Wytze Schouten

Hi everyone,

Thanks for those last responses from Bryant and Aljaz and Sue. An amazing thing happened: in my parents' documentation, I found a report from a government-subsidized project that actually tested the mineral content of the trees. Pine trees were tested in three areas for six major minerals (N, Ca, P, K, Mg and one more) and it turns out the trees contain too little K and Mg. All the other elements are within normal range.

K deficits often occur in light sandy soils where lots of rain falls because it is easily dissolved in water. That applies to our forests.

Mg deficits can be caused by too much K (so that's conveniently ruled out) or by a plain lack of the mineral in the soil. It doens't leach particularly easily.

Bryant, thanks to you in particular for your thoughtful suggestions. Grazing would be hard to organize but it certainly seems the preferred natural solution. Perhaps we could electro-fence sections and have some pigs or sheep or goats root around. Then again I've looked into grazing and it seems like most animal species would only be useful in very low numbers - which in turn makes me wonder how much manure they might ever add.

The role of pine: I agree. Plus their long needles ventilate the soil much more than other tree species, so it dries out faster. We do need to have some spruce and fir for economic reasons, but in general my goal is to have a much more broadleaved forest. Nature is taking care of that all by herself. I just wish there was a cheap and easy way to help it through the stage in which the broadleaf that does all the broadleaf colonizing is that shrubby black cherry.

As for previous forestation: it's uncertain what grew here before the heath. Historical sources don't go back far enough. Judging by the histories of similar landscapes and soils, it's likely to have been a strip pattern of oak and pine (on sandy soil) and richer broadleaf forest (on richer soil: this area used to have strips of clay/loam that were mined in the nineteenth century) and perhaps peat bog on the flatter sections with poor soil.

Thanks again!

Wytze

Hi Leila and CJ,

Thanks for these awesome tips!

The overgrazing has been pretty intense and certainly long-term: the place has most likely been heather since the Middle Ages. Many similar parts of the Netherlands (usually the parts that are between 10-30m above sea level, and higher than their immediate surroundings) were so overgrazed that they had become full-blown deserts by the 1900s. Photos from our area around that time show small areas that were essentially sand dunes.

Over a century of forestry has left a decent amount of organic matter on the forest floor, but in this one section it's mostly pine detritus, which is highly aerated (dries out), resists decomposition and lets most of its minerals leach out over time. So in this sense, at least, some of the stuff that a plant needs is indeed present but locked up.

The indicator weeds would under normal circumstances be heather. Because of consistently high atmospheric nitrogen deposition over the last few decades, heather now tends to lose out to brambles and Wavy Hairgrass, which are both nitrogen lovers.

So: an acidic soil with lots of atmospheric nitrogen.

As far as I understand it, some extra nitrogen is rarely a problem for a forest, but lots of extra nitrogen (more than plants and soil can absorb) will actually cause acidification. The nitrogen will be stored in the form of ammonium, which acidifies the soil. Some of the ammonium will be converted to nitrates, which binds to positively charged minerals like calcium and magnesium and get washed out of the soil by rain. Acidification somehow also causes aluminium (which is likely to be present in this soil) to become 'mobilized' and reach toxic levels.

So: based on the general chemistry, calcium and magnesium are likely to be scarce, and aluminium is likely to be overabundant.

I realize now that I'm not just interested in which minerals are deficient. I want to know how to get them back, on a forest scale, preferably in a permacultural kind of way. Enclosing cattle and giving them the minerals they lack sounds like a good idea (though hard in practice, as we don't live on-site).

Perhaps I could do a small-scale experiment where I try adding calcium, magnesium or both to an few plants or to a selected small area. Trouble is, even if I found that one mineral did the trick, I wouldn't know how to expand to a larger scale.

Thanks again!

Wytze

Hi R Scott,

Thanks for your suggestions!

What grew there before was: heather. Calluna vulgaris. The soil was probably podzol, i.e. a hardpan of iron and aliminium at 50cm depth, and bare sand above that which would periodically be waterlogged and whose nutrients would mostly have been leached out. The hardpan, if it was indeed there, would have been broken by the plowing.

I guess one way to go about it is to add some of the nutrients you mention to different specimens, and see which nutrient begets the best response.

Regards,
Wytze

Hi Cj,

Thanks for your reply. I'm not sure I agree with all of your beliefs though.

And I remain interested in anyone who can answer my original question: what minerals tend to get depleted first when sheep overgraze a particular patch of land?

First off, a photo as requested:

Photo 1 Black cherry (the crooked one) under a canopy of pine. Most of the thinner trunks in the background are crooked cherries, most of the thicker trunks are pine from circa 1960. The cherry looks dead but all its foliage is at the top, outside the picture. The green haze against the sky is the foliage of the cherries farther back.

In answer to your questions:

I am trying to grow trees with straight trunks, for timber. The section I'm talking about is part of 50 hectares of forest that we own. This particular section has been a pine monoculture since around 1900, with periodic invasions of black cherry that we have fought back with lots of labor and glyfosate.

Our problem with black cherry is its unhappy combination of crooked growth (meaning no hardwood value) and its tendency to shade out other tree species. The only value they have is that they are willing to grow on this poor soil and that their leaf litter improves the quality of the soil over the course of several decades.

The crooked growth is not a wind thing. The 'hill' we're on is extremely shallow and fully forested, so it's not a windy place, certainly not below the canopy. The black cherry grows crooked everywhere, regardless of wind or light conditions, and the crookedness goes in all directions, and differently so in each individual plant.

In part that could be because these trees are descended from a shrub variety that was planted on purpose in the mid-20th century to improve the soil. They turned out not to stay quite as shrubby as expected (they grow to about 15 meters), so that was a big bummer for my great-grandparents and for foresters all across Western Europe who tried the same cheat.

Getting the cherries to be more tree-like is most certainly dependent on the quality of the soil: they can't grow straight unless it is moist and rich in minerals. That's why the one individual with garden waste heaped below it is growing so nice and straight, while all the others are higgledy-piggledy. So this is why I ask my question: what soil minerals get depleted when sheep overgraze the soil and their manure is taken away?

You suggest compaction: that could certainly be a good explanation, but it doesn't apply here. It's been forest for over a hundred years, which is well over the threshold that soils need to recover from any compaction (80 years). Besides, when it was first planted, the soil was plowed down to 50cm, which would have taken care of any compaction by sheep trampling right at the start. Harvesters may compact some soil, but certainly not all of it. Being mostly sand, the soil there is not prone to much compaction at all.

I disagree with your belief that minerals can't be depleted. Check out Australia: it's got some of the oldest surface on the planet, and most of its soils are dirt poor, because all the minerals have been leached out over millions of years. It's not a matter of acidic conditions locking out the minerals: they've simply been removed. Though to be fair to Australia's soil, large parts of it could be a lot less dry and shrubby if it were better managed by sheep-herding humans.

Minerals needed by trees don't ususally come from deep underground. Trees prefer to get them in the easiest place they can: the topsoil, where most of their roots and most of their fungal support system sit. If the topsoil doesn't have the minerals, some trees may grow deeper roots. This is why our forest was originally mostly pine: they root deeper, they need less calcium, and they don't need good topsoil.

A topsoil poor in minerals will support little micro life, which means it won't have much water-retaining capacity. Which means trees will have a harder time too. Now black cherry is a kind of zombie in this respect: its seeds will germinate anywhere, and some individuals will survive even in thin and poor and dry soil. But though they will survive, they won't thrive. They will stay shrubby and crooked, and part of the blame is with the soil.

So this is why I'm into the soil mineral thing.

If grasses and shrubs keep extracting new minerals from the soil for their own growth, and sheep keep eating that growth and pooping elsewhere, then eventually the part of the soil that's accessible to roots will run out of certain minerals. I'm sure fungal activity and weathering can unleash new minerals from stone and bedrock over the long run, but that's going to take millennia, and those fungi need a moist soil to live in while they do their work.

So forgive me for rudely re-asking my question: what minerals do sheep deplete first when a soil is overgrazed?

Best regards,
Wytze

Hi everyone,

I've got a sheep-related question but it's not about keeping sheep. It's about forestry.

Does anyone know what kind of mineral deficiencies are most likely in a soil when it is consistenly grazed (and overgrazed) by sheep?

I am asking because I own a small patch of forest that was established on an overgrazed hilltop. It's likely that the grazing had been happening there for several centuries (this is in Europe: the Netherlands) before the forest was planted around 1900.

Many tree species don't do well on the soil, and in part that may be because it is high in sand and low in clay or silt. But I also believe it has something to do with the fact that it's been exploited for sheep grazing. The sheep were generally taken back downhill at the end of the day, so that their dung could be collected near the farm.

The problems I see in the trees are primarily crooked growth. Black cherry (imported from the US, now something of a pest) in particular will grow almost everywhere, but it never has straight stems as seen on better soils. Only one individual, which has had garden waste heaped onto the soil below it, grows nice and straight. It also has a much shinier bark.

Serious leaf problems are rare, except on native (European/English) oak, which is always susceptible to mildew, but particularly so on the driest parts of our soil.

I'm thinking of testing if it would help to add certain minerals to the soil. But it would be great to get some pointers to the most likely deficient minerals.

Thanks for any tips!

Wytze

Hi Jay,

Thanks for your comment. It strikes me as odd that you have a hard time believing in active wood worm in older wood.

There's no doubt at all about the wood worm. It's been a recurring issue over the last few decades and we have most certainly not mistaken old holes for new ones. There's fresh powder below the holes in at least one new section of the house every few months.

Keep in mind this is a moist, Canadian-latitude country, and the house is smack in the middle of a woods. And it has no central heating, only a fireplace. And most of the time it is not used at all and boarded up. And as I mentioned, there are fundamental moisture issues. One of which is ground water soaking into the foundation walls, right up to the top where it also keeps the floor so moist that they have rotted through in a few points.

So I have no doubt that at least some of the time, the varnished wood is above 20% moisture. Besides, most of the planks are varnished only on the "public" side. And wood worms sure know how to find the unvarnished sides.

Here are some of the holes on the outside of the house.

https://plus.google.com/photos/101990122925168193127/albums/5899628086050737137/5899629054561942946?pid=5899629054561942946&oid=101990122925168193127

I hope this convinces you

And if it has, I'm curious what you know about smoking/charring wood as a prevention measure. Cause that was what *I* am curious about.

Best regards,

Wytze

Okay, so charring wood and exposing it to smoke seem to be effective ways of preventing rot and woodworm attacks, and it seems that these techniques have been used in times before chemicals came into the picture. I'm really happy I discovered this thread because it confirms what I had instinctively assumed.

My question is: has anybody actually been using smoke in an existing wooden house in order to stop or prevent woodworm plague?

The background: my family owns a small cabin in the middle of a wood that was built in 1927. It's all wood, with thin walls and no central heating. Since it is only used on weekends and is sometimes left alone for months, it is basically defenseless against the moist air from the surrounding woods, except through its passive design (on top of a hill, with sufficient sunlight and ventilation holes).

It's got a woodworm infestation that is hard to treat, because most of the wood has been painted/varnished, which means sprayed insecticide cannot penetrate into the wood and will not stick to the outside for long either. We are currently in the process of solving one cause of this infestation (a basement moisture problem), but with its location in the woods, it feels like this house will always remain an open invitation to a lot of critters.

Up until the 1980s, it was fumigated every decade or so: completely wrapped in plastic, then pumped full of chemical nasty. That was evil but effective, and now it is evil, effective and illegal. So we're not doing that.

So I am really curious to know if it might make sense to just build a fire in the fireplace, choke off the chimney, and let everything be smoked through and through. Is it even doable (you'd be smoking and choking yourself as well)? Or are there more professional ways of going about this? Has anybody tried it? Will the house stink of smoke forever? Did it help?

Thanks for any suggestions!

Wytze

Hi Glyn,

Great to hear from someone who seems to share my intuitions. Yes, the arguments against external air supply are mostly arguments in a debate about modern homes vs ultramodern homes. Where no thought is given to ultra old or ultra thin homes.

I do think the risk of blowback / backdraught / whatever you call it, should be seriously considered. Does this ever happen with your wood stove?

As an example: the interior of the room with (soon) the wood stove has wood panelling up to about 1m80 (6 feet) high, and above that it's burlap nailed onto a frame of thin wooden joists (unsure if that's the right word). Behind the burlap some air, then wooden planks about 1 or 2 inches thick that make up the outer wall. Then you're outside. Recently a candle slowly bent over one evening and burned a hole in the burlap (fortunately it stopped there), and now you can feel the wind sucking through that hole like nobody's business.

You're also the first one to directly answer my question about moist air going into the wood stove. Bonus points, thank you! So maybe not the very wettest fungi-ish air from right at the basement floor.

The wood stove is going to be a Dik Geurts (Dutch builder). It's designed to be a lot of visual fire and a minimum of steel frame, but its performance is still pretty good.

http://www.geurts.nl/assortiment/houtkachels/vidar_triple.aspx

Thanks again!
Wytze

Hi Keith,

That's correct, the basement is mostly below ground. It's rectangular: 1.5 meters wide, 7 meters deep. And 2 meters (6ft 7in) high.

The top 40cm (1ft 4in) are above ground and that's where the holes are. They are indeed on opposing sides. There is also a big opening, just below the ground-level floor, to the crawlspace under the rest of the house. And that crawlspace has holes on all other sides. So you're right, if the wind blows in from any direction there is always plenty of opening on other sides, and it's unlikely that pressure will build up.

Best regards,

Wytze

Hi Mike,

Thanks for your response. I read the article you linked: it's very informative. It looks like it really is almost never a good idea to feed your wood stove direct air from outside the home's envelope.

However, my intention is not to grab the air from outside the building. All I want to do is to take the air from another place inside the house: the basement. The basement is sealed off from the rest of the home by a wooden floor: not airtight, but pretty good.

The part of your linked article that does leave me a little worried is the fact that the basement has some ventilation holes to the outside. This means that the air pressure in the basement is more strongly influenced by wind than in the living room where the wood stove is located.

So I'm left without a definite question, just a feeling that it should be possible to do something constructive with the air supply to the wood stove. Make it kickstart a circulation that was missing in the house.