Urban Agriculture? Only 1 Percent Of Seattle Residents Could Eat Locally Even With All Viable Space

[NickB79]

http://www.science20.com/news_articles/urban_agriculture_only_1_percent_of_seattle_residents_could_eat_locally_even_with_all_viable_space_in_use-163422

The results show that it would require a 58-mile expansion around the city to meet 100 percent of Seattle's food needs. In other words, conventional agriculture with food shipped in. But a lot of people in urban areas believe food security is possible locally. The researchers combined imagery and available Lidar data for Seattle, which are captured by flying aircraft and scanning the landscape with lasers. The resulting 3-D data are useful for geologists and geomorphologists looking at topography and landslides, but also for measuring tree cover in a city, including the height and leaf density of individual trees.

Because Lidar lets researchers see a 3-D version of a city, down to an individual tree or building, it can also figure out how much sunlight hits an area -- and how likely a food crop could flourish in that spot. The researchers combined this data with nutritional information from the National Nutrient Database that assesses the calories, macronutrients and micronutrients in each food group. They analyzed nutrients needed for a vegetarian diet, because growing vegetables, grains and nuts usually requires less land than raising livestock for meat.

In order to meet the nutritional needs of an adult eating a vegetarian diet, only about 6,000 people (1 percent of Seattle's population) could be fed if all single-family backyard space were converted to farming. That number rises to about 24,000 people (4 percent of the population) if all additional public green spaces were converted.

It's an eye-opening figure and it forces urban idealists to really think about what must be eaten to survive. A city can grow tomatoes, kale and lettuce but it gets more complicated once you factor in other necessary proteins, fats and carbohydrates that often travel from across the county and world.

I'm very impressed by the sheer detail that went into this study (down to individual trees and the shadows they cast? Wow!).

However, I find one glaring issue with this. They assume the existing tree cover would stay intact, which I think is a good thing. However, they then assume the existing mix of mostly ornamental tree and shrub species couldn't be replaced with comparable, edible species. For example, a chestnut tree with the same form as an oak or maple can generate 100 lb of nuts per year within 15 years of planting a foot-tall sapling. At 50 calories per ounce, that's 80,000 calories per tree. Walnuts yield 180 calories per ounce and can bear within 10 years. Hazel bushes can be substituted in for other shrubs and yield 180 calories per ounce and bear in 5 years. Pinyon and Korean pine can substitute in for other ornamental pines and their pine nuts yield 190 calories per ounce. And don't even get me started on the myriad forms of fruit you could grow as well.

And any nuts and fruit humans miss during harvest would feed a massive population of groundhogs, rabbits and squirrels, which could be trapped and hunted for their meat.

Food forests, people. Plant food forests and permaculture.

[postulater]

1. If only there was an edible acorn.

We have lots of oaks around.

Or even a black walnut that was tasty and easy to shell.

[NickB79]

2. Many acorns are actually edible. They comprised a sizeable part of the Native American diet

The key is removing the tannins from the nutmeat to reduce the bitterness, which is easily accomplished by soaking the ground nuts in water for a period of time. With more bitter species, several soakings may be required.

And there has been work done to breed oaks with low-tannin acorns, such as the Sweet It Is Bebb's Oak: http://oikostreecrops.com/products/oaks/the-edible-acorn/sweet-it-is-bebbs-oak/

http://oikostreecrops.com/products/ashworth-bur-oak/

[postulater]

3. That burr oak looks nice.

Maybe I can fit one in my front yard.

That nursery looks interesting too.