Butternut - Another tree in trouble
By Barb Boysen, Forest Gene Conservation Association
The butternut tree, like elm, oak and pine is a touchstone species for many people. It evokes memories of other times and reconnects us to the land, to the forest. I remember, as a new forester in the hardwood forests of eastern Ontario, watching for the flat grey ridges of bark forming diamonds up the trunk; and many years later, helping my children see the moustache below the bud on a twig. In our woodlot, I seek out butternut to find the first signs of wild ginger in the spring, and in the fall I search again hoping to see a few ginseng berries. And once in the last 20 years, there was a bumper crop of butternuts - I can still feel them rolling under my feet in the early fall woods. My mother reminisces about cracking butternuts with her dad on the back porch of the farmhouse. I ve seen my husband’s fingers, stained for weeks, after husking and cracking nuts for my butter tarts. My newest memory - the sweet, sweet taste of butternut syrup made by a friend from Akwesasne.

Memories might soon be all that we have. Butternut is dying all across its range in the USA and Canada from butternut canker - a virulent fungal disease. It is currently being assessed by Environment Canada for endangered status under the Species at Risk Act.

While butternut canker is threatening the species, a threat to individual trees is early removal - the mindset that “every tree is doomed, so cut it now.” This same attitude saw too many diseased elm removed from our landscape. Many of these trees may have had the resistance researchers have since found. And butternut is even more vulnerable than elm. The cut-it-now attitude could greatly limit its chances for recovery. These vulnerabilities include naturally low numbers, short life span, shade intolerance, highly predated seed, wood that is valued for speciality products and the fact that all ages of the species are vulnerable to the canker.
Figure 1. Cankers on a butternut stem caused by Sirococcus clavigignenti- juglandacearum. Note active cankers as indicated by the symptomatic black exudate and older cankers, which the tree has attempted to heal-over as indicated by seams in the bark. (Photo - Canadian Forest Service, captions - Davis & Hopkin)

There is likely a butternut in every woodlot in south central Ontario, but it rarely shows up in forest inventories. We rely on landowners to tell us about its occurrence and health. It has less commercial importance than more common species and is therefore less studied. It is short-lived - 100 years is an old butternut, compared to 200 years for maple and oak. And it needs full sunlight to grow vigorously. It can lose its place in the canopy to longer-lived, more shade tolerant species such as maple and oak, and its seedlings need open areas to thrive. Its seed, butternuts, are quickly devoured each year by many animals. Wood workers prize its wood, and there is pressure to use it before it dies and rots. On top of all this, the canker has spread quickly across its range and kills all ages.

However, there is hope. Butternut researchers expect that some butternut will demonstrate canker tolerance or resistance. American conservation efforts have located about 200 possibly resistant trees, although true resistance remains to be demonstrated. It is therefore critical that we keep what live butternut we have to allow tolerance or resistance to be found.

If Environment Canada decides to list butternut as a nationally endangered species, a National Recovery Strategy will be developed. In the meantime, an Ontario Team is creating an Ontario Butternut Recovery Strategy, building on the work initiated by the Forest Gene Conservation Association (FGCA) over the last 12 years. Our long-term goal is to restore butternut and its functions in our forests. A key strategy will likely be to re-introduce disease tolerant, climate-adapted butternut across southern Ontario. In support of this our activities will:
1. encourage people to retain butternut, especially vigorously surviving trees;
2.

encourage people to report butternut;
3.

establish a butternut database;
4.

educate landowners on how to increase butternut vigour and regeneration;
5.

study the genetic diversity of butternut for a potential resistance breeding program and establish seed transfer guidelines for planting;
6.

study butternut’s link to forest species such as ginseng;
7.

work with seed collectors and growers to propagate butternut from vigorously surviving trees;
8.

clonally propagate surviving trees in protected archives and assess for genetic tolerance.
Butternut is just one of an increasing number of native species in trouble. In this program, we will also help people understand how a single species helps support the web of life in a forest. And hopefully this understanding will extend to how important healthy forests are to our quality of life.

Extensive contact with landowners and strong partnerships with other conservation, forest management and research groups are the keys to butternut recovery. One partner, the Eastern Ontario Model Forest (EMOF), has worked with the FGCA on butternut for over 10 years. The EOMF, with its charitable status, has set up a butternut fund to support long-term recovery efforts. If you are interested in donating to the efforts to save butternut, please call (613) 258-8241 or visit the EOMF Web site at <www.eomf.on.ca>. Sponsors will receive tax receipts for their donations.

Demonstrate your commitment to sustaining our natural forests. Help us help a species many think is doomed. Help us give your grandchildren and their children a chance to build their own memories with this unique species.

If you have questions, or want to help with this program, please contact Barb Boysen, FGCA Coordinator at (705) 755-3284, <barb.boysen@mnr.gov.on.ca>or <www.fgca.net>.
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