Natural wild ecosystems are amazingly beautiful and complex. Though northern forests may not be as diverse as many areas nearer to the tropics, there are still thousands of species found on our farm alone, plants, animals, insects, fungi, micro-organisms and more. These species all exist in a delicate balance, each with its own niche in the environment, feeding on and being consumed by others. I am not alone in my love of being out at the lakes and mountains, forests and fields, just to soak it all in. On the other hand, the energy moving through this system is not well optimized to produce food for people. In the time before the invention of agriculture, humans everywhere existed primarily by hunting and gathering, traveling over large areas and collecting what food they could find naturally occurring in the wild.
At first blush, it seems like there would be lots of food available right out in the woods. There are many different species that have historically been hunted available right in our area. Over the last few years, just on our own property, I have seen white-tailed deer, snow-shoe hares, squirrels, ground hogs, porcupines, skunks, beavers, otters, coyotes, ruffed grouse, spruce grouse, wild turkeys, ravens, Canadian geese, several species of ducks, and even a couple of black bears. While only some of these are hunted today, they were all on the menu when times were tougher than today1.
Then there is a great diversity of wild plants that one can eat in the form of leaves, grasses, tubers, berries, nuts, and more. There are also edible mushrooms growing in our woods, including such species as morels, chanterelles, chicken of the woods, and puffballs. While I haven't been that much of a forager myself, I have dabbled in wild berries, dandelions, the occasional hickory nut. I will instead defer to other sources of expertise, and my understanding is that a couple of the very best foraging books for plants in my climate in eastern Canada come from Samuel Thayer, who lives and forages around Wisconsin, The Forager's Harvest and Nature's Garden.
Pin cherries are a bit tart but still tasty
Of course lots of variety doesn't mean that there is large total availability. We don't see too many people living as hunters and gatherers today, and there are some very good reasons for it. Though there is a bewildering array of diversity just on our farm, the flora and fauna are spread rather thinly across the landscape, with animals ranging across many acres of land to find their food. For the plants, there are only a relative few concentrations of those that provide good food sources to people. Another major problem with great diversity is the harvest. With hundreds of different species to be hunted and gathered, it takes both an incredible amount of time and depth of knowledge to find it all and harvest it efficiently. There are very few peoples in the world who have continued a hunting and gathering lifestyle for any great length of time after they have been exposed to the food concentration that comes with farming. Finally, a climate like that found in eastern Canada makes food very seasonally limited, with many types of food only available during a short window each year.
So how far will an acre get us? Unlike some of the other land uses that I discuss throughout this piece, I couldn't find any precise estimates of the total availability of wild food. So, I've taken a couple of methods and done some 'back of the envelope' calculations.
Estimate #1: Density of Native Americans prior to European colonization
Now I realize that it isn't being fair to native Americans to classify their lifestyle as solely hunting and gathering, as they did a great deal to modify their environment and practiced many forms of agriculture. However, archeological and historical knowledge of our area of eastern Canada2 suggests that hunting, fishing and gathering accounted for most of the food of the local Amerindians. The history that I have read suggests that immediately before the arrival of Europeans the local natives summered in large camps along the Ottawa River and hunted their way through the hinterlands during the winter, relying mostly on small game and stores from the fall's harvest. Our property falls squarely in the middle of those historical winter hunting grounds, being forested hills near a major navigable river. This same text suggests that the population density of these peoples was only one individual per each 27 square kilometers.
We know how much food energy each person needs, and we have an estimate of the population density, so we can make an estimate of the total food energy production per acre per year for native peoples:
(2.32 kWh/person/day) * (365 days/year) *(1 person/27 square kilometers) * (1 square kilometer / 247 acres) = .12 kWh/acre/year
This estimate suggests that each acre produced on average much less one day's worth of food each year. Most years a given acre of forest probably didn't provide any food, while others would give up a few handfuls of mushrooms, some berries, or in a lucky year, some wild game.
This sort of estimate doesn't account for seasonality or technology. There was much more food available in the summer and fall with all of the ripening plants and young of the year animals, but pre-European peoples did not have the same abilities to harvest, preserve and store food that we do today, nor did they have modern weapons that would allow them to harvest all of the available game. To account for that, and the amount of time that would really be needed to harvest all of the hundreds of edible species throughout the year, let us say that the actual population was only able to fully take advantage of 1/100th of the total potentially available food. This brings us to an estimate of:
.12 kwh/acre/year * (100 units food available/1 unit fully utilized) = 12 kWh/acre/year
Estimate #2: Ecological estimates of the carrying capacity for wild edible species
Another way to come at this same question would be to take a look at the science of ecology, in that biologists have long been studying the populations and distributions of native flora and fauna. I will start with the wild game, and then move on to a semi-educated guess about available plants and fungi.
For almost all of the larger animal species found on our property, especially those that are hunted, there are relatively good estimates of the population densities. These are especially useful for natural resource agencies and are used to evaluate the health of populations and set hunting regulations to maintain the health of those populations. To make the estimates below, I found what sources are available for the number of animals/acre. Many of these species actually have ranges of tens of acres or more per individual, so the numbers can be quite small.
Providing a few ecological estimates:
White tailed deer - 30 deer/mi sq *(1 sq mi/640 acres) * (1 of 3 deer harvested per year) * 40 pounds meat per deer * (.7 kWh/pound) = .4375 kWh/acre/year of venison
Ruffed Grouse - 50 grouse/mi sq*(1 sq mi/640 acres) * (1 of 2 grouse harvested in fall) * .5 pounds meat per bird * (.6 kWh/pound) = .012 kWh/acre/year of grouse meat
Other calculations end up being similar, for species such as wild turkeys, small mammals, bears, etc. Being generous, wild game could add up to something like 2 kWh/acre/year of meat in our region.
Edible wild plants that I have seen locally: Berries (blueberries, raspberries, strawberries, hawthorne berries), tree fruit (wild crabapples and plums, edible tubers (e.g., cattails), nuts (acorns, butternuts), stems and leaves (dandelions, basswood leaves), young growth (fiddlehead ferns, wild leeks), mushrooms (morels, chanterelles). This is of course not a comprehensive list, nor could I find precise figures on harvest rates of wild plants and edible fungi, but I did come across many admonitions to avoid overexploitation of these species, as it can cause their decline. For the sake of argument, one could imagine that it may be possible to harvest 40 pounds of plants and mushrooms per acre in unmanaged forest, field, and marsh, which would yield:
(40 pounds/acre/year) * (500 Calories/pound on average) * (1 kWh/860 Calories) = 23 kWh/acre/year
This total estimate of 25 kWh/acre/year is roughly in line with the first calculation above.
Estimate #3. Percentage of total available photosynthetic energy
From here we have an estimate of 35790 kWh/acre/year worth of energy harvest by plants on our property. This energy is the original source for all of the wild edible species available, whether they be plants, animals or even fungi. From the estimates above, this means that something on the order of one part per thousand of the total energy captured by plants in the forest reaches a form that could reasonably become food for someone who is hunting and gathering. If it truly were one part per thousand, then we would have:
35790 kWh/acre/year * .1% efficiency at creating human food = 36 kWh/acre/year
As all of these estimates are so small as compared to other land uses, we will go ahead and use this last and largest estimate going forward.
How far would hunting and gathering get me and my family?
36 kWh hours worth of tubers, berries, leaves, seeds, meat, and fungi. This really is not very much on the scale of human needs, as this is only 15 days worth of human food for each acre of land. At 150 acres, our farm property could then support the food needs of 6 people, if those people had the skills and time to harvest, process, and store all of the naturally available foods available on the property.
(36 kWh/acre/year of food produced) * (150 acres) / (849 kWh/person/year of food) = 6.4 people supported.
Even with the proper skills and knowledge, the harvest and processing of all of this food would be close to a full-time job, leaving very little time to, say, hold down a job to support those needs other than food. This would be bare subsistence and there would be no excess to sell or trade. On top of all that, even though I consider myself fairly knowledgeable in such things, I don't have anywhere near the expertise necessary to find and process all this variety of food. I think that the best takeaway from this analysis is to show that in today's world, hunting and gathering belongs in the place where it sits, as a pastime for those who enjoy being out in nature and like to eat in a more adventurous way.
Wild plums in early August
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1 I have a copy of a classic cookbook called the Joy of Cooking that I inherited from my grandmother. This edition is from 1950. The most fascinating section to me in this book is on wild game, with instructions for skinning, cleaning and cooking a wide variety of species that I have never heard spoken of as dinner possibilities, including raccoon, porcupine, and beaver.↩
2 Gaffield, Chad et. al. History of the Outaouais. Laval University Press, 1997. ↩