It has long been my belief - 1

The start of a new topic – a way of introducing new things, and building a knowledge base for those to come. But let me be quite clear here – I am talking about evidence-based observations, not subjective faith in the rightness of my hypotheses. As much as possible this builds on material in my book, though does not necessarily follow any particular section.

I shall start this off with a short discourse on shell energy value and how to make use of it. At more than 19MJ/kg the shell energy value (the SEV to follow the conventions of my book) of black walnut is higher than wood pellets, and the odd handful tossed into the fire-pot of a lit pellet stove has always burned with a good blaze. To avoid the pitfall of having to use energy to pelletize the shell, I asked my student collaborators to a) see what they could do to make cracked shell flow well when in a hopper, and b) how one would have to modify the auger of a pellet stove to adapt it to feeding this modified cracked product. I'm glad to say they've made progress on both fronts, so I'll get them to report on their work.

Shell is approximately 75% or more of the dry weight of the nut, so will always be the largest by-product, by weight or volume. In fact, any production strategy for kernel should build in an energy-based destination for shell. Long gone are the days when it was seen only as an abrasive end-product, or dumped as waste.

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

Pruning and felling

Finally getting around to collecting this year’s prunings before the grass gets too high. By my standards I did some severe pruning, and probably raised the lower height of the canopy by an average of at least 30cm!

I also had to cut out two trees which were encroaching on the hydro wires, which allowed me to do something I have wanted to do for a while – relate total subtended branch basal area (their footprint where they join the trunk, if you like) to the tree’s DBH. This is best expressed in the graph, where each point represents a branch plotted against its positional number away from the tree’s tip. There were about 25 branches on each tree.

Why did I want to do this? I have been intrigued for years about the switch from height increase to canopy expansion in open-grown black walnut, as mine are. In their early years the trees ‘concentrate’ on increasing the height of the leading tip. After this period, in an open-grown plantation each branch continues to grow outward and upward, taking some resources from the leader in so doing. With time what I have previously termed the ‘conical growth rule (CGR)’ must break down for the central stem, - DBH continues to jncrease, but as an expression of total canopy subtended rather than vertical height of the leader.

Each tree was just under the 15cm DBH, and I measured both this and the diameter of every subtended branch, working my way up the trunk (though they are plotted numerically in reverse). Height at which they were subtended (where they joined the trunk) was not taken, as there was no apparent relationship here – small branches could be found between larger ones. Hence the dispersion in the graph. Twigs on the trunk only a year old were ignored.

The numbers can be summed up in two ways: either by relating the relative cross-sectional areas (CSA), or by relating the relative perimeters (P; both cumulative in the case of the subtended branches). In both cases both the CSA and P of the subtended portion exceeded that calculated at DBH by between a factor of roughly 2 (CSA) or 6 (P), implying that a switch has indeed occurred. Which measure we use is not important as long as we be consistent. Remember, however, that DBH is measured at a point below the subtended canopy (or almost – the bottom pairs of branches on both trees were still below DBH), so it expresses an integration of accumulation of all biomass above it.

In physiological terms, the tree is growing mostly outwards, somewhere between twice and six times as much as it is growing upwards (a principal leader was still visually detectable on both trees and was not counted). This is in terms of deposition of carbon, the main structural element of the tree. At this DBH or earlier, the CGR is no longer applicable to the central trunk (closed canopy plantations may be the exception) and a ‘subroutine’ needs to be added for the canopy as a whole.

The relationship appears to be quite consistent, though two examples do not make a large sample (for the statisticians among you, the R² value of each line shown was about 0.50). It does seem that this will be the best way of noting when the competitive effect between trees occurs – if the pooled line (pooled because they are so close) does represent more than just these two trees then a change in slope (downwards, or less slope) should infer this, i.e. the branches will not grow so big (their footprints will be less). Variability in footprint under these conditions may be less.

This variability is curious. In open grown conditions the tree may continually be testing the immediate environment, and some of the variability may be due to competition between branches within the tree. This suggests that the leaves must be sensitive to slight differences in light intensity, because the black walnut does not have what might be termed a dense canopy.

Whatever it is, another relationship emerges, and I am again left marveling at the flexibility in expressed life around us (if the trees were closer the expression would be different).

As I walk the walnuts - 10

As I walk the walnuts I reflect on the progress we have made in the last five years and my hopes for this one. All of the technological components are beginning to come together, albeit at different rates, and in spite of glimpses of future bottlenecks that seem to parallel what our climate throws at us, adding to the challenges of nut production so far north, we have the market waiting for what we can supply, so no fears there.

Useful US studies show that we import about $110 m annually of tree nut products from the US alone (the study was commissioned to find this out). I raise gales of laughter when I tell my collaborators that I’d be happy with 1% of that market, but the truth is that if we could achieve a gross return of $25,000 annually to 40 landowners, we’d be well on the road to a sustainable partial livelihood across the region, which is far preferable to one or two producers making greater gains.

But this still requires effort, and perhaps more than we have brought to the task so far. I shall be egging my collaborators on even more, trying to increase the range of skills we bring to the questions that remain, showing why the biological issues of productivity parallel the technological challenges of bringing a product to market. I am more convinced than ever that BNP was, happily, a viable strategy, and that it is easily replicable on a wider scale. But there is a lot of black walnut currently out there on the landscape, and we need to harness this resource, as well, to add to the B of BNP and to our bottom line.

I see as a challenge now, how to add a focus on shell usage as a biofuel. With one of the highest energy densities in natural by-products, and at about 75% of our physical output, shell can be (should be) part of our market strategy, and while I am aware of its usage as an abrasive, amongst other things, in our climate this energy density cries out for a different end-use. We are in the age of renewable energy. Not exploring this would be like throwing the baby out with the bath-water.

As I walk the walnuts – 9

As I walk the walnuts I think about the graying of the population and the fact that the mean age of the attendees at past nut society meetings has been greater than my own, and I am on the cusp of retiring! The fundamental challenge is how to interest young people. The answer, I believe, is only through income potential. Remember that question? Can I make more money from that than from what I’m currently doing?

But perhaps there is another way. And that is to build associations in the mind between nuts and play. To that end, behold the Walnut Express, a model railroad layout that snakes around a peripheral shelf in the cracking shed, ferrying nuts from the Walnut Mountain (or Forest!) to the cracking machine. It’s still under construction so I am not sure whether it’s a Mountain or a Forest, and only time will tell. But one thing of which I am certain – the cracking shed will be a boring place for young people without it. Just ask my grandchildren.

As I walk the walnuts - 8

As I walk the walnuts and look at each tree, it is like a snapshot. Snapshots, by definition, are images captured at an instant in time, and tend to reflect something that we were doing at that given moment. Yet an image of a tree is misleading. It is certainly a snapshot of the tree at that given moment, but the tree is the ultimate interpolator, the summer-up of expression over its lifetime, the presenter of the all-gone-before. A tree, then, while in the present, is all of the past, as interpreted by its individual genome in that unique environment.

I say this because a tree is a prisoner of its roadmap for fixing and depositing carbon, and, once started, it cannot deviate from this roadmap. Oh, the roadmap may be altered for it – spring frost effects on bud growth, branch removal by pruning - but a black walnut always looks like a black walnut, no matter its shape, and will always yield nuts, not acorns.

With time I am less involved with the form my trees take. I matched their early growth with my own energy, interfering according to my criteria at the time, but now am content to let the trees fill their space however they will, their response to that interference an acknowledgement of my then-presence on the landscape, an element of biodiversity as ephemeral perhaps as the guarantee that the snow buntings will return every year. Nothing is guaranteed, not even that the energy to interfere goes undiminished, but I prefer to think that I just understand myself better now, and that however the trees fill that space is the way it should be.

Nuts aweigh

Six months without a word. I should apologize. 2009 went down in the yearbooks as nutless, so I hibernated. Things have not been static, however. The continuous-flow walnut washer joined the suite of black walnut technologies on the farm, and through the efforts of my good friend Rod enough walnuts found their way to the farm back in November for the washer to be given a trial run. Rod also asked me some penetrating questions, so rather than repeating everything here, follow this link to Rod’s blog and photos of the washer in action.

http://rodcroskery.wordpress.com/2009/11/09/a-visit-to-lostwithiel-farm/

Find the wiki

Just to let you know there'll be a new string to the bow from now on. Somewhere to post files without extensive editing so that they fit on the page. Products, activities, all that stuff.

http://BlackWalnutsdotCa.wikispaces.com

Not planning a full migration just yet, but we'll see. This is not yet a private wiki, so you should be able to access it, but just in case I convert it to a private site send me an email for your invitation to join. Tell me who you are, and why you're interested in black walnuts.

Line Index Explained

The following values have been calculated for five lines (trees) as an example. Please note that data collection on this portion of the farm only began in 2006, so not all variables were quantified every year. For the table to fit this window, 2006 data had to be excluded.

Line (Tree)			2007					2008
			A S	NY	SI	DBH	K%	NY	SI	DBH	ABNY
1	1	14	1	3.51	0.69	13.5	21.9	3.27	0.70	15.4	0.50
1	2	12	1	0.65	0.61	16.7	25.7	7.88	0.51	18.5	0.75
1	1	17	1	1.81	0.69	12.5	19.5	0.00	0.70	14.7	0.90
1	7	12	2	5.49	0.67	8.6	21.8	2.93	0.70	10.1	0.61
1	4	27	3	1.49	0.57	10.0	24.2	3.44	0.55	11.3	0.24

Codes

AS: Anthracnose Score - Incidence of Leaf Spotting Disease 1 (low) to 5

NY: Nut Yield - Number of nuts per sq cm trunk diameter at DBH

SI: Shell Index - Shell weight per cc nut volume

K%: Kernel Percentage - Kernel proportion of nut by weight

DBH: Diameter at Breast Height - Measure of tree size (at 135cm from ground)

ABNY: Alternate Bearing Index (from NY) - Annual variability in NY 0 (low) to 1

On the far right-hand side are the calculated (multi-year) Alternate Bearing Indices, where it can be seen that 1-4-27 and 1-1-17 are the two extremes, the latter so far expressing high alternate bearing (closest to 1). If you find this hard to understand, or want to know how to calculate it from the above data, several references to this characteristic can be unearthed by searching on the term on the internet. High ABI or ABNY is not desirable, unless the biennial compensation in NY makes up for non-production in the off years. I am not ready to thin out 1-1-17 just yet.

In a future post I will discuss using the combination of these variables as a selection tool.

Line Index Variables

What is the Line Index? It is my quantitative description of the best nut producers (the ‘3’ trees, if you are familiar with the term from previous blogs), using the variables I currently think the most important. These are:

· Anthracnose Score (AS)

· Nut Yield (NY)

· Shell Index (SI)

· Kernel Percentage (K%)

· And, derived from NY, the Alternate Bearing Index (ABI or ABNY)

Below is an explanation of each variable, but not the reason why I consider them the most important. Just be content for the moment that a range of quantitative descriptors has been attached to each line (line = a single tree, which may or may not have an identifiable maternal parent on or off-farm). DBH (Diameter at Breast Height) is included for interpretation.

Anthracnose Score (1-5). The expressed incidence of leaf-spotting disease (which may have non-anthracnose components), which is commonly considered to depress a tree’s productive ability. 1=low, 5=high, thus a 1 indicates nill expression, which can be considered a strong tolerance (if not outright resistance) to leaf-spotting disease.

Nut Yield (no.nuts per cm² of trunk diameter at DBH). A measure of productivity based on nut count per tree, adjusted for the tree’s size. All trees in a plantation will vary in growth rate.

Shell Index (shell wt proportional to nut volume: g per cm³). A measure of the energy partition occurring at the individual nut level.

Kernel Percentage (kernel weight as a proportion of dry nut weight). A measure of the edible yield of the nut. Can be used in combination with NY to determine Kernel Yield (KY).

Alternate Bearing Index (0-1). A measure of the consistency in nut production. Black walnut shows variable biennial productivity. Here adjusted for DBH, thus accounting for tree size, and calculated from NY, thus more truly ABNY, not ABI which, used by others, does not account for change in potential productivity across time based on tree growth.

Diameter at Breast Height (cm). A standard, convenient measure used to determine annual change in tree size at 135cm from the ground. DBH, for all its convenience, is a moving target. While it remains constant in relation to the ground, it does not remain constant in relation to the top of the tree. Thus, successive annual measures of DBH are taken at different points within a tree’s geometry.

Core Business - Line Index

Things have been a little slow among the walnuts for the past six months, or rather I have been. Catching my breath, and trying to refocus on the core business. Not so much a reconfiguration, as a reconfirmation. The result is the development of the Line Index, which will tell you about the top trees here at the farm, and the order in which I rank them. Look for the Line Index section. Removed from the blog will be that cursed entry of Nov 2007, which attracts every human soul who wants to know what happens when we take a chainsaw to a standing tree. I can’t actually use the description of the process, otherwise every search engine from here to Australasia might pick out those few words, thus defeating my purpose. Sorry about this, but my core business has to do with black walnut, not educating every Tom, Jane or Harry about the carbon cycle. There, I can already hear the hits….

As I walk the walnuts - 7

As I walk the walnuts, !st January 2009, -18ºC, I think about the year to come and how much farther we will get. First, though, Happy New Year to all my collaborators, from the tree end to the machinery end. None of this would work without you. To warm you up on a cold winter’s day, I have chosen a summer photo.

Then a swing past the barn, where, a short six weeks ago, I was finishing up the wet processing of the 2008 harvest. My rapid departure to warmer climes for a couple of work weeks is evident: the final pile of hulls is still there, along with the mess made by three squirrels I have recently managed to move out. The final nuts are still on the dryer, though the remainder are bagged up and labeled ready for weighing.

In the fields, the range scoring tape is evident, splashes of colour on the naked trees. How much that system has helped me to understand what is going on at the tree end. The tape will come off at pruning time to avoid confusing next summer’s work, when the trees will be re-scored.

Still to do is the nut report, which entails cracking and measuring the kernel and shell fractions of the ‘3’ trees. That will happen sometime in February. Observation of the samples suggested some surprising things to come, but I will wait for the hard data before saying anything more.

So, 2009 will be the year of ‘nutmastery’ and a separate blog to deal solely with that end of things – machinery, markets, etc., while this one may slowly wind down. We’ll see.

Those good seed trees

Rod Croskery (he of the only site currently on my blogroll) wrote to me recently posing a question that I suspect many would like to ask:

[About the tree in Westport] planted in 1937 by Dr. Ford Goodfellow, the parent tree has very little trunk but an enormous canopy. [The owner] assures me that it has borne heavily every year for the last twenty. If the nuts are well-filled, the parent might meet your criteria for a good orchard tree.

This is a bit of a challenge, because it is growing in a site distinct from the farm. I responded to Rod that currently I was only interested in selecting from the population that I had on the farm. Many rural Ontario communities have populations of black walnut trees, many of which (I am separately informed) would be descendents of the original parent stock brought up by United Empire Loyalists a couple of hundred years ago. This ignores the other common knowledge that First Nations’ peoples also spread the black walnut eastwards from southern Ontario.

These populations I have observed to be regularly productive, so here is my suspicion: that the environment in many of these communities reduces the risk of early spring frost damage to the trees’ flowering, mainly, I believe, through low-level mixing of exhaust gases from heating systems. Most of these trees are within or just moderately above the mean roof line of the community, where such effects could be expected.

How could we test this? If you have a potential seed tree in such a community that you are interested in, I suggest you hang a max-min thermometer on the trunk at breast height (1.35m) on the north side, inside some sort of shield to protect it from the elements, and compare the readings with Environment Canada’s values at the nearest observation site on those nights when spring frosts occur. Do the readings match or not? Remember to reset the thermometer daily.

Because my fields are frost prone, I believe my good seed trees must be relatively later flowering than the rest of the on-farm population. Alternatively, my non-seed bearers are too early for my site, something I must quantify this coming spring. More on this later.

2008 harvest report

Well, over 2 tonnes of fruit were harvested over about five weeks from about 10th October. This includes on- (75%) and off-farm (25%) sources. On-farm, harvesting of ‘3’ trees was independent of ‘1’ and ‘2’ trees (see earlier post on range scores). All nuts from fruiting trees were counted, though 1 and 2 trees were counted at time of pick up (three different sweeps of the fields), and the fruit pooled by field during each sweep. Fruit from each 3 tree was kept separate in plastic lugs in the field, and totals counted when there were no further nuts to fall.

All pooled fruit was processed first – weighed, hulled, then washed and dried. Fruit from 3 trees was weighed, hulled, washed, then sampled and dried. Three-nut samples of 3 fruit were retained for drying, then subsequent cracking and separating. This analysis will be reported under the 2008 Nut Report.

Within the global number reported above, there was much hidden. The two main experimental populations (Fields 1 & 3) are reported below (you can click on the image to open it in a larger format).

Firstly, the nut range scoring system was successful in separating trees by eventual yield (at harvest). In each of the two fields, there are in excess of 500 trees. In each field, more than half of the population did not fruit. The number of trees fruiting (total n) was 187 (F1) and 254 (F3). The average number of nuts per tree was 20 (R1), 94 (R2) and 299 (R3). The biggest contrast between fields was for R3, where F1 gave 448 nuts per tree and F3 gave 151 nuts per tree. Correction of these totals by cross-sectional area (CSA) at DBH (diameter at breast height; multiplied by 100 in the above graph to be able to use the same vertical axis) almost completely reduced this variability to 5.09 nuts per sq cm of CSA (F1) compared to 5.53 (F3). I have termed this value Nut Yield (NY), which you can see was, on average, >1 for R1 and between 2-3 for R2 (remember the 100 factor in the graph above). Groups of bars for same range score number are from fields 1 and 3, reading from the left.

So what? (you might say). Well, it confirmed that it is not just tree size (measured here as DBH) which accounts for NY. There are other factors which make some trees more productive than others. It also suggests that you could forget about harvesting R1 trees and still collect just about the same total weight of fruit, or, put another way, R1 trees contribute very little, individually, to the total harvest, though they make some of this up by sheer numbers. As we are embarked on an inter-generational venture, as long as NY is the main contributor to total kernel yield (KY) per tree, it is only from R3 trees from which we should wish to select. We would want to analyze this characteristic only within the population of R3 trees. It also offers the means (i.e. a sufficient number of very uniform nuts) to set a cracking machine to crack optimally for a given set of nut characteristics, which is some of the rationale underlying US selection of black walnut ‘cultivars’ based on kernel percentage (K%; sometimes measured in efficiency terms as ‘crack out’), though high K% is the other aspect.

In my top-yielding F1 tree, nut number was >1700, with a NY of 7.88. However the top NY (16.15) was from the top F3 tree which gave only 343 nuts. Correction for size is thus immensely important to understanding productivity within a relatively uniform environment, and were both trees to show the same K%, the first would be of greater economic importance to me at this point in time. The former had a 2007 K% of 26% in a nut weight of 15g, which suggests a total KY of 6.4kg from this tree this year. Not insignificant.

Why do I think so many trees are not producing? Probably because they are too early for my site. I shall test this next spring, comparing a random sample with the ‘3’ trees.

Finally, you probably think I’m crazy to do so much counting. Learn to do it, for it will tell you a lot. Use range scoring first, though, so you only count nuts from the ‘3’ trees.