Cherry Orchard Choppers in -20?

[cv23]

The air flow keeps the frost from settling. Air in motion even cold air, will do far less damage than static air. I f hard frost, like what we have had over the past few days settles on the buds, it could be very bad indeed.

How then would the windchill created effect the buds when -20 air is propelled at 40kph?

[voice of reason]

thats all fine and dandy but as soon as the chopper stops flying overhead the -20c air settles in again and the choppers fly for an hour or so out of the day. cherrys are going to be 100 bucks a pound and orchardists are going to have to start putting in helipads if this keeps up. so they get a couple hours of air movement during the warmest part of the day but then its dark for 12 hours when the choppers cant fly and the temps are the coldest. seems like a strange and costly plan

[Catri]

The air flow keeps the frost from settling. Air in motion even cold air, will do far less damage than static air. I f hard frost, like what we have had over the past few days settles on the buds, it could be very bad indeed.

How then would the windchill created effect the buds when -20 air is propelled at 40kph?

Windchill doesn't affect things like trees in the same way it does us warmblooded creatures. In simple terms the reason air feels colder to us in the wind is that it carries away the heat that our bodies radiate to try to keep us warmer than the air temperature. Plants/trees don't generate heat so they don't lose heat to the wind. It's the same reason that a thermometer reading doesn't reflect wind chill.

[alanjh595]

How then would the windchill created effect the buds when -20 air is propelled at 40kph?

Windchill doesn't affect things like trees in the same way it does us warmblooded creatures. In simple terms the reason air feels colder to us in the wind is that it carries away the heat that our bodies radiate to try to keep us warmer than the air temperature. Plants/trees don't generate heat so they don't lose heat to the wind. It's the same reason that a thermometer reading doesn't reflect wind chill.[/quote]

That is correct.
Thermal dynamics 101.

There are three different means of heat transfer.
Conduction
Convection
Radiation

Just consider typical household cooking.
Conduction is the burners that you put a pot on.
Convection is the oven, and to make that even more efficient, a convection fan that moves the air around in the oven, radiation is from a microwave.

conduction
heat transfer through stationary matter by physical contact
convection
heat transfer by the macroscopic movement of fluid
radiation
heat transfer which occurs when microwaves, infrared radiation, visible light, or other electromagnetic radiation is emitted or absorbed

https://pressbooks.bccampus.ca/introduc ... 0radiation.

[cv23]

How exactly are helicopters doing anything beneficial to the fruit crop? It's not an inversion layer situation or frost pocket. It's -10 to -20 for days in a row not just a few minutes or hours.

[dodgerdodge]

If you drive around the valley, especially in soft fruit growing areas you will find the remnants of large fans in these most long gone orchards. The purpose was air movement. Summer and winter. Extreme cold at the wrong time is a detrimental as extreme heat or rain at the wrong time. I would think these choppers are trying to warm the orchard by bringing warmer ground temps into the cold overnight air temps in an effort to increase the orchard temp just enough to mitigate the harm to the new buds being formed on the branches. This action is the same action that the large fans would have performed if still in use. Unfortunately for the orchardists, because of encroachment by the residential community they have to put up with these types of complaints when it is a normal function of operating their farm which has had ALR status for decades.

Of course developers build right up next to alr farming lands (no different then building right up to an airport).
New residents can’t stand either the noise or smell etc... so they start to and complain.

Guess what folks, before buying how about checking out who or what is in your potential new neighbourhood i.e active farm, gun range, airport etc... etc

Rose Valley, large residential area getting bigger all the time, no orchards but a bloody helicopter base right next to houses on Stevens Road. (I'm not talking about Alpine) woken up at early hours some days while they sit warming up and ready to fly. It's annoying particularly at weekends. Never had this issue when we moved here 14 years ago! God alone knows what its like for those very close to the edge of that area and no wonder the lot by the turtle pond hasn't sold!

[Jonrox]

I'm a little stuck on the theory here. If it is ice covered, it will still follow the temperature other wise how could you get 2 feet of ice on a lake?

There is more to the icing of trees, if it was intentional.

It's meant to be a short-term insulator... that's all. Typically it's done just to protect the trees for several hours from nighttime lows until things warm up in the daytime. It's not just Florida citrus growers that do it... California strawberry growers will do it too.

It's done in places like Florida and California when temperatures approach damaging levels and will only be that low for a few hours (it's usually done just as a last resort). It wouldn't really work as effectively up here if the temperatures are dropping for a significant amount of time.

It sounds counterintuitive, but the ice acts as a great insulator.

[LANDM]

Ok, I can see the rationale behind drying the cherries but tell me the science behind helicopters blowing -20 air around cherry trees? Does it make sure that they get destroyed for insurance purposes?

An insanely disruptive strategy during the summer months is now all year round?

No, it is an insanely expensive way to protect a very valuable crop. That’s what farming is all about.

[LANDM]

thats all fine and dandy but as soon as the chopper stops flying overhead the -20c air settles in again and the choppers fly for an hour or so out of the day. cherrys are going to be 100 bucks a pound and orchardists are going to have to start putting in helipads if this keeps up. so they get a couple hours of air movement during the warmest part of the day but then its dark for 12 hours when the choppers cant fly and the temps are the coldest. seems like a strange and costly plan

They can keep the wind machines on all night. And, the temperatures are actually coldest just as it’s getting light.
It is well thought out and very proven in use for many decades. It’s not really something that should need too much thought or argument as to it’s value.

[LANDM]

I'm a little stuck on the theory here. If it is ice covered, it will still follow the temperature other wise how could you get 2 feet of ice on a lake?

There is more to the icing of trees, if it was intentional.

It's meant to be a short-term insulator... that's all. Typically it's done just to protect the trees for several hours from nighttime lows until things warm up in the daytime. It's not just Florida citrus growers that do it... California strawberry growers will do it too.

It's done in places like Florida and California when temperatures approach damaging levels and will only be that low for a few hours (it's usually done just as a last resort). It wouldn't really work as effectively up here if the temperatures are dropping for a significant amount of time.

It sounds counterintuitive, but the ice acts as a great insulator.

Again, sort of correct but not totally. As the water turns to ice, it releases heat, thus protecting the plants.

[cv23]

OK , got some more info and hopefully an explanation.
If you check the weather you'll see that even though it's -10 outside the humidity is still 43% and the dew point is -19. While its hard to believe there would be frost at -20 there obviously can be given a 43% humidity level. The longer it stays cold the lower the humidity level will become and the lower the dew point will drop to. We went from +8 to -15 in a few short days so the humidity level is still fairly high for temperatures we are presently experiencing.
Overnight lows are almost always recorded close to dawn which presently is 7:15 am. We have had overnight lows approaching -20 the other nights so just below the dew point. If the helicopters can keep the air moving for that brief window before dawn when the dew point is exceeded they can save the trees from frost exposure.
Again hard to believe there would be frost at -20 but the science doesn't lie.

[Glacier]

Cold air is heavy and sinks. For example, my mom's place was only -35C last night. 200m below her house and 30 km down the road looked like this...

149948056_2779118172346308_4457841390087030023_n.jpg

If there's no wind, the cold air sinks and you get a massive invasion. If you stir up the air, you don't get the cold air sinking so not as cold at the surface.

[Brushy Bill]

Those are the cherries destined for export to the Chinese market right ?
Owned by foreign investors? Maintained by tfw's ?
mmm fresh cherries .....

[Symbonite]

Those are the cherries destined for export to the Chinese market right ?
Owned by foreign investors? Maintained by tfw's ?
mmm fresh cherries .....

Thats right...because farmers can not rely on locals to support them anymore. Domestic prices can never match Foreign Returns.

[one wheel]

I don't know what or who to believe anymore regarding the food supply system ?

Cherries are grown in Kelowna & are flown to China while cherries from Chile & the USA are on our store shelves ?

The quality I've seen in the big stores isn't worth buying so I choose local instead.