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Climatic changes and hardiness

Posted by Todd Parlo 
Climatic changes and hardiness
February 15, 2013 09:21PM
Climatic change is becoming a large part of the discussion of fruit hardiness. I have been looking at records this week and found some interesting stuff. Here in Vermont we had the wettest year (2011), unprecedented periods of low snow cover (2011, 2012), average higher daytime and lower nighttime temps (2011), latest snow on record (2011), and record highs in mid November (2012). 2012 was the warmest year on record, while having lows in the mid 30’s below zero in 2011. Maple sugar season is now 3 weeks shorter than in 1966. This year (2013) Vt. State legislative joint hearings are being held on the impacts of climate change on business (including but not exclusive to agriculture). The spring temperature swings have been devastating to fruit growing in the northeast. I have included a few posts from our website journal to give an idea of changes at our farm:

1/16/12 -Finally, it seems like winter here in the Northeast Kingdom. The past two eves have dipped below -14F which is the coldest this winter, but long in coming as regards real northern temps. We are always quick to enjoy the frigid weather, but have been a bit worried about the odd events leading up this normally cool situation. Here is the complication: Until the last week or so, we had nearly no snow cover due to the wierdly mild weather this year. This of course gives little insulation for plant roots, and so there was much hoping for some of the white stuff. Luck was with folks around here and we received just under a foot last week. Here’s the point, whether or not you believe humans are messing about with the global climate (we are), it is hard to dismiss things are getting unusual out there. Those hoping for the silver linings of global warming and the visions of peach trees and sweet cherries in the north should look closer to the fine print.. The reasons for the distinction between the popular term “global warming” and the term ”global climate change” embraced by the scientific community is that of the effect. Warming, maybe, to your home town. But change, certain. This means, maybe warmer, maybe colder, definitely different. So, here in Walden this year we had one week with only 2 or 3 inches of snow (normally many feet) and we almost had 14 below in those conditions. We did have 9 below with almost no snow a few weeks back. Those who have trees and bushes that have survived for years, especially those in lower altitudes in the surrounding valleys (which characteristically have less snow) will see damage and losses. This is the sort of complications we need to understand. Most so called hardy plant roots can only sustain 20 degrees ABOVE zero in the root zone, so they need protection that snow allows them. No or little snow cover due to warmer temps spells disaster when inevitable arctic blasts swing in from Northern Canada. That so called global warming may likely mean you have to grow hardier plants, not the other way around

2/12 - Ok it is the second week of Jan and we are waiting for the bill chills. We saw about 15 below last week, but that was the roughest of the season. There is still time for the deep temperature plummets, but it is making me nervous, I’d hate to loose my bragging rights. The trend the last few years has been ,overall, milder despite snaps in the last few years near 40 below so we are still in the game. Apparently there have been revisions to the zone charting in the US, placing alot of formerly zone 3 regions at 4. But since snow cover has been poorer and riddled with warmer spells, the likely cold plunges could be disastrous to growers. The irony is the new zone 4′s could be worse off than zone 2′s as regards cold damage to plants. Complicated isn’t it?

3/27/12 -The unprecedented warm weather over the last two weeks has initiated premature budbreak in nearly all the fruit species here in Walden. Temperatures tonight of 6 degrees will spell trouble we fear. We have greentip on a fair amount of apples and pears, but the furthest advance is on black currant and gooseberry with leaf emergence (half inch green)
Spring ’12 -The premature growth on most species has led to some marginal damage. Following record breaking warm temps this spring, some freezing temperatures ruptured cells in new growth. Leaves damaged were on most species, but not all individual plants. Pear, apple, currants, gooseberries, cherries, plums, aronia, juneberry, and lilac all showed damage. Plants seem to have recovered, but the affected tissue has wilted and decayed or displayed “black tip”. Dissected flower buds on pear appear no worse for the wear, thankfully.

I hope to springboard a discussion on the mechanisms of and protocols we can invision as regards plant selections and orcharding techniques to deal with these problems.
Re: Climatic changes and hardiness
January 07, 2014 07:34PM
The weather conditions this week have given turned more attention to the unpredictability of the climate change model. After a lot of poking around, the most interesting for me was the situation in the Chicago area. The arctic blast this week reached -19F or lower. The punchline is that the zone hardiness maps were recently changed to put Chicago firmly in zone 6a. The 6a min temp is -10F. So those getting giddy about all the tender plants they can plop in their newly established zones may want to do a little more research. Nationwide we have had record cold this week, in the same places we set record highs last summer. Gonna be a bumpy ride.

Walden Heights Nursery & Orchard
Zone 3 in Vermont
Re: Climatic changes and hardiness
January 09, 2014 12:28AM
I agree Todd. Bumpy indeed.

I was reading an article about the Polar Vortex and that scientists feel it may begin oscillating erratically during the winter months (due in part to less & less summer ice pack being present) vs staying in a fairly predictable circulation at the polar cap as it normally does.

If this theory is right, the extreme cold that most of the US just went through, and you speak of, may be come a more familiar winter phenomena.

Higher highs in summer and lower lows in winter . . . water scarcity here, flooding over there . . . spooky, no matter how you slice it.

Out west . . . We are in the midst of a drought of historic significance here in California right now. Many areas are seeing rainfall totals thus far (since July 1 2013 to date) that are even lower than the historic 100+ year California drought of 1976/1977. Sacramento, Los Angeles and San Francisco (to name a few) each set an all time record for lowest calender year rainfall totals ever in 2013. . . . records going back to 1877.

The 2014 California wildfire season is setting up to be one for the ages.

The good number of folks are convinced that global warming is going to simply raise temperatures and they are looking only for that factor. . . Personally, I fear it is much more than that. Higher (and lower) temp extremes are just part of the uncertain future we will all share.

Gopher Hill Apples
Zone 8 in California
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