Tre e C a re A d v i s o r N ew s l e t t e r http:// www.mntca.org Inside This Issue: “Kings Broad-arrow Tree” Dave Hanson
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Quick Hits /
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Volunteer Opps White Pine Blister Rust
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Barb Kirkpatrick Putting Down Roots Cliff Johnson
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Arboricultural Myth:
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Summer time! Things are certainly happening in the world of trees - we have bugs, storms and fungi eating States. Yes, back in 1992 it was reported that the largest organism in the world was eating Michigan (an Armillaria fungus in the family Basidiomycetes) and Cliff is telling us about one of its other attributes, foxfire. Several record breakers showed up in 1992, first was the Armillaria bulbosa covering an estimated 15 hectares in Michigan, about 9.7 metric tons and estimated at 1500 yrs old, then an Armillaria ostoyae organism in Washington State checked in at an estimated 600 hectares (6 square kilometers). But, hang on, along came an aspen clone (Populus tremuloides) in southern Utah with an estimated 47,000 individual stems covering 50 hectares and with an estimated weight of 5,000 metric tons above ground. I suppose I’ll have to go on the road to get pictures for a future issue, Ok Gary?
Ian McKiel A Thank You!
Volume 10 Number 3
Dave Hanson and Gary Johnson, Managing Editors
The King's “Broad-arrow” Trees
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with the “Kings BroadArrow” as property of BritResearch: A top 10 list 8 We’ve all heard of the ain. One can understand Gary Johnson American Revolution and why the early American pioContacts 12 some of the trigger events neers, shipbuilders and other like that little Tea Party in craftsmen were more than a the Boston Harbor. ConLumber from these trees little irritated. Donald spiracy theorists and speculators might wonder, “Was it was very light, yet extremely Peattie in his book A Natural strong. The wood was very History of Trees points out all about tea and taxation?” easy for a carpenter or wood that “Swamp Law” was exerThey would be giddy to cised by many of the pioknow that - there was more worker to work with and due to its characteristics and neers. Many fine pines were to the story; in fact a tree species had a part in stirring slow growth it was very re- cut illegally, the “Kings Broad Arrow” mark was oblitersistant to rot. up the American pioneers ated and the wood was put against the British Royals. The early American pioto use. North America was home neers had this timber on This species and its lumtheir properties, within their to the finest pine tree the ber truly shaped early AmerEuropeans had ever laid eyes grasp, yet they were not to “King’s Broad-arrow” ica. Houses, businesses, touch it. All of the lands on and it was so plentiful bridges and countless other that early explorers (timber were “Crown Lands” and structures and day-to-day hunters) referred to the ex- singled out on these lands was a species of pine marked utility tensive stands as “veins”. Continued page 10 items Dave Hanson
Dave Hanson
Unbelievable trees 150 to 240 feet tall and trunks free of branches to heights of 80 feet or more were plentiful. Almost all lumber species today pale in comparison.
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Quick Hits Got Storm Damage While I was enjoying a wet week in the BWCAW, Gary and assorted others were out collecting storm damage data and photos In the Richfield / Edina area. Some of the photos and related information can be seen on the U of M Forestry Extension web site at the address below: ( http://www.cnr.umn.edu/FR/extension/gotstormdamage.html )
Photos from the June 25th, 2003 storm event.
Research Update: Management of White Pine Blister Rust Barb Kirkpatrick
Branch flagging and dieback associated with white pine blister rust.
Yellow aeciospores (fruiting bodies) on bark of white pine.
Asia, subsequently established itself in Europe in the Ramsey County TCA th Have you ever wondered 18 century, and then was introduced to North Amerwhy one pine flourishes in ica circa 1906. It is believed the midst of a stand of diseased pines of the same spe- that the fungus first arrived cies? Does the pine that es- in New York from Germany on nursery grown white pine caped disease have an ‘inherited’ genetic resistance seedlings. This is the strain or are there other reasons it of C. ribicola that exists in Minnesota today. A second seems unaffected? Dr. strain of C. ribicola was introRobert Blanchette, Univerduced to Vancouver Island, sity of MN, Department of Plant Pathology, is conduct- British Columbia around 1920. During the early ing research into this phenomenon. Specifically, what 1900’s white pine was extensively logged as a premium makes some eastern white timber species. By the 1950s pines more resistant than WPBR had spread to most of others to infection by the the commercial white pine fungus Cronartium ribicola? regions in North America. Cronartium ribicola is the Recently a third strain of C. causal agent of white pine ribicola has been identified in blister rust (WPBR) This the Southeastern United causal agent originated in
States. To best manage a disease, one must understand it’s life cycle. WPBR is a fungal disease with a rather complicated life cycle. This disease cannot spread from pine to pine, but rather requires an alternate host (Ribes spp.) to complete the disease cycle. There are 5 spore stages to WPBR: two (pycniospores and aeciospores) occur on pine, and the remaining three (urediospores, teliospores, and basidiospores) occur on the alternate hosts, currant and gooseberry (Ribes spp.) bushes. For many years it was thought that eradicating the cultivated European black currant (Ribes nigrum) would eliminate this disease. After Continued on page 11
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Putting Down Roots Cliff Johnson
wisp, faerie fire or honey
from rapidly growing and
Carver County TCA
fungus.
healthy fungal cells
Carver and Scott County Master Gardener
Each of the names re-
(rhizomorphs) consuming
fers to a soft glow or light wood. coming from leaf-covered
Around 40 species of
Research uncovers answer ground or dead wood. Lu- fungi and certain bacteria to stumps that glow in the minous wood, most com- are capable of carrying out dark The question was one of the more unusual I’ve been asked in 11 years of fielding horticultural phone calls: “Can you explain why the stumps in my backyard glow at night when I walk out to put a trash bag in the garbage?”
monly called foxfire, has
chemical reactions that
been known for centuries
give out light, sometimes
among people living near
causing the wood or
forests. Foxfire is a curios- leaves they attack to beity, an educational toy for
come luminous. One of
children, and part of folk
the most common species
tales and cultural myths
growing on rotten stumps
concerning elves, ghosts,
capable of luminescence is
and supernatural “cold”
honey fungus (Armillaria
Rhizomorphs or shoe strings of
fires. Mark Twain makes
mellea).
armillaria species. Look under
reference to it in Adven-
My first impulse was to tures of Huckleberry Finn. ask whether the caller had What causes a stump been hitting the gin a little to glow in the dark? Is it too heavily before bedfungal, algal or extraterrestime. trial? Fortunately, I went Despite all the rowith my second impulse, mance and myth surwhich was to explain that I rounding foxfire, its couldn’t explain the phesource is fungi rotting nomenon but I would find wood, explains Kim out and call him back. Coder, a forestry profesA little internet search- sor at the University of ing led to a fascinating dis- Georgia. The most comcussion of -- and you mon luminous fungi in a may know it by any one of forest is a tree root rot these names -- biolumines- and wood decayer. The cence, foxfire, will-o’-the-
glow of foxfire comes
The technical name for foxfire is bioluminescence
the bark of dead and dying trees and you may find these structures.
-- the emission of light from living things (i.e., fungus). Bioluminescence is produced by the sudden decay of a high-energy molecule to a lower energy form. One way to understand bioluminescence, Codor says, is by comparison to photosynthesis. Bioluminescence is the reverse of photosynthesis. In photosynthesis, a living organism captures light and carbon dioxide to make organic materials
Douglas fir trunk rotting on the forest floor
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and release oxygen. In bioluminescence, light and
3.
carbon dioxide are released by breaking apart organic materials using oxygen. Nature provides instances of bioluminescence in other creatures, including bacteria, animals,
4.
original magic wands.
NWFG monthly meeting
Soldiers in WWI put pieces of decaying wood on their helmets; the glow helped them avoid comrades in nighttime trenches.
consists of? Setting out to see foxfire can be difficult, especially where there is light pollution. Coder says that
In WWII fire wardens covered timber stacks to foxfire is a very lowprevent enemy aircraft energy light. He suggests spotting them.
picking overcast or
Honey fungus is the
moonless nights without woodlands’ hyenas, jackals fish and insects, including surrounding artificial lights. fireflies. Some mystery re- and vultures rolled into Your eyes will need to be mains attached to foxfire, one. It is a scavenger. It fully dark-adjusted for 20however, since researchHoney mushrooms - the fruiting structure of Armillaria species. The mushrooms appear in late summer or early autumn confirming the presence of armillaria.
glow. I found an interesting website (http:// honeyfungus.htm) for a
ment of Agriculture, Forest Service. Source: Forest Insect and Disease Leaflet number 78, Armillaria Root Disease.
insects can digest. With-
than starlight. Forget flash-
out honey fungus the sur-
lights, fires, candles, watch
face of the world would be lights, or other light piled high with the corpses sources. Passive photoof dead trees.
multiplier binoculars (night
in northern England. A
The greatest interest in scopes) can be helpful. Finally, Coder suggests, befoxfire and honey fungus
page of their website is
appears to be in the UK. I
stump-removal company
tesy of the Unite States Depart-
30 minutes. Leave flash-
ers are unable to ascertain whether it wants it or not. lights off and get away any survival advantage for It reduces the lignum and from any other types of fungi emitting this strange cellulose to glucose, which light reflectance other
www.stumps.biz/
All photos for this article cour-
cleans up woodland
ware the other denizens
devoted to honey fungus
even discovered a website of the nighttime forest.
and offers the following
by an organization called
facts:
the North West Fungus
Given all the interest in
foxfire, perhaps I should Group. NWFG was estab- suggest to the Scott 1. Aristotle noted honey lished in 1994 as a regional County caller that he fungus 2000 years ago. charge admission for 2. In medieval times people umbrella group to prolit hay barns with clusters of rhizomorphs, and roots covered with rhizomorphs were considered to have medical power. These were the
mote an interest in fungi in guided tours of his lumithe Northwest of England nescent backyard stumps. and Wales, UK. What do you suppose a typical
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Arboricultural Myth:Tree Fertilization Will Fix any Malady published paper on trees Horticulture Student, from the University of University of Minnesota Wisconsin Extension Most people think states, “If leaves are light of tree fertilization as food green or yellow-green, for trees. It provides nu- you’ll need to fertilize. trients the plant needs for Fertilizer is probably also fast growth, greener needed if trees and shrubs leaves, and a longer life show short annual twig span. Putting a tree on a growth, excessive dead regular diet of nitrogen wood, or sparse foliand other essential nutri- age.”(Hasselkus) When ents is equated to making reliable sources swear by sure a child gets healthy it, how can this practice be meals. Whether or not wrong? this is the case, it does Unfortunately, it is. seem to be the public perA tree is a system in which ception. So, why is it then nutrients provided by ferthat at the first sign of a tilizer are only a part of problem, a wilted leaf or the total function. Chlodead branch, the immedirosis or yellowing of the ate response is to fertilize? leaves, heavy dieback, and Would it make sense to stunted growth are all give a child with a broken signs of a tree going arm a cupcake and expect through stress. To fertileverything to be fine? ize in response to sympThis perception of toms like these is not only fertilizer as a catchall rem- ignoring the actual cause edy for trees is wideof the stress, but also has spread, and the green in- the potential to add stress dustry does little to to the tree. change it. Many media There are many gardening “experts” have factors that can cause been heard to say that the stress to a tree, and many first thing to be done different visible symptoms when there is any sign of a to that stress. Putting plant problem is to blanket aside the fact that what is on the fertilizer. Even a the “normal” appearance Ian McKiel,
of any given species is highly variable, there are several common abnormal traits that indicate stress. Chlorosis, or yellowing of the leaves, can signify a lack of nutrients, as can stunted annual growth or dieback in the canopy. However, assuming fertilization is the remedy to any of these symptoms without further investigation risks not only the tree’s further decline, but the possibility of accelerating the process. Consider for example, a Littleleaf Linden (Tilia cordata) planted in a boulevard showing significantly reduced stem growth over the past two years, and some dead branches within the canopy. An application of a general fertilizer could be detrimental once it was discovered that a new sidewalk and curbs were constructed shortly before the tree began showing signs of stress. “Fertilizer, especially nitrogen, causes the tree to grow more leaves faster. The energy that should be used for defense is redirected to growth.
Pinus strobus: White Pine - Twisted needles. - Off color? Is this herbicide damage? Is this a nutrient deficiency? Not at all - remember the number one diagnostic rule: - Properly identify the host and its characteristics! Host is: Pinus strobus ‘Contorta’
Quercus alba leaf pair - Leaf on the left has definite inter-veinal chlorosis. Will Fertilizer help?
Not likely - This tree is the source of the leaves above. The chlorosis is not consistent throughout the tree. There is more going on here than a nutrient issue.
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Fertilizer continued An overfertilized tree may be susceptible to disease and is in danger of using up all of its remaining energy reserves” (Van Ells). In this case, fertilization may now put the tree under greater stress, and could lead it downward in the spiral to becoming strained, and subsequently firewood.
Information from a reliable source - these lindens are approximately the same age. Note the obvious disparity in height, dbh, and crown. One could surmise that fertilizer is required - the real problem occurred at planting time. This is a planting depth problem.
Leaves of a Pin Oak exhibiting chlorosis - this is typically a high pH problem and there are remedies, but it is not a one time solution.
In the above example, visual inspection of the tree was the method of determining that fertilizer was needed, and that is a good first step. However, once a nutrient deficiency is suspected, it is imperative to do a soil test. This will show the concentration of micro (required in small amounts) and macro (required in larger amounts) nutrients. Most Minnesota soils have a sufficient amount of micronutrients and nitrogen will be the limiting nutrient (generally soils have enough potassium and phosphorous to support most plants). The micronutrient most commonly lacking in Minnesota soils is iron, which results in iron chlorosis (Gillman).
Soil tests will also show the pH of a sample. pH refers to how acidic or alkaline the soil is. On a scale of 1 being the most acidic and 12 being the most alkaline, soils can range typically anywhere from 3.3 to 8.5. Different tree species tolerate different pH levels. If the pH of the soil is outside the range that a tree will tolerate, the root system is prevented from functioning normally. The ions that cause pH to be either acidic or alkaline can tie up nutrients, thus preventing the roots from taking up those nutrients even if they are present in sufficient quantities in the soil. Therefore, piling on even greater amounts of nutrients that the tree is unable to access is obviously a waste of money, time and effort in this situation. Once a soil test has determined specific nutrients are absent, fertilization is an effective way to give the tree the support it needs to grow. With trees, as in most cases, it’s better to investigate a little further than a
little later. For More Information on the Value of Fertilizing Trees: http:// www3.extension.umn.edu/ distribution/horticulture/ DG7410.html#deter http://www1.uwex.edu/ ces/pubs/pdf/A2308.PDF http://www.wnrmag.com/ supps/2002/oct02/ ouch.htm http://www.agctr.lsu.edu/ enr/urban_shade/ fertilization.asp
Note: Hasselkus wasn’t misquoted, but in the paragraph preceding the quote he does talk about soil tests. I believe it’s more a case of bad writing than anything else, but a layman wouldn’t know that and might take the information at face value.
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A Campus Field Day
At left: The swim tank and data collection area.
“Just demonstrate it one more
We had fun!
time, please.”
This is a public thank you to several TCA laborers. On June 18th the following people took part in harvesting 120 trees from the TRE nursery planting depth study on the U of M Saint Paul Campus. Joe Baltrukonis
Bruce Nelson
Renae Chesley
Gail Soens
Bret Hubert and son Tyler
Kim Sullivan
Annette LeDuc
Sara Tinetti
To make the list complete we also had Patrick Weicherding and Katie Frerker lending a hand. With this large group the work went fairly quickly. Many of the removals were completed with an air knife, while some were shoveled out of the ground. The trees were then placed in a tank of water until data and photos could be gathered on each individual. Results are promising, yet are still being finalized. Thanks! I apologize to those that may not have been contacted. Due to short notice and tight schedules - E-mail was used to get in touch with people.
This group probably wasn’t learning as slowly as they made Gary believe. Gary had been duped!
Gary and the air knife
Photos from the field: Look to the arrows for some fine Future SGR examples on lindens
Stem
There are actually several potential SGRs in this photo.
Future SGR
There are actually several potential SGRs in this photo.
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Research - A Top 10 List An Update on Stem Girdling Roots and Planting Depth Research, or "No, that's not what I said!" by Gary R. Johnson It's been awhile since I've chatted with you about the ongoing work at the University regarding tree health and depth of soil over roots. Many of you went through the TCA core course training several years ago when we were just beginning our research. And for many of those people, regular attendance at update sessions and conferences has kept to pretty much up-to-date on the status of our work and recommendations. However, not everyone has the opportunity to attend update sessions, so I thought that I would take the time to fill you in and maybe dispel some rumors.
Mike Haugen: Demonstrating root excavations with the air knife on elms in the TRE nursery.
Rumor number one: Gary is doing all of this research. False. Gary is part of a great team that keeps expanding. Currently, the core research team includes Patrick Weicherding (Extension urban forester), Dave Hanson, Chad Giblin (TRE research nursery manager), and Jeff Gillman (Department of Horticulture). Quite often we are joined by others when we do work in areas off-campus: Doug Courneya (Olmsted County Extension Horticulturist), Rich Hauer (MN Dept. of Agriculture) and many TCAs who have devoted many volunteer hours at the research nursery. I don't want to slight any of the TCAs who have helped, but I want to particularly applaud the help that Bruce Nelson has contributed on a weekly basis at the nursery. And finally, Mike Haugen, grounds manager for part of the St. Paul campus, who has helped us so many times by providing the Air Knife that has made our lives more bearable during root collar examinations and harvesting trees. Now maybe you'll understand why I look bothered when people refer to this as "Gary's research." Rumor number two: Everyone knows about this problem now and contractors or growers can be sued if they plant trees too deep or harvest/grow trees with too much soil over the roots. This kind of relates to an associated rumor: Minnesota now has standards that require all tree roots to be within one inch of the soil surface. Both are false. First of all, not everyone knows about our research work, so we have a lot more work to do especially regarding getting the word out. Most people still believe that "deeper is better," unfortunately. And many growers and contractors have not received the information or are resisting the new information. Passing on the information to both audiences require the same approach: do it respectfully, with an open mind, and not in a confrontational manner. No one will be receptive to this research if it's stuffed down their throats. They WILL choke on it, and spit it out! Our challenge is to present it to them in a manner that they will see the benefits to their landscapes and their pocket books.
Planting specifications diagram showing trunk flare, stakes, watering and backfilling.
Minnesota HAS NOT developed any standards regarding the maximum amount of soil allowable over root systems. There are several municipalities and agencies that have developed their own standards or specifications, but they are unique to those entities. For instance, MnDOT will only accept trees/ shrubs with less than 4 inches of soil over the root systems. Then, when those trees and shrubs are planted, enough topsoil and roots must be removed so that the first true branch roots are within an inch of the soil surface. Other communities such as Minneapolis and St. Paul also have specifications, some more strict, some more liberal.
Therefore, in the absence of standards, growers and contractors can't be sued or denied payment‌ unless they don't adhere to the specifications of those particular agencies or municipalities contractspecifications booklet which is ing the materials or services. So, does that leave the average person totally helpless? Nope. Draw often referred to by municipaliup your own specifications for accepting plant materials or landscape installations. Then, the providties. Once the specs are in ers know what to expect and have the choice to provide you with plant materials or services based place - then policing begins. on the specifications in your contract. You do it when you buy a new car or house, don't you? Do it MnDOT has an extensive
Diagram courtesy of USFS.
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Research - A Top 10 List with plants or installation services, too. Rumor number three: Pot-bound trees will end up with stem girdling roots. Not if the stem isn't buried in the container soil! Oh, I suppose it COULD happen. I've seen plenty of trees with stem girdling roots above ground. However, we still don't know if tissues in the flare area of a tree react the same as pure stem tissues. There is a possibility that roots can graft to flare tissues, with little to no harm. Encircling roots become problematic when they come into conflict with buried stems. If that stem is buried 6-10 inches below ground and there are encircling roots within a few inches of the stem, I can almost guarantee you that stem girdling roots will develop. Rumor number four: Growers, retailers and landscape companies know they are selling/planting trees that will be short-lived, which just gets them more business in the future. Oh, come on! There may be some like that out there, just as there are unscrupulous politicians, doctors, dentists, mechanics and teachers. But I honestly believe from my experience that they represent a small minority. Most are just ignorant of the problem and research.
Rumor number five: If we get growers, retailers and installers to fall in line with best practices for growing and planting trees, our problems with stem girdling roots will be over. False; not as long as people keep over-mulching trees. Plus, most trees and shrubs are still planted by homeown- Commercial site: Overmulching commonly referred to as ers who still believe in "deeper is better." Rumor number six: All trees with stem girdling roots will die. Well actually, they will die, but not “the mulch volcanoâ€? necessarily from stem girdling roots or planting depth problems. Some actually live with SGRs Note the pop can (arrow) - it deeply imbedded in the trunks for many years and look just fine. But it's just like any other stress is dwarfed by the mulch pile. on a living organism, and SGRs affect some trees more severely and quickly than others. The problem with doing research is that all recommendations are based on probability: what is the likelihood of failure when you plant 1000 trees too deep? Well, if they're littleleaf lindens, over 90% will eventually have problems with stem girdling roots, and if a straight-line windstorm rips through the area, expect about 3/4 of them to snap off at compression points from SGRs. However, you cannot walk up to one tree and say "this is the tree that will have problems and fail in a windstorm." When you work with your clients, that is what they are asking you, and you can only give them probability information, not specific to that one tree in their yard. What we have found: trees with 50% or more of their stem circumference compressed by SGRs will decline in health and condition faster, will be short-lived, and are more likely to fail in windstorms‌but it depends! (don't you hate that word?) Are all other growing conditions ideal? How big is the tree? Is it 10 feet tall or 70 feet tall? Is it in a wind-protected area, or is it facing the full force of winds in a new subdivision? Is there decay associated with the compression or elsewhere in the tree? Is it a dense tree, like a spruce, or more open, like a honeylocust? SGRs are part of the diagnosis and predictive process. Rumor number seven: All trees planted too deep will get stem girdling roots. Nope, but depending on the species and size of the tree planted, a significant number will develop them. Then, their health and condition can be affected as in rumor number six. Rumor number eight: Stem girdling roots are the biggest problems associated with planting too deep. They are definitely a huge problem, but a bigger problem is simply the lack of soil oxygen and moisture that deep planted roots have at their disposal. The deeper you entomb roots (regardless of soil type), the less oxygen and moisture is available to a plant, most critical is the oxygen. Way too many trees and shrubs die long before they can develop SGRs simply Continued Page 12
Planting Depth Study: F24 A sugar maple planted with first order roots at 10 inches. No SGRs after 3 years, but some adventitious roots (see arrows).
Page 10
5 needles per fascicle on an eastern white pine Note the smooth bark in the picture
Eastern white pine branch tip
Eastern white pine cones Note the rougher bark at the base of the tree
King's “Broad-arrow” (from page1) were built from the wood of Eastern white pine (Pinus strobus L.). However, the popularity of white pine brought with it a very high cost. Eastern white pine was extensively harvested during the 1800’s on into the early 1900’s leaving very few “virgin” old growth stands today. Eastern white pine has made a remarkable recovery and an indication of white pines reproductive capability shows in another common name used around some Northeastern States, “old field pine.” As farming left the Eastern States in the 1860’s for the Midwestern prairies, white pine was able to re-inhabit the abandoned fields and today there are once again nearly pure stands of eastern white pine. One of the whispering pines of the north woods, Eastern white pine has 5 soft needles per fascicle or bundle. The needles are roughly 2.5 to 5 inches long, dark bluish green in color, soft and very flexible. The needles tend to persist until the end of the second season or the spring following that. The 3 to 5 inch cones of eastern white pine are small in comparison to its cousins out west. Western white pine (Pinus monticola) cones can be up to 10 inches while those of sugar pine (Pinus lambertiana) can be up to 20 inches in length. Around Minnesota white
hot and dry, being along the western edge of the white pines range. With this in mind, realize that white pine will require a consistent moisture regime (mulch) and young trees require protection from harsh drying conditions (wind and sun) of winter and summer. Road salt in the form of salt spray is another damaging agent prevalent around the State of Minnesota. Proximity of a landscape site to a road should While the bark of a young always be considered when choosing white pine as it is white pine is quite smooth and has a greenish tint, with quite susceptible to salt damage. age the bark of white pine Now, I refer you to becomes quite dark and furrowed or ridged. The bark is two other sources: First, in not as fire resistant as some this issue look to Barb Kirkpatrick’s companion artiof its cohorts such as red cle on white pine blister rust. pine. For this reason white pine is often found within the This disease must be considered when white pine is on mosaic of the forest on the the list to be planted on a east side of lakes, streams site. Second, refer back to and ridges protected from Mike Zin’s article titled the fires driven by westerly “Pines”, Tree Care Advisor winds. Newsletter, vol 9, number 1, The cool shade of a pine grove, the pine scent and the pages 18-21 (January 2002, whisper of the wind through available on the web). pine is found on a variety of sites, but develops best on the well drained, moist, sandy loams of ridges. As the tree matures and begins to gain advantage over neighboring trees the top begins to spread with the branches reaching distinctively upward much like the horns of a stag. This trait makes white pine fairly easy to distinguish along Northern Minnesota’s skyline and even within the confines of the Metropolitan area.
the boughs have long made pine stands of the north woods a pleasing site to visit. The experience touches human emotions so strongly that pines are often a choice for urban landscapes. Unfortunately, the white pine is not always the perfect or even the best choice for urban environments. It grows here, don’t get me wrong. It can grow to be quite large but the Twin Cities are a little
So, the next time you hug your white pine, maybe not, or you are standing in a grove of whispering white pine think about the early pioneers and their disdain for the “King’s Broad-arrow” emblazoned on the white pine on their property. In reality the Revolutionary War was about many things and believe it or not the Eastern white pine weighed heavy in the decision to go to war.
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King's “Broad-arrow” Works Cited: Peattie, Donald C., A Natural History of Trees of Eastern and Central North America. Houghton Mifflin Company, Boston MA, 1991
White Pine Blister Rust (continued from page 2) implementing an extensive eradication program in the white pine regions of the United States, it was realized that wild Ribes also serve as an alternate host to WPBR. Thus a new strategy for management of this disease was developed that focused on selecting and improving blister rust-resistant white pines. For decades, it has been noted that wild white pines exist that appear to be resistant to blister rust. If the mechanism(s) by which a resistant tree protects itself from infection could be identified, we may then be one step closer to being able to screen and grow blister rustresistant eastern white pine. This is where Dr. Blanchette’s research comes into play. He has artificially inoculated different strains of white pine with C. ribicola and studied the plants responses at a microscopic level. What Dr. Blanchette and his graduate students have found is that some white pine families tested reacted differently in his study to infection by C. ribicola. Normally the fungus initially infects needles and then moves into the
into the needles. So there appears to be two mechanisms of defense at work in this first white pine seed source: cell death adjacent to the infection, and wax covOne seed source of inocu- ered stomata. Two other families of lated seedlings exhibited a ‘hypersensitive-like’ response seedlings responded differwhere death of cells adjacent ently to inoculation by exhibiting a concentration of pheto the infection site occurred. Keep in mind that C. nolic compounds near the ribicola is an obligate parasite site of infection. These phethat needs live host cells to nolic compounds appear to stay alive. The death of host restrict hyphal growth as cells surrounding the infecthese seedlings also exhibited tion effectively restricted the some degree of resistance to fungus, as its colonization infection. could not continue without To date, Dr. Blanchette’s live host cells. Additionally, research has shown some when non-infected seedlings intriguing results. Primarily, from this resistant family there seems to be more than were examined under the one way white pine respond electron microscope a to and resist infection by the greater portion of their nee- fungus C. ribicola. Furtherdle stomata were plugged more, these responses apwith wax when compared to pear to be genetic in nature. infected seedlings’ stomata If research can unlock the from the same strain. This ‘genetic code’ that makes seems to be significant bewhite pine rust-resistant, percause C. ribicola initially inhaps some day eastern white fects pine by penetrating the pine will once again flourish needle stomata with its hyin massive numbers. phae. It is thought that this wax covering the stomata may play a role in preventing the fungus from penetrating branch, and then into the main stem where it attacks the food and nutrient conducting tissues of the tree. This results in cankering which gradually kills the tree.
White pine seedling trials. Seedlings inoculated with Cronartium ribicola .
Ribes spp. growing in a green house for use in the white pine blister rust trials. The alternate host for C. ribicola
Photos for Barb’s article courtesy of Doctor Robert Blanchette, University of Minnesota, Professor in the Department of Plant Pathology.
Contact Phone Numbers Program Contacts:
TCAAG Members:
Paula Denman, Chair – 612-338-1871, pjdenman@mn.rr.com Bob Condon – 952-890-1228, bobnbunny@juno.com Gary Johnson – 612-625-3765 or grjonson@.umn.edu Laurie Drolson – 651-464-9829, ldrolson@yahoo.com Dave Hanson – 612-624-1226 or dlhanson@umn.edu Mailing Address: 115 Green Hall, 1530 Cleveland Ave. North, St. Paul, Bruce Granos – 952-423-5211, bjgbjgbjg@hotmail.com Mimi Hottinger – 507-388-4838, mimih@mctcnet.net MN 55108 Barb Kirkpatrick – 651-490-9816, sambucus@attbi.com
County Contacts: Anoka County (Patrick Weicherding) – 763-755-1280 or weich002@umn.edu Blue Earth – (507)389-8325 Carver County (Jackie Smith) - (952) 442-4496 or smith515@umn.edu Dakota County (Barb Stendahl) – 952-463-8002 or stend004@umn.edu Hennepin County (Bob Mugaas) – 612-374-8400 Olmstead County (Doug Courneya) – 507-285-8250 or courneya@umn.edu Ramsey County – (Doug Foulk) – 651-777-8156 Scott County (Jackie Smith) - (952) 492-5410 or smith515@umn.edu St. Louis County (Bob Olen) – 218-726-7512
Additional Reference Contacts: Debby Newman (Info-U) – 612-624-3263 Don Mueller, DNR Forestry – 651-772-6148 or don.mueller@dnr.state.mn.us Great River Greening – 651-665-9500 Ken Holman, DNR Forestry – 651-296-9110 or ken.holman@dnr.state.mn.us Rich Hauer, Minnesota Department of Agriculture (certified tree inspector workshop coordinator) 651-296-0592 or rich.hauer@state.mn.us Paul Walvatne MNDOT – 651-284-3793 or Paul.Walvatne@dot.state.mn.us Tree Trust – 651-644-5800
Research - A Top 10 List
(From page 9)
because their roots are too deep and the root systems wither away. No soil oxygen, no root growth. Poor soil oxygen, poor root growth. Poor root growth, unhealthy plants above ground. Unhealthy plants above ground, plants that are more vulnerable to common insect problems, diseases and other environmental stresses. Our research has shown that at least with bicolor oak, green ash, littleleaf linden and sugar maple, deep planting (regardless of the presence of SGRs) leads to declines in health and condition above ground. Someday with more research, we'll know more about other species, but I have no reason to believe that most others will be dramatically different from these species. Rumor number nine: Stem adventitious roots are bad roots. False, if they are growing away from the stem. Only those that are growing back or around the stem can develop into girdlers and potentially harm the tree. So, if they're growing away from the stem, they're doing no harm. Rumor number ten: Tall or bare-rooted or grafted trees MUST be buried deeply, otherwise they will lean too much or windthrow during storms, or die from cold winters. False. Our research conducted in 2002 revealed that there is no advantage to deep planting in regards to stability. Other research conducted on grafted fruit trees in the early to mid-1980's had the same conclusions. If it's real windy and the trees are poorly rooted, you'll probably need to straighten them regularly or give them some temporary staking…regardless of planting depth. And burying the graft union adds no extra winter hardiness protection. As a matter of fact, it weakens the trees' long term health. Sooooo many rumors, so little time. I hope this clears up some of the misunderstanding surrounding our work, what we feel we have learned, and all that we feel we still need to learn. This research is in its infancy, relatively speaking, but we're plugging away and added three new research projects to our plate this year. Little by little we're learning more and hopefully helping you as TCAs to better help your clients (and keep your own trees alive!). Stay tuned for more.
Below is a link from Ken Holman - Minnesota DNR. The .pdf brochure Experts Agree Don't Top Your Tree info is from the Missouri Community Forestry Council. http://www.mocommunitytrees.com/images/MOBroch2002.pdf