Bert Cregg

Closing the loop

Just a short post today as I am participating in an Extension planning meeting for most of the day. One up-side to the meeting is we are meeting and having lunch at Brody Dining hall here at MSU. If you’re around my age and attended college in the 80’s, the thought of eating at a dormitory dining hall might elicit memories of a hair-netted cafeteria lady glopping amorphous slop on your tray next to the mystery meat of the day. Boy, how times have changed. Today, the quality of dining hall food is point of competition for universities angling for students. The Brody dining center is set up like a food court, daily choices for students include a fresh salad bar, southwest food, sushi, made to order pizza, home-style comfort food, even kosher food.

The dining halls are also part of MSU’s sustainability initiative. Food wastes from the dining halls are collected and sent to an anaerobic digester and composted at the MSU Student Organic Farm. The compost is used at the recently completed Bailey hoop-houses on campus to produce salad green and herbs for use in the dining halls, providing a closed-loop system. Is the food produced in the hoop-houses going to make the dining halls completely self-sufficient? Probably not in the foreseeable future. But they do provide a good opportunity to promote horticulture. The project has generated numerous press articles and there are posters around the dining hall highlighting the project. In an age when many bemoan the public’s disconnect between farm and fork, the Bailey GREENhouses remind students, especially those that might not think about it otherwise, where their food comes from.

Does fertilization increase insect herbivores?

Always fun when you find a research paper that confirms what you’ve suspected all along. I ran across a paper last week in the Annals of Applied Biology entitled ‘Fertilisers and insect herbivores: a meta-analysis’ (Butler et al. 2012. Ann Appl Biol 161: 223–233). I’m interested in the topic because in recent years a dogma has emerged that if you fertilize a landscape tree it will be immediately devoured by insects. In this study the authors conducted a meta-analysis (basically a compilation of studies on a given topic and then combining and analyzing the aggregated results) and looked at dozens of studies of the response of insect herbivores to fertilization to answer the question, does fertilization increase insect damage? The answer was absolutely no surprise to me: It depends.

What does it depend on? First, what type of insect. Secondly, what kind of fertilizer. For example, fertilizing with nitrogen greatly increases populations of sucking insects. This makes sense when you stop to think that aphids and other sucking insects have to consume a lot of phloem sap –which is essentially sugar water – in order to get sufficient nutrients. Nitrogen fertilization did not significantly increase populations of chewing insects, however. This could be related to off-setting effects of improved nutritional quality of leaves versus increased presence of defense compounds or leaf toughness. For other fertilizer elements Butler et al. found that phosphorus decreased insect populations in 2/3^rd of the studies (14 out of 21) and that potassium decreased insects in 7 out of 10 cases. As with nitrogen only, complete fertilizers (NPK) tended to increase insect populations, especially for sucking insects.

I should hasten to point out some limitations of the study as it relates to tree fertilization. First, of course, is the British spelling of fertilizer. Second, the study mainly dealt with fertilization in agronomic crops, not trees. Lastly, the authors only included studies on insect adults. In many cases insect larvae, not adults, are the most damaging life stage, especially for insects that affect trees. Nevertheless, the study highlights the difficulty of making generalizations when discussing host stress and insect interactions. In addition to type of insect and type of fertilizer, we could have added nutritional status of the plant before fertilization to the ‘It depends’ list. My rule of thumb is that trees shouldn’t be fertilized unless a problems is noted by visible symptoms, a soil test, and/or a foliar test – and preferably by more than one of these.

Bottom line: Before you buy into the notion that fertilizing a tree is going to increase insect problems make sure you know what type of pest you’re dealing with, what type of fertilizer and the current nutrient status of the tree.

Why oh Why? Christmas tree edition

Hope everyone has had a chance to digest their Thanksgiving meal and is spending a productive day at work shopping on-line. My daughter and I enjoyed one of our Holiday traditions this weekend and brought home a Christmas tree from a local choose-and-cut farm. This was followed by another tradition at our house known as the “Annual cursing of the Christmas lights.” Seems like no matter how careful I am when I put away the lights when we take down the tree, they are always a mangled mess the next year.

Christmastime is also time for another ‘Why oh why?’ As in, why do people make such a big deal out of watering their tree? Working in Extension with Christmas trees, I’m glad that we’ve gotten the word out and people are concerned with keeping their tree watered. But is it really that hard to put water in the stand? I use a watering can with a long stem and it seems to work fine. Let’s look at some of the devices people have come up with water Christmas trees. I’ve rated each on scale of 0 to 4 watering cans.

The tree IV. I’ve mentioned this one on the blog before. The theory here is that the tree will suck up water from a reservoir you attach to the trunk. Trunk injection is possible with conifers but requires pressure and resin quickly fills the hole. 0 cans.

The watering cane. OK, maybe you’ve got back problems and bending over with a regular watering can could be an issue. 4 cans.

Water funnel system. I’m not sure the video convinced me this is faster and easier than the watering can. 2 cans.

Water reservoir cleverly disguised as a package. Assuming the issue is you don’t like to bend over and put water in the stand, I don’t see where bending over to put water in a fake package is a big improvement. And what happens if you forget which package is which? 2 cans.

Funnel cleverly disguised as an ornament. Gets around the bending over issue, but can you really hide the tubing? 3 cans.

Christmas Vacation anti-transpirant. According to the advertisement you can put this stuff in the first time you water the tree and then you are good to go for the next month. The same product is sold as ‘Stasis’ and is used to protect bedding plants from wilting during shipping. The theory is that the product induces stomatal closure by increasing abscisic acid levels. I’m withholding judgment on this one until I see some data one way or the other, but to say I’m dubious is an understatement.

Keeping a Christmas tree hydrated is like most things; you can’t go wrong with the tried and true. A fresh tree that is kept well-watered will retain needles for weeks and is very unlikely to be involved in a tree fire. A tree this is allowed to dry, on other hand, is another story. So before depending on a gimmick to keep your tree watered ask yourself if you’re willing to bet your house on it.

What would YOU do?

Once in a while we end up flicking around the dial on Friday evenings and land on a show called “What would you do?” It’s a hidden camera-type set up where viewers get to see the reaction of everyday folks faced with awkward or contentious situations like an overbearing customer berating a waitress over a minor mistake in their bill. The scenarios are played out by actors but the people responding are not. Personally I find the premise of the show slightly annoying because it smacks of entrapment but it seems to lure in the rest of my family.

Today we’ll do our own version of “What would you do?” In this case, however, the situation is real. Here’s the deal. Michigan State University has begun work to complete the Facility for Rare Isotope Beams or FRIB across the street from the Horticulture building. This $615 million dollar project will enable physicists to study rare nucleotides, the kind of elements that only exist for fractions of seconds. It’s definitely big science stuff and can lead to all kinds of exciting discoveries. In looking at some of the plans for the FRIB, however, some of my colleagues discovered that the FRIB completion will require removal of several large mature oak trees that close to 100 years old. The initial effort to save the oaks focused on re-locating the portion of the FRIB that conflicted: No dice. The next option was to move the oaks. Due to various factors, only one tree, a bur oak about 3 feet in diameter, can be moved. The price tag: approx. $150,000. The move date is currently set for Dec. 10. Now another option has surfaced: remove the mature oak and use the $150k to plant new trees around campus. Our landscape services typically plants 2” caliper shade trees and 6’-7’ conifers so we’re probably talking 400-500 trees. I am part of a group that will try to hash things out on Wednesday.

So, what would YOU do? Save one large mature tree or plant 400+ new?

Here’s a look at the oaks through the years…

Today. Oaks trees are located in median in center of the image.

1980 during construction of the Wharton Center for Performing Arts

1965

1955

Finding agreeable things not sought for

As a graduate student at the University of Georgia many years ago I took a course in research methods. One of the discussions that stuck in my mind all these years centered on the word ‘Serendipity’. The classic definition of the word is “the faculty or phenomenon of finding valuable or agreeable things not sought for.” As scientists we rely heavily on the scientific method as a systematic method of inquiry to make new discoveries. But we also need to need to keep our eyes and minds open to serendipitous discoveries along the way as well.

So what got me thinking about serendipity? A few weeks back I visited a Christmas tree grower in northern Michigan with Jill O’Donnell our state-wide Christmas tree educator. The grower called us in because he had some questions about some unusual trees in one of his Fraser fir plantations. And, not only were the trees unusual, they were gorgeous. The only question was; what were they? The plantation originated from seed the grower had collected himself from some older Fraser fir trees he kept as a seed orchard. He sent the seed to a large forest nursery in the Northwest, which grew the seedlings and sent them back to him. The grower wondered if seed of another species could have been introduced in the process. Possible, I told him, but not very likely. Nurseries that are serious about contract growing are meticulous in keeping seed lots separate – few things are worse in that business than sending the wrong seedlings. Plus, I’ve worked with many species of fir and this was one I didn’t recognize. The trees had many characteristics of Fraser fir but also had attributes of concolor fir; long bluish needles and a slight hint of citrus scent when the needles were crushed. Many fir species can hybridize and all I could think was these trees had to be hybrids. “Are there any mature concolor firs near the seed orchard?” I asked. The grower brightened, “Actually there’s a group of older concolors about a half mile up the hill from the Fraser fir orchard.” We jumped in his pick-up and visited the concolor firs. Many of the trees had cone stalks indicating they were reproductively mature and could produce pollen. Conifer pollen can travel for miles so it’s reasonable to expect that some of the concolor pollen could reach the Fraser firs, which were downhill and downwind based on the prevailing winds in the area.

Excellent tree form of the mysterious hybrids

So what’s next? There are several reasons to follow up on this serendipitous discovery and try to make some additional crosses. First, as evidenced by the photos, the trees look fantastic. Second, Fraser fir and concolor fir are each great trees but they also have some liabilities. A downside of concolor is that they break bud early and often suffer late frost damage – Fraser’s break bud late. Fraser fir need acidic, well drained soils – concolor fir can grower on a broader range of sites. It’s possible that the hybrids will have intermediate characteristics that would make them ‘the best of both worlds’.

Foliage close up

The only thing left is to decide what to call the hybrids. Nurseries like to combine common names. So, Craser fir? Froncolor?

A different kind of storm chaser

As an Extensional Specialist working on urban and community forestry issues, I am frequently asked to respond to questions about tree damage after storms. One standard bit of advice I give is to be wary of ‘door knockers’ or ‘storm chasers’; individuals that descend like locusts upon storm-ravaged areas with pick-up trucks and chainsaws offering to clean up storm damage. Sometimes these are just honest folks trying make a buck but there are also less scrupulous folks in the mix that are clearly exploiting the misfortune of others. In either event, they usually lack the training, not to mention insurance, to tackle the dangerous chore of removing downed trees around homes, cars, and people.

In trolling the internet the other day for photos for Monday’s post, I ran across a different kind of storm chaser. It seems the internet has gone viral with photos of Brazilian glamour model, Nana Gouvea, who was photographed by her boyfriend in various settings among the devastation of Superstorm Sandy. The photos were posted on (and subsequently removed from) from FaceBook. Needless to say, many people were offended and have taken the model and her boyfriend to task for the photos and a FaceBook site has popped up with Photoshopped images of the comely model amidst other disasters from the killing of Bambi’s mother to Noah’s flood.

Personally, I think the public needs to cut Ms. Gouvea some slack. This intrepid beauty has captured a teachable moment and performed a great public service for extension personnel everywhere. I can see future hazard tree assessments talks and bulletins enlivened with her images. Well, here, let me show some examples.

Note the upturned in roots in the upper left. Poor root anchorage is a common cause of tree failures during storms.

Trees breaking at ground-line (far left) during high winds is often the result of girdling roots.

Trees snapping at mid-stem is often the result of a subtle defect. Note the evidence of frost cracking below this breakpoint.

Superstorm Sandy aftermath: A modest proposal

Initial estimates from insurers indicate that Superstorm Sandy may be the second costliest storm in US history. A large portion of the damage attributable to Sandy and several of the deaths associated with the storm were due to falling trees. In many cases the winds were severe enough to topple healthy trees, but I’m sure many GP blog readers share my frustration in looking at storm-related tree damage photos and seeing obvious defects that a professional arborist would have readily spotted.

This brings me to a modest proposal: I propose insurance companies provide discounts for homeowners to have a hazard evaluation of trees on their property. I did a quick search on the major insurance companies and they currently offer homeowners discounts of up to 15% for, among other things:

Smoke alarms

Burglar alarms

Fire extinguishers

Security systems

Roofing materials

Sprinkler systems

The rational is self-evident; the cost of the discounts is more than off-set by damage and subsequent claims that are prevented. How much of a discount should homeowners get for a hazard assessment? I dunno, but I’m sure there are actuaries somewhere that could figure out cost-benefit breakdown of identifying hazards and removing them on a calm, clear day versus waiting until they come down in a major storm and destroy a car or a house or worse.

It’s the bomb!

Between Hurricane Sandy and the inglorious end of the Tigers’ season, the news today has been pretty depressing here. So I figured I’d stay with something light today and talk about a bombing incident that occurred on campus last Friday. In case you’re wondering how a bombing on a major university campus can be considered a light event, I need to point out that this was a Yarn Bombing incident. Yarn Bombing (also referred to as Yarnstorming or guerrilla knitting) is type of street art – in this case garden art – where trees and other objects are covered with colorful yarn. What’s the point? I don’t know; does art have to have a point? Anyway, to add a little whimsy to your day, here are some photos from this weekend’s Yarn Bombing at the MSU Gardens.

For more photos go to the MSU Gardens website

A guest blogger (sort of)

One of the best things about my job is I get to work around bright, enthusiastic young people everyday. And not just students here at MSU. Through conferences, meetings and other contacts I get to interact with students at other universities as well. Over the last couple of years I have had a chance to sit in on a couple talks by Alison Stoven O’Connor, who is an Extension Agent and Ph.D. student under the direction of Jim Klett and Tony Koski in Horticulture and Landscape Archetiecture at Colorado State University (and you thought you were busy!). For her Ph.D. research Alison is working on a subject near and dear to the hearts of the Garden Professors; nursery production and tree root development. After I saw her talk at the ASHS meeting this summer I invited Alison to take slot as a guest blogger but she declined, citing her time constraints – we’ll call it an excused absence. She did, however, graciously share some photos from her trial which, as you’ll see, pretty much speak for themselves.

A brief run-down on Alison’s study. She grew Chanticleer pear trees in #15 containers, including both standard black plastic containers and Smart Pot fabric containers in summer 2010. After growing the trees in the nursery for the summer, she transplanted the trees into a landscape-type planting in the fall of 2010. Last week (remember you come to the Garden Professors to get the latest!) she began sampling the roots of a subset of her trees with the aid of a local landscape company with an air spade. The depth of rooting appears to be consistent regardless of the type of container the tree was grown in. Width of the root system; that’s another story… While Alison has a ways to go in gathering and analyzing data, the photographic evidence looks pretty good for the Smart pots over the status quo.

Trees in nursery production.

Trees in the ‘Landscape’ after transplanting,

Air spading to harvest roots

Root systems two years after planting in the landscape. Left – tree grown in conventional black plastic pot. Right – tree grown in Smart Pot. 630 miles between East Lansing and Minneapolis and I can already hear Jeff gloating, “Neener, neener, neener…”

SoMeDedTrees update

Things have settled down briefly here and I have had a chance to summarize some of the data from the container tree transplanting experiment we installed earlier this year. For those that aren’t familiar we installed two tests this summer using 96 ‘Bloodgood’ plane trees grown in 25 gallon containers that were leftover when we completed an earlier trial in our Pot-in-Pot nursery. I decided to use this as an opportunity to look at some tree transplanting recommendations. With input of our GP blog readers, we installed two tests. In both tests we applied three treatments to the tree root-balls before planting (‘shaving’ the outer roots to eliminate girdling roots; ‘teasing’ apart the rootball to eliminate girdling roots, and a control or ‘pop and drop’ to use Linda’s nomenclature). At one site we fertilized half the trees at planting and left the others unfertilized. At the second site we mulched half the trees with 3” of ground pine bark and left the others unmulched.

On the fertilizer trial we have not seen anything remarkable. We conducted measurements of leaf chlorophyll content using a SPAD meter (a device that measures light transmittance through leaves) but did not see an effect of either fertilizer or root ball treatments. This is not completely surprising. In the nursery trial we fertilized the trees at standard production levels, so their nutrient status was pretty good at the outset. What will be interesting is to see if either treatment at planting has a longer term impact.

In the mulch study we have seen some more immediate impacts. We measured soil moisture to 15 cm (6”) and 45 cm (18”) inside the rootball and just outside the rootball periodically during the summer. Soil moisture levels were consistently higher for the mulched trees that for the trees that were not mulched (Fig. 1), especially at the shallow (15 cm) depth.

Figure 1. Soil moisture of trees with and without mulch in the SoMeDedTrees study, summer 2012. (Sigmaplot wizardry by Dana Ellison)

This was reflected in tree moisture stress levels during August. We measured predawn water potential with a pressure chamber. Using a pressure chamber enables us to estimate the level of tension with which water is being held inside a tree. We remove a leaf from the tree and put it in a chamber with the cut end sticking out. We gradually increase the pressure in the chamber until we see water appear on the cut end. The more stress the tree is under the more pressure we have to apply to get water back out. In this case, mulching, by virtue of the fact it increased soil moisture, resulted in lower water potential values, indicating less stress (fig. 2). The root ball manipulation treatments, on the other hand, did not affect tree stress.

Figure 2. Mean pre-dawn water potential (in -MPa) of plane trees in the SoMeDedTrees study, August 2012.

So where does that leave us? Well, as we’ve noted all along, this is long-term trial. The plan is to track the trees over 3-5 years and maybe longer. But long-term responses are the cumulative results of series of shorter-term effects. So far, mulching appears to be the only factor that has made a difference but we are still early in the game.