September 22, 2006

Butternut Grove at rapid transit station

In 2005, while following up on the Environmental Assessment for the Transitway Extension Project, OFGAC found a butternut grove near the site of the Berrigan Station. Knowing that butternuts are endangered, OFGAC invited ECSONG to help identify all nut trees on the site and confirm their health status. OFGAC wanted to alert City staff and its consultants on the project to the significance of the butternut grove at Berrigan and Greenbank, for the purposes of preserving the nut trees to the extent possible.

OFGAC and ECSONG created an inventory of the Butternut Trees, which was provided to Senior Engineer of Infrastructure Projects for the City of Ottawa responsible for the Berrigan Transitway construction. A tree preservation plan was prepared by the City’s Consultants and Landscape Architect.

Construction started during the summer of 2006. On 22 September, members of OFGAC's South-Barrhaven Subcommittee and ECSONGer Hank Jones visited the Butternut and Walnut Grove at the Berrigan Transitway Station to observe the condition of the nut trees. After observing the condition of the nut trees, both groups voiced their concerns to the senior engineer for the project.

See ECSONG web site for story and pictures of the visit and photos (below) of some of the problems discovered during the visit.

Follow-up: On October 12, OFGAC met with the City's senior engineer and two construction technicians responsible for this project to discuss protection measures for the butternut and walnut trees. OFGAC pointed out the close proximity of the construction fences to the trees to be protected.

Construction crew are completing work on the gutters and within a couple of weeks will have the area filled once again. Meanwhile the City's construction technicians assured OFGAC that they are vigilant in preventing any heavy equipment or material from coming close to the fence. They have advised the contractor and are supervising the work every day.

Butternuts and walnuts at site of Berrigan rapid transit station Left: OFGAC member, Bill Grant, stands in front of the western line of butternut trees. Fence separating construction site from the mature tree is much too close to the tree. The active zone of tree roots extends from the "drip line" out as much as two or three times the width of the aboveground part of the tree. Below left: Three-quarters of the roots of this tree seem to have been removed during construction. This Butternut Tree has been damaged previously by the introduction of a make-shift tree house and was already struggling. Although this mature butternut is on the edge of the construction project, the construction technicians have opted to try and retain it. However, an area within its drip line had to be removed for access. No large roots appear to have been severed, but the grade is being altered significantly. OFGAC has requested that measures be taken to try and preserve this butternut, i.e., replace soil at least out to the drip line, restore the grade as much as possible, and move the construction fence out to the drip line. Below right: Hank Jones, of ECSONG, inspects a young Walnut tree, which has also been disturbed by the construction. OFGAC reiterated its concern about the closeness of the construction fence and that the trees identified for retention should be protected out to the drip line as an absolute minimum.

BUTTERNUT - FACT SHEET

In Ontario, the Butternut generally grows alone or in small groups in deciduous forests, commonly associated with trees such as Linden, Black Cherry, Beech, Black Walnut, Elm, Hemlock, Hickory, Oak, Red Maple, Sugar Maple, Yellow Poplar, White Ash and Yellow Birch.

The tree starts to produce nuts at around 20 years of age and produces a good crop every 2 or 3 years, reaching maximum production between 30 and 60 years of age.

Biology - The Butternut flowers from April to June, depending on the location. Separate male and female flowers are produced at different times on the same individual. The male flowers are thick green catkins (dense, flowering spike). The female flowers, which are shorter, are wind-pollinated. Depending on pollination, the fruits develop individually or in clusters of two to five and reach maturity in September or October. The mature fruits are ovoid, green nuts. They generally stay on the tree until after the leaves fall. The tree starts to produce nuts around 20 years of age and produces a good crop every two or three years, reaching maximum production between 30 and 60 years of age. The seeds are dispersed by water, squirrels and other small rodents. The species can also multiply by means of sprouts from young stumps. This species prefers rich, fertile soils, and does not tolerate shade.

The Butternut is a relatively short-lived tree, rarely exceeding 75 years. It is very sensitive to spring frost and to Butternut canker, a disease caused by a fungus which can infect and kill individuals of all ages and sizes. A combination of factors, including canker and the limited dispersion of seeds, has reduced the diversity within the Butternut populations.

Threats - The most serious and widespread threat currently faced by the Butternut is Butternut canker. The most obvious symptom of the disease is the formation of elongated sunken cankers. In spring, a black fluid seeps from the canker. In summer, the cankers produce very black, often white-bordered spots on the tree. In the United States, the Butternut mortality rate due to this fungus reaches levels of up to 77 percent in some States. Butternut canker has spread northward and eastward, and is now encountered in the three Canadian provinces where the tree is present.

There is no known means of fighting Butternut canker. It is not known whether the Butternut has any natural resistance to this fungus. Rare individuals exhibiting no signs of the disease have been observed in some infected stands. In regions where canker has been present for a long time and where high mortality is observed, it may be that the surviving Butternuts, regardless of whether they are canker-free, possess some resistance. If such is the case, the selection of resistant individuals is one of the most promising avenues for recovery programs.

Protection - The Butternut is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide. The Ontario Forest Management Guidelines recommend conservation of healthy trees belonging to a species threatened by a harmful organism, and forest management to foster the regeneration of species of special concern growing on Crown lands. More information

Tree Canada Invests in Butternuts

March 10, 2006 — The Rideau Valley Conservation Authority (RVCA) and the Ferguson Forest Centre in Kemptville are very pleased to announce receipt of a generous gift of $2,000 from Tree Canada, Canada’s largest tree awareness organization, to continue work on the Regional Butternut Recovery Program.

Although the butternut is widespread in southern Ontario, it is relatively uncommon across its range. More recently, the tree has suffered a drastic decline due to Butternut Canker, an incurable fungal disease. The threat of this disease is so severe that butternut has been designated as an Endangered species. In January 2005, an Ontario Butternut Recovery Team was formed to coordinate conservation efforts. A draft recovery strategy is being developed and in the meantime, a number of recovery activities are planned. One of the key activities is to identify and propagate disease-resistant trees. Another critical aspect to butternut recovery is working with landowners, since most of the land on which butternut occurs is privately owned.

There is also a national Butternut Recovery Team working on a Canada-wide strategy. (See Featured projects)