Biochar and flooding

I have read many reports of flooding recently.  It made me think that flooding is getting worse. One reason is that as climate change happens, warm air holds more water in it.  It also has more energy so extreme events are more likely to occur.  It made me think of the world before it was all settled.  Lots of giant old growth forests. When there was a fire, it would burn a lot of wood and create a lot of accidental biochar.  Not pure, but a lot of it.  Old growth forests have deep soils, which retain water and drain water well.  A lack of trees means the draining water will be moving quickly with a lot of water and force.  The soil will erode more and flooding events are likely to be quicker and more extreme.  Biochar in soil improves both water retention and drainage, which is awesome and prevents some flooding.  

I don't think we are going to allow giant forest fires to continue burning until they run out any more.  Those days are long gone.  There are some controlled fires, but they are much smaller than they used to be.  There is therefore much less "natural accidental biochar".  The way we chop down the forests and plant farms encourages more clay soil, as there is much less organic matter in the soil and fewer plants growing in the soil.  Soils begin to trend toward clay, which drains extremely poorly.  When it doesn't drain well, we get way more flooding.  

What can we do about it? Incorporate more organic material and biochar into our soils.  Encourage the building of food forests at people's houses.  Encourage parks to build food forests and put biochar into their soils.  Encourage parks around wetlands.  

Any other ideas?

John S
PDX OR

Hard to say. I see biochar as a tool in the toolbox, not a solution in and of itself. I still produce giant bins of it though; great tool to have on hand.

In my part of the world, in deep drought, I expect the coming year to produce appalling amounts of "natural accidental biochar" through forest fires. It's going to get ugly if the rains don't come.

As you say, soil devoid of vegetation is subject to destructive erosion. Biochar is a good tool for supporting the vegetation that holds soil and slopes together in freak downpours (which were once categorized as 100-year storms, now appearing rather more frequently it seems). This is a long term project though.

Missing one of the best ways.  Log it.  That will generate slash piles.  Make the logging contracts require a mixture of biochar and hugelkulture be made with that slash and bury it.  That way the logging companies will be paying to improve the ground.  If it is done a set of small clear cuts and selective logging a pattern of fire breaks can be built in and slowly moved over a mountain.  In some places add a few swales slowly too.  All moisture traps.  Pattern it to add and improve micro climates.

Logging is one of the best ways to stop flooding? That is a really interesting statement.  When you log a forest, you remove the trees, which sucked up a lot of the water.  The roots die, so they won't hold the soil in place as well anymore.  You are tremendously decreasing the amount of organic material in the forest area, so the soil will turn more clay-like. You won't have a fire, so there won't be any natural biochar.   You decrease the mushrooms, small plants and mycorrizhae.  Runoff will be fast and swift, increasing erosion. I don't see it stopping flooding. Quite the opposite.  I do like the strategies you used to defray the damage caused by the logging, though.

John S
PDX OR

For an example of how recently logged hillsides respond to excessive rainfall, look at what happened on the east coast of the North Island last year during Cyclone Gabrielle. Logs and slash went down rivers, jammed up under bridges and took them out, and silt was dumped across all the flats where the farms are. The cleanup is still going on and it's a wretched mess.

I was up there a few years ago after another set of floods, not as bad as last year's but to be honest they're getting hammered so regularly that it feels like the new normal. I did a workshop with a portable sawmill crew turning their offcuts into biochar. Lots of opportunity in this region for remediation and using biochar from slash to help establish native trees that won't be logged is going to be the hot ticket.

Forest management, aka logging, takes many forms. The clear-cutting idea is just one, and especially in mountainous areas, a particularly bad one. Selective logging can remove high-value trees, produce biomass for on-site biochar and not aggravate erosion.

But aside from biochar, there is a whole separate carbon fixing concept called soil carbon sequestration. Healthy soil with well-established vegetation can store an immense amount of carbon, but modern row-farming agriculture replaces the "machinery" of healthy soil with quick-absorbed mineralized nutrients. Although the crops grow well, the underlying soil is steadily worse. As a result, much agricultural land is low in organic matter and has a high capacity to be improved by changing farming techniques. Of course, permies know all about this, but shifting the thinking of large commercial operations has apparently not been an issue of common sense. I think the world will have to resort to more directive approaches, unfortunately.

Plant more trees!
I have seen this on a small scale on my own treefield. We have a slope of  about 1 in 6 on average over 250m down to a river. Our rainfall is pretty high, but comes pretty steadily through the year, rather than in a seasonal flood. At the bottom of the field we have culvert across which intercepts seasonal run off springs and diverts them into a pond. As our trees have grown over the last 15 years we have noticed this ditch and pond is dried out more often although no decrease in the rain! The trees have intercepted the rain and either it has reevaporated from their foliage, or is utilsed by the trees themselves or the surrounding vegetation.

John Suavecito wrote:Logging is one of the best ways to stop flooding? That is a really interesting statement.  When you log a forest, you remove the trees, which sucked up a lot of the water.  The roots die, so they won't hold the soil in place as well anymore.  You are tremendously decreasing the amount of organic material in the forest area, so the soil will turn more clay-like. You won't have a fire, so there won't be any natural biochar.   You decrease the mushrooms, small plants and mycorrizhae.  Runoff will be fast and swift, increasing erosion. I don't see it stopping flooding. Quite the opposite.  I do like the strategies you used to defray the damage caused by the logging, though.

John S
PDX OR

In the very short term it may make things worse but if done correctly it should do little damage.  Limit clear cutting to small areas.   Other areas do selective harvest and reach in a bit and strip ladder  fuels around both while working through to reduce fire hazard and increase the slash pile size.  If the roots  from the cut trees are mostly not disturbed they become hugelkulture holding moisture as they start to rot away which will take years to decades so they are there to hold the soil short term.  Do some limited digging(yes worsen erosion)  into the hill make swales and  pits at carefully chosen locations that the slash piles from the timber harvest go into.  Do some burn pits to make biochar with some and then while the machinery is there mix the biochar, dirt  while burying the main slash piles.    Most place the slash is all burned so if most of it is gone while generating massive air pollution.  But if you only burn some of the slash that pollution is reduced  If you plan carefully your bio char pits can become your swales etc. Now over the next decade as the slash pile begins to rot away it begins storing water as hugelkulture and biochar.  If we plant the top in soil builders and work with faunal succession, we should create small zones that super support future forest.  If we work up the hill in say 5 year steps much of the erosion should have growing filter strip directly below it reducing any soil losses.  If the cutting areas are zig zaggy strips with small clear cuts we can create temporary meadows and small growth forest stages to act as fire break without creating the eye sore of a big clear cut.  On some drainages plant sections of forest to support beaver to encourage beaver dams as additional future self repairing swales.  In the short term this all will decrease down stream water but as this all gets charged up springs and seeps will grow providing a slow steady water source reducing down stream flooding, reducing erosion and reducing the effects of droughts by storing more water literally in the hills and mountains.  The areas of higher moisture holding will reduce fire risk in those areas.  They will improve micro climates over and even wider area also reducing fire risk  Giving a better chance of eventually being able to harvest big trees for use in building materials that will sequester that carbon for decades to millennia.  Neat thing is the end customer actually pays for that sequestration.  We can improve the world slowly without burdening anyone but a few consumers of resources with the cost of the improvement.  Thus making the economics work too while improving the environment at all levels.  And since biochar and hugelkulture are good for millennia we will have room for multiple runs at improving those area.  Millennia? you say.  Yes we can look at the drought hills in the UK from almost a decade ago.  On the drought killed hills the green outlines of forts showed from nearly 2000 years BC so nearly a 4000 year affect of burying wood.(possibly charred wood.)  And we know as we increase water holding and moisture in from most coast we can create basically a bucket brigade system that carries more water inland in the form of rain.  Will this possibly help fight climate change?  It should most certain increase our available long term resources.

C. Letellier wrote:

John Suavecito wrote:Logging is one of the best ways to stop flooding? That is a really interesting statement.  When you log a forest, you remove the trees, which sucked up a lot of the water.  The roots die, so they won't hold the soil in place as well anymore.  You are tremendously decreasing the amount of organic material in the forest area, so the soil will turn more clay-like. You won't have a fire, so there won't be any natural biochar.   You decrease the mushrooms, small plants and mycorrizhae.  Runoff will be fast and swift, increasing erosion. I don't see it stopping flooding. Quite the opposite.  I do like the strategies you used to defray the damage caused by the logging, though.

John S
PDX OR

In the very short term it may make things worse but if done correctly it should do little damage.  Limit clear cutting to small areas.   Other areas do selective harvest and reach in a bit and strip ladder  fuels around both while working through to reduce fire hazard and increase the slash pile size.  If the roots  from the cut trees are mostly not disturbed they become hugelkulture holding moisture as they start to rot away which will take years to decades so they are there to hold the soil short term.  Do some limited digging(yes worsen erosion)  into the hill make swales and  pits at carefully chosen locations that the slash piles from the timber harvest go into.  Do some burn pits to make biochar with some and then while the machinery is there mix the biochar, dirt  while burying the main slash piles.    Most place the slash is all burned so if most of it is gone while generating massive air pollution.  But if you only burn some of the slash that pollution is reduced  If you plan carefully your bio char pits can become your swales etc. Now over the next decade as the slash pile begins to rot away it begins storing water as hugelkulture and biochar.  If we plant the top in soil builders and work with faunal succession, we should create small zones that super support future forest.  If we work up the hill in say 5 year steps much of the erosion should have growing filter strip directly below it reducing any soil losses.  If the cutting areas are zig zaggy strips with small clear cuts we can create temporary meadows and small growth forest stages to act as fire break without creating the eye sore of a big clear cut.  On some drainages plant sections of forest to support beaver to encourage beaver dams as additional future self repairing swales.  In the short term this all will decrease down stream water but as this all gets charged up springs and seeps will grow providing a slow steady water source reducing down stream flooding, reducing erosion and reducing the effects of droughts by storing more water literally in the hills and mountains.  The areas of higher moisture holding will reduce fire risk in those areas.  They will improve micro climates over and even wider area also reducing fire risk  Giving a better chance of eventually being able to harvest big trees for use in building materials that will sequester that carbon for decades to millennia.  Neat thing is the end customer actually pays for that sequestration.  We can improve the world slowly without burdening anyone but a few consumers of resources with the cost of the improvement.  Thus making the economics work too while improving the environment at all levels.  And since biochar and hugelkulture are good for millennia we will have room for multiple runs at improving those area.  Millennia? you say.  Yes we can look at the drought hills in the UK from almost a decade ago.  On the drought killed hills the green outlines of forts showed from nearly 2000 years BC so nearly a 4000 year affect of burying wood.(possibly charred wood.)  And we know as we increase water holding and moisture in from most coast we can create basically a bucket brigade system that carries more water inland in the form of rain.  Will this possibly help fight climate change?  It should most certain increase our available long term resources.

This sounds like proactive post logging regrowth forest management to me, whereas “logging” of old growth forest is the primary cause of much of western North America’s current flooding and wildfire problems. A large tree does far more good standing and living than in any other form. Many western conifers grow faster each year of their life until their maximum age (1000-4500+yrs depending on species) and their heartwood’s exponentially increasing growth overtakes the sapwood which is where the tree makes more living cells. This means exponentially more carbon sequestration, water absorption, filtration, transpiration and flood mitigation as they age. I agree that an unprecedented number of fire prone young trees need to be thinned from forests to allow the largest and healthiest to persist, and these can be used for the benefits mentioned above. We cannot afford to lose any more old growth though, which for the purposes of this thread topic of flood mitigation, can absorb 3/4” of rain per hour in their foliage, before it even hits the ground. We need proactive and regenerative forest management, and this includes cutting a lot of young and unhealthy trees doomed to die regardless as a part of forest succession. Logging, to me at least, instead connotes what created these problems of fire and flood in the first place, which was the extraction of wester old growth forests in the largest biomass removal in human history.

Really great ideas! Yes, logging by itself is not the solution.  All of the practices that C Letellier is mentioning are great for limiting the damage of logging. Some logging needs to happen, so it's important to do in as harmonious way as possible.  Flatter areas away from creeks and rivers are a great start.  I love how much knowledge there is on this site.

JohN S
PDX OR

Yes, excellent ideas on how logging can be a positive method based on a revised and integrated method.

But as it currently exists, it's a low margin and high-speed business, with international competitors nipping at your heels and they don't care about biochar. I'm not sure how this entirely rational transition can be achieved at scale.

Ben go check your numbers.  

Very few trees live that long.  Most species are 150 to 600 years with more normal life numbers in the 200 to 400 range.  Trees like Limber Pine live a long life but you can hardly call their living location a forest right up at the tree line as mostly individual trees.  Yes we have red wood forests and others.  A quick google gives 866 million acres of forest down to 698 million acres.   Lets pick 700 million just to keep the math easy.  If we did 20% old growth(10% increase in old growth over current) that would still leave 560 million acres of forest.  If we assume 560 year life expectancy that means we should be harvesting a million acres a year of timber simply to sequester it in useful goods.  Ideal would be to get the trees to say 90% of life to be sure we got to them while still good to make durable goods with.  There is some balance point giving the most sequestration of carbon as durable goods.

As for pulling carbon from the air, good grasslands pull as much or nearly as much per year as a forest.   And the roots are less vulnerable to be destroyed as dirt doesn't often burn deep.  The disadvantage we have very little opportunity to sequester it for longer.

Water use and storage there is a bunch of discussion on this, and it could go far deeper.  How many times the water is recycled by evaporation and rain before it runs back to the ocean is one piece of it.  There is also a bunch of conflicting information how much water a forest stores.  You are looking at soil building, moisture holding etc, that  match rain forest conditions that don't exist in most of the US.  Even if those forests are king at water storage we can still increase it even more thru soil building.  Adding biochar extending deep and hugelkulture for example.  Soil aeration extends how deep the tree roots can go plus Concentration of soil carbon is another piece and  evergreen forest does both of those more poorly.  Go hiking in the mountains in most of the US, find a blown over tree and look at the soil.  It is almost never black deep(indicator of soil carbon).  We can change that.

Now you are point on, that older trees are producing more wood per acre and older forests have greater value this way.  This is a balance act though as the longer the tree lives the greater the chance of it being destroyed in a way that costs its value.  We need to look at the statistics of where the best point to harvest is with greatest chance of success.  And old growth has other problems of rigid limits of life it supports.  We need to work to biodiversity too.  

C Letellier writes, " Soil aeration extends how deep the tree roots can go plus Concentration of soil carbon is another piece and  evergreen forest does both of those more poorly.  Go hiking in the mountains in most of the US, find a blown over tree and look at the soil.  It is almost never black deep(indicator of soil carbon).  We can change that."

Deep soil aeration in coniferous forests is a positive thing.  Concentration of soil carbon is low in evergreen forests because there is spectacular carbon concentration above the soil, so not really a valid point.  When I go hiking in our coniferous forests, the soil is extremely deep and filled with mycelium and other life.  The greatest concentration of life in the world is in the evergreen rainforest here in PNW USA.  

JOhn S
PDX OR

The 1862 flood story from the PNW was an eye opener.  Seems like it wouldn't take much more than 900mm of warm rain over 3 days on plenty of snow pack throughout the western mountain ranges, to completely overwhelm the reservoir system and fill the Willamette and Sacramento valleys with 10-20ft of water.  Big time crop failures and shortages, cities and infrastructure erased.  Wonder which orchards can handle being underwater for a weeks or 2?

This is probably a 200-500 year event, being more common towards the end of the global warming phase.  And many people living here have not heard of it, including government and corporate leaders.  

Sorry that had nothing to do with biochar.  But yea, you can pretty much plan on it.

Don't you mean the 1962 Columbus Day storm? Many dams were built because of that storm.  I believe that dams have to be part of the solution, but some need to be removed.  

John S
PDX OR

C.L., of course few trees alive now are actually that old, and a very low fraction of a percent reach that age in any species at any time, even before logging. Still, I do know my numbers, and, doug firs can live well over 1000yrs, western hemlock can get close, spruce can live over 1000, western red cedar 2000+, yellow cedar 3600+, redwood ~2250 (for a given trunk, the root systems could be multiple times that old), bristlecone pine 4500+. Of course these are exceptional specimens of any given species, but are as 96-98% of old growth has been cut and the biggest trees were generally harvested first, undoubtedly much bigger, older trees existed than these record trees. I can go 10mi from my house and be in a grove of trees 1000yrs old on average, and 500yr old trees look relatively small all over. Of course, only a small percentage of seedlings or reiterations even reach 100yrs under the most forgiving of circumstances, and too many trees per acre is a wildfire risk. So by all means take out a high percentage of those younger trees and use them for the purposes mentioned.

If I want wildfire, flood and erosion mitigation, I’d leave the largest and healthiest of each age class, with a higher percentage kept the older and healthier they are. Thinning would focus on younger and less healthy trees. The remaining healthy trees will grow better wood faster than before, and surprisingly quickly will regain multi story canopy cover, and that is the best flood and erosion mitigation. Thin again similarly when wildfire risk is exacerbated by understory regrowth. Wood is only gong to get more valuable, and older trees are more fire resistant until they are on their last legs. In terms of biodiversity, old growth conifers can have the most biodiversity of any soil on earth. Much of the biodiversity in general, but also in the soil, is in the canopy that only occurs in the oldest, largest trees.