Cool tree App for i-Phone users

I’m preparing to give my Woody Plant Physiology students their first opportunity to flaunt their new-found knowledge (aka Exam one) so only time for a short post.

As my fellow Garden Professors are aware, I am among the least tech-savvy people roaming the halls of academia these days and was long ago declared roadkill on the information superhighway.  However, I recently found out about a new App for the i-phone that could lure me back into the 21st century.

Programmer Brett Camper has developed an i-Phone app called ‘Trees Near You’.  The App is based on a street tree inventory for the City of New York and allows users to view maps of over 500,000 street trees.  For each tree users can look up info about individual trees including their size and estimated environmental and economic benefits based on energy savings and storm water retention.   The App also links to Wikipedia pages that provide more info on the tree’s botanical characteristics.  For more info, including a QuickTime movie demo, go to:

While it may be easy to quibble with particular estimates of tree values or a particular bit of info from Wiki, there is no arguing this is pretty cool stuff.  Hopefully other App writers will be inspired and Trees Near You-type Apps will start appearing for other cities.  This is a great educational tool and a great way for urban and community forestry programs to promote the value of trees where we live.

Native vs. introduced species – the discussion continues

I was asked earlier today to comment on the Garden Rant blog regarding the issue of nonnative plants and insect survival, specifically in reference to Dr. Tallamy’s research.  Though I haven’t read his popular book (Bringing Nature Home), I did read one of his most recent papers (DW Tallamy and KJ Shropshire, 2009.  Ranking lepidopteran use of native versus introduced plants, Conservation Biology 23(4): 941-947).  The authors argue that lepidopterans prefer native to alien species for egg laying.  A serious problem I see in this paper is that the authors are literally comparing apples to oranges.  They do not compare effects among species in the same genus (the reasoning is there aren’t enough publications to look at), but among genera.  Thus, they lump at least 179 “alien” woody species into “native” woody genera and compare those to woody genera that are completely alien.  There are only 112 species in the latter.

I would bet that if he separated out these 179 woody species and added them to the alien genera list his findings would be quite different.


So much for my happy summer vacation

It figures.  After I write a happy post I get an email question that brings me back to reality.  I plan on sharing a little more about the question – and my answer – with you later, but I’m going to give you some homework.  Let’s see what you can find out about these topics:

International Ag Labs

High Brix Gardens

Reams’ Biological Theory of Ionization

Hint: they are all interrelated.  Post your comments on the blog and let’s see where we go with the discussion.

Friday quiz…yes it’s coming

As you might know, I’ve been at the NW Flower and Garden Show this past week, and yesterday I had two seminars to give.  So I didn’t have a chance to post a quiz, and this morning I’m back over for a few hours before I’m done.

I’m hoping to find an interesting Garden Prof question topic at the show, so I’m taking the camera today.  If I can’t, I have a backup.  But I promise there will be a question up by today!

Checking up on FreezePruf

As winter continues to hold its icy grip over the middle of the country, our thoughts don’t stray too far from plants and cold.  Recently one of the graduate students in our department, Nick Pershey, brought to my attention a new product called FreezePruf that claims to improve plant cold hardiness by up to 9 degrees F.  Since a couple of degrees of improved cold tolerance can be a big deal (just ask a Florida citrus grower after a 29 deg. F night), nine degrees F. is huge.  At first blush, FreezePruf looks ripe for the Garden Professors’ picking.  The promotional claims are sensational and are followed by the obligatory exclamation points.  “Just spray it on.  It’s like moving your temperature zone 200 miles south!”  So the obvious questions are: What is it? What does it do?  Does it work?

What is it? FreezePruf is a mixture of several fairly common compounds.  These include WiltPruf (a film-forming anti-transpirant), SilWet (a surfactant – helps material spread and stick to leaves), AgSil (potassium silicate), polyethylene glycol (an osmoticum – PEG is widely used in cosmetics and laxatives), and glycerol.

What does it do?  To understand what FreezePruf does it’s helpful to understand how freezing injury occurs in plants and how plants tolerate freezing.  First, remember that water exists in plant tissues between plant cells (extracellular) and within cells (intracellular).  When plants are exposed to freezing temperatures ice forms first between cells (extracellular ice) but not within the cells.   This is due to the fact that water within cells contains solutes that depress the freezing point.  Freeze damage can occur in a couple ways.  One is ice formation within cells (intracellular ice).  Tissues can also be damaged if cells become excessively dehydrated as a result of extracellular ice formation – the ice between cells acts like a salt or osmoticum to continue to draw water of the cell and into the intercellular spaces.  The formulation of FreezePruf apparently acts to depress the freezing point within the cells (due to potassium ions and PEG) and to limit cell dehydration.

Does it work?  At present the only data available on FreezePruf is from the product developers in their patent application.  To date, nothing on the product has been published based on peer-reviewed studies; which always makes the Garden Professors skeptical.  The product development team, however, is lead by Dr. David Francko, a plant biologist and Dean of the Graduate School at the University of Alabama.  Data in the patent application show improved cold hardiness on the order of about 4-5 deg. F for a variety of cold sensitive plants, mostly palms, bananas and annuals.  In some cases the protection was only a couple of degrees but in one case ranged up to 9 deg. F.

What’s the bottom line? For most gardeners the principle benefit of FreezePruf would be to protect plants from the first few early frosts in the fall.  The question is whether you’d rather spray a relatively untested product versus relying on tried and true methods (e.g., bringing container planters in, covering sensitive plants with old bedsheets).  The developers claim FreezePruf can last up to 6 weeks – that could save a lot of dragging bedsheets around the yard.

Caveats: FreezePruf is marketed as ‘Eco-Safe’  – whatever that means – although the MSDS sheets of some of the component products indicate eye and skin irritation are possible.  Until a longer-term database is available I would be cautious of unintended results.   For example, could this stuff make plants more attractive to pets or wildlife?  We’ve seen reduced cold hardiness in conifers using WiltPruf alone, it would be interesting to see some data on Freeze-Pruf on conifers before recommending it for use on those.

Odds ‘n Ends

Some odds and ends today that I either #1 was asked to post or #2 couldn’t resist posting.  First for the picture that I was asked to post.

This, as far as we can tell (we being myself, my technician, and our grounds department), is the American elm tree that was being planted in that picture from 1909 which I posted on January 21.  Dutch elm disease was devastating here in the mid 1900s as it was everywhere, but this region of the world was lucky and there were a number of escapes — and resistant trees (that’s an ongoing project of mine — working with DED resistant elms — I’ll probably post more about it this spring).  Anyway, the tree is a little smaller than I would normally expect for an elm of this age, but the proximity of the road and sidewalk could easily have stunted its growth.

Now for the stuff that I can’t resist posting — mostly having to do with Bert’s post on January 25.  Chad (my technician — if you follow the blog you’ll remember him, 6’4″ — etc.) was showing me a book titled Shade-Trees in Towns and Cites by William Solotaroff published in 1911 and it had this great shot of filling a tree cavity.  So here it is:

The book also had a great shot of what they did to a trees canopy before they planted:

This type of pruning isn’t necessary at all.  When trees are planted they adapt to the amount of roots which they have by producing fewer, or smaller leaves.


Here is a photo of the leaves of a freeman maple which was severely rootpruned right before planting and, below it, the leaves of a similar maple whose roots were left pretty much intact (both plants were container grown).

As you can see, trees have their own methods of dealing with root loss — no need for us to come in and clip their tops off.  Now, two years later, both of these trees (and all of the others in the research plot) look pretty much identical.

The evolution of tree care

I’m one of those people who can’t resist things that are free.  When you pass a yard that has a ‘FREE’ sign on a rusted-out lawn mower or an old piece of exercise equipment and wonder, “Who on earth would take that home?” Uh… that would be me.  Actually, I blame my dad.  The Old Man’s garage was crammed full with outboard motors missing pull-cords, mismatched lawn furniture, and all manner of secondhand tools in varying states of disrepair. So my defect is genetic.  Only my hyper-organized wife prevents my garage from suffering the same fate as my dad’s.  But, like a blind pig finds an acorn, sometimes a scavenger finds something interesting.  Recently a retiring professor in our building was cleaning out his office and put a stack of old books on a table by his door.  And there was the magic word: FREE.  I sifted through the stack and found my treasure; a 1948 edition of Maintenance of Shade and Ornamental Trees by Dr. P.P. Pirone.  Granted, I have ready access to several modern tree care texts plus an ocean of information on the International Society of Arboriculture (ISA) website, but after thumbing through a few pages I knew this one was a keeper.  The main reason the Pirone book interested me was to see how tree care has changed over the years and how things have stayed the same.

What’s changed?
  The most obvious example of how tree care has changed in 60-plus years is that an entire chapter of the 1948 text is devoted to cavity filling.  For those not familiar with the process; cavity filling, as the name implies, is the practice of filling hollow areas in trees with concrete, just as a dentist fills a tooth cavity with amalgam or composite materials.  Filling cavities in trees was once a relatively common practice.  Today we recognize that filling does not stop decay and there is little value in the practice (and it certainly complicates removals).  If anything, we would replace this chapter with ‘hazard tree assessment’, seeking to determine if the tree has enough solid wood to be structurally sound.

Filling a tree cavity.

The finished job

What hasn’t changed?  I was surprised to see a fairly lengthy discussion of problems related to girdling roots from 60 years ago.  This actually causes me to eat a little crow.  I have sometimes questioned whether the current ‘epidemic’ of girdling roots is actually related to the fact that arborists and urban foresters are spending more time looking for them and have better tools (specifically air spades) for finding them.  Of course, Pirone’s text also suggests that girdling roots were an issue before the advent of evil nursery production systems such as container growing.  The discussion of treating girdling roots points out another change in practices.  In 1948 the arborist was advised to carefully dress the wound with paint or tar.  Today we generally advise against treating wounds except for situations which risk certain exposures such as if oak trees must be pruned when they are at risk for infection from oak wilt.

Girdling root removed and wound dressed.

So there you go, another book to clutter my shelf and another example of one man’s trash turning into another man’s treasure.  I think Dad would have been proud.

Science rant coming up later today…

I’ve got a good post for today…but have a seminar to give this morning and the blog has to wait.  If you have time, go onto the web and look for “water drops burn leaves” or something like that.  You’ll find reference to an article in New Phytologist that has the gardening world all a-twitter.  I’ll be dissecting the paper – and the surrounding hype – later today.

Is This Really a Good Idea?

Transgenic plants have been with us for well over a decade now.  I have had the opportunity to work with many of the tools used for this technology, though most of that is far behind me (over 15 years now since I “ran a gel”) — I’m much happier being outside or even in front of a computer writing than in a lab.  Fortunately I have a number of “lab rat” colleagues so I’m relatively up to date on what’s going on and what “gene-jumper” scientists can and can’t do.

To make a long story short, over these years transgenic plants have proven to be useful in some cases (by reducing the use of certain dangerous pesticides), and concerning in others (because some genes have escaped cultivation).  I’m not going to go into the crazy ins and outs of the benefits and drawbacks of genetic engineering here except to give you my general opinion which is that every case needs to be handled individually.  I do not believe that this engineering is, in and of itself, a bad thing.  That said, I do believe that genetic engineering could get us into trouble if we’re not careful.So, with that little disclaimer I thought I’d mention something that I question — I’m not going to call it bad — but maybe it is.  There’s an “artist” at the University of Minnesota — Eduardo Kac, who had some of his genetic material placed into a petunia so that some of the proteins from his body were expressed along with the petunias.  I don’t have a picture of the petunia itself, but here on the St. Paul campus of the University of Minnesota you can see this structure, created by Kac, which is a graphic representation of a protein from the petunia.

(It was around 20 degrees outside when I took this shot — positively balmy compared to what it’s been like).

Anyway — as I said above — Though I have some concerns, I’m not opposed to using biotechnology for the “good of man.”  Nor am I afraid that Kac’s creation is dangerous — from what I know it was kept in a closed system and the petunia was ultimately destroyed — not that it would have been particularly dangerous even if it had been released.  But….to me anyway….This seems like a frivolous use of a powerful tool (that tool being the ability to move genes from one organism to another).  I don’t know if I’d call it bad….but the words Wasteful and Inappropriate come to mind.

By the way, though I know less about it, it seems that Kac also transferred genes into a rabbit for the sake of art.  But this is, after all, a horticulture blog so I thought I’d stick with plants!