well adapted to North Carolina. Winning trees will be recognized on Arbor Day 2017. Please read the official rules before submitting a nomination.

 

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