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Well, students just finished finals here at MSU so I suppose it’s appropriate we put our faithful GP readers through their own gauntlet of quizzes…

Top marks to Terry for determining the damage on the conifer seedlings was due to incomplete overlap on the sprinklers the grower used for frost protection during our most recent freeze.  Our record-setting March warm up pushed budbreak ahead by about a month in most locations in the state.  Fruit crops (cherries, grapes, blueberries, and peaches) have been devastated but nursery crops and landscape trees came through relative unscathed until the freeze the weekend before last.

I know Linda normally handles quiz duties, but I received a couple of intriguing pictures last week.  Rather than just tell you all what’s going, I thought we’d have a little sport with it.

The photo below was taken last week ago at a container seedling nursery in western Michigan.  These are trays of container-grown spruces.  Most of the seedlings are green and growing but some are tip-damaged – with a specific pattern.  What’s going on and what caused the pattern?

Last August I posted some photos from a field tour in Austria where we saw an organic Christmas tree farm that used Shropshire sheep as their principle form of weed control.  The particular breed of sheep is suited to the task since they will graze on grass and weeds but not on conifers.  Since then I have shared the pictures elsewhere and found out the Shropshire sheep are also employed in the U.S. and the U.K. for similar purposes.  Recently, I have had several people share websites for a service known as ‘Rent-a-Ruminant’.  As with the Shropshire sheep, these services use grazers to control vegetation, but instead of sheep these companies use goats. 

Unlike sheep, goats are much less selective grazers; so call these guys in when you’re in need of land-clearing or invasive species removal.  I have seen Rent-a-Rumant advertised in the Pacific Northwest http://www.rentaruminant.com/goats-clear-land.html and in Australia http://thebegavalley.org.au/24484.html so clearly this is a widespread idea.   And, I suppose, an example of an old idea that’s new again.  As many GP blog readers probably know, I have issues with the ethics (not to mention efficacy) of exploiting grade-school children to pull garlic mustard or purple loosestrife in the name of invasive species control.  But using goats to control invasives?  That might be a solution everyone can get behind

Not baaaad work if you can get.  Rental ruminants chomping on English ivy in the Northwest. (Just for you, Linda)

Why does everyone want to kill dandelions?  I like dandelions.  I like that my kids go and pick them and give them to me.  I like that they break up the monotonous green of my yard.  I like that they can be used to make wine (though I’ve never had any).  I like that I can pick one and take it apart to teach my kids and the kids in my classes about the basic morphology of flowers.

I don’t like the fact that the most common herbicide used today to kill dandelions, 2,4 D, may have serious effects on the health of dogs, in part because it isn’t rapidly excreted from the dog’s body.

I also don’t like the fact that many shrubs and perennials are killed every year because of poor spraying techniques intended to kill dandelions.

But what’s most irritating to me is that we have a technique out there for controlling dandelions which is pretty darn effective, but which is almost never used.  It’s not a 100% control, probably not even an 80% control, but it still works pretty well if we’d just give it a go.  And that technique is….wise fertilization.  You see, dandelions like to be fertilized with potassium.  They love the stuff.  In fact, they love the stuff more than grass loves the stuff, so if we’d just reduce the amount of potassium we applied to our yards…we’d have fewer dandelions.

But if you just can’t get over the idea of having a yard clear of dandelions, there is a new, relatively safe, product out there that will kill them though it may take a few applications.  It is not an “organic” product – though in my estimation it’s safer than many organic products.  The active ingredient of that product is FeHEDTA, which is an iron chelate that delivers a dose of iron the dandelion can’t handle but which, apparently, grass can. This stuff is available in two products I can think of offhand – Ortho elements lawn weed killer and Whitney Farm lawn weed killer. 

But come on — dandelions are cool.  They’ve been in the US just about as long as European settlers and their descendants have — and taken over the landscape just about as effectively.  Shoot, we should probably have the dandelion as our country’s official flower! Why are we so anxious to toss ’em?

Well, things continue to run fast and furious as we get rolling for a new round of field research projects.  But we did find a little time to break out the Cornhole set and initiate a new season at Daisy Hill farm.  Life is good!

After Jeff’s recent eclectic musical selection of Rasputina’s 1816, I thought I’d go a little more mainstream with Lynard Skynard’s ‘Swamp music’.  Turn it up and remember; if it’s too loud, you’re too old. http://www.youtube.com/watch?v=_wJWBcj7lsY

So, what got me thinking about the swampy backwoods down South and the late, great Ronnie Van Zant?  The arrival of pallet after pallet of bagged cypress mulch at every gas station/convenience store in the area.  Like the first robin, the annual appearance of bagged cypress mulch is another harbinger of spring.  Awhile back (Oct 2009 to be exact) I commented on efforts by some environmentalists to boycott cypress mulch.  The rationale behind the boycott is that cypress mulch is harvested from wetlands in Louisiana and Florida.  Many of these areas are environmentally sensitive and it is difficult to regenerate new stands after harvest because of frequent inundation.

In response to the calls for a boycott, the Louisiana Forestry Association countered with a series of Cypress FAQ’s. http://www.laforestry.com/site/ForestFacts/Cypress/FAQ.aspx The Forestry Association, not surprisingly, deems the proposed boycott an overreaction, noting that cypress makes up only a small proportion of all timber harvested and that only about one-fifth of cypress harvested goes into mulch.  While it’s true that cypress is a comparatively minor species in terms of acres logged, much of this area includes some of the most sensitive ecosystems in the country.  And I was actually surprised to learn that the proportion of cypress that went into mulch was that high (20%).  Cypress timber is extremely valuable for decking and other high-end uses; I had always assumed mulch was a fairly minor component of the overall market.  But clearly, diverting a portion of the harvest to mulch could tip the balance and make some marginal logging operations profitable.

So, where do I come down on the boycott issue?  I suppose in a sense I boycott cypress mulch because I’ve never bought any and never intend to buy any.  Bob Schutzki and I conducted a study several years ago that showed that landscape shrubs grew as well or better when mulched with locally produced ground pine bark or ground hardwood bark than with cypress mulch.  Even mulch from ground recycled pallets (yes, that stuff dyed a red color not found in nature) did better than cypress.  So for me the issue has been moot.  Buy a local product and support your local forest products industry.

Rotenone is an organic insecticide that has been voluntarily withdrawn by its manufacturer because it’s quite toxic, it’s dangerous to the environment, and there is some evidence that it causes Parkinson’s disease.  And there are safer choices.  For my post today I was thinking of posting about all of the places I could still buy rotenone, but after doing a web search I couldn’t find many – and most of the places I found to purchase it don’t really have it (I don’t think) – they’re just old pages that weren’t taken down.

But in my string of results I kept getting this one weird hit – something called Goodwinol ointment for dogs.  So I looked into it, and sure enough, there’s an ointment you can buy for your dog that contains    1.25 % Rotenone.  It’s supposed to be for mange, but no prescription is necessary, so anyone could buy it.  To me this is a little concerning.  Rotenone is some nasty stuff, 1.25% is a relatively large dose, and I’m not sure that most people using it would be careful to use gloves.  So I’m wondering, should this stuff really be out there?   

Despite Linda’s assertion to the contrary, I was not cow-tipping nor was I sampling micro-brews last week when I missed my regular post.  As usual, the beginning of spring is a busy time on the research side of my appointment.  This past week we began setting up for a major new project.  The goal of our newest study is to look at physiological traits of street trees that may enable them to better withstand future climate change. 

If you think about it, trees that are planted today may experience future climates in their lifetimes that will be different than the climates under which they were selected.  So how do we ensure that trees that are planted today can withstand a potentially different environment in 50 or 75 years?  It’s a very complex question.  An easy response would be to plant species or seed sources that have evolved in warmer, southern locations.  The problem is climate change is predicted to occur gradually so southern trees moved northward today will be subject to increased frost and freeze damage in the interim.

Grad student Dana Ellison (L) and undergrad research aide Aniko Gaal (R) pot up shade tree liners for a new project.

Another approach, and the one we are investigating, is that trees that are best suited for the future may be those that have a high degree of phenotypic plasticity.  What is phenotypic plasticity?  Simply stated is the relative ability of a species or genotype to acclimate to changes in their environment.  In our case we are going to look at the photosynthetic response of a range of street tree cultivars in order to identify their optimum temperature for photosynthesis or Topt.  But we know from other studies that Topt can vary depending on the environment to which trees are acclimated.  So we will acclimate our trees to a range of temperatures in a greenhouse study and determine which species or cultivars are best able adjust their physiology to changing environmental conditions.  In addition to the greenhouse study we will out-plant trees from the same cultivars in a parallel field study with the Greening of Detroit.  Working with the Greening we will identify sites around Detroit with contrasting temperature regimes and plant trees at these locations.  We will follow up with a similar suite of measurements as our greenhouse trial.

Will one study tell us everything we need to know about selecting street trees for a changing climate?  Of course not.  But it provides some important base line information and insights on approaching the problem.  Trees in urban and community forests are already operating at the margins and subject to myriad of stresses.  The argument can be made that urban ecosystems are among those most at risk under climate change.  Trees are an important component of many climate change mitigation strategies but they must be able to survive and grow in order to contribute this function.

The study “Urban tree selection in a changing climate” is funded by Michigan State University Project GREEEN, with material and in-kind support from J. Frank Schmidt and Sons Nursery, Nursery Supplies, Inc., Renewed Earth, Inc., and the Greening of Detroit.

I like to say that my taste in music is eclectic, but it’s not really true.  I like music that is known as classic rock (60s – 80s rock once known as pop) and I like music known as "alternative" (really a meaningless term — but I don’t invent the labels).  The one band that I love who might be considered completely out of the mainstream is Rasputina — a cello based group who sing about many things, including history.  1816 in particular.  Listen, it’s a history (and meteorology) lesson in a song.

So, that said, In 1816 there were freezes in every month of the year across much of the Northern part of the US.  Leaves were frozen off trees almost as they formed — and yet, unless trees were small and/or weak, they lived to see 1817 (also a tough year), and beyond.  Sure, fruit production was way down, but trees are prepared for tough conditions — they store plenty of carbohydrates to protect themselves against that very thing occurring.  So, if anyone asks what’s going to happen to our trees if they flush out early (which they are doing) and then there are some late frosts, just point to 1816.  Or, better yet, let them listen to the song.