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.

Environmental Services

A simple definition would be services provided to recover some of the tremendous environmental costs incurred by society. Most of the environment has, until lately, been considered a free good, and that we (wherever we are) can continue to spend environmental capital as we like. I think Al Gore has more or less laid that assumption to rest. But what, apart from energy conservation as a means of reducing emissions, can we do? How could a landowner provide a service? Even more how could a landowner benefit financially from doing so? Doughty questions, those, and it may take a post or two to crack them.

Multiple Income Streams

If you corner an avid nut-grower he (generally, not she) will be fixated on the amount of edible kernel he can produce and extract. This is his market product. It is peculiar that in a species where edible kernel tends to be the lowest percentage by weight of any of the fruit’s components (shell and husk are the others), and where larger industry has successfully commercialized walnut shell, that the smaller grower has not caught on to the importance of multiple income streams as counting towards the effective bottom line. If shell and husk are trashed without further thought, the bottom line starts to look pretty thin. My calculations have shown, for example, that if shell can be monetized to 25% of kernel value, the general proportions of each allow equal returns from a 20% kernel line if the shell can also be sold, and a ficticious 40% kernel line where the sole product is the kernel. I say fictitious, because I have only seen data confirming occasional 38-39% kernel percentage in some lines, with this value often being influenced by environmental factors.

And what if we could also sell environmental services? What are they? How could we calculate them? Perhaps that is for another post