@hobilus May I ask that you not turn this thread into a debate on climate change?
I don’t want it to stir up negative feelings, or get locked.
Thanks for understanding!
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@BlueBerry May I ask that you not use this thread to debate climate change?
I’m just asking about fruit tree planning, and don’t want my thread to stir anything up.
Thank you!
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yes exactly the problem. it’s not that it’s too hot- it’s that we can’t use the past to predict when it’ll get hot.
the extreme weather events in a lot of areas are frightening. we are high desert and accustomed to heat but the last few years we have had heat waves and domes that just sit for weeks, summer here used to max out around 100 for a few days, 90 for a few weeks- now it’s up to 110+ for over a week.
the suddenness of seasonal change is really taking a toll here the most I think. we never had long transitional seasons, but now it’s overnight, summer to winter and vice versa with no time for anything to get ready. late frost and early freeze, not at any predictable time.
common knowledge here is not to plant anything until mother’s day- but most people who still follow this instead of the yearly weirdness end up with all their annuals flowering during a time when it’s too hot for pollination to happen.
we are lucky in climate, we are better insulated than many people and regions (excluding wildfires outside of town) but it’s still onerous.
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Remind me in 15 years.
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Start a thread on climate change, then ask that climate change not be discussed.
Okay…
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@smsmith I’m asking about fruit tree planning.
I’m not asking people to debate whether climate change is real. This isn’t the place for that - there are a lot of other websites where we can go to do that.
I value the civility and kindness on this site.
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Yup. This past winter, many of my citrus plants got killed stone dead. My rosemary and other plants got the same. The texas growers report the same. The warmer winters mean that the plants never fully enter dormancy, so the inevitable cold front does horrific damage. I noticed a few years ago that very mild winter frosts did much more damage than expected for the same reason…
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Here’s what started the climate change discussion:
“Are you taking into account warming when you plant trees?”
Recognize that? That’s your OP.
If you don’t want to discuss climate change, don’t post questions which are based upon climate change assumptions.
I presented my viewpoint. I have nothing further to say on the topic unless you once again direct a comment to me.
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I think @IntrepidNewbie is hoping we could parse some of the thornier aspects and/or maintain a civil discourse, both noble goals in my view. Obviously, it’s the ultimate slippery slope. Maybe religion is worse. Maybe. There are definitely bandwagons at play. I make a habit of staying off of them, myself. I’m more the singer songwriter type, I guess.
For my part, I have no political horse in the race. There are those who feel that anthropogenic effects are not significant, and that is a valid position to hold. But asserting that the climate in fact isn’t changing, that the sea isn’t in fact rising is not, in my view, valid. Data itself should be apolitical, and it’s ubiquity across institutions like our military is evidence of its validity (the data that is, we needn’t extend this automatically to analysis of the data or policy based on that analysis)
It’s not really possible to discuss this subject without delving into the observable facts of the altered jet stream. We’ve all seen it, unless we haven’t been paying attention. Have these polar vortices always happened, and are certain areas prone to them, sure enough. But historically these would best have been described as outliers, now they seem to be the norm.
The actual warming is observable too. Changes in the mean are by definition apt to be slight. From a grower’s perspective, though, in my region we’ve for example gained 30 frost free days per season, an increase of nearly 25%. The cause of that change and what we might hope to do (or not) about these observable facts are far far into the rhubarb patch from acknowledging the phenomenon and digging into some of the particulars of how it seems to be playing out. Is it erroneous to extrapolate these trends into the future? Perhaps, I could see that as a reasoned statement (which doesn’t require agreeing with it). But to deny that the very thing we are seeing happen is happening? That is simply incorrect.
Sea level may seem a far cry from fruit growing, but it’s ocean currents after all that generate and direct weather patterns. My main reason for mentioning it is that it’s really in the dynamics of these systems that all of the important and interesting stuff lies. And that’s fundamentally the difference between weather and climate. Moving of the mean in itself may seem unimportant, except when one considers the way the energetics driving that increase cause potentially dramatic differences in the way that system behaves. That certainly is the case with a match and a pile of tinder. Things can chug along in a given pattern for a long time, but that doesn’t mean it will always be that way. To acknowledge some of this at its core should not be inflammatory or controversial.
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Yes, and she’s asking that people who want to argue against it not ruin the thread for the people who want to talk about using climate models and trends to plan your plantings.
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Thanks for the welcome!
The data I ran was daily min and max temperatures recorded in eastern NC. When I selected the coldest day for each year and divided the dataset into 1970-1995 and 1996-2021, the average annual low for the first was 10.58 F, while the second was 14.81, a pretty big jump, from barely 8a to almost 8b.
The dispersion is still really high, though. My average might now be 8a, borderline 8b, but I still get plenty of zone 7 winters, and even some zone 9s. And previously, there were even a smattering of zone 6b winters.
1970-1995
1996-2021
Going by the last two and a half decades, for a given winter I’ve got a 50/50 of it being 8b or warmer, which is pretty epic, but I’ve also got a nearly 1 in 5 chance of a nasty zone 7 winter coming through and murdering all my half-hardy plants.
Even crazier is the first and last frost dates. I didn’t save the analysis, but I was seeing something like a difference of up to two months in the total frost-free growing season. It’s wild. My conclusion was that I should always try some early plantings, knowing that it’s a die roll whether or not they’ll get zapped or I’ll get an early start to the growing season. Same with late plantings–I may get some super late season vegetables, or I might loose my big healthy pepper plants to a light early frost and then have a fully month of warm, frost free ‘autumn’ weather.
My take-away: just try stuff, some years it’ll work, some years it won’t. And stagger everything, because if I plant all my tender starter plants out at once, I might loose all of them.
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For those curious:
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Yeah, ditto. One season hardly a trend makes, but it’s pretty astonishing to consider that we’ve had made it through all of April essentially without frost. This in a locale where even 30 years ago, planting date for tender crops would have been June. 15. I’ve scoured historical documents showing frost free periods of 120 days for mild regions of my state, like the Champlain and lower CT river valley. I’m routinely seeing 160 frost free days over the course of my 15 + years of growing. I start thinking about getting tomatoes in the ground May 15.
At least this year we have some actual spring weather. It seems 3 out of 4 years (during my tenure have featured little in the way of spring rain and April temperatures more appropriate to July.
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Back to the topic at hand, I would be amiss if I didn’t mention that climate trends are big part of why I decided to start the PNW cold-hardy avocado breeding project that I’m organizing:
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That being said, here’s the chart for the annual high:
As you can see, it actually dropped ever so slightly (about 1 degree). But that’s probably just statistical noise, especially considering:
Now this is pretty fun. Average daily highs for the summer months, the whole year, and for winter. Summer crept up by about a degree, but I’m not super confidant in that trend, since it’s being help up there by a single drop in the 1970s and two fairly warm years in the 200s. Annual average highs are almost dead flat, but, lo and behold, winter highs have gone up the most.
Like I said before, the biggest changes are not when things are hot, it’s when things are cold. On a more macroscopic scale, you can see a similar phenomenon when you look at the record highs for given locations along a scale of latitude (adjusting for humidity, which ends up being super important). The hottest days in different cities around the world (excluding those in arid climates) really doesn’t change much at all: London: 104, NYC: 106, Beijing: 107, Tokyo: 103, Rio de Janeiro: 109, Orlando: 103, Kolkata, 111, Jakarta: 96! Think about those numbers, the hottest day in NYC was hotter than Orlando’s (hint as to why: humidity). Overall, the difference in highest summer temperature is a few degrees. Coldest? The difference is close to a hundred degrees. Winter lows vary far, far more than summer highs.
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Running the numbers as super helpful for me. I now have a dataset I can draw upon for making planting gambles. Do I want to set out a couple of early plants each year in case it’s a mild one (yes), if so, what is the earliest date I can get away with and not get a frost (iirc it was sometime in early march). Will I lose some of those early plantings? Yes. Is it worth it on the odd year I don’t get a frost? Yes.
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I’m a little unsure what the relationship is you’re alluding to. Humidity is latent, not sensible heat, and so shouldn’t affect the temp reading in any direct manner. If anything, I’d think it might be more related to day length. I appreciate you’re input, especially the effort you’ve gone to crunch the data and show it on the forum. Just thought I’d ask for some clarification about that particular point.
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Day length makes some difference for max temperatures, but not much. What’s far more important for hitting record high temperatures is dry air. The hottest temperatures on record are in places like death valley, the Sahara, southern Iran, etc. All of them extremely dry. The lack of humidity means that the air has very little heat capacity, and so a full day of summer solar radiation will push the atmospheric temperatures way way up. Contrast that to most of the cities I listed above, which typically have summertime relative humidity of 70%, 80% or higher. There’s so much water in the air that the sun really struggles to heat the atmosphere up beyond 100 F. In a humid climate, 100-110 F is about as hot as it can get. NYC got hotter than Orlando because NYC occasionally gets heat waves during periods of low(ish) humidity, whereas Orlando is always, always, humid to the max, and there just ain’t enough Florida sun to heat all that water that high (this is also why the coldest major city in the world, Yakutsk in the heart of Russian Siberia where they’ve had temperatures of -83 F, also has a record high of 101 F, it gets pretty dry there in the summer, and being hundreds of miles from the ocean just makes things worse).
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Thanks for filing in the blanks. Now I see what you’re getting at. I understand how big a factor latent heat is, I just wasn’t seeing how you were applying it. It would cut both ways, I would think, humidity adding some storage capacity to the lower atmosphere as you point out. But then air has very low heat storage capacity in any case. The bigger factor I would think is what happens at the ground. It’s the earths surface that actually captures that short wave solar radiation and radiates it outward as long wave heat, and if there is water to be evaporated at the surface, that phase change will absorb the energy, reducing the amount of sensible heat that can be brought to bear on the atmosphere. That in turn creates humid air.
Extending this slight adjustment of causation for clarity, I’d say what’s needed to achieve the highest temps is not dry air, but dry ground, lack of foliage. No evapotranspiration = maximum sensible heat.
Not to quibble, mind you. The overall point is well taken.
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Climate is what you expect. Weather is what you get. Robert Heinlein though I don’t know if he was quoting someone.
Beekeepers tend to watch what is happening weather wise very closely. I started beekeeping in 1969 at 10 years old. By the time I was 17, I had a dozen colonies and was an enthusiastic beekeeper. Why is this important? in the 1970’s and early 1980’s, I could count on first fall frost about September 20th. We have not had a fall frost in September in over 20 years. Recent first fall frosts have ranged between October 15th and December 5th. This has a significant effect on trees I can grow. As an example, I have several apples grafted specifically because they are rated to perform well in warmer climates. Interestingly enough, we had an official low December 21’st of 3 degrees Fahrenheit. That would suggest I am in a zone 6 climate instead of the zone 7B it is normally rated.
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