Eric Silveira

Definitely chopping wood, the sound of a clean chop alone makes it so refreshing.

Dear Paul,

I am happy to hear you have a plan and people around you to support you. I wish you all the best with your journey!

I made a couple of things here and there, but the one I use most often is this fire poker.

I appreciate the input Mimi and Eino. My confusion over how a woodland walnut tree in a standard terrestrial environment could create iodine-containing husks is what prompted me to make this thread. It is good to hear that from a specialist. Also, the mention of seaweed is another fantastic idea, that's generally what I turn to for iodine sources too.

Since you have the goal of leaving tappable trees for future generations, it's worth mentioning there are other woodland trees that you can tap for making syrup. Trees like Sycamore, Walnut, Beech, and Birch can all be tapped with various levels of success. I have also heard of Linden and Hop Hornbeam. I have personally tried Black Walnut Syrup, Maple/Beech, and Birch and found them all to be delicious in different ways!

The big differentiating factor is the sugar content in the sap, the gold standard of 40:1 (On a good day) for Sugar Maple is going to be much higher for other species but not all. There's a lot of wiggle room and room for improvement, but it may help you in your search. Finding an existing woodland with tappable trees is much easier when you expand the search parameters beyond just maple.

To be clear, Birch syrup is very different from Maple syrup. It is closer to molasses in color and flavor, with tangy and fruit notes. Not something you use for pancakes, but more for glazes and sauces. Besides having different sugar makeups (Mostly fructose and glucose compared to maple's sucrose), the big difference is the sugar content. Birch is closer to 100-120 gallons sap for 1 gallon of syrup so there is substantially more non-enzymatic browning occurring during boiling. I only bring this up to say if you want a milder syrup from trees with lower sugar content in the sap, try to use fractional freezing and/or reverse osmosis to remove some water without applying heat.

I hope this helps,
Eric S>

Those are some good points! I feel as if I am coming to a better conclusion.

The weathering of biochar through, heat, freeze/thaw, and other elements does seem to make it smaller in size in most cases. I am curious about the fire pits mentioned by J Hillman, but perhaps there are vastly different rates of weathering given local conditions.

But as you mention this size reduction greatly increases available surface area for microbial interaction and the like, so it increases its benefit to the soil. Initially, I was worried that at some point the biochar would be weathered so much that this microscopic pore structure would be eliminated entirely. To be clear, it still can be eliminated over time, it is not immune to entropy, but I think this process is ridiculously slow. In other words, the complete destruction of the pore structure only occurs over the entire lifespan of the biochar or close to it.

I was initially hesitant to include examples of Terra Preta in this discussion because they do not experience the freeze/thaw cycle which was my main concern. That being said, they are not static and still experience weathering to a great deal in this scenario, the lack of seasonal inactivity of the soil life may contribute more to the weathering of biochar. Any further statements on that are beyond my current knowledge base.

The regeneration of Terra Preta is also fascinating! The biochar and unglazed pottery shards are not regenerating in the soil, so I have always theorized that the organic matter content is the key. Almost like a foothold, the former two elements allow for the accumulation of stable organic matter and a robust microbial community. Once that community is established, it can ideally be self-perpetuating and incredibly resilient.

Eric S.

Thank you all for the excellent and insightful comments.

So clearly the particle size of biochar does get reduced through repeated exposure to the freeze/thaw cycle, but since the porous structure is microscopic, it can still confer benefits to the soil despite this size reduction. Temperate soils with fire regimes are an excellent point and they demonstrate the presence of pyrogenic carbon dating back thousands of years. These cooler fires don't cook the soil and incinerate the seed bank like uncontrolled wildfires from years of fire suppression policies. The regular cycle of these burns allows for a large build-up of pyrogenic carbon and stores huge amounts of carbon.

There seem to be some diminishing benefits to biochar as it weathers in the soil, not only from the freeze/thaw cycle but also from the pores filling and the attachment points being occupied by various minerals. As for how long it is until biochar transitions from a useful soil amendment to solely carbon storage is likely far longer than I initially thought. Biochar is known to last for thousands of years in the soil but I was curious as to whether it is a beneficial soil amendment for those thousands of years. While it certainly is not a negative influence due to the carbon storage, I think there is a threshold where biochar becomes simply carbon storage. That being said, most fire regimes or garden users replenish the supply of biochar in their land regularly, consistently supplying fresh biochar for optimal benefits.

It certainly depends on numerous environmental factors but I do wonder when that transition takes place.

To start, I have often heard that biochar can last for hundreds if not even thousands of years in the soil as a stable source of carbon, however, I am more concerned with its use as a soil amendment. Especially in the context of temperate soil.

When looking into Terra Preta, I kept thinking about the viability of such a product in temperate regions. It has well-established benefits in the Amazon but my concern is the freeze-thaw cycle of the temperate regions. Both unglazed pottery shards and biochar are critically important due to their porous microstructure, which in turn allows for microbial housing as well as nutrient and water retention. My main concern is that the retention of water, combined with the expansion of the subsequently formed ice will rupture channels in the internal structure and degrade the structure with each freeze-thaw cycle. That being said, I know pottery can indeed crack and break with water freezing within it, however, my experiments have shown the effect is not as dramatic with smaller shards.

On the other hand, the soil may act as a thermal mass and reduce the severity of temperature swings, especially in warmer temperate regions where the soil does not freeze very deep. Even as a fine powder, biochar still retains its benefits as the microstructures are substantially smaller. Greater microbial access might also occur due to increased surface area. So perhaps even if the freeze-thaw cycle broke the pieces down repeatedly, it could still confer benefits as it becomes smaller. The established microbial community and built-up organic matter could act as a foothold, perpetuating soil fertility even with the diminished or used-up effects of biochar.

Does biochar break apart under the freeze-thaw cycle of the temperate region? If so, how long can it confer benefits as a soil amendment? Biochar would still likely remain stable for carbon sequestration, but how long can it benefit soil?

Any thoughts or resources are greatly appreciated,
Eric S.

Hi Jay,

I appreciate your input. In my head, this method, which I have dubbed The Spike Method, is now closer to a soil conditioning regime rather than an aspect of hugelkultur. My main goal is to use this method to break up heavy or otherwise poor soil without digging up all that earth. A French double dig or even digging holes to fill with organic matter as you mentioned, both can work but require the movement of a lot of dirt to make them feasible. That being said they are quicker than the spike method, which also still requires work.

The wicking effect on a hugel bed makes sense, and that supports another aspect I would like to get from the spike method, channels for water. Wood is great for absorbing water, and along with the decomposing wood, liquid applications, and biochar, I think soil life will flourish in that immediate area. A high density of these spikes would allow these channels to eventually connect, as well as provide channels for perennial roots into the deeper parts of the soil.

In my head, I initially thought about driving the spikes downwards in a grid fashion, and while I think that's a good guideline, I don't think it will work on excessively rocky soils. Shifting positions, as well as angles, can help avoid some rocks. I also appreciate the floating wood aspect, I have heard about that in the context of hugelkultur beds but I didn't connect it to this method. I think, as you said, that the friction will be sufficient but I will keep an eye on it in my test.

I have a few concerns moving forward. Will there be sufficient oxygen in those soil depths? And will driving the poles into the soil prove to be too laborious? Or rather not worth trading the immediacy of simply digging up and amending all that earth.

Eric S.

In addition to the poles driven down into the soil, it would be beneficial to use some biochar when incorporating the poles. After this, it would make sense to use primarily liquid fertilizer like compost tea, biochar slurries, weed juice, bacterial mineral water, or some other KNF or JADAM concoction.

I initially thought to try and differ the rot resistance of the wood poles by choosing different species. But, I think as long as they're hardwoods, and not allelopathic then this consideration is not as useful.

As they decompose, I am hoping they will, at some point, connect with the other poles driven in the area through the activity of roots, fungi, and other soil microbes. Once I have land of my own I am excited to try this, especially with heavy clay and/or compacted soil, in order to determine real numbers. Things like pole spacing, time, viability, and the like. Obviously, this system will not work with root crops, certain annuals, and any crop that requires conventional tillage, but the possibilities excite me!