Cold enough for ya?

Like many people we spent the past couple days digging out from the massive snowstorm that swept across a large swath of the country.  This was definitely a made-for-TV-weather event as national and local TV weatherfolks took up their positions and gave us breathless live-remotes of the “Blizzard of 2011”.

40 mph wind + 1 little crack = a barn full of snow.

Almost as predictable as video footage of snow-ploughs on the streets and locals snow-blowing sidewalks; climate change skeptics are using the recent round of winter weather as proof that global warming is a hoax and that there’s really nothing to worry about except the economics of ‘cap and trade’.  Just google “climate change skeptics blizzard” and you’ll get the idea.

Bob and Quincy were unfazed by the sub-zero wind-chills.

The problem, of course, is that climate patterns don’t move in a strictly linear trajectory and looking at one extreme event doesn’t prove anything one way or the other.  Even looking a few years time sequence may not present the full picture.  Deroy Murdock used the illustration below to argue in the National Review Online that there is no link between rising CO2 and increasing temperatures.



But looking at a broader timescale tells a different story.  While there are year to year fluctuations a clearer association between rising CO2 and global temperature begins to emerge.

The figure above was taken from an article by Stamhoff et al. 2007, “Recent Climate Observations Compared to Projections” (Science 316 (4): 709).  The dashed lines represent the ranges predicted by a major climate model starting in 1990 – the solid line represents what actually happened.  As shown in the figure, climate models have been fairly accurate overall and, if anything, have been conservative in predicting climate change; especially with regard to changes in sea level.


So where am I going with this? There are certainly enough climate change debate/Al Gore bashing blogs out there to go around and I don’t want to devolve entirely into that debate, but the simplistic ‘exception proves the rule’ mentality of the skeptics gets a little tiresome.  I remember hearing my first talk on global warming at a forest biology conference in the mid-1980’s.  The main point that stuck with me then was that increasing global CO2 would not necessarily result in warming every year but that we would see an increase in the frequency and severity of extreme climatic events; droughts, hurricanes, floods, and yes, even blizzards.  Even some of the earliest discussions on climate change in the early 1980’s (e.g., Manabe and Stoufer 1980) recognized complex feedbacks in the global climate system that would result in some regions getting wetter while others suffered drought.  So while the skeptics may use this weeks’ blizzard as evidence against climate change, increasing frequency of severe weather actually argues for it.

A few other climate facts to ponder:

-Global CO2 is increasing and continues to increase (see top panel in figure above).

– Globally, 12 of the 13 warmest years on record have occurred since 1995.

-Intensity of hurricanes and cyclones is increasing (Webster et al., 2005).  While Fox and Friends were happily using the Blizzard of 2011 to debunk climate change; did they notice the most powerful cyclone on record was slamming into Australia?

-Frequency and severity of droughts is increasing worldwide (Burke and Brown, 2006).

-Glaciers are disappearing.  If you want to go to Glacier National Park and actually see a glacier, you need to hurry.   In 1850 there were 150 glaciers in the park.  Today there are 25 and they will likely be gone in 10 years.


Planting trouble: multiple trees in one hole

[I enjoyed Jeff’s Valentine story so much that I thought I’d stick to the theme of togetherness…for better or worse.]

A week or so ago a reader asked about the practice of planting three or four fruit trees in the same hole.  Having not heard of this before, I checked on the web and found many “how to” pages geared to home gardeners who either want a longer harvest of a particular fruit (early to late) or a mixture of different species.  Doesn’t it sound just great, especially for smaller urban yards?

One of these sites has these written instructions: “Plant each grouping of 3 or 4 trees in one hole at least 12 to 15 inches apart.”

Now, I’m sorry, but this is just asking for trouble down the road.  Readers of this blog know that root systems extend far past the drip line, and that roots from different trees are going to compete with one another.  You’ll end up with three unhappy trees, all jostling for space and resources, just like kids in the back seat during those long car rides.

But wait! you might say.  There’s research on high density tree planting, and it’s been shown to increase fruit yield on a per acre basis!

Yes, in fact there is a lot of planting density research on many different species of fruit trees.  What’s considered by researchers to be “high density” varies, but it rarely exceeds 2698 trees/acre (6666/ha for our international readers).  Optimal and sustainable levels of high density planting are also variable, as they depend on not only species but rootstock and the crown architecture; 1214/acre (3000/ha) might be a mid-range number.  This can be converted to a per-tree requirement of 36 sq. ft. or a 6’x6’ planting area.

How does this compare to the 12-15” recommendation given earlier?  If we’re generous and use the 15” recommendation, this translates to 6.25 sq. ft. per tree or 6970 trees/acre.  The 12” recommendation would lead to a whopping equivalent of 10,890 trees/acre.  (And no, it doesn’t matter if you’re using dwarfing rootstock or not; most of the higher densities in the literature are for dwarfing rootstocks.)

You don’t have to be a math whiz to see that these densities are totally out of line with reality.  Sure, you can probably keep overcrowded trees alive with lots of water and fertilizer, but they’ll be under enough chronic stress so that pests and disease might take hold, and fruit production will likely be poor.  And it’s about as far from a sustainable practice as you can get.

More Master Gardener Fun!

Am just heading out the door for Fairfax, Virginia – part of the greater Northern Virginia metro area, with traffic that scares the pants off of us country mice. I’m doing the Master Gardener training for the Fairfax Master Gardener Association.  Their attendance is so huge, they have to split into a morning session (150 people) and an evening session (100+). Two and a half hours of training on “herbaceous plants” twice in one day – that’s a lot of yakking even for yours truly.   But what a terrific group. I led the herbaceous sessions in 2007 and was impressed at the diversity of age, ethnicity, levels of knowledge, you name it. A complete cross-section of the area, all with the common desire to learn. Merrifield Garden Center generously (and brilliantly) hosts the training in their large meeting room. Alas, after we all get worked up over the fab perennials, annuals, and tropicals, there’s not much to buy this time of year.
I’ve written about the tremendous contribution of volunteer hours that Master Gardeners make to our state.  As the budget axe drops hither and thither, Extension programs always seem to be at risk. All of the Garden Professors have noted their own state’s struggles with such. Here’s the (slightly) brighter side, though – the Fairfax Master Gardener Association receives no funding from federal, state, or local government. Just some training materials from Extension Same with most of the other associations across the state. Not much to cut, really. In turn, it was calculated that MG volunteers across the state reported 334,000 hours of service for 2009. That’s a pretty good return on very little investment from the state.  Heck, I don’t even have an Extension appointment. But I’m a believer in the MG system, and want to help in whatever way I can, even if it means leaving the peaceful mountains and driving to Northern Virginia. A bit of a bonus is there’s really good shopping up there. Heh.