Biomass Nut Production in Black Walnut

Well, the book is finally out:
Biomass Nut Production in Black Walnut: Exploring Management
and can be reviewed on and obtained from Lulu

Managing for growth

In a previous post (A bit more about cultivars, Feb 3) I promised to come back to the topic of managing for growth. All that I’ve seen in our plantations suggests that rapid seedling growth (increasing height, expanding DBH) leads to more rapid physiological maturity, and that this in its turn is displayed as fruit setting (nutting). At the core of management for early growth will be weed control, and if you plant, as I did, in old pastures or hay fields, this means grass control. Grasses are particularly pernicious, if you’ll forgive the alliteration. A little while ago I gave a talk to a local woodlot association, where I was tackled about my use of glyphosate. “Why” I was asked “didn’t I mulch my trees?” Laziness, I suppose, though economists would probably interpret that as awareness of an infinitely low return to labour were I to do so, because I am not inherently lazy. The difficulty lies in the number of trees we have – we would have to mechanize the mulching process if we wanted not to have to work around the clock. Let me first, though, defend myself to the purists. In the early years, I did work around the clock, using a Honduran sickle (don’t ask right now) to control grass and weed growth manually. The trees didn’t grow. I also used plastic brush mats (inorganic mulch, if you like). The trees didn’t grow. So I bought myself a backpack sprayer, having seen the local CN maintenance crews spot-spraying for brush control along the local railroad track. I even bought the same model. The trees began to grow. By this time I had 1,500 trees, and found that I could spot-spray the lot in one good day’s hard work. Much better than bending over for several days with my old Honduran friend in hand, without result. The trick was to lower a piece of old 15cm stovepipe over each tree, for protection, while whipping the spray-wand around it. That tells you how undeveloped they were, because even a 50cm seedling can develop enough branches that you’d need a 50cm diameter stovepipe if you were to lower it over the tree quickly.

So the trees grew, and outgrew my technology. Then I picked up an old orchard sprayer from my local machinery dealer, and gravitated to band spraying (switching a tractor-mounted sprayer off between trees requires more dexterity, accuracy, and even controls, than I had, and doesn’t do the machinery much good). Though by this time the trees were getting to the point where a continuously clear band was only going to be good for expanding root growth, so I didn’t begrudge them that extra bit of herbicide. They grew wonderfully. So the lesson in this is that herbicides can be very useful and, if the sums were done, probably far more economical (let alone effective) than mulching. And in case you believe ‘herbicide’ and ‘conservation’ shouldn’t be mentioned in the same breath, or the same sentence, just try g**gling them together, e.g. http://www.appliedeco.org/conservation-research/prairie-restoration-research, or http://www.ecologyandsociety.org/vol7/iss1/art6/
So, let me finish this post off with a couple of photos. The first is courtesy of the Ontario Ministry of Natural Resources and dates from the early 1980s when a lot of work on hardwoods, especially black walnut, was being done. The photo shows the contrast in tree growth between herbicide (background) and no herbicide (foreground). When I find the booklet (it’s lost in my files somewhere) I will confirm the herbicide (simazine, I think) and the agency involved (Canadian Forest Service, I think). Fred Van Althen was the principal researcher. I think the photo speaks for itself about grass effects on black walnut.

The second is from our farm, and dates from 2004. Two years before, these trees were very much like the trees in the foreground of the previous photo. Glyphosate sprayed at the recommended level of active ingredient per hectare gave the grass control you can see here. Some of these trees nutted in 2004, which does not speak to an immediate herbicide effect but rather that the previous spot-spraying was itself effective. Now, I only spray seedling trees under establishment (mainly the selection blocks). My current weapon of choice (not used in this photo) is an ATV-mounted Enviromist Sprayer, with a 60cm spraydome. I can now do hectares of plantation per hour.

Let me mention some of the other consequences of vegetation, mainly grass, control with herbicide. As I generally spray only once, in the spring, there has been an interesting proliferation of broad-leaved species, with an accompanying increase in insect and bird diversity. Note that I say broad-leaved ‘species’, rather than ‘weeds’. The definition of a weed is ‘any plant growing where you do not want it to grow’. While I was quite surprised by the influx of milkweed, and of some other species, it is only ragweed that I truly dislike. Ragweed, apart from its noxious asthmatic-inducing pollen, is a plant with no redeeming features, and can be as oppressive to young black walnut as grass can be. So a second application may be called for. The remaining vegetational diversity I value, as it co-exists with the trees without direct competition. As the trees grow they quickly shade the other species, and I am now mowing beneath them as some grass has returned. There seems to be no juglone intolerance in these broad-leaved species, as I see no major species-difference where they grow between fields with trees or without.

Applied Research Day

Yesterday (10 April 2008) was Applied Research Day at Algonquin College, where student teams showed off the technology they worked on during their final year at the college. Front and centre was Black Walnut Team 3, exhibiting the current iterations of the harvester and cracker/separator (shown in the picture), and taking up the largest footprint in the exhibition hall by far. I say Team 3, because this is the third annual iteration of students to work on machinery development. It has been a pleasure to work with each team, each bringing its own assortment of personalities and skills, working towards our goal of cost-effective farm-scale technology for black walnut nut production (I think we’ve been a reasonable partner, because I frequently hear the words ‘patient’ and ‘supportive’ applied in our direction; from our perspective these are just elements of our commitment to the emergence of a regional nut production industry).

This event marks a milestone: the completion at the College of work on the cracker/separator, and the production of an experimental harvester which we can begin to analyze practically, i.e. under field conditions, before embarking on a ‘second generation’ model. Both units will come to the farm over the summer and be exhaustively tested. Only the harvester will feed back into Team 4’s program; the cracker/separator will be taken up by the members of Team 2 who demonstrated the first proof of concept to the NNGA last year. They will work with us at the farm to define efficiency, where cost savings in manufacture can be made, and to complete (by the end of the year) the construction of the first five units which we hope to offer to the market. Bookmark this post!

The Triumph of the Tree

John Stewart Collis, in his lyrical prose in the book of the same name, begins: We were nursed into life by trees. It is to trees that we owe the development of a physiology which made Man possible – that is to say, made conceptual thought possible. JSC was a remarkable writer, more a natural philosopher, a conscript to WW II who requested to spend it on the land, and who served in an agricultural brigade as a result (he’d actually served in the conventional sense in WW I, so one cannot question his motive). Out of this came The Worm Forgives The Plough (1973) among others, the first book of his I read. His writing had far more in common with the blogging style of today than with the writing of the time http://transitionculture.org/book-reviews/the-worm-forgives-the-plough-john-stewart-collis/). Again, in The Triumph of the Tree (1950), in fact it is not unlikely that in the course of the next few decades after we have had some really rude shocks – we will gradually return (this time on the plane of consciousness) into the Order of Nature, as one factor of the whole. If this happens, the turning point will undoubtedly have been this century. It seems that he was probably just a decade out, a remarkable insight into the perils facing us at a time when global warming was unknown. He is able to conjure questions enough to make a tree laugh, but in spite of its lyricism this is very somber reading, because, sixty years on, one can really see how much further out we now actually exist on the edge, and all, if we accept JSC’s arguments, because we lost our wonder (perhaps fear) of trees, and fled the Era of Mythology. I would like to think that the Era of Science could restore some of this wonder (perhaps respect).

(There have been various publishers of The Triumph of the Tree, starting with William Sloane Associates, and House of Stratus. Most are now extinct, but I see that the used book is still available through the Internet).

A bit more about cultivars

I should probably qualify my last remarks, because there are undoubtedly some mid-Westerners getting a bit hot under the collar right now. What I think it is important to add is ‘especially at the northern fringe of the species range’, i.e. where I am, where graft unions are very prone to winter damage, ultimately leaving one with an expensive tree growing from the rootstock (which, by the way, will have been a common black walnut seedling grown from a nut, sacrificed for the greater good of the scion). This, also by the way, is the Third Law of Nut Production: Rootstocks Make Very Expensive Nut Trees. The following are the First and Second Laws: Use Selected and Named Varieties, and, Grafted Trees Don’t Like Marginal Conditions. If you read them in order, there is a modicum of sense to them. So, no matter how good your soils are, if you live in the same climate zone as we do, you can take the conditions as marginal.

Now let’s address the energetics of nut production. A grafted tree will produce nuts at a very young age, because it grows from a scion which is already mature wood. A common black walnut will take some years to reach physiological maturity, and the only way to speed that up is to create the best growing conditions possible so that the tree grows as fast as it can. Still you will not know when to expect nutting, but my goal is to minimize this period (more on this later). But we must still deal with the issue of the tree’s ability to fill all those nuts it is going to produce, which will be related to the canopy size for the number of nutting sites within it. A young grafted tree will still not produce an ‘economic’ yield, because it will be too small to do so. Pushing a tree to nut at an early age creates the risk that too much energy will go into multiple shell production, leaving insufficient resources for the kernels to fill them. Cumulative solar energy incident on the canopy declines with increasing latitude, so, once again, there is a risk that a tree genetically driven to produce large quantities of nuts, will, at our latitude, leave those shells empty. The tree’s root system grows in tandem with its above-ground structure. Resource capture by the roots is also important here, as the tree requires nutrients to produce fruit. Small root systems will not sustain heavy nut loads.

So, all in all, my original post was fair even if it wasn’t fully explanatory. Just remember the three Laws of Nut Production, and make your choice.

To cultivar or not to cultivar?

I am prompted to write this post because I recently received a form inviting me to list the cultivars I grow on a web-based North American inventory of nut tree cultivars. If I grew any, I’d be delighted to do so. However, I don’t, and if it’s not clear anywhere else in this blog why not, here goes…

A ‘cultivar’ is short form for cultivated variety, and is standard speak among those who’ve bred something new by crossing plants, or who’ve identified something in the wild they’d like to put a name to because of some useful characteristic – in the case of black walnuts it is so far the latter, generally related to kernel content or crackability of the nut, and because maintenance of that cultivar is wholly dependent on grafting (black walnut cuttings will not root). In such a case, the name gives that particular genotype an identity, e.g. Emma K.

Now, let me be unkind here and say that I believe the naming of black walnut cultivars has only been of benefit to the horticultural nursery industry. It has resulted in the sale of young trees at about $20-30, whereas a forest nursery will sell common (i.e. non-cultivar or unnamed) seedlings for $1-2 apiece if you buy them in bulk. The lads in Missouri* have roughly calculated that planting cultivars can bring a nine-fold advantage in nut yield over nut production from plantations of the best common trees (if you knew which they were). My response to this is that the planting stock will still be cheaper if you plant nine times as many common trees. There may still, of course be a yield disadvantage because the potential productivity of the common trees won’t be known for some years, but then again I could say the same of any cultivar, if it is planted at a site far removed from its point of origin, where growing conditions may be significantly different.

Why do I make that unkind statement? Because, and unlike the cases of the pecan and Persian (aka Californian) walnut ‘industries’, fully based on named cultivars, there is no farm-based equivalent in the black walnut. The only commercial equivalent (i.e. black walnut example) is Hammons, also based in Missouri, that survives on the annual US wild harvest (thousands of tons) . The reasons for this lack of a farm-based equivalent are various, and I shan’t go into them here and now, but one good one is that nursery stock is too expensive for the return on investment when the principal nut-buyer (already mentioned) buys at or near to equivalent-to-wild prices.

So, no cultivars, just 2,500 common trees, building the natural capital to let me exploit various income streams, and at least $45,000 of avoided-costs in the bank.

As a footnote, in 2007 I made my first selections from the trees that nutted, and am now growing 25 F1 lines from seed. These will not be clones of the mother trees, as grafted cuttings would be, but until someone has done the science that convinces me that $18 ($20-$2: I could have said $29, or $30-$1) will make up for the reduction in heritability of the productive characteristics important to me as a grower in an industry which does not yet put value on any key trait of named cultivars, I prefer to select for traits which I have observed as useful here at the farm, rather than risk capital on Emma K, when it could turn out to be Humpty Dumpty

Actually, I have some F1 Emma K also…..

*Jones, J., J.Haines, G.E. Garrett, and E. F. Loewenstein, 1993. Genetic Selection and Fertilization Provide Increased Nut Production under Walnut-Agroforestry Management. Proc. Third North American Agroforestry Conf., 16-18 Aug 1993.

So, how many generations?

Another doughty question. Generation time in our black walnuts is somewhere from 8-15 years, depending on the individual. This is not necessarily the same as the age at which a tree produces a its first nut. The generation time requires that we, as service managers, have enough time to identify and quantify key abilities. If a tree first fruits at six years of age, it is likely to be year 8 or 9 before we have enough data to decide whether we want to add its offspring to our biomass plantations. The nuts will not germinate before the subsequent year. Some trees are not producing fruit even at 15 years of age. Thus, while they are providing environmental services, unless we can identify an income stream independent of fruit production, these less prolific trees are unlikely to add to the farm's bottom-line. As we use a planting layout which requires that some trees be removed to leave room for others to grow, it is more likely to be these less-prolific trees which pay the ultimate price. The first identification of mother trees for on-planting was made in 2007. Offspring will germinate next year. From here on while those offspring will not be evaluated for several years, we will continue to on-plant from useful mother trees, according to several criteria.

Inter-generational assets - 3

Let's put a bit of a different spin on this. Under Biomass Nut Production (BNP) I gave a definition. But I neglected to take it as far as it must go. If I use non-select material, my first generation of trees (the ones I plant) will have some with useful characteristics (or abilities, to use the service concept), and others with less useful ones. What I want to do is try and increase the gene frequency of the trees with useful abilities in my total population. Unlike the orchard of selected grafts, which I noted was the dominant model, I am not starting with an 'end'-product. By means of generational selection I am looking for the optimal outcome on my particular site (one of the 'land' concepts). In overall terms, I am trying to enhance the overall service value of my inter-generational asset (to me, the population) using the medium the tree gives me to do it - the fruit. In that the genetic content of the fruit (hidden away in the chromosomes of the kernel) allows me to pass on recombined abilities of the known mother and unknown father trees, it is in itself an inter-generational asset. On average, I wish the abilities of the offspring to be enhanced vis-a-vis the known abilities of the mother tree. Only by sowing a large number of nuts from the mother tree can I identify whether the ability(ies) of interest is (are) heritable, that is to say, some quantifiable level of continuity in ability from the mother tree to its offspring. As the black walnut is wind pollinated, the father remains unknown, not unlike, some would say, outcomes of male behaviour in our species.

Inter-generational assets - 2

Assets -1 was important to placing the rest of this in context. My friend's maple is an example of such an asset - it provides services and, to him, has aesthetic value. So, really, does the beaver - he just doesn't know it. And that is the crux of the matter. How do we inculcate this sense of value of invisible processes, and of those silent sentinels of the land which have stood across their own generations passing on carbon at rates and by pathways which we can only imagine? Farmers have spent centuries removing trees from the landscape, an appropriation of environmental processes in order to feed their own families and ours. None of us is innocent. How little hubris we show when we protest at further deforestation, given increasing populations, competing uses of physical space, and systems that demand ever-increasing economies of scale in order to stay in business. We are the asteroid.
You probably realize by now that I think a tree is the prime example of the physical expression of an inter-generational asset. A 50' tree is the outcome of years of metabolic and physiological processes grabbing and storing carbon in the physical form which we label black walnut, oak, Norfolk Island Pine, mahogany. A tree, by definition, given how long it takes to reach its final size, is inter-generational (ours, at least, though I'm not sure about elephants). Embarking, as we have, and my friend Rod Croskery has, on extensive planting of black walnut, has thrust us into thinking about generations and inculcation of values.

Inter-generational assets - 1

At the heart of my discussion is the concept of inter-generational assets. These are assets that get passed down or across generations and contribute to the well-being of the recipients. They may be measured in financial terms, but if we are talking about environmental services then they are more likely to be sustained processes of some importance, such as carbon sequestration. Where I live there is much emphasis on private ownership of land, i.e. 'this' land is 'mine' (There is a very common sign on fences or in windows: Hands off Government, this land is mine). This is an indicator of the very simplistic idea of what we think we are, and what we think we control. 'This' land was here long before 'me', and will be long after. 'I' am therefore no more than a temporary occupant, one more sedentary than your average mammal, but one even more damaging than the beaver (I have a friend with a particular dislike of the beaver, for the damage that particular individuals of the species do to some of his young maples, which he views as inter-generational assets. 'What bloody use are they?' he asks of the beaver. After some thought the answer is clear - to make more beaver). We are beaver to the power of ten, given how we have stripped the land to grow something that we, rather than the beaver, can eat. Our agriculture has largely reduced environmental services from long-term cycles of naturally-sustainable processes to annual cycles of chemically-catalyzed rapid carbon flows, effluents, and other consequences which gradually impoverish the soil's ability to withstand our onslaught. We are really just stewards of the land, during our ownership, but what sort of stewardship is this? Another friend says 'We must leave this land in better condition than we found it'. That is a far better concept of stewardship, and one which can lead to the asking of the key question of 'What is land?' Land is not just the physical 20 acres of real estate. Land is processes, biodiversity, the functional interface between a gaseous atmosphere and a solid mineral base which sustains all beings (seas excepted) in their physical existence, and if we do not come to the realization that these sustain us as well, we are pretty well doomed. This 'land' therefore is the ultimate inter-generational asset.

Carbon balance

Not just another nut website. Black walnut is our vehicle for working towards a low-carbon emissions farming system, with a net storage of carbon back in the landscape. We calculate our carbon balance annually, working out our methods, and as the data become increasingly available; where positive this will then become the basis for small-scale emissions trading through our Carbon Club. This will be launched later in 2008

Use of English

If 'mastery' is the dominance of a particular skill, 'biomastery' is, for me, the successful outcome of 'biomassing' - the amassing of sufficient biomass, or carbon accrual (sequestration), in a low-energy intensity system so that the reversal of past carbon extraction is achieved by cumulative net annual accrual via the carbon balance within the farm limits. There is no point in expending vast amounts of fossil fuel to achieve this outcome. The objective is to achieve a positive annual balance as soon as possible in our annual ledger. The earlier we do it, the more successful we have been in matching our accrual strategy with our expenditures.