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Black Locust Part III

Garth Brown |

In parts I and II of this series I discussed some of the great things about Black Locusts. In this post I’ll finish the overview of this marvelous tree.

The rapid and vigorous young growth Black Locusts exhibit is worth exploring in more detail. Most forestry products at the small scale are difficult to make money on because the timeframes for investment are so long. I’m not here to argue about what we should do to properly value nature’s services or discuss what could perhaps be done to make our financial system better reflect the value of the good and services mother nature provides us. The fact is that our interest based financial system is predicated on the concept of perpetual growth, and as long as that is the case we’re forced to value things that are near in time more highly than those that are distant. Locusts are among a select few types of woody agricultural crops that can realize a substantial return on investment in a bit over 10 years. Other examples of temperate woody plants with positive cash flow in a ‘reasonable’ amount of time include blueberries, apples, and hazelnuts. But these are all fruiting plants. It is unusual to say the least for a timber crop to yield a marketable product in such a “short” time (setting aside the tropics with year-round growing conditions). It is the wood’s incredible durability in damp and dirt that make them so - as a locust planting can be harvested for fence posts at 12-15 years and net a reasonable amount of money for the landowner. Other trees have to get much bigger before they are large enough to be valuable to “the market”. With selective thinning the best trees in a grove can be saved for future lumber while the posts can pay for ongoing expenses.

Fence posts obviously hold a place of importance on grazing farms whether they’re sold for income or used directly to offset expenditures. Two old-timer sayings I’ve heard about locust posts include - “Locust posts… they last two years longer than stone,” and “Locust, it lasts longer than the dirt you stick it in.”* That kind of longevity means less labor and less material use over the long term. If a post only needs to be placed once in working life that is pretty darn great. The one fence that came with the farm when we bought it was built with pressure treated southern pine. I’ll be lucky to get another 15 years (25 total years) out it before it needsa lot of TLC. I’m currently building fence where my pasture meets the woods. Doing this well and inexpensively means I need to use some live trees as posts. Rather than stapling straight to the trees as farmers around here did in days gone by, I’m using small locust boards as ‘nailers’. The growing tree can expand against the board and press all the hardware away from itself, rather than gradually engulfing the metal. This is better for the tree’s health, and *a lot* better for the future health and safety of humans who get it in their heads to fell a fenceline tree 80 years from now. Here are two photos to illustrate the point - one with nailer I just placed and one with barbed wire done the old-fashioned way.

The rot-resistance that affords posts and nailers long life means Black Locust lumber is a great option for construction applications destined for the out-of-doors, e.g. picnic tables, benches, and playground structures (visit the link and if you have small kids you might wish to emigrate to Europe!). Using Locust lumber for these needs is the eco-friendly choice because it’s locally produced, and more importantly, doesn’t require logging in ancient forests to get the wood. An old Black Locust is one that has made it to 100 years. An old Western Red Cedar could easily be well over 1,500. Cedar and Locust are pretty different in their working properties - the former is quite soft, the latter quite hard - so perhaps the best substitute Locust can stand in for are the rot resistant tropical hardwoods from around the world, many of which are now in short supply. Relieving pressure on the world’s remaining tropical forests is an unalloyed good in my mind.

Active farms have a high demand for lumber of all sorts. Here's an example of a use I just put some knotty and uneven locust lumber to -

These are boxes I'm going to bury in the ground to house hook-ups for my pipelines I use to keep water available to my livestock at all times. When I first built the water system I didn't know enough about what I was doing to do it exactly right the first time. Now I know what I want and have gradually replaced the hydrants I installed years ago with in-ground valves and hook-ups. Boxes like these keep everything accessible and nice to work with.

Another positive attribute to being a ‘hardwood’ is the density of locust firewood. Crooked, twisty, and otherwise unusable lengths of locust provide really good, hot burning fuel. I like my firewood as dense as possible because it means that much less splitting and stacking for the same amount of heat. One locust log can easily have 2-3 times the heat value of something lighter like poplar or hemlock. Before the days of HVAC and easily accessed world markets for fossil fuels this was a well appreciated fact for anyone who lived in a cool or cold climate. Small-holders living close to the land knew well the advantages of dense firewood.

And yet another reason some people like Black Locusts is their flowers. A stand of locusts in full bloom in a pretty site, and one that does good by local bees. I don’t keep bees, but I love the idea of planting locusts for them and having it redound to my neighbors’ benefit who do produce honey.

Now that I’ve made a convincing case that Black Locusts are a panacea for the world’s problems allow me to fire a few warning shots across the bow before everyone goes planting locusts willy-nilly. Three attributes of the locust tree would give me pause before planting it if I only owned a small amount of land.

1. Prodigious suckering is a boon for the livestock farmer. For a suburban lawn, less so. Especially if the upsurging thicket crosses a property line.

2. “Thicket” in the above sentence is the appropriate term. Even more descriptive would be to call it a “thorny thicket”. Young locust trees often (but not always) have thorns on their young branches.

3. The hardness of locust lumber also means it’s pretty brittle. Black Locusts lose limbs under wind and ice/snow conditions, so care not to plant close to buildings is prudent.

I hope this series of blog posts affords Black Locust its due and ending on a few points of possible notches against planting locusts doesn’t detract from the overwhelmingly positive sentiments I have about the species. There is a lot of unrealized potential with these trees and I for one intend to plant a bunch of them in the coming years. I also intend to select trees for upright growth form that will provide future generations with good quality lumber.


Photo credits - Edmund Brown

* I wonder if the origination of the phrase “...longer than the dirt…” was literally true. On a poorly farmed, sandy, erodable soil, posts planted at the edge of a field could easily have lasted longer than the dirt itself.

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