Category: Cool Research

The Canary in the Coal Mine

Three weekends ago marked a milestone of sorts as mean daily CO2 levels at the National Oceanic and Atmospheric Administration observatory at Mauna Loa, Hawaii topped 400 ppm for the first time ever.  Rising levels of CO2 and other greenhouse gases could result in significant increases in temperature in the Upper Midwest over the next century.  When we think about trees in cities the scenario is even worse since not only will urban trees have to deal with overall temperature increases but they must also contend with urban heat island effects, which can add another 8 deg. C or more of heat load.  Because of this ‘one-two punch’ of global climate change and urban heat island effect, I often refer to urban trees as the proverbial ‘canary in the coal mine’ with respect to climate change since they will likely be impacted sooner and more dramatically than trees in woodlands.

 

 

In general, organisms have three options to deal with a change in their environment: They can migrate, they can adapt, or they can acclimate.  Since trees are sessile organisms, they can’t pick up and move so migration is out.  Current predictions are that climate will change faster than trees can evolve so natural selection and adaptation will be limited.  Which leaves us with acclimation, or the ability of a tree to adjust its physiology and morphology to its environment.  A common example of an acclimation response is the development of sun and shade leaves on the same tree.  Another example of an acclimation response is an increase in the optimum temperature for photosynthesis in response to exposure to increasing temperatures.  In theory, trees that have a greater capacity to adjust their physiology to increasing temperature will be better suited for future, presumably warmer climates.

We are currently testing this idea in a two-part study.  In part one we are growing trees from several shade tree cultivars in greenhouses under three temperature regimes; ambient temperature, ambient + 5 deg. C, and ambient +10 deg. C.  In part two of the project we planted trees of the same cultivars in two sites in Detroit in cooperation with the Greening of Detroit.  The Greening of Detroit is community based non-profit organization that assists neighborhood groups, churches and schools in their efforts to improve the ecosystem in Detroit through tree planting projects, environmental education, urban agriculture, open space reclamation, vacant land management, and workforce development programs.


Many hands make light work.  Greening of Detroit volunteers plant trees along a street median.

With the help of Greening staff and about 90 Greening volunteers, we recently planted 160 shade trees in downtown Detroit.   One site of the study is in a park, representing a relatively mild micro-climate; while the other site is along a street median surrounding by asphalt with a much higher reflected heat load.  Both sites with be instrumented with environmental sensors and we will compare growth over time as well as physiological responses such as the response of photosynthesis to temperature.  The long-term goal is to identify traits that will be most important to guide future selections of trees of urban and community forestry under changing climatic conditions.


Research Technician Dana Ellison (left) and Research Aide Aiman Shahpurwala finish planting a park tree.


A pick ax as a planting tool?  Dana shows how it’s done in Detroit.


Should back-fill be amended?  My usual answer is ‘no’, but then again it depends what your back-fill looks like…


Sizing things up.  Aiman and Dana collect initial data on trees after planting.

Scientists Put the Dog in Dogwood

(special guest post by/with permission of good friend Mr. John Friel, marketing manager for Emerald Coast Growers – Holly Scoggins)

How do you recognize a dogwood? By its bark.

That old joke might not be a joke anymore, if the innovative folks at Metamorphic Agriculture Developers (MAD) get USDA approval for a new line of ornamental and functional shrubs that blur the line between the animal and vegetable kingdoms.

MAD scientists claim to have successfully introduced genes from Canis familiaris into a cultivar of Cornus canadensis. In other words, they’ve crossed a creeping groundcover dogwood with … a dog. Specifically, a dachshund.

“Imagine a guard dog that you never have to feed, license, or walk,” enthused Dr. Horace Sass. “Imagine a shrub that not only beautifies your home but guards it when you’re away,” adds his colleague, Dr. Ariel Sturgeon. The two bring a unique perspective to their work: Dr. Sturgeon is a mermaid, while Dr. Sass is a centaur.

After considerable trial and error, the team believes its Canis /Cornus combination is the best of both kingdoms. The first hurdle was finding the right plant.

“We tried Physocarpus first,” said Dr. Sturgeon, “but every one that grew to maturity would bark nine times when approached. Our focus group said that was too many.”

Crosses involving Cornus alba succumbed to a fungal disorder that afflicts that species. Said Sturgeon, “The blight was worse than their bark.”

Once they’d settled on Cornus canadensis, the next step was to find the right canine breed. “The pit bull shrubs were tough and sturdy, but their bite was worse than their bark,” said Sass, gingerly rubbing his right foreleg.

While they hope for widespread acceptance of their remarkable new hybrids, the team admits there are challenges, In winter, the plant/pet eventually goes dormant, but not before trying stubbornly to get into the house.

“The whining may be a turn-off for some homeowners,” Dr. Sturgeon admits. “In those cases, we recommend large containers, overwintered in the garage.”

News flash – genes don’t explain everything!

Last week dedicated blog follower Ray E. sent me this link to a story in the Smithsonian magazine.  It’s a fascinating look at adaptive responses by frog eggs and apparently is causing quite a stir in the evolutionary biology community.  Phenotypic plasticity, which is the ability of an organism to modify its appearance or behavior based on environmental cues, is being hailed as a “revolutionary concept in biology.”

I don’t get it.

Anyone who’s studied plants for any length of time knows about this phenomenon.  It’s why plants grow taller in the shade than they do in the sun.  It’s why leaves inside a tree’s canopy are larger and thinner than those on the outer layer. In fact, it’s that darn phenotypic plasticity that can make data collection so difficult for those of us who do field research.  Minimal differences in wind, water, soil chemistry, etc. in a research plot (or a garden, for that matter) are magnified once plants start responding to them.

This leads to one of my pet peeves about the state of biological research over the last few decades.  If you look at the research that gets the big grant dollars, it’s either at the smallest scale (like molecular genetics) or the largest (like systems ecology).  Those of us who are fascinated with how organisms work are pretty much left to our own devices to fund research.  (The exceptions to this rules to a certain extent are human and veterinary medicine.)

While this may seem abstract to most of you, the funding imbalance filters down into the teaching function of colleges and universities.  When I was doing my undergraduate and graduate degrees, my university had a bryologist (someone who studies mosses), an algologist (marine and freshwater algae), a botanist who specialized in diatoms, and so on.  Most major universities had a reasonable number of faculty with expertise over distinct groups of organisms.

As these faculty retired, they were replaced by new faculty whose value was measured more by potential grant dollars than by replacing the loss of expertise. Thus, we have fewer entomologists or mycologists or even horticulturists, as universities scramble for the federal dollars (and substantial overhead) needed to support their institutions and obtainable by a small and select group of researchers.  And university curricula reflect this shift, with the disappearance of distinct programs in botany and horticulture and plant pathology and weed science and crop science, as they are mishmashed into bland and unappealing “plant science” departments.  Or worse, simply “biological sciences.”

So it’s no great surprise, I guess, that many evolutionary biologists are amazed at the “revolutionary concept” of phenotypic plasticity.  I’m not sure many students – or their professors – spend as much time looking at and learning from organisms as they used to.

Research that gardeners should appreciate!

Today I received my November 2012 issue of Arboriculture and Urban Forestry.  This is one of the few peer-reviewed journals that generally has information of immediate value to gardeners and landscape professionals as well as academics.  This issue contains an article entitled “Evaluation of biostimulants to control Guignardia leaf blotch (Guignardia aesculi) of horsechestnut and black spot (Diplocarpon rosae) of roses.” (And before you ask, no, I can’t attach the article or link to it.  You’ll need to read it in the journal itself or wait for a year when the organization makes it available to everyone.)

Anyway, this study looked at eight different self-identified biostimulants, including Superthirve (which every gardener must have heard of by now).  In addition to Superthrive, the other products tested were Maxicrop Original, Resistim, Bioplex, Fulcrum CRV, Redicrop, Crop Set, and Systhane. Purported active ingredients within this group include seaweed extract, molasses, vitamin B, and Lactobacillus fermentation product.

And the $64,000 question – did they work?  Here’s the authors’ summary: “Irrespective of pathogen or concentration applied, none of the biostimulants used in this investigation provided a significant degree of Guignardia leaf blotch or black spot control compared to water-treated controls.”  In other words, you can expect the same results by spraying your black spot-infested roses with water compared to any of these biostimulant products.

The authors end their article with a caveat sure to warm the cockles of every Garden Professor’s heart: “Results of this study indicate that where independent scientific data are not available to support the pathogen control claims of the manufacturer, then using an unevaluated biostimulant for this purpose is not recommended.”

(I’m glad this article is finally out. I was one of the peer reviewers for it, and I’ve been wanting to share the results on the blog ever since I read it.)

A Note To Horse Owners

Every once in awhile I get to work with really, really cool people who do really, really cool work.  This is one of those times.  About a year ago I received a message from Dr. Stephanie Valberg, a Professor over at the University of Minnesota’s Equine Center.  It seems that she was interested in looking at a deadly disease called Seasonal Pasture Myopathy which she thought might have something to do with horses ingesting maple leaves.  Specifically, at the time she contacted me, she thought that this disease might be associated with horses ingesting tar spot, a common disease that maples get. Seasonal Pasture Myopathy is a particularly nasty disease because it is fatal in over 90% of cases, and the death is far from painless.

After doing site visits to many farms where this disease was found, she discovered something very important: Every farm had box elders in a location where horses could feed on the seed when they got hungry.  And for most of the farms, horses were also dealing with scant pickings in terms of food.  They usually had sparse pastures and not much supplemental hay.  So, in these conditions, the horses might find box elder seed attractive, or at least palatable.

After a literature search, Dr. Valberg discovered an old article showing that box elder seeds could very well contain a toxin, hypoglycin A, which might cause this disease if they were eaten.  After testing the seeds for the presence of this toxin (Done by a friend of mine, Adrian Hegeman, located here in the University of Minnesota’s Department of Horticultural Science) it was established that, Yep, box elder seeds have this toxin, and if your horse eats them, it might be in trouble.  You can find out more here.

Right now more work is going on to see if this toxin is more or less present in box elder trees that are under stress, if it is present in other parts of the tree besides the seeds, and at what time of year the toxin might be most present in the seeds.  It also looks as though some other maples may have this toxin in their seeds, most notably sycamore maple.

All in all, having the opportunity to watch this work unfold has been one of the highlights of my career.  It was like watching an episode of House unfold in real life.  And the great part is that this work has the potential to save the lives of dozens, if not hundreds or thousands, of animals.  So if you have horses, and box elder or sycamore maples in your pasture, be careful!

Ideas needed for webinar

I’m doing a webinar for WSU Extension folks next week with the decidedly unsexy title of "How to run literature searches when writing extension publications and how to develop client material using the information from the lit search." In reality, it’s how to research gardening topics, identify the myths (those practices and products with no basis in science), and then write up the valid scientific parts for use by gardeners.  I’d hoped to get some ideas from this group on specific topics to demonstrate the process, but have gotten nothing.  And I’m doing this a week from tomorrow.

So…how about you all? What practices or products that we’ve covered on this blog (or haven’t) that you’d like to see put through my sorting process?  I don’t think people outside the WSU system can watch the webinar, but I’d be willing to post something on the blog about it later.

Feel free to comment below – the earlier the better, as I have to have this done by the end of the week so I can develop the presentation. And thanks in advance for your ideas!

Tree research continued

Not to be outdone by Bert’s recent postings, I thought I’d show you what’s going on with MY tree research in Washington State.

As you might remember, we installed 40 1-gallon mugo pines and 40 B&B Japanese maples at the end of December 2011.  Here’s a photo of the site in April of this year:

I’ve been collecting data on above-ground growth during this year, but have had an unexpected twist to my research, as shown here:

That’s a pine tree.

Yes, we have moles…BIG moles apparently…in Puyallup.  There’s not much I can do besides move the soil away, but obviously the pine trees are not going to be happy with this additional treatment.  The maples are tall enough where it’s not going to be much of an issue.

Note to self: next time install guard Dachshunds next to pine trees. (Thanks to the Fremont Tribune for this great photo!)

New study on pesticide use and GMOs

Some environmental extremists discount agricultural research done by universities, because they receive funding from Big Ag and therefore their researchers can’t be trusted. So this news report of a recent study by one of my Washington State University colleagues is doubly important: it dispells this baseless assertion and it provides some significant – and troubling – information about pesticide use and GMO crops.

Briefly, the article links an increased use of herbicides as a result of increased use of GMOs such as Roundup-ready crops. Weeds build up resistance to herbicides over time, meaning that Roundup becomes less useful as a weed killer and farmers have to turn to more toxic substitutes like 2,4-D to control weeds.

Dr. Benbrooks’s results, published in a peer-reviewed journal, are contested by the chemical industry, and other scientists question the seriousness of the problem. But next time you hear someone malign university scientists as being in Monsanto’s back pocket, please refer them to this post.

Deconstructing the cornmeal myth

Back in June of 2010, I wrote about an online column that recommended applying cornmeal as an antifungal soil amendment. (Important note: we are not talking about corn gluten meal. Just cornmeal.) The upshot of the post was while some gardening personalities extol the use of cornmeal to kill soil pathogens like Rhizoctonia and Sclerotinia, no published science supports the practice.  The post was effective in encouraging the author of the referenced online column to update her information, but the controversy didn’t die. In fact, new comments have been added to the original post on a fairly consistent basis, mostly in the form of personal anecdotes or angry rebuttals. Some commenters, however, have tried to carry on rational discussions, so today we’re going to look at cornmeal from a slightly different angle: what effect does it have on microbes in general?

To start, let’s look at the Stephensville, Texas research that’s most often highlighted by cornmeal proponents.  There’s no peer-reviewed work published on this specific research, but in an online copy of the Texas Peanut Production Guide I found a paragraph referring to “Biological Control of Soil-Borne Fungi.” Here it is in its entirety:

“Certain fungal species in the genus Trichoderma feed on mycelium and sclerotia of Sclerotinia minor, Sclerotium rolfsii and Rhizoctonia spp. All peanut fields in Texas tested to date have natural populations of Trichoderma. For several years, tests have been conducted in Texas using corn meal to stimulate Trichoderma development as a way to control the major soil-borne disease fungi. When yellow corn meal is applied to fields in the presence of moist surface soil, Trichoderma builds up very rapidly over 5 to 10 days. The resulting high Trichoderma population can destroy vast amounts of Sclerotinia, Sclerotium and Rhizoctonia. This enhanced, natural biological control process is almost identical to the processes that occur when crop rotation is practiced. The level of control with corn meal is influenced by organic matter source, soil moisture, temperature and pesticides used. Seasonal applications of certain fungicides may inhibit Trichoderma. Testing will continue to determine the rates and application methods that will give consistent, economical control.”

And that’s all there is on the topic. Most scientists would conclude that further testing was inconsistent and the researchers abandoned their efforts without publishing anything further. But this summary is at least a starting point, though it contains no data, references, or even authors.

First, there’s no argument that Trichoderma is a powerful antagonist of some nasty pathogenic fungi. Likewise, cornmeal most certainly can encourage the growth of Trichoderma, both in the lab and the field.  But cornmeal also encourages the growth of many other fungi – in fact cornmeal agar is commonly used for culturing fungi in the lab. So what about those three pathogenic fungi mentioned in the Texas peanut guide? Do they like cornmeal?

Indeed they do! Published research (about 20 or so articles) shows that cornmeal (not cornmeal agar) has been used to enhance growth of Rhizoctonia fragariae, R. repens and R. solani, Sclerotinia sclerotiorum and S. homoeocarpa, and Sclerotium rolfsii. In some cases the pathogens became more virulent in the presence of cornmeal.

Cornmeal is nothing more than a carbohydrate-rich resource that can be used by many microbes. If you happen to have a lot of beneficial fungi in your soil, cornmeal will feed them. If you happen to have pathogenic species in your soil, cornmeal will feed them too. So it depends on what fungi are already living in your lawn, vegetable garden, or rose bed on whether cornmeal will help, or just make disease problems worse.

The best thing to do – as the paragraph from the peanut guide suggests – is to mix things up a little in your landscape. Use mixtures of lawn grasses rather than growing a monocultural turf. Rotate plant placement in your vegetable garden every year. Add a microbe-rich organic mulch to your rose beds. Natural methods will keep pathogens in check much more effectively than a hyped-up home remedy that’s anything but antifungal.

UPDATE: Since this is a myth that refuses to die, I’ve published a peer-reviewed fact sheet on the topic. Feel free to pass on to others.

Cool website with info on amendments

Not to horn in on Bert’s posting day….but I was just sent this link to Iowa State’s compendium of research reports on nontraditional materials. Though this database is targeted towards crop production methods, there may be nuggets of information relevant to home gardens as well. And it includes a product list if you’re not sure what to put into the search box.

Unfortunately, the collection is focused on north central USA, but look at the filter a report or article has to go through to make it onto the site:

Criteria for inclusion of a research report or abstract in the compendium includes: 1) at least two site-years of research, with multiple crops or varieties substituting for a site-year; 2) authors listed; 3) replicated with statistical analysis; 4) reasonably applicable to north central USA crop production; 5) reference source available; and 6) author permission.

It’s a great start to building a credible database on the topic. Let us know if you find relevant gardening information by posting a comment below.