Category: What About the Trees

Maybe common sense isn’t so common after all

I noted in my Sept. 22, 2009 post on the threat posed to ash trees in the Midwest by the emerald ash borer (EAB), and included photos of the famous grove of 500 ash trees surrounding the Gateway Arch in St. Louis.  I was in St. Louis that summer for the ASHS meeting and saw that the National Park Service was planting trees from a variety of species around the monument.  I assumed at the time that the Park Service was preparing for the eventual loss of the ashes to EAB.  Boy, did I get a wrong number.

Last week my former grad student, Sara Tanis, alerted me to an article from the St. Louis Post-Dispatch.  The Post-Dispatch reports that with the destruction of the grove of ash trees looming, the National Park Service has contracted with a Los Angeles-based landscape architecture firm to replace the monoculture of ash trees with, I am not making this up, a monoculture of linden trees.  I’ve heard that the definition of insanity is to keep doing the same thing and hoping for a different result.  Apparently the landscape architects that are drawing up these plans have never seen what Japanese beetles do linden trees.  Oh, that’s right; the L.A.’s are in L.A.

 

The article is available on-line if you can stomach it.  http://www.stltoday.com/news/local/metro/article_1e65095d-96ae-507a-acda-574d9f54a73b.html

On the bright side, since this is a Federal project it will likely move forward at glacial speed and will require public input.  Here’s hoping the Park Service gets an earful and common sense will prevail.

So what to plant under power lines?

I’m going to add a bit more to Bert’s discussion.  Through the efforts of Dr. Eric Wiseman of Urban Forestry at Virginia Tech, we have a
Utility Line Arboretum (ULA).  Modeled after Dr. Bonnie Appleton’s original ULA for Virginia at the Hampton Roads research station, Eric’s includes many woody taxa suitable for planting in the vicinity of power lines (see a nice list of Bonnie’s favorite power-line-friendly taxa here).

Eric came to me with his plan in 2006 and we found some space in our Hahn Horticulture Garden to get it going. Funding came through from both the Virginia Department of Forestry and the USDA. He’s now up to 50+ specimens, including a “no-no” tree for a demonstration of relative size. The Urban Forestry Club students maintain the site and Eric uses the ULA for both education and outreach.  Our hort garden visitors are free to wander through the well-labeled display. Interesting story:  obviously, this would be more effective with a faux power line for scale, like Bonnie has at Hampton Roads. Our campus architect said “heck no.” Apparently Virginia Tech has gone to great lengths and expense to get all power lines/utilities below ground.  And the ULA is adjacent to the much-visited baseball field.



That’s Eric on the right, demonstrating proper planting techniques.

Our Horticulture department has a great relationship with Forestry; especially the Urban Forestry section. Their students take our Landscape Establishment and Urban Horticulture courses and we encourage our landscape contracting students to take Arboriculture. Several are minoring in Urban Forestry (or vice-versa). Just thought I’d share a nice success story – one that should make Bert’s maligned arborists happy!

Utility arborists: Give ‘em a break

One of our semi-recurring themes on the Garden Professor’s is our WOW’s or “Why Oh Why’s”.  As in “Why oh why do nurseries continue to sell invasive plants?”  Today, I’d like to turn things around a bit and look at a group of people that are often maligned by the public but, in fact, are getting a bad rap and could use a break; utility arborists.

 


Right tree, right place?

Utility arborists face a nearly impossible and unenviable task.   The goal of every electrical utility is to provide safe, uninterrupted power to their customers.  What do their customers do in return?  Plant large, fast growing trees under powerlines.  This invariably necessitates line-clearance pruning and, in some cases, tree removal.  So who takes the wrath of the neighborhood?  The oblivious homeowner who planted a row of Norway spruces under the lines? Or the trained professional arborist that does the trimming?

 


Betcha can’t top this…

Among the arborists with whom I interact, utility arborists are often the best trained and the most professional.  They have to be.  An amateur pruning around electrical lines suspended 50’ in the air in a bucket lift is virtually guaranteed a Darwin Award nomination.  Arborists can’t even win when they try to do the right thing.  Many utility forestry programs utilize directional pruning as an alternative to topping or removing trees.  When done properly, directional pruning allow trees to coexist with powerlines and enables neighborhoods to continue to benefit from large trees.  A survey by Mike Kuhns at Utah State a few years ago, however, found that homeowners actually preferred the look of a topped tree to a tree that had been directionally pruned.  Granted, directional pruning isn’t always pretty but it’s vastly preferable to topping or removal.

 


The utility arborists I know are dedicated and ‘tree people’ in the best sense.  If they lived in a perfect world, the right tree would always be planted in the right place.  Since it’s not they have to rely on techniques like directional pruning to help ensure safe and uninterrupted power.  So give ‘em a break.

Newsflash: trees will die if their roots can’t establish

I’ve blogged before about the importance of getting tree roots in contact with the landscape soil during transplanting (you can find those posts here, here, here, here, and here). My advice to bareroot woody species upon installation is often ignored in favor of the quick-n-easy methods so often showcased on HGTV (“A complete landscape makeover in a weekend!”). And of course everything looks great…for a while. Let’s see what happens after a few years.

Below are photos of a pine tree, several of which were installed in 2007 at my children’s school (The Bush School in Seattle):

 

Not only is this pine tree planted too deeply (you can’t see the root flare, so it’s too deep), but the twine and burlap were not removed, leaving the roots encased in clay.  Furthermore, we’re not sure how great a root system this tree has since we can’t see it.  Even more horrific, the orange nylon twine is beginning to girdle the trunk.  What’s been planted is a big ball o’ trouble.

I sent these photos and my concerns to the administration and advised them to have the installers (low bid, of course) redo the planting before the one year warranty expired.  My advice was ignored, and here we are three years later:

This particular tree has declined to the point that the foliage is chlorotic and the uppermost needles are dead.  It’s symptomatic of a root system that has failed to establish, which is what I predicted would happen.  But it’s long past the warranty period, so if this tree is replaced the school will have to pay for it…again.  (Though it’s hard to see in this compressed photo, the pine next to this one also has top dieback, and I’ll continue to follow its decline.)

Many professionals, including some of my fellow GPs, disagree with the bare-root approach.  But based on this evidence, how could one argue that bare-rooting would not have been preferable to decline and death?

A lawn alternative we can support: Conifers!

As many of the blog readers are aware, I do a lot of writing about conifers.  In the process I mingle with members of the American Conifer Society or ‘ACS’ for short -although some wag has suggested that ACS actually stands for Addicted Conifer Syndrome, such is the devotion of these enthusiasts for their beloved conifers.  A couple weekends ago I was privileged to attend the first ever ACS ‘Illinois Conifer Rendezvous’ hosted by Rich and Susan Eyre, owners of Foxwillow Pines nursery in Woodstock, IL.  Rich and Susan are a wonderful, enthusiastic couple and conifer addicts of the first degree.  Their nursery boasts one of the largest assemblages of rare and unusual conifers anywhere in the country.  The program for the ‘Conifer rendezvous’ included speakers and tour of the nursery.  The highlight for me, however, was the tour of a couple of local homes featuring outstanding conifer gardens; including the home of Rich’s 92-year-old mother Margaret Eyre.  Margaret is an incredibly energetic woman with a passion for hostas and philanthropy (see the Heifer International link on the Foxwillow Pine website http://www.richsfoxwillowpines.com/).  Margaret decided years ago to dispose of her lawnmower – no small feat since her house sits among homes with vast expanses of lawn typical of the sprawling suburbia that radiates from Chicago.  What to do without a lawnmower? Plant plastic turf?  Margaret had other another idea…

Margaret Eyre’s conifer haven sits like an oasis in the Chicagoland suburban sprawl

I didn’t get an exact count, but I’d estimate Margaret has about 80 to 100 specimens tucked away on a standard-sized city lot.  Most are dwarf or unusual conifers, though several are full sized trees.  No need for a lawn mower here.


Pseudolarix amabilis Golden larch


Abies lasiocarpa Subalpine fir off of Margaret Eyre’s back deck


Mixing forms, textures, and colors provides a study in contrasts

In addition Margaret Eyre’s place we toured the home of John and Margaret Havlis.  The Havlis’ landscape is quite large – a couple acres – and shows what conifers and a little creativity can accomplish.

Conifer border around the Havlis backyard.  Note the winter deer protection for new specimens.

Recurved needles on Abies koreana ‘Silberlocke’


Microbiota decussata Russian cypress.  Conifers in this part of the garden are set of by hardscaping that imitates a dry creek-bed.

Off with their heads!

About a year ago I posted my thoughts about the nursery production practice of heading young trees (“whips”) to stimulate lateral branching or columnar form or whatever.  (You can find this original column here.)  A healthy discussion ensued, much of which revolved around the need for appropriate follow-up pruning to ensure the development of a stable crown structure of headed trees.

Fast forward to last month, where a column I wrote for NPM (Nursery Production and Management) magazine hit the web.  And then the fan.

I made some people very unhappy with this article.  I had a lengthy and productive conversation with one such person last week, during which we agreed on many things, including (1) trees that are headed develop multiple leaders; (2) multiple leaders, however they’re created, need to be thinned to one central leader; and (3) uncontrolled multiple leaders can create hazardous conditions.  The bottom line, from a nursery production perspective, is that headed trees require regular pruning to create and maintain natural, structurally sound crowns.

And here’s my problem:  how many homeowners are going to perform this regular pruning?  Furthermore, how many homeowners KNOW how to perform corrective pruning?  We all know that number is going to be abysmally small.  Even for those situations where competent arborists could do this regular pruning, how many communities budget for this activity?

More troubling for me as a scientist is the lack of peer-reviewed scientific papers on this practice.  Though there are numerous papers documenting the effects of pruning, I can’t find any that specifically look at the long-term effect of heading trees during nursery production. You’ve heard all of us GP’s say it before – unless you can show us the data in a published and peer-reviewed format, we can’t regard anecdotes as anything but.

The nursery industry has invested a lot of time and money in a practice that leads to problems for which no one will claim responsibility.  Production nurseries wash their hands of the issue once the trees leave their facility.  Many retail nurseries don’t perform the necessary follow up pruning while the trees are in their care (do any retail nurseries do this?  Are they aware of the problem?).  Homeowners don’t receive information or training on how or why to perform corrective pruning.

What I’d really like to see the nursery production industry focus on is consumer education.  The metamorphosis of a sapling into a maturing tree is a wondrous thing.  Rather than interfere with the process, we need to cultivate patience as well as a respect for tree physiology.

My Long Suffering Basil

Sometimes I am not such a good garden professor.  That’s because, when I get home, I sometimes (OK — often) don’t give my plants the attention they need.  It’s also because, when we leave for vacation, I often forget to tell whoever is watching the animals to keep their eyes on the plants too.  Now, really, you would think that someone who saw a plant on the back porch in full wilt would think “Hey, Maybe I should water that!”  But still, I blame myself for not spelling it out.

What this all leads to, of course, is that we had a group of really nice basil plants in a container on the back porch which weren’t watered for a week while we were on vacation.  There was little rain over this week, and subsequently the basil was in full wilt for at least 2 days (perhaps as long as three).  We watered these plants soon after we arrived home (my wife loves caprese salad) and the plants perked up a bit, but the leaves were obviously damaged and now our salads will be a little less flat.

It’s not just basil that is affected by an incidence of drought.  Most plants, including trees, will actually suffer for a considerable period of time after the event.  Sometimes growth won’t return to normal for as much as a year or two.  This is a really bad situation if you’re buying trees grown in containers.  If the grower, or retailer, didn’t know what they were doing and let the tree wilt severely prior to selling it to you then buyer beware!

Dying dogwood diagnosis

Lots of good, thoughtful answers from you over the weekend about these trees.  Here’s another photo from a bit farther away:

As Laura pointed out, there’s a relatively new parking lot here.  The creation of the parking lot both compacted the surrounding root zone, then covered it with impermeable surface.  The dogwoods are huddled on their little island, which is unirrigated, unmulched, and indeed hot in the summer as Daniel said.  All of these environmental insults, in addition to the mature age of these trees, have led to what we call a “mortality spiral”:  trees are environmentally stressed and then become more susceptible to opportunistic pests and diseases.  Jon and Wes both did a nice job of discussing this.

There’s a couple of take-home messages here:

1)  If you must disturb a significant portion of an existing tree’s root zone, you should both protect the zone from undue compaction during construction, and then follow up with heavy-duty aftercare of irrigation and mulching.

2)  If you can’t follow point #1, then for heaven’s sake just remove the trees when they start their inevitable failure.  “Lingering death” is not an attractive landscape theme.

Why bother having trees?

Sorry to be late with my post this week – I was away reviewing grant proposals.  It was interesting and useful work, but really drains your brain.  So with that being said, my post is long on pictures and short on words.

One of the things that bugs us GP types is poor plant placement.  Why bother planting a tree if you’re not going to allow it to grow naturally?  Here are some photos to mull over the weekend.  While I have lots of bad pruning pictures, these ones are chosen specifically because the trees were obviously poor choices for either site usage or size.

Because my sense of humor seems to have been left at the grant reviewing venue, I can’t think of amusing captions for these pictures.  But I’ll bet you can!  Just submit them in the comments sections, and I’ll repost the photos later next week with your contributions.

Photo #1

Photo #2

Photo #3

Photo #4

Photo #5