5. “[This special report]
looks at ways to boost
yields of the main
crops…
…the reaction against
intensive farming is a
luxury of the rich.
Traditional and organic
farming…cannot feed
the world”
The Economist
February 2011
6. Swamp White Oak
Quercus bicolor
photo source
Native Trees for North American Landscapes
by Sternberg and Wilson
7.
8. SOURCES
1900 Wheat USDA Wheat Data Yearbook Tables
1950 Wheat USDA Wheat Data Yearbook Tables
2011 Wheat USDA Wheat Data Yearbook Tables
Acorns UCR David A. Bainbridge Use of Acorns for Food in California: Past, Present, Future
Acorns FK Forrest Keeling Nursery - 200lbs averge yield 35' canopy Kimberley Oak
Note: Acorns assumed to contain 45% nut meat
from Sean B. Dunham Nuts About Acorns: A Pilot Study on Acorn Use in Woodland Period Subsistence in
the Eastern Upper Peninsula of MI
0
500
1000
1500
2000
2500
3000
3500
4000
1900 Wheat 1950 Wheat 2011 Wheat Acorns UCR Acorns FK
Flour Yield: Pounds/Acre/Year
12. What Is a Forest Garden?
PERENNIAL
LAYERED
PATCHY
POLYCULTURAL
SELF-FERTILE
13. “soils…act as the principal
medium for plant growth, regulate
water supplies, modify the
atmosphere, recycle raw materials
and waste products, provide
habitat for many kinds of
organisms….soil is a major
ecosystem in its own right”
Quotation and graphic from
The Nature and Properties of Soils
by Brady and Weil
PERENNIAL
20. Diagram source:
The Nature and Properties
of Soils by Brady and Weil
Image source:
Plant Biology
by Graham, Graham
and Wilcox
Nitrogen-Fixing
Bacteria
Root Nodules
x
Image
source:
Plant Biology
by
Graham, Gr
aham and
Wilcox
Mycorrhizae
PERENNIAL
LAYERED
PATCHY
POLY-
CULTURAL
Many people subscribe to the idea that there is no way to successfully combine ecosystem function and production for human needs. The Economist, in its special report on feeding the world from early 2011, quickly dismisses concerns about the ecosystem impact of people’s land use. The solution the article proposes for feeding the world in the future is to continue developing the yields of our existing staple crops.The strange thing about this position is that the Economist notes that the growth of yields has been slowing down. But they are counting on human ingenuity and the promise of genetic engineering to push the pace of yield growth back up again.My question is: what if we applied human ingenuity to the problem of feeding the world together with the problem of sustaining the world’s ecosystems? I am not calling a halt to development of our traditional crops, I am recommending that we not invest all our energy into systems that seriously impair global ecological function.In order to inform the discussion of people designing systems to restore ecosystem function, it is worth getting our minds around the size of human impact on ecosystems at this point in history….
This is looking at one important species for order of magnitude purposes only.
A production planting whose selection and distribution of plants mimics the architecture and functions of a forest ecosystemPatchy state of cover, resembles a mid-successional woodland more than a mature forest (intermediate successional state has highest NPP)Because it is modeled after a forest, it is layeredPolyculture – different species togetherInter-species tolerance and mutualism Diversity of plants, both productive and those intended for system benefitSelf-renewing soil fertilityNatural pest control, stability
It’s not even too much of a stretch to say that soil IS the terrestrial ecosystem.Soil is the ecological capital accumulated over thousands of years by an ecosystem. In Eastern North America, there’s a range of environmental conditions, but on average, soil forms at a rate of about 1” per 250 years. Tilled soils are as barren below ground as above ground. Compare a forest with the bare soil of a tilled field – even more life and complexity was removed by tilling below ground as above. Ecosystem function is inhibited by tilling.
Resembles a mid-successional woodland more than a mature forest.
By ordering plants by mature height, all the plants will end up receiving close to full sun exposure.
In this photo, south (and sun exposure) lie to the left, so the taller orchard trees are to the right where they will not shade the shorter plants. Moving from right to left, plant height steps down: trees, shrubs, perennials and annual vegetables.
Resembles a mid-successional woodland more than a mature forest.
POLYCULTURE - growing multiple species togetherOne scarcely ever finds a monoculture in the wild, in a functional ecosystem.In a monoculture, each plant seeks the same resources as every other: same sunlight, same water, same nutrients.In a polyculture, resources are partitioned [pic from Edible Forest Gardens]. We are aware of competition between plants. But what we have overlooked is beneficial interactions between plants. There is evidence to show plants in the woods are doing more than just tolerating one another – indeed, they may benefit in many ways from one another’s presence. Forest gardeners seek to understand and make use of the beneficial interactions between plants. This image shows a fruit tree growing at the Central Rocky Mountain Permaculture Institute – underplanted with species known to have root systems more effective at retrieving hard-to-reach minerals than the fruit tree, which are made available to the fruit tree when the leaves fall.
MUTUALISMFrom The Nature and Properties of Soils, one of the most widely used soil science textbooks. Grass’s more extensive root system better at retrieving scarce minerals like Phosphorous (P). Legume’s symbiotic bacteria fix Nitrogen (N) from the atmosphere into plant-available form. Mycorrhizae are fungi that have symbiotic relationships with most plant species – they help the plants retrieve minerals in exchange for sugars. In this case the mycorrhizae are connected to both plants and actually transfer nutrients from places of abundance to places of need. Isotope tracer studies record this effect. [possibly a good topic to start with] [size of mycorrhizal hyphae compared to fine root hairs]“A large oak tree may be feeding not only its fungal partner, but also other plants nearby” Plant Biology page 366.1 cubic inch of soil may have more than 1,000’ length of fungal mycelium.A side point: this is awesome stuff, we haven’t known about forever. There is likely some other stuff going on in the ecosystem that we haven’t noticed yet. I’m just guessing. So we should include as many of the puzzle pieces as we can in the agroecosystems we design, to give a better chance that some of the processes will go on even without us specifically providing and planning for them.
Nitrogen is one important example of an element important to plant growth, but there are many others.This planting also illustrates layering:The pecan is a canopy species, and will eventually grow as tall as 100’ or more.The pawpaw is an understory species, which will top out around 30’The bayberry is a shrub that may reach 10’ or 15’You might be wondering how the nitrogen and other nutrients get from the plant with abundance to the plants with lack… [next slide]
CONCLUSIONA forest garden is a forest adapted to people’s needs, and people’s needs adapted to the forest.
