[Scpg] steep permaculture slope ideas? Now also: general site analysis

[John Calvert]

This topic has generated far more responses than any other on this list 
since I joined in June 2005.

I wonder why that is?

JC


Dan Hemenway wrote:
> Well, you went into more detail than I wanted and raised some 
> interesting points.  It is reassuring that you concur with me that 
> raising food may not be the
> best option for this site, except for suitable tree crops.  The only 
> one I am confident would be suitable is apricot, because of its 
> root-sprouting habit when soil
> around the roots is disturbed, eg., after some subsidence or gully 
> erosion.  The long establishment time of tree crops also favors 
> stabilization before human
> traffic.  In a garden, one wants food in as many months of the year as 
> possible, but here traffic for food production and harvesting seems 
> quite undesirable.
>
> I am a bit concerned, on reflection, about the suggestion of net and 
> pan by another contributor.  I think one would do well to develop some 
> skill with this over gentler slopes.  If I recall 
> correctly, this system was developed in the Mid-East drylands, 
> historically, on very stony soil.  I suspect that the grades were not 
> as precipitous as described for this site. Net and pan was practiced 
> in the context of a whole culture which had generations of accrued 
> experience on the landscapes involved.
>
> I have developed a 20-page questionnaire that I license to clients, 
> with a full credit if they complete it, and with other provisions.  A 
> major purpose of the survey
> is to bribe, if you will, the client to learn much more about the 
> site, climate, etc., than perhaps s/he had thought about.  If the 
> client is not willing to do his/her own
> legwork, they are not going to properly implement anything that I 
> design, wasting my time.  I've got plenty of work to do at home. 
>  After I review the answers to 
> the questionnaire, usually on the plane en route to the site, I can do 
> a better site walk or walks (depending on lots of factors--usually I'm 
> on site for at least one full day.)
> I always advise the client that costs will be less and results better 
> with a training event where participants develop a site plan based on 
> the client's desires.  The client
> also gets training, and participates in the development of the design, 
> so better understands how permaculture works and has a deeper grasp of 
> why the design 
> calls for certain actions.  Optimum is for someone to be well trained 
> and then live on or near the site for at least three years, during 
> which experiencing the site is 
> a major objective.  Three years isn't much, admittedly, and as you 
> point out, causative events that can precipitate catastrophes may be 
> on the order of decades or
> centuries.  A knowledge of local natural history is thus extremely 
> beneficial. Yet in three years in places were people ought to live at 
> all, which does not include precipitous 
> slopes, people can get in tune with what is going on while acquiring a 
> lot of objective knowledge as well.  And three years may be the limit 
> for most people's patience 
> to forebear from irreversible actions.  
>
> All that notwithstanding, I think that the original question was 
> useful, and reflected a sincere effort to act responsibly by 
> soliciting additional advice.  It is possible and
> practical to start with principles and then revisit the specific site 
> and see if they apply.  I'm sorry to say most of the principles I've 
> learned have come from observing
> when the Earth is mistreated, such as the deforested slopes that I 
> mentioned in the Philippines, and then determining, from observations 
> of factors such as root 
> structures of the pines of the are, why the subsidence was a new 
> factor, consequent to deforestation and probably the traffic, mainly 
> foot traffic in this case, to haul
> out wood to burn for charcoal.  
>
> Dan Hemenway
> www.barkingfrogspermaculture.org
>
>
> -----Original Message-----
> From: Owen Dell <owen at owendell.com>
> To: Dan Hemenway <permacltur at aol.com>
> Cc: jcalvert at crystal3.com; scpg at arashi.com
> Sent: Wed, Sep 8, 2010 9:36 am
> Subject: Re: [Scpg] steep permaculture slope ideas?
>
> Yes, it's vital to be on site in order to understand what is specific to that 
> particular situation. What is the soil type? What is the nature of the 
> underlying geology? What plants, native and introduced, are currently on site? 
> What is the native and introduced fauna? What is the aspect of the slope 
> (N/S/E/W)? How much if any water runs onto the site from elsewhere? How much 
> water soaks into the soil and how much runs off? Where does the runoff water go? 
> What is the history of the site in terms of land use, erosion problems, soil 
> movement, fires, etc.? There are many questions to be asked, and most people 
> don't even know that these questions exist. That is why I caution that in 
> addition to seeking site-appropriate strategies, a knowledgeable professional be 
> consulted when working on slopes where poor decisions can lead, literally, to 
> disaster.
>
> True success comes partly from knowing what is local and particular to the site. 
> Each site is unique. There are no general, non-local conditions; there are only 
> principles that can be applied to local conditions. And true success is measured 
> in centuries, not months or years, of stability and health of the system without 
> the need for external inputs.
>
> Type conversion of any given piece of land from one ecosystem to another is not 
> to be done without taking into account many factors. Some land is not suitable 
> for production, or for various reasons it is not safe or wise to disrupt the 
> native conditions. I assert that no form of human intervention, even 
> permaculture, is better for any given piece of land than the original native 
> ecosystem. Permaculture is a fit practice for healing disturbed and urban lands 
> and making them productive, but when it encroaches upon wildlands it becomes 
> just another pernicious human activity. Agriculture in general is a massive 
> wipeout of ecosystems that have evolved for millions of years. Agriculture 
> supplants complex ecosystems with overly simple, totalitarian ones that depend 
> on the continuing brutal exclusion of all forms of life that are not of 
> "economic value." To be in harmony with our surroundings, we should be hunting 
> and gathering, removing individual food units from intact wild ecosystems. 
> Unfortunately, there are far too many of us for that to work anymore, but it 
> remains the one truly environmentally justifiable way of surviving. It is what 
> all the other animals do. As a result of our overpopulation, we are forced to 
> turn to various forms of agriculture to meet our needs. Permaculture is helpful 
> as long as it remains within its proper bounds, but it is important to 
> understand that all forms of agriculture, including permaculture, are 
> destructive. 
>
> I mention all of this because the original posting was about growing food on a 
> slope. I know nothing about that slope, but if it is in or close to a native 
> condition I would, were I on site as a consultant, probably advise against 
> destroying the native flora and fauna in order to grow food. Chaparral or 
> coastal sage scrub lands in our area are not particularly or not at all suited 
> to any form of agriculture, and the stability of such lands is often dependent 
> upon the extensive root systems of native plants. Therefore it is my opinion, 
> consistent with commonly accepted good practice, that such areas are best left 
> alone. Not to mention the fact that wild places, however homely they may seem to 
> the casual observer, perform essential ecological services that cannot 
> necessarily (or in most or all cases cannot ever) be replicated or improved upon 
> by human manipulation. And of course, there is the matter of the morality of 
> destroying wild places, on which I am adamant that such destruction, in the name 
> of any human cause, including permaculture, is wrong. We must not use 
> permaculture as a rationale for ruining natural systems. 
>
> On the other hand, if this is a disturbed slope which has not been in a native 
> condition for some time, and if I were assured by a geotechnical expert that 
> there was no risk of either surface erosion or landslides (called, dramatically, 
> "mass wasting" in the profession), I would certainly consider some form of 
> productive use. Most likely my approach would concentrate on low water use trees 
> and shrubs and perennial plants, since it's very challenging to grow annual 
> crops on sloping terrain. But I would also urge that restoration of the native 
> ecosystem be considered. (Of course, in our area there is also the matter of 
> fire, and when people move into wildland interface areas they create the 
> conditions for destruction of wildness in the name of fire safety. That is a 
> whole other big question that I won't get into here.)
>
> Looking to one of the specific strategies under discussion here, grasses are 
> indeed a diverse group of plants. Because many grasses, particularly annual 
> species, are shallow rooting, they form a slip zone at the interface immediately 
> below the bottom of the root mat they develop. In the absence of deeper-rooting 
> shrubs and trees, there are no roots below 12 inches to help consolidate and 
> hold the soil in place. The number of stem penetrations per square foot in a 
> grassland runs in the thousands (compared to one or fewer stem penetrations per 
> square foot for shrubs and trees), and the individual grass blades act as tiny 
> funnels to channel rainwater into the soil. This results in supersaturation, and 
> the slip zone becomes lubricated. Due to the supersaturation, the soil becomes 
> both heavy and plastic. Eventually, gravity overcomes the diminished friction at 
> the slip zone, and the entire mat of soggy soil and grasses slides downhill. In 
> an unstable soil, the lack of roots in deeper horizons can result in a far worse 
> outcome than mere loss of the foot or so of surface soil; the entire mass of 
> soil down to a depth of many feet can collapse onto the area below. 
>
> I should also point out that mass wasting can occur after many years of 
> seemingly successful type conversion. It takes years for the root systems of 
> native plants to decay to the point where they have stopped performing 
> soil-holding services. It is common that some time after a piece of land has 
> been turned to agriculture or urban landscaping, it will "suddenly" fail. This 
> happens all the time, and people are mystified as to the cause. It is simple: 
> the fine and delicate equipoise of the native conditions was interrupted, with a 
> catastrophic outcome. We mess with land at our peril, and at the peril of 
> others.
>
> I hope the above information is helpful to all. There is, of course, much more 
> to this. I am happy to continue the discussion and to hear dissenting opinions.
>
> Owen
>
> Owen E. Dell, ASLA
> Owen Dell & Associates
> Landscape Architect • Educator • Author
> P.O. Box 30433 • Santa Barbara, CA 93130
> 805 962-3253
> owen at owendell.com <mailto:owen at owendell.com>
> www.owendell.com <http://www.owendell.com>
>
>
> QUOTE OF THE DAY
>
> "O take heart, my brothers. Even now...with every leader & every resource &
> every strategy of every nation on Earth arrayed against Her -- even now O even
> now! my brothers, Life is in no danger of losing the argument! For after all...
> (as will be shown) She has only to change the subject."
>         
>             Kenneth Patchen
>             from Hallelujah Anyway, 1960
>
>
>
>
> On Sep 7, 2010, at 2:14 PM, Dan Hemenway wrote:
>
> > Owen:
> >     If it isn't practical, it isn't permaculture.  That's basic.  That's not 
> to say that the word isn't misused, but that is not the fault of the word, or 
> the practice that the word represents.
> >     Grasses are a huge family and quite variable.  I was silently skeptical, 
> myself, about a plants that are largely mat-rooted holding soil in place on a 
> steep bank.  "Bunch" grass could be any of hundreds of species.  On the other 
> hand, with the correct woody plants, grasses may be OK.  We are talking too much 
> in generalities here, and the specifics of site and of habit of candidate 
> species for the site are important.  Neither you, nor I, nor anyone who has not 
> visited the site can know what will work.  On the other hand, I am profoundly 
> skeptical of an approach that favors surface runoff, since that is just another 
> way of saying soil erosion, particularly on steep slopes.
> > 
> > Dan Hemenway
> > 
> > 
> > 
> > -----Original Message-----
> > From: Owen Dell <owen at owendell.com <mailto:owen at owendell.com>>
> > To: John Calvert <jcalvert at crystal3.com <mailto:jcalvert at crystal3.com>>
> > Cc: scpg at arashi.com <mailto:scpg at arashi.com>
> > Sent: Mon, Sep 6, 2010 1:29 pm
> > Subject: Re: [Scpg] steep permaculture slope ideas?
> > 
> > Grass is a very poor way to protect slopes against erosion. The large number 
> of stem penetrations results in a very effective transmission of water into the 
> soil, which can lead to supersaturation and slope failure. No offense to anyone, 
> but I recommend that people not speculate about what is going to work. There are 
> accepted standards for this kind of activity. Permaculture is a great thing, but 
> it doesn't always address real-world issues and it isn't always right. Slope 
> failures can cost hundreds of thousands of dollars to fix, and the cost is not 
> covered by insurance. I say again, PLEASE consult a professional before you go 
> off implementing half-cocked ideas. 
> >  
> > Owen 
> >  
> > Owen E. Dell, ASLA 
> > Owen Dell & Associates 
> > Landscape Architect • Educator • Author 
> > P.O. Box 30433 • Santa Barbara, CA 93130 
> > 805 962-3253 
> > owen at owendell.com <mailto:owen at owendell.com> 
> > www.owendell.com <http://www.owendell.com> 
> >  
> > QUOTE OF THE DAY 
> >  
> > "You take a number of small steps which you believe are right, 
> > thinking maybe tomorrow somebody will treat this as a dangerous 
> > provocation. And then you wait. If there is no reaction, you take 
> > another step: courage is only an accumulation of small steps." 
> >   George Konrad 
> >   Hungarian novelist & essayist 
> >  
> >  
> >  
> > On Sep 6, 2010, at 10:23 AM, John Calvert wrote: 
> >  
> > > 
> > > I was gonna say grass... the bunch grass sounds like a very good idea. 
> > > 
> > > lfunkhouser at juno.com <mailto:lfunkhouser at juno.com> wrote: 
> > >> Kevin, 
> > >> 
> > >> You might also want to talk to Mary Scaran, who is an acupuncturist >> in 
> SB (she's in the phone book) and has a very steep slope running >> the entire 
> length of her oak wooded and desert upland property that >> is permeated by a 
> spring. She has planted lots of things to >> stabilize, including Persian 
> mulberry trees (edible!) and some kind >> of grass -- can't remember which -- 
> but a type of bunch grass that >> she selected for its very specific properties 
> of soil >> stabilization. Mary practices permaculture, studies horticulture, >> 
> and is a very fine acupuncturist. 
> > >> 
> > >> Good luck. 
> > >> 
> > >> --Laura 
> > >> 
> > >> ---------- Original Message ---------- 
> > >> From: Kevin Gleason <kevin at kevingleasonart.com <mailto:kevin at kevingleasonart.com>> 
> > >> To: John Calvert <jcalvert at crystal3.com <mailto:jcalvert at crystal3.com>> 
> > >> Cc: scpg at arashi.com <mailto:scpg at arashi.com> 
> > >> Subject: Re: [Scpg] steep permaculture slope ideas? 
> > >> Date: Mon, 6 Sep 2010 07:14:15 -0700 
> > >> 
> > >> Thanks, John, and all others who have replied. This is such a >> helpful 
> community. I am going to look into the "net and pan" >> technique Susan 
> recommended and am trying to find some good >> "pinning" shrubs and trees per 
> Dan's advice. I need to pay good >> attention to the plants that seem to be 
> holding up west facing >> slopes next time I'm out hiking. It is okay with me if 
> this >> really steep section doesn't grow food.... Maybe I'll just grow >> food 
> for the birds there. 
> > >> I appreciate eveyone's help. 
> > >> Thanks! 
> > >> 
> > >> 
> > >> On Sep 5, 2010, at 9:22 PM, John Calvert wrote: 
> > >> 
> > >> > 
> > >> > 
> > >> > I started out writing a response to this, looking in the >> direction > 
> of what grows native on our steep coastal mountain >> canyons. 
> > >> > 
> > >> > But I realize that there isn't much edible on the really steep > >> 
> slopes. It seems the more fruit-bearing types are more likely to >> > appear 
> where there's better soil and moisture. 
> > >> > 
> > >> > So, that leaves the plants that do well in poor soil and least > >> 
> moisture... 
> > >> > 
> > >> > nopal cactus, various wild sages, maybe fit in a hollyleaf >> cherry, > 
> chia ?, maybe some kind of mulberry, wild golden currant >> (?). 
> > >> > 
> > >> > so, mostly natives, and then some select fruit-bearing plantings >> w/ > 
> drip irrigation. ? 
> > >> > 
> > >> > JC 
> > >> > 
> > >> > 
> > >> > Kevin Gleason wrote: 
> > >> >> Hi all, 
> > >> >> 
> > >> >> I was wondering if anyone has good advice for creating a garden >> on >> 
> a VERY steep slope (more than 45 degrees.) I'd love some >> feedback >> on 
> alternative terracing methods, whether this is too >> steep for >> small swales, 
> good soil-holding, drought-tolerant >> ground covers >> and other plants that 
> would be useful and other >> ideas. I remember >> hearing Brock Dolman talking 
> about making >> retaining walls with >> burlap tubes filled with soil and a 
> little >> cement. Anybody tried it? 
> > >> >> 
> > >> >> Thanks for your help! 
> > >> >> Kevin 
> > >> >> _______________________________________________ 
> > >> >> Scpg mailing list 
> > >> >> Scpg at arashi.com <mailto:Scpg at arashi.com> 
> > >> >> https://www.arashi.com/mailman/listinfo.cgi/scpg 
> > >> >> 
> > >> > _______________________________________________ 
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> > >> 
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