Edible Forest Gardens: Vol 1. Chapter 5 -- Underground Economy

On to chapter 5 of Edible Forest Gardens: Structures of the Underground Economy.

Random notes:

• Manually deepening shallow roots before planting offers major benefits.
• Rhizomes are botanically stems. Their leaves are adapted into defensive scales.
• Check out Wild Roots, by Douglas Elliott.

Edible Forest Gardens: Vol 2. Chapter 5 -- Site Preparation

After resuming my reading in Edible Forest Gardens, I picked out some techniques that seem promising for site preparation: 

• Rock dust
• Cover Crops
• Mulch -- 1/2 - 4 inches. Not next to woody trunks. 
• Torching weeds
• Infiltration Swales
• Double Digging
• Radial Trenching -- sort of like double digging for trees (figure 5.10, p. 361)
• Mounds -- but need to consider the impact of soil texture transition

I found the last line of the chapter to be telling: 

One thing is true, though. If you skip site preparation, you are likely to regret it for a long time to come.

Edible Forest Gardens: Vol 1. Chapter 4 -- Social Structure

Continuing my reading through Edible Forest Gardens (EFG) Volume 1, chapter 4 was on Social Structure: Niches, Relationships, Communities. Any given species has over time adapted to find some mix of strategies for food gathering, self preservation, and reproduction that result in it serving particular functions and roles in its ecosystem. Other species in turn have the opportunity to respond to these choices by competing, cooperating, or co-opting. However these relationships are not simple across-the-board affairs: always and in all ways cooperating or in always and in all ways competing. Rather in some aspects or phases of life they may stand in one relationship and in others another.

• Adaptation -- a particular evolutionary response to the environment
• Strategy -- a collection of coherent adaptations that work well together, but will likely preclude other "paths not taken"
• Function -- an effect the organism has on the environment
• Role -- a "job" the organism does providing certain environmental services
• Niche -- the combination of functions, roles, and requirements
• Relationship -- who eats whom, treatment of limited resources, trade
• Social Structures -- the web of relationships
• Food web -- cycle nutrients throughout the community

From a design point of view, we can pay attention to mutualism and neutralism to form guilds based on one or both of

• Resource-sharing guilds -- with members that reduce competition by sharing resources. Such as plants with different depths of roots (spacial redundancy) or that demand resources at different times of year (temporal redundancy).
• Mutual-support guilds -- members that actively benefit each other

One important design consideration is predator support. Places for predators to shelter, eat, and drink so that you can maintain a healthy population to suppress pests. Some specific families of plants that are good for predators are Apiaceae (carrot/dill/parsley family), Asteraceae (aster/daisy/sunflower family), and Lamiaceae (mint family), which all happen to be Asterids.

Edible Forest Gardens: Vol 1. Chapter 3 -- The Five Elements of Forest Gardens

I've been reading my way through Edible Forest Gardens (EFG) and just finished Chapter 3 of Volume 1 -- The Five Elements of Forest Architecture. What are these five elements, you may ask? They are:

• Vegetation layers: the vertical structure of the forest
• Soil horizons: Organic, Assimilation, Eluviation, Banking, Chemical, Durable
• Vegetation density: much like our sense of "personal space" plants have preferences
• Patterning: the forces of edge effects and surface area effects
• Diversity: an attempt to bring more nuance to the discussion of species diversity

Interestingly vegetation layers came up in a different context this week when I went to the orientation for volunteers for the Backyard Habitat Certification Program where they talk in terms of 5 vegetation layers: tall and low trees, tall and low shrubs, and the herbaceous layer. In EFG they add to this list ground covers, and vines. They also introduce relative layers for the overstory, canopy, understory and root zone.

The soil horizons was largely review from the soils class I took last quarter at PCC. Yet it is always good to recall that half the plants and most of the life forms are living in the soil. The Organic or O horizon is often above what we usually think as the soil and includes the leaf litter and other organic mater in various stages of decomposition. Eventually hard working soil organisms incorporate this material into the lower horizon. The Assimilation or A horizon is the topsoil where most of the action happens: root growth, soil life, incorporation of organic matter, etc. Some soils have a distinct Eluviation or E horizon, some don't. This horizon accumulates clays that are carried by water (illuviated) from the A horizon and are deposited (eluviated) in the E horizon, it is usually light colored. The Banking or B horizon is often called the subsoil and tends to have less organic mater. A good way to develop organic matter in this horizon is by planting deeply rooted plants so that as the roots die back they leave organic matter in addition to the decaying soil life from the rhizosphere. They also help improve the soil structure and provide channels for good drainage and while alive a mechanism for pulling up nutrients into higher soil horizons. The Chemical or C horizon is where most of the soil formation activity happens chemically. Finally the Durable or R horizon is where it all got started with the parent material.

The section on vegetation density addressed the issues of vegetative cover and crowding. I found this to be interesting and instructive. Depending on the ecosystem that a plant targets as its niche it may have quite different preferences or tolerances to crowding, contention for root space, shading, etc. It also interacts with the choice of reproductive and dispersal strategies. This will be an important design consideration for me as it will be very tempting to crowd too many plants into too small a space. So the balance is between plant selection to accommodate this density and proper design to provide the plants the space they need to do their thing. At the Backyard Habitat orientation I saw a survey map of the greater columbian region from 1851 where my neighborhood was classified as "woodland" so probably 40-70% tree cover. It might then be reasonable to shoot for that same range in my design.

The patterning section was almost a tease -- the mathematical implications are intoxicating. The author investigated both the forces at play that lead to different sorts of patterns as well as the inferences we can draw to use as tools to weed less (less edges), or maintain easier access (more edges).

The text made the point that many discussions of diversity seem to treat it as an end unto itself rather than a factor to consider in ecological systems. Diversity can also take many forms beyond the simple count of species.

A couple misc. notes:

• Nitrogen fixers need full sun to work.
• Ribes (currants and gooseberries) fruit in shade.

Introducing the University of Here

I have been enjoying taking classes again. That said, I find that there are many things I wish to focus on that are not being covered. This has lead me to start a program of self-study that I am calling the University of Here at Campus Vorax. The basic recipe is:

1. Pick a topic of study
2. Identify texts or other relevant supporting material
3. Identify learning objectives
4. Identify evaluation criteria and learning "forcing functions"
5. Write up a simple syllabus

I have written up four courses for the spring term:

• Edible Forests Gardens (working through the two volume book of the same name)
• Landscape design of our Front Yard
• Plant identification on our property
• Stained Glass

My hope is that having a week-by-week schedule will provide enough impetus to make forward progress in the face of the myriad distractions which will present themselves.