Urban Trees Provide Diverse Foods
Peter Duinker, Halifax Tree Project
2020-12-06
The range of foods people can obtain from trees is so great (Trail, 2017) that, in writing this short article, I will surely miss some that are important to some readers. The reaction might be: “how could you possibly forget [insert favourite tree food here]?? This article will not address two other important themes related to tree-born ingestibles: (a) the importance of trees as food for a plethora of animals – I don’t have room at all to discuss this huge topic; and (b) the use of tree parts for medicinal purposes – I don’t have the knowledge to write with confidence about tree-based medicines, a vital topic in its own right.
First to mind as we consider what parts of trees we eat are probably the soft fruits. Most people see domesticated fruit trees as part of agriculture. I can agree with that, but since those plants are trees, I see them equally as part of the woods. We are well known in Nova Scotia for apple production (pictured), but we also can and do grow pears, plums, peaches, various cherries, and others. We don’t grow (except possibly indoors) the citrus fruits – lemon, lime, grapefruit, orange – nor olives and figs.
Next up we might think about hard fruits or nuts. Native to Nova Scotia are acorns, hazel nuts, and beech nuts, but these are rarely used today for human consumption. Imported nut-tree species that can grow outdoors here are hickory, sweet chestnut, walnut (small tree pictured below,left), butternut (nuts pictured, right), nut pine, and surely others. Finally, nut trees elsewhere that probably won’t grow outdoors here are cashews, macadamia nuts, almonds, and brazil nuts (but my knowledge here is skimpy).
I should mention the palms even though, in strict botanical terms, experts don’t consider palms to be trees. Let’s overlook that and accept palms as trees for this discussion. Dates and coconuts grow on palms, and we get huge amounts of food oil from oil palms. I don’t think we have food palms among the few palms planted in Dartmouth a couple of years ago.
To round up this incomplete survey of foods from trees, we can consider: syrup and sugar from sap, particularly sugar maples; flowers and their use in teas and gin infusions; flowers delivering nectar to bees that make honey; tree barks that can be chewed or brewed; edible young leaves of some species; mushrooms arising from fungus associated with tree roots. Pretty much the only part of trees that we don’t eat is the wood!
A key point to make in this article is about edible trees in the city – can we pursue this, and should we? Isn’t it better to focus on farms and rural forests when it comes to tree parts we can eat? In my view, the growing room for edible trees in the city is absolutely huge, so finding places for them to grow is not a limitation – IF we choose to plant and take care of them. Nevena Gazibara (2011), a former student of mine at Dalhousie, studied the “is there room” question on the Halifax peninsula. If residents were willing to plant fruit trees in their front yards (now mostly grass with scattered trees) in the south-end neighbourhood where Nevena took her data, she found that there is room for about 15 fruit trees for every 100 m of street length. Assuming that these front yards are replicated across the peninsula (surely an overestimate of possibility), there would be room to plant about 36 thousand fruit trees in front yards. If these trees were all producing apples, that number of trees could conservatively yield about 12 kg apples per resident!
Clearly those numbers are biophysical potentials and not realistic estimates given people’s preferences for what they grow on their properties. It doesn’t seem to be characteristic of our urban culture in Nova Scotia to grow fruit trees at home. When my family and I lived on the outskirts of Vienna, Austria, in the mid-1980s, our landlord, with a backyard of modest but ample proportion, grew walnuts, apples, pears, plums, and sour cherries – one tree of each. This was the pattern in our suburb – EVERY backyard was producing fruit!
I conclude that we can do that too, and do it well – if we wanted to. Another approach is to capitalize on the community-garden movement and grow fruit trees in those gardens along with the usual annual food crops. The City of Halifax website names about 15 such community gardens (there may be more), all established on municipal land and managed by a local community organization. In 2014, in cooperation with the City, we undertook a small project to research and promote the concept of urban orchards (Lesko et al., 2014a; 2014b). Soon after, fruit trees were planted at each garden where the organizers expressed interest. Do check out https://www.parkoven.ca/category/community-orchard/, a site that showcases the fruit trees planted in 2015 near the community oven in Leighton Dillman Park in Dartmouth.
Another of my students, Kendra Marshman, studied the prospects for increased fruit trees to grow on school grounds in the Halifax peninsula. Her study (Marshman, 2015) revealed high social and biophysical capacity for fruit trees on school grounds (one is pictured), as well as strong benefits for students to connect more strongly with nature at school. Barriers were identified as space, money, and time. In my view, each of these barriers can be overcome with enough willpower on the part of school staff and students.
Edible trees do indeed provide challenges to their owners – if the fruits are not picked to eat, they can make a mess once fallen to the ground. To remain productive, fruit trees require more maintenance than other kinds of trees. Gazibara (2011) pointed out some of these drawbacks to having more fruit trees in the city. However, a far larger list became obvious once she studied the benefits. These range across all the major themes of sustainability - ecological, social, health, and economic benefits.
The focus of both municipal governments and town/city residents in Canada has been on trees for non-food benefits like shade, beauty, air-pollution abatement, stormwater attenuation, cooling, and many more. I for one would like to see a huge expansion of the edible-tree population in Halifax – wouldn’t you?
References
Gazibara, N. 2011. The Case for Fruit Trees in the City. MREM Project Report. School for Resource and Environmental Studies, Dalhousie University, Halifax, NS. Available at https://www.halifaxtreeproject.com/reports
Lesko, M., B. Roach, and L. Slapcoff. 2014a. Halifax’s Urban Orchard Project: Workshop Discussion Paper. Report to HRM. School for Resource and Environmental Studies, Dalhousie University, Halifax, NS. Available at https://www.halifaxtreeproject.com/reports
Lesko, M., L. Slapcoff, K. Marshman, B. Roach, and P. Duinker. 2014b. Urban Orchards in Halifax: Results of a Consultation Workshop in Halifax, June 2014. Report to HRM. School for Resource and Environmental Studies, Dalhousie University, Halifax, NS. Available at https://www.halifaxtreeproject.com/reports
Marshman, K. 2015. The Fruits of Nature: Investigating the Prospects for Fruit Trees on Halifax School Grounds. Unpublished Honours Thesis, Programs in Canadian Studies, and Environment, Sustainability, and Society, Dalhousie University, Halifax, NS.
Trail, JV. 2017. Edible trees: foraging for food from forests. American Forests 123(1):17-23.