Tag: woody

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.

Big Trees for Crime Reduction

Like Linda, I believe that we don’t plant enough bare-root trees.  Trees that are harvested and sold bare root tend to establish better and recover faster from transplant shock than trees sold in containers or as B&B (balled and burlapped) stock.  But, in general, trees that are purchased in as bare-root stock are smaller than the other two styles, with B&B generally being the production method which yields the largest trees.

I disagree with Linda that, as a general rule, B&B stock should have its roots washed off prior to transplanting — I’ve done it and I’ve lost trees.  Most of the B&B trees that I know of where root washing has been successful have been small, relatively easily transplanted stock.  Once we have a few nice, big, long term studies that shows that B&B trees with their roots washed perform comparably to, or better than, normal B&B trees I’ll start to believe.  (I will note that, as a rule, it looks like B&B stock is dug and cared for much better here in Minnesota than Washington!)

I’m not going to go into the nuances of the arguments here — we’ve done it before if you want to check the archives.  But what I am going to point out is that a new study in Oregon has shown that bigger trees might help to deter crime.  Yet another reason for the people of this country to demand larger stock.

Despite what all of the research shows (that it’s better to plant smaller trees — preferably bare-root) people want big trees — they want an instant landscape.  They want it because to them it looks nice — and now its a way to protect your family too.

Historically this big stock comes B&B and is very expensive, cumbersome, and not the easiest things to successfully plant.  We need a new, cheaper way to grow large stock.  A number of researchers are working on different methods to produce large stock (special containers, bare root from a gravel bed) but nothing has worked out perfectly yet.  It’s going to be interesting to see how all of this shakes out in the future — especially with the loss of ash trees in the Midwest.

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.

When history and good stewardship collide

One of my colleagues emailed me a couple of pictures last week taken in Puyallup, WA.  As you can see, there’s a trellis supporting a massive old trunk…

…and crown…

of an ancient Hedera helix ‘Baltica,’ a cultivar of English ivy.

For those of you not in Washington or Oregon state, English ivy is a designated noxious weed.  Thousands of dollars and hours of labor are spent on removing this species from forested areas in Washington state, where it crowds out native species and increases tree failure simply through the weight of vegetation.  It is not a well-mannered ornamental in our climate.

So why, you may ask, is this particular English ivy prominently displayed and obviously cultivated?  Chris Pfeiffer (my colleague) found out that it had been planted by Mrs. Ezra Meeker, wife of the founder of Puyallup, over 140 years ago at their original homestead.  It is part of Puyallup’s cultural history and is considered a heritage “tree.”

But as you can see in the second photograph, the ivy is in flower and presumably will set seeds, thus contributing to the invasive problem.  I don’t know enough about the City’s management plan for this specimen, but I doubt it includes removal of the flowers before seed set.

So what should communities do in situations like this?  I think the city needs to remove the flowers, though this would be a labor intensive activity.  But it would only take one person a few hours to hand prune the flowers.

I’ll be curious to hear what you all think, and whether you have seen similar collisions between historical significance and appropriate plant choices.

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.

How to Kill Buckthorn

Last year we completed a small research study on how to kill buckthorn.  If you live in the upper Midwest then you’re familiar with this plant as a shrub which has escaped cultivation, been spread by birds, and generally made a nuisance of itself, particularly at the edges of forested land.

Buckthorn is notoriously difficult to kill after it gets more than about a foot high.  It laughs at single applications of roundup. If it’s pulled out of the ground any roots that don’t come with it have a good chance of sprouting shoots themselves, and it seems to enjoy being treated with organic herbicides like vinegar.  So, to try and kill bucktorn, we used an herbicide which had the active ingredient triclopyr.  This is an active ingredient which is usually great against all manner of weedy vines like poison ivy.  This herbicide is labeled for homeowner use and is available in most garden centers.

We applied this herbicide to buckthorn in the spring, summer and fall, and we used a few different application methods including painting the herbicide onto cut stumps and spraying it onto the leaves of uncut bushes, as well as painting the product onto the lower portion of stems.  Some of these application methods were experimental.  Do not attempt to apply an herbicide in any way besides that which is listed on the label!

That said, we found that the fall was by far the best time to apply the herbicide and that spraying the foliage wasn’t nearly as effective as other application methods, particularly painting the cut stem with the product after cutting it down.

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.