The Serviceberry

James Steenberg, Halifax Tree Project

2020-06-29

Consider the serviceberry. It is the sixth most abundant street tree in Halifax. It may not have the stature or longevity of some of the more prominent street trees in Halifax. But, what ground it loses in these categories it strives to make up in springtime showiness and its smooth silver-grey bark (photo, below). The serviceberry is one of the first street trees to flower in early spring, when it dons a snowy white array of small flowers with long skinny petals.

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Some have said that the name of ‘service’ berry is a reference to the funeral service. In the olden days, the flowering of the serviceberry signalled the springtime thaw, which allowed for the burial of the winter’s dead that had accumulated while the soil was frozen and too hard to dig. However, this etymology has been disputed.

Nova Scotians may know this tree better as the shadbush (or shadblow), named for the shad fish and shad run that happens in many local rivers and streams when the water hits ten degrees in May or early June. Other common names have been known to include juneberry, saskatoon or saskatoon-berry, wild pear, bilberry, and sarvis. If you’re in Newfoundland, you might call it a chuckley pear.

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If you’re out in the streets of Halifax and trying to identify a serviceberry specimen, you may find it challenging above and beyond these many different and regionally specific names. Species identification is incredibly difficult with serviceberries. Typically for tree species identification you first check whether the leaves are needles or broadleaves. If the latter, you then check if there are many leaflets coming off a single leaf stem (like an ash or chestnut) or a single leaf. If a single leaf, you then check if they have lobes (like a maple or oak) or are a simple oval. If oval, you then check if the leaf margins are smooth or serrated. The single-leaf, broadleaved, toothed-margined tree group includes the serviceberry (photo, left), and it is the most populated grouping of trees that you will come across.

What’s more, serviceberry species themselves are incredibly difficult to discern. In addition to being a single-leaf, broadleaved, toothed-margined tree, all serviceberries look quite similar unless they are flowering or yielding fruit. They also frequently interbreed (hybridize), complicating matters further. In natural woodlands, they may have a single trunk or many (examples of each pictured below) and are typically found in the understory or in younger forests. They have oval leaves that are 3 to 7 centimetres long and small berries that are reddish or purple. In the street, they are more likely to be a single-stemmed tree and probably not taller than ten metres with a trunk diameter that is less than 20 centimetres.

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According to the Canadian Forest Service, there are 10 to 15 native serviceberries in Canada, including three commonly found in Nova Scotia: the Canadian serviceberry (Amelanchier canadiensis), the smooth or Allegheny serviceberry (A. laevis), and the downy serviceberry (A. arborea).The downy serviceberry tends to be the most abundantly planted and cultivated for city life, with different varieties that have been bred for bright fall colours or spectacular flowers. There is also an often-planted hybrid called apple serviceberry (A. x grandiflora).

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The serviceberry has several other admirable qualities. I have never tried this myself, but I’m told that serviceberry pie is quite a delicacy. However, what I know to be true is that their berries (pictured on the right) attract many different species of wildlife and are a staple of one of my favourite species of bird, the cedar waxwing. The serviceberry also has one of the hardest woods of native tree species in Nova Scotia, being at least twice the density of white pine or our provincial tree, red spruce. This bodes well for either a hot fire in a woodstove or carbon storage to mitigate climate change.

As a final note, I unfortunately do need to take a few points off the serviceberry for its smaller size. Many of the benefits that city-dwellers get from urban trees – ecosystem services is the official term – are closely correlated with the size of the tree and the amount of leaves that are contained in its crown. Big trees with lots of leaves yield big benefits. These ecosystem services range from slowing down stormwater in big rain events to removing air pollution to cooling the urban heat island. Because the serviceberry is smaller in size, it supplies fewer of these benefits. Moreover, my own research (in Toronto, not Halifax) has shown that residents are increasingly favouring smaller-sized trees like the serviceberry when a large old tree is taken down precisely because they are smaller and easier to manage.

We at the Halifax Tree Project have considered this issue often, along with the issues of when to plant street trees and how close together they should be planted. Common practice has been to plant large-stature tree species in the streets and to plant them far apart. But, the serviceberry is an understory species that can handle the shade and competition of an understory life, beneath large elms or maples. What if we planted our street trees closer together (so we could have more of them) and had an urban forest understory of serviceberry and other smaller trees that still provide great beauty and pleasure to people without reducing benefits? Perhaps we could still have our ecosystem services and eat our serviceberry pie too?