I'm curious if anyone has had experience with foehn winds and permaculture. If you're not aware, foehn winds are hot, fast and dry winds created when air rushes down the side of a mountain. Besides melting away snow in the winter, they can also last long enough to bring plants out of dormancy, which can kill the plants when the cold weather returns.
I'm looking a establishing a permaculture homestead in about two years time, but the area where I'd like to live (southern Alberta foothills) experiences very frequent foehn winds (known locally as chinooks), and I'm worried that it may make growing fruittrees impossible.
I've heard Sepp has grown fruit trees, and Austria is a place known for foehn winds. How does he do it?
From what I read -- and I don't know whether he mentions these winds anywhere specifically -- he uses a combination of windbreaks and shelterbelts; rocks and boulders to moderate the temperatures by storing heat during the day and releasing it at night; frost-resistant species; ponds to reflect the sun to where he wants it in winter weather; and proper planting and placement of the trees in the first place. The windbreaks ought to work against winds of whatever temperature, I would think. (I don't remember what tree varieties he uses for the windbreaks, but Mollison has written on this and would have suggestions.)
But Paul's the expert on Sepp Holzer around here, so maybe he'll chime in on this.
Mollison talks quite a bit about winds running up and down slopes, and channeling them along earthworks and/or absorbing them with vegetation.
From his writing, it might be necessary for fruit trees to be the minority before the air is still enough for them to yield, but it won't be impossible.
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Hello Mark Rose (if you are still here). I'm a little north of you.
I am starting an experiment, and it will probably be more than another 9 years before I have a clue if it is working.
When we get Foehn (chinook) winds here, they are mostly from the SW.
My farm (40 acres) is on a north facing slope, and in some sense has not been managed since perhaps 1970 (earlier?). My family bought the farm in 1975, it is now mine. Full of stuff I don't want for the most part.
In the NE corner of the farm, I want to start a "sugar bush", which is mostly sugar maple, with some other species as well. Along the north edge of the farm, is a row of mostly aspen (aspen is the dominant tree species in the forest here), and lots of the aspen show damage from waking too early, in part due to Foehn winds. The idea is to replace the aspen with sugar maple (and other things for the sugar bush), and also expand the treed area in that corner. On the winter solstice, that corner is the last part of the farm to see direct sunlight, with "sundown" being about 2:30 in the afternoon (I am on MST all year long).
While I agree that the Foehn winds have an effect, the damage I am seeing also suggests that (direct) sunlight is also playing a part.
Near the SE extent of the sugar bush in the NE corner, I am planning to start 4 rows of trees (only 3 on this plan). The 3 planned rows are Siberian pine, Korean pine and Siberian pine. From near that SW extent of the NE sugar bush, these 3 rows of evergreen conifers will head basically a bit west of SW, to about the middle of the property. They won't be abutting the sugar bush, but they won' be too far away either. As the Foehn winds are expect to be coming from slightly more south than this line of evergreen conifers run, they should serve as a deflector to keep the Foehn winds from getting directly to the sugar bush. The evergreen conifers are also there to serve as a sunbreak for the sugar maples, to keep them from getting direct sunlight in the winter.
The tallest aspens on the farm are near the SW extent of that triplet row of pines. And they are possibly 60 feet tall. To the west of where the sugar bush will be, I am planting oak, walnut and some fruit trees. My hope is they get above 50 feet at some point, but that is probably after I die. So there is something of a windbreak to the west of this "triangle" where the sugar bush will be, and that windbreak should become more effective with time. The Siberian pine has been seen at 100 feet plus. The Korean pine to 170 foot. I am not expecting either tree species to get as tall as they can, but I wouldn't be surprised if they get above 80 feet. I am not expecting the sugar maples to get much more than 50 feet tall, but to have 80 foot pines to the south (and sightly uphill), those pines should keep the winter sun from getting to the sugar bush.
The fourth row of trees? They may not grow here, they may not grow well here. I don't know. The tallest trees on the planet are the Coastal Redwoods, getting close to 400 feet tall. The most massive tree on the plant is a cousin of the Coastal Redwood, the Giant Sequoia. They don't grow quite that tall. In the fossil record was another related species, Metasequoia. They were discovered as live trees abotu WW-II in China, and people have been growing them. They get to be considerably wider than a pine tree does, so they will be planted quite a bit further south than the pine row offset, and much further apart. Metasequoia is the pipsqueak of the family, they may only grow to 200 feet. Like tamarack (larch), they are not evergreen. But, to have 4 rows of trees all capable of growing well beyond the 60 foot aspens I have now; I think it is possible I could get some tall trees out of this.
For people in the city of Dawson Creek (1 mile away) in the autumn, there would be this wall of green, in front of which is the sugar maples doing all the various colours they do. And a significant chunk of the farm would not be visible from Dawson Creek any more.
Time will tell. First job, is to get these trees to grow well.
My plans changed and I didn't end up in southern Alberta.
From my reading of dealing with chinooks, the trick is keeping the roots cold to prevent the trees from waking up prematurely. In other words, don't let the snow melt. Methinks the solution is thick bushes to help block the wind. As you are already setting up a wind block with pine trees, I would also consider planting blueberries in front of them. Blueberries love the acidity pine trees provide, and should help slow down the low-down winds from reaching the maples in behind.
Being in growing zone 2, and on a north-facing slope, you may not have much success with fruit trees, walnuts, or oak. I know there are some trying to grow fruit trees around Grande Prairie, and that my be your best source for seeds that will survive. Prairie Gardens farm may be able to help you out.
I hope things going well for you in Toronto. I don't think they get chinooks. I never got chinooks when I did my M.Eng. in Pittsburgh many years ago.
I moved here in 1975, it was Zone 2 then. It is border line Zone 3 now. Maybe another year or two. AgCanada has a research facility at Beaverlodge (closer to Grande Prairie than here, but midway between us) and they have 60 and 90 year old oaks on the farm.
I think the trees will grow. Fruiting might be different. But I have 40 year old apple trees on the farm that produce well, and the pear trees I start a couple of years ago are meant for Zone 2. So some fruiting (besides Saskatoon berries) happens up here.
As long as we're commenting on 9-year-old threads, I might point out that Sepp Holzer's old Krameterhof (now in the hands of his son as Sepp takes on other projects) is on the South side of the Alps, not the north, so the windward side for the purposes of discussing Foehn winds. Foehn winds have their effect on the leeward sides of mountain ranges, so Germany benefits from the Foehn winds over the Alps but Italy and Slovenia do not. In Switzerland and Austria, which have the Alps running through them, it would depend on whether you're in the north (leeward) area or the south (windward). Anyway, just to say, the amazing things the Holzers do at Krameterhof are not due to Foehn winds. But the climate of Alberta is certainly warmed by the chinooks/Foehn winds there as it's on the leeward side.
The effect doesn't go on forever and the praries in Canada are big, so I wouldn't expect any effect at all half a (big) continent away in Toronto. Or Pittsburgh.
I would look at locally adapted species and micro-climate altering techniques (sunscoops, thermal mass, greenhouses, annualized solar geothermal, Sepp Holzer secret sauce...) to push what you could get going productively in NW Alberta. North orientation doesn't make things easier.
It's really too bad that you have to block the chinooks in the Spring to keep your trees from flowering too early when they might be really helpful later on to ripen fruit. But I'm not sure what times of the year you get them besides Spring. Mark has sound advice for windbreaks above.
I don't know if you get any warning before the chinooks come up, but maybe running the sprinkler on a freezing night before you're expecting them could get some cold thermal mass (aka ice) on the ground?
Citrus growers farther south will stick a sprinkler in the top of a tree and run it all night during a freeze to insulate the tree with freezing ice at 0ºC (need to keep the sprinklers running all night) rather than letting them be exposed to -10ºC air which will kill them. I know you laugh at such temperatures, but still, maybe you can use the principle for something.
I was attempting humour on the chinooks in Pittsburgh thing. That didn't work, sorry.
I have read about chinooks as far east (of the Rockies) as North Dakota I believe.
The winds here are a bit different than say from Edmonton south on the leeward side. We have two sources of weather. In the winter, the source of our weather tends to be the north Pacific (Gulf of Alaska), and in the summer it tends to be from a bit further south. The Pine Pass is an almost N-S mountain pass, and that is one mechanism for weather from the south to get up to this area. When we get these warming winds in the winter, we can see the clouds characteristic of that weather pattern (or maybe everything is clouds, and we see nothing on cloud shape). In the summer, I think there are times where we are getting what seems to be a chinook; but I haven't run into anyone else that calls them chinooks.
But in terms of weather from the Gulf of Alaska, there seems to be a "low" spot in the Rockies pretty much due west of us, which is how these weather systems can move more or less straight east off the Gulf of Alaska and come crashing down on us. Occasionally weather will go north from the Gulf of Alaska, and then come south along the leeward edge of the Rockies. How we know this happens is from volcanic ash from the volcanos in Alaska.
I believe I've read that Foehn winds exist on Baffin Island and Greenland.
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