Record-breaking warm weather advances beginning of growing season

Recent, abnormally warm weather is putting us at least two or more weeks ahead of schedule, bringing most perennial crops and vegetation out of their protective dormant states.

Published March 15, 2012

           

Jeff Andresen and Aaron Pollyea, Michigan State University Extension, Department of Geography

Recent abnormally warm weather has resulted in a very early start to the growing season across the Great Lakes Region and much of the central and eastern USA. The trend towards warmer than normal conditions is not new, with above normal mean temperatures observed across Michigan during much of the period back to the middle of last November. The winter of 2011-2012 (December through February) was the fourth mildest on record.

The prolonged warm spell is the result of a very persistent jet stream configuration across North America that generally prevented cold, arctic-origin air masses from moving out of their high-latitude source regions southward into the central and eastern USA. This left the area under the influence of relatively mild Pacific-origin air masses. The current jet stream pattern, with deep troughing across the western USA and ridging across the east has accentuated the pattern. The result is record-breaking warmth brought northward from the Gulf States on southerly winds.

Looking like a record-breaking March

Characterizing the current warm spell as highly unusual is an understatement, both due to the magnitude of the warmth (recent high temperatures have exceeded 70ºF over many areas of the state) and due to its length. For climatological comparison, normal high temperatures during the third week of March range from the mid-30s far north to the middle to upper 40s south with lows from the mid-teens north to the upper 20s south. Thus, recent temperatures have been running in the range of 20 to 30°F or more above normal.

Short- and medium-range forecast guidance strongly suggests a general continuation of the current pattern with warmer and possibly wetter than normal weather likely through the end of the month. A map depicting forecast conditions across North America early next week is given in Figure 1. The upper air trough over western sections of the country, ridging across the Midwest and east, and strong southerly flow all suggest maximum temperatures into the 60s and 70s statewide through at least the middle of next week. Use of the latest forecast information suggests at least the potential for mean temperatures this March to exceed the existing record (1945 in most locations) for warmest on record in the state.

Figure 1. Projected weather conditions at approximately 5,000 feet above sea level, 8 p.m. on Monday March 19, 2012. Color contours depict temperature (°C) while winds are expressed in arrow/vector form on grid points in white (direction of arrow indicates direction, length of arrow depicts velocity). Solid white lines depict general pressure pattern and air flow. Figure courtesy of Unisys, Inc.

Base 50ºF growing degree accumulations during the ten warmest Marches on record at Benton Harbor, Mich., plus the current month are shown in Figure 2. A projection of accumulations through the end of March 2012 data was obtained with temperature forecasts from latest short- and medium-range National Weather Service forecast guidance, including the assumption that mean temperatures during the last week of the month averaged 10ºF above normal. With these assumptions, the GDD total by the end of the month exceeds 200 units as well as the old historical record of 146 set in 1945 and the normal value of 45. The abnormal warmth already has or will shortly bring most perennial crops and vegetation out of their protective dormant states. Given that this is taking place at least two full weeks or more ahead of normal, and that the relative susceptibility of plant tissue to frost and cold damage generally increases with increasing growth stage, there is an overall elevated risk of cold injury this spring season.

Figure 2. Observed (solid colored lines), normal (solid black line) and projected (dashed line) base 50°F growing degree accumulations for 10 warmest Marches on record at Benton Harbor, Mich. Projections for the 2012 data include latest short- and medium-range National Weather Service forecast guidance through March 31. Growing degree days are calculated with the Baskerville-Emin methodology.

What are the chances of a hard frost?

Relative risks of spring freezing temperatures across Michigan are given in Figure 3. Even though current long lead outlooks for April and the spring season call for more of the same warm pattern across Michigan, further cold weather at some point in the next several weeks is virtually a certainty (see Figure 3). The climatological average number of daily spring freeze events (32ºF or less) after March in a given season ranges from about eight in the southwest and southeast corners of the state to more than 20 in interior northern sections of the state. In terms of hard freezes, the average number of low temperature events of 28ºF or less for the same period ranges from four to more than 15. Very cold temperatures are still possible during the month of April, with lows below 10ºF in the south to the single digits below zero in the north.

Figure 3. Numbers of daily April-June freeze events (32ºF or lower) at selected locations in Michigan, 1941-2011. The top number (red) is the average number of individual freeze events during the three-month period, the second- number (blue) is the range of total freeze events in a given season, the third number (green) is the average minimum temperature (ºF) for all freeze events, and the fourth number (orange) is the range of minimum temperatures (ºF) for all freeze events during the period of record.

Potential positive outcomes

It is also worth noting that there is some minor reduction of frost and freeze risk in years with very warm Marches. When only the top 10 warmest Marches were considered, there is an approximate reduction of 10 to 20 percent in the frequency of subsequent freeze events. This is very likely associated with the persistence of the upper air pattern that led to the abnormally warm March weather into April or longer.

Finally, there may also be some positive impacts of the unusual weather. Warm temperatures will accelerate soil evaporation rates and may allow some early fieldwork opportunities, but this will depend greatly on upcoming rainfall frequency and intensity (the forecasts generally call for wetter than normal weather). Similarly, depending on weather conditions later this year – especially rainfall patterns – there is at least the possibility that seasonal yields of some crops (e.g., forages) could be higher due to a potentially longer than normal growing season.

This article was published on MSU Extension News. For more information from MSU Extension, visit http://news.msue.msu.edu. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).

Come See Our New Site

Come see the new OwenLawnCare.com site! We have added a lot of new information on the services we offer as well as the disease or pests we treat for. We have also added a place to ask our Certified Arborists any questions you may have. also coming soon will be a new info center with information on everything form lawn insects and pests to lawn diseases and also many tree issues. Please check back soon for any new info regarding the new info center or you can leave any comments or topic ideas here. Thank you for visiting us and stay tuned for more info coming from us here at Owen Lawn Care.

What’s new with Imprelis?

Questions remain about residual soil activity and recovery of trees affected by new herbicide.

Published February 3, 2012

           

Bert Cregg, Michigan State University Extension, Departments of Horticulture and Forestry

This past summer, severe damage and death of thousands of trees, mostly conifers, associated with application of a new turf herbicide (Imprelis) was widely reported in the media and ultimately resulted in EPA issuing a Stop Sale, Use or Removal order for the product in August 2011. Subsequently, the manufacturer, DuPont, initiated a claims process for applicators and homeowners with damaged trees. As part of the claims process, DuPont is working with a claims resolution company, which has contracted arborists to assess and evaluate dead and damaged trees. As one would expect in a case of this magnitude, the resolution process is moving slowly and applicators and homeowners continue to have questions about the impact of Imprelis on trees. Some of the common questions we have received are noted below.

What trees were affected by Imprelis?

Conifers were by far the common trees that were affected, especially eastern white pine and Norway spruce. This is consistent with Imprelis’ mode of action as an auxin-mimic herbicide since these are normally fast-growing trees and their spring growth flush coincided with Imprelis application. It is important to note, however, that other tree species were also affected. The Purdue Plant and Pest Diagnostic Laboratory has compiled a list of about three dozen tree and shrub species in which Imprelis injury symptom have been observed or in which the Indiana State Chemists office has detected Imprelis residues.

How long does Imprelis last in the soil? When is it safe to replant?

The amount of Imprelis remaining in the soil will depend on the initial concentration and the rate of soil degradation. Imprelis is degraded mainly by microbial activity and photo-degradation, so the rate of breakdown can vary widely. The soil half-life of Imprelis applied to turf is 37 to 103 days. This means the initial concentration is reduced by 50 percent after one half-life and then reduced by 50 percent again (25 percent of initial) after the second half-life and so on. Assuming the half-life data are correct and at least three half-lives will have passed since 2011 applications, soil concentrations of Imprelis should be no more than one-eighth their initial level by early spring 2012.

For areas in which trees received only minor damage, this suggests soil concentrations will likely be below damaging levels by spring. Where initial soil concentrations were higher and trees were killed or severely damaged, however, it is less clear that it will be safe to plant this spring. DuPont conducted a study in which they planted cotton, soybeans, and sunflowers in fields one year after Imprelis application and found that responses varied from no plant damage to plant death. Therefore, a conservative approach would suggest waiting until at least fall 2012 before replanting where trees were severely impacted.

Will affected trees recover?

This depends on the extent of tree damage, desired function of the trees in the landscape, and homeowner tolerance (Photo 1). For trees in which Imprelis damage was largely confined to the uppermost terminal shoots and did not decline further during summer 2011, it seems likely they will survive.

Photo 1. The ability of trees to recover from Imprelis injury will depend on degree of damage,
function in the landscape, and homeowner tolerance.

The question then becomes, will they be acceptable in the landscape? If the primary function of the trees is as screening elements, this level of damage may be tolerable. If, on the other hand, these are specimen trees where an upright, symmetrical form is desired, the trees will require corrective pruning and training of a new leader or may require replacement (Photos 2 and 3).

Photos 2 and 3. Although this Serbian spruce appeared to suffer relatively minor damage, it will require
considerable top-work in order to regain its desired form.

For trees in which more than the uppermost portion of the crown was affected, judgments will need to be made on a case by case basis factoring in landscape function and client tolerance. The more challenging question, and one for which we don’t have an answer, is what is the long-term prognosis for affected trees? The degree of visible injury to shoots can be estimated, but the nature and extent of damage to roots is entirely unknown. It’s possible, and perhaps even likely, that some trees that reflush and appear healthy this spring may be more susceptible to damage by drought or other severe stresses further down the road.

References

• DuPont. 2009. DPX-MAT28 Technical Bulletin, 8 pp.
• Strachan, S.D. S.C. Nanita, M. Ruggiero, M.S. Casini, K.M. Heldreth, L.H. Hageman, H.A. Flanigan, N.M. Ferry, and A.M. Pentz. 2011. “Correlation of Chemical analysis of residual levels of Aminocyclopyrachlor in soil to biological responses of alfalfa, cotton, soybean, and sunflower.” Weed Technology, 25(2):239-244.

Dr. Cregg’s work is funded in part by MSU‘s AgBioResearch.

This article was published on MSU Extension News. For more information from MSU Extension, visit http://news.msue.msu.edu.

Creeping Charlie Update

With the removal of Imprelis from the marketplace, treating stubborn weeds like Ground Ivy (Creeping Charlie) has become a bit more complicated.  Last fall we spent some time looking for an alternative Creeping Charlie weed control that showed some promise and our research suggested that there were a few weed control products that were effective when applied in mid to late fall.  I recently attended a winter tree care & lawn care trade show attended by a range of green industry professionals, and had a chance to talk with a golf course superintendant about this weed control strategy.  I was gratified to discover that our intended plan of action was the same as his and he reported very good success in controlling Creeping Charlie on his golf course fairways. 

That said, be aware that Creeping Charlie is a weed that we cannot make go away overnight.  It prefers to grow in part shade and these areas have turf that usually is not as robust in its growth habits.  The plant has a very waxy leaf that resists absorption of lawn weed controls.  Strategies revolve around spraying Creeping Charlie in early spring when the leaves are tender and again in the fall as noted above.  Depending on the severity of the Creeping Charlie infestation, it may take a couple seasons of applications to rein it in, but it can be managed with persistence. 

      

Come see our new About Us page on our blog to meet our Certified Staff.

                Quality comes with knowledge & experience

For Immediate Release

Owen Tree Service, Inc. Tree Service Employee(s) Gain(s) Certified Treecare Safety Professional Status.

Mark Richards, CTSP  tree service employee(s) recently completed the Certified Treecare Safety Professional (CTSP) program offered by the Tree Care Industry Association.  The CTSP program allows one or more key employees at a given company to become certified tree care safety experts, thereby empowering and encouraging a culture of safety within that organization. 

Owen Tree Service, Inc. is a commercial and residential tree care company located in Lapeer County, Michigan. Contact this company at  800-724-6680, or 810-724-6651

Maintaining a Certified Treecare Safety Professional on staff means that organizations are committed to safe practices in arboricultural operations.  CTSP’s are kept abreast of the latest technological advances and regulatory activities affecting the industry through the TCIA safety network, and must commit to ongoing education in the safety field in order to maintain their certification. 

Because safety regulations and industry standards are continually evolving, the ongoing education requirement is vital to maintaining a legitimate safety program within a given company. In order to fulfill program requirements, CTSP’s must complete a study guide, attend a two-day training workshop, and pass a rigorous exam.  Once certified, CTSP’s must complete at least 30 hours of training others, or receiving education themselves, every three years.

Consumers can have greater peace of mind with the knowledge that hiring a tree care company with a CTSP on staff helps to ensure safe and professional arboricultural work on their property.

About the Tree Care Industry Association (TCIA): Founded in 1938, TCIA is a public and professional resource on trees and arboriculture. It has more than 2,000 member companies who recognize stringent safety and performance standards and who are required to carry liability insurance. With access to the latest and best safety standards and training, the typical TCIA member company has 50 percent fewer accidents than a typical non-member. An easy way to find a tree care service provider in your area is to use the “Locate Your Local TCIA Member Companies” program. You can use this service by calling 1-800-733-2622 or by doing a ZIP Code search on www.treecaretips.org.

For more information about the Tree Care Industry Association, visit www.tcia.org.  For more information regarding the Certified Treecare Safety Professional program at TCIA or to obtain digital photos, contact Peter Gerstenberger at (800) 733-2622 x109 or email peter@tcia.org.


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