Biochar by-products from silvopasture thinnings

[Brett Chedzoy]

In 2020, a local grazier friend did an intensive thinning on 70 acres of mature woods to create silvopasture.  Learning from other's past mistakes (including mine) of leaving too much logging debris (aka "slash") behind after the harvest, this friend paid the loggers extra to remove most of the non-merchantable material and windrow it in nearby pastures.  At the time, covid had dried up any chance of selling the material for chips, though that normally would have been the most cost-effective way of cleaning things up.  

In a silvopasture version of "lemonade from lemons" he invested in a couple of "Big Box Biochar" units that were made by a local fabrictor.  The boxes are essentially a double-walled dumpster on skids, with a hinged side for easy unloading.  I'll explain the process in future posts, but so far the experience has been very positive.  The biochar is being used as a base in bedded packs and will eventually be composted and spread back on pasture/silvopasture.

The fist picture shows the units with piles of slash in the background.  The 2nd picture shows the end of the biochar process just before the box is extinguished with water (about 400 gallons needed).  The 3rd pictures shows the finished product being transported to the barn areas.

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[Gabe Smith]

seems like a great way to reduce the "slash" that otherwise has no purpose. 

A few questions I have are: 

what are the negatives of too much "slash"?

the second is more of an idea, which is wondering if this provides some of the benefits of burn management without the need for doing controlled burns, and whether or not controlled burns are an option for land owners interested in creating silvopasture from overgrown paddocks?

[Brett Chedzoy]

Fire would be a great management tool for both forests and silvopastures in the Northeast, but requires a lot of effort to make it happen (permits, trained personnel, and a bit of luck with the weather - for starters).  The Finger Lakes National Forest and maybe a handful of the state forests are the only groups that I know of doing any prescribed burns in New York.  

The downside to "too much slash" in silvopastures is that it becomes an impediment to the grazing animals to effectively manage the ensuing understory vegetation growth following the thinning.  

[Scott O'Bar]

I really like this idea. Sounds like a game changer.

[Scott O'Bar]

Are those containers actually starving the material of oxygen during the burn? I heard that properly made char can no longer be burned, which is what differentiates it from charcoal.

[Brett Chedzoy]

The unit has to be "continuously" top-fed to minimize oxygen reaching the lower half of the box.  Once there seems to be a critical mass of charred material in the box, the fire is quickly extinguished.   

[Brett Chedzoy]

A "white paper" that gives a good overview of the applications of biochar:

https://www.usendowment.org/wp-content/uploads/2011/08/issues_in_th...