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HomeMy WebLinkAbout2004 08 09 Regular 506 COMMISSION AGENDA ITEM 506 CONSENT INFORMA TIONAL PUBLIC HEARING REGULAR X August 9,2004 Meeting Mgr. tv'; /~ept. Authorization REQUEST: The Arbor Division wishes to provide the Commission with the results of the Tree Evaluation that was recently conducted by an independent consultant pursuant to an increase in tree deaths within the city. PURPOSE: The purpose of this agenda item is to provide the commission with the findings by Selmer Uhr, a professional consultant hired to investigate possible causes of recent tree deaths in the Rights-of- Way areas within the City, CONSIDERATIONS: As trees are dying due to many causes throughout the year within the City, replacement canopy must be established on an ongoing basis to replenish the urban forest. A tree replacement and canopy program is being developed by staff and will be represented to the Commission in the near future. RECOMMENDATION: Staff recommends the Commission review this Agenda Item along with the attachment and provide any direction it deems appropriate. ATTACHMENTS: 1. Landscape Tree Evaluation Report COMMISSION ACTION: ATTACHMENT A LANDSCAPE TREE EVALUATION CITY Of WINTER SPRINGS SEMINOLE COUNTY, FLORIDA Prepared for: City of Winter Springs 1126 East State Road 434 Winter Springs, Florida 32708 Prepared by: Selmer C. Uhr Forest & Urban Tree Consultant 1317 American Elm Drive Altamonte Springs, Florida 32714 Tel. 407-292-2454 July 7, 2004 @ Copyright Selmer C. Uhr, 2004 Landscape Tree Evaluation City of Winter Springs. Florida 717/04 PURPOSE AND LIMITATIONS This tree evaluation and report presents the results of a one-half day visit to several areas within the' City of Winter Springs where recent tree deaths have caused concem for city employees, council persons and citizens. Most of the problem trees inspected were in the Tuscawilla area. Since the site visits were brief, this tree evaluation is necessarily limited in scope and thus represents a sampling of tree problems which are likely more widespread. Conclusions presented in this report are based on general observations from ground level; tissue samples were not analyzed, trees .were not climbed and an extensive excavation of tree roots was not undertaken. GENERAL OBSERVATIONS The most obvious and extensive tree problems were associated with the browning of leaves on laurel oak trees (Quercus hemisphaerica) with leaves adhering to twigs for weeks and possibly months. This symptom represents, in nearly all cases, a tree that is dead and beyond recovery. This is in contrast to trees that lose their leaves and then often recover. On our site visit there seemed to be three prevalent causes for stressed and dying trees: . The most common problem encountered was tree death as a result of infection by hypoxylon canker (Hypoxylon spp.), a fungal disease common to stressed water oaks (Q. nigra), laurel oaks and turkey oaks (Q. /aevis). The fungus that causes this disease is widely disseminated and is found often growing in otherwise healthy trees. This disease only becomes a problem when the host tree is stressed, usually in Florida by drought and heat. Moisture stress was probably a significant factor this year as a result of rainfall deficiencies during the spring months. When a well-established tree is noted with brown leaves adhering in late spring or early summer (Photo No.1), it is most likely succumbing to hypoxylon canker. As the disease progresses, the thin outer layer of light gray bark begins sloughing off exposing a reddish-brown deeper layer of bark (Photo No.2). There is some evidence that squirrels may contribute to the removal of the outer bark either to sharpen teeth or consume the fungal Selmer C. Uhr, Registered Consulting Arborist Altamonte Springs, FL 32714 Page I Landscape Tree Evaluation City of Winter Springs, Florida 7 nl04 mat. Later a tan to gray cushion-like material forms which then hardens, becoming silvery or black depending on the species of fungi (Photo No.3). Once established in"a stressed1ree there is no effective treatment for this disease. Dead and dying trees often will harbor wood-destroying insects, such as round-headed borers and ambrosia beetles. Controlling these with insecticides is an exercise in futility. Once hypoxylon canker is confirmed, the best course of action is to remove the infected tree. . The second problem encountered was failure to remove the upper portion of synthetic non-biodegradable burlap and ropes, from trees after planting. While the synthetic burlap is unlikely to cause the death of a tree, it can reduce the rate of root growth' and result in structural weakness where roots penetrate the burlap. This material, which fortunately is not used at the present time to my knowledge, should have been slit or at least the upper portion removed to allow unrestricted root growth. The more serious problem . is leaving the heavy poly-rope, straps or twine that are used to lift the tree into the planting hole. These can girdle the trunk of a tree, resulting in death. An example is the row of trees planted along the southwest side of Northern Way in the vicinity of Wildcat Court (Photo No.4). . On the northeast side of Northern Way a ditch was dug for utilities in late 2003. One dead and removed tree was observed adjacent to Wildcat Court. The excavation may have seriously impacted this tree's roots although the roots of this tree were not exposed to establish the extent of root removal. The trees along this side of Northern Way were located approximately 7 to 8 feet from the excavation, a distance that should not have resulted in tree mortality. Depending on the equipment utilized, tree roots can be seriously damaged well beyond the excavation particularly when a backhoe is used. The jerking of major roots can tear loose the many smaller feeder roots, in some cases a11 the way back to the trunk of the tree. . . While mistletoe is normally is not considered to cause tree mortality, this true parasite can cause severe stress by extracting moisture and nutrients from a tree. It is my opinion that often it can combine with environmental stresses to result in the death of a tree. Certainly it can add to the drought stress, Selmer C. Uhr, Registered Consulting Arborist Altamonte Springs, FL 32714 Page 2 landscape Tree Evaluation City of Winter Springs, Florida 7 n /04 pushing the host tree beyond the point of recovery or making it more susceptible to failure from hypoxylon canker or other diseases: An extensive mistletoe infestation on a water oak located at 1606 Woodchuck Court illustrates this phenomenon. . While drought often is associated with tree decline and death, too much water can be equally detrimental particularly when applied to trees that normally grow on dry sites, such as sand pine (Pinus clausa) and turkey oak. This becomes a particularly acute problem when the flow of lawn irrigation sprinklers goes directly on a tree's trunk. Dead t,urkey oaks observed at 820 Dyson Drive illustrate this problem. CONCLUSIONS AND RECOMMENDATIONS It is my opinion that the extensive oak tree deaths in Winter Springs are similar to experiences in other areas of Central Florida where dead and dying trees have become common over the past several weeks. In nearly all cases this is happening with laurel, turkey and water oaks (members of the red oak group) which are very susceptible to hypoxylon canker. Almost always active infection by this fungus is the result of environmental stress, either natural or man induced. With the onset of summer rains the incidence of this disease problem should lessen. Once a tree shows symptoms, there are no effective treatments. Applications of fertilizer, soil amendments and trunk injections have no proven benefit and should be avoided. The only effective treatment, to my knowledge, is to reduce stress prior to an active infection. This can by done by irrigating laurel and water oaks with 2 to 3 inches of water every 2 to 3 weeks during periods of severe drought. Usually this occurs during the months of March through May, but in some years it occurs during August after summer rains begin to diminish. Too much water, in contrast, can stress Turkey oaks. Zoning of irrigation should be encouraged by the city. This means applying infrequent (every 2 to 3 weeks) but heavier watering (2 to 3 inches) to tree and shrub areas while limiting the amount of water (1/2 to 3/4 inches) applied to lawns on a more frequent basis (2 times/week). This will keep all of the landscape plants happier. Planted trees most often die as a consequence of improper planting techniques. This includes planting too deep and leaving ropes and straps wrapped around the base of the tree, which can result in girdling. Often a tree will not die until 10 of 15 years after Selmer C. Uhr, Registered Consulting Arboris! Altamon!e Springs, FL 32714 Page 3 Landscape Tree Evaluation City of Winter Springs, Florida 717/04 planting. City tree planting contracts should specify proper planting to prevent future problems. Where trees were planted with straps and ropes intact, such' as on the . . southwest side of Northern Way in the vicinity of Wildcat Court, they should be removed before more trees die. Excavation for installation of utilities near trees should be accomplished at an appropriate distance from existing trees. A tree's critical root zone (CRZ) is usually defined as having a radius in feet equal to the tree's diameter in inches. Thus an 8-inch tree will have a CRZ extending 8 feet from the trunk of the tree. With care, a healthy tree can sustain an encroachment equivalent to 30 to 40 pe~cent of the area of the CRZ without incurring a significant risk of crown dieback or depth of the tree. Where ex'cavations must be made which encroach on the CRZ, root pruning 6 inches to a foot towards the tree from the new edge of the excavation some six months to a year prior to the activity will greatly enhance the survival and health of the tree. Where there are large specimen trees in the path of an excavation, directional boring, while more expensive than excavation, will often save an otherwise doomed tree. A final recommendation is for the City of Winter Springs to provide timely and accurate information to the city's citizens. This could take the form of a seasonal pamphlet covering current tree protection and health issues. Not only would this improve the retention of tree cover; but also could protect the citizens from applying and paying for treatments that are only marginally beneficial and, in some cases, harmful to trees. Selmer C. Uhr, Registered Consulting Arborist Altamonte Springs, FL 32714 Page 4 . PROFESSIONAL QUALIFICATIONS SUMMARY SELMER C. UHR, REGISTERED CONSULTING ARBORIST 1317 American Elm Drive Altamonte Springs, FL 32714 Tel. 407-292-2454 Fax - 407-292-5790 EXPERIENCE: Since 1989, self-employed primarily as an urban tree consultant in central and northeast Florida providing consulting services to real estate developers, contractors, attorneys, real estate appraisers, governmental agencies, architects, insurance companies, tJomeowners associations and homeowners. Consulting services have included pre-development tree inventories, selection and protection of trees during development, evaluation of construction damage to trees, tree value appraisals, tree risk analysis, insect and disease diagnosis and appearances as an expert witness in court proceedings and administrative hearings. From 1979 to 1989, consulting primarily involved providing professional forestry services to forest landowners and investors in forest land. These services included forest management plans and assistance, economic analysis and timber marketing. Prior to 1979, employment was with major forest product manufacturing firms where positions involved technical forestry, research and land management responsibilities, including overall management of 400,000 acres of timberland in Florida. EDUCATION: . Iowa State University - Bachelor of Science . · Yale University - Master of Forestry · Seminole Community College, Sanford, FL - Successful completion of 75 hrs. of advanced course work in real estate appraisal, including appraisal standards, methods and applications. · Completion of numerous courses, seminars and training sessions in various aspects of forestry, environmental analysis, urban tree care, tree risk analysis, tree appraisal and related fields. PROFESSIONAL CERTIFICATIONS: · American Society of Consulting Arborists - Registered Consulting Arborist · Society of American Foresters - Certified Forester · International Society of Arboriculture - Certified Arborist PUBLICATIONS, AWARDS. CERTIFICATIONS AND PROFESSIONAL ACTIVITIES: Author of articles in professional and trade publications. Chaired professional and trade association conferences and committees. Currently an Advisory Board member to the University of Florida School of Forest Resources & Conservation. ABBREVIATED LIST OF CLIENTS: Appraisal Group of Central Florida (real estate appraisal) Attwood Phillips Incorporated (real estate management) Cambridge Homes (home construction) Centex Homes - Orlando Division (real estate development and home construction) City of South Daytona (municipality) City of Orlando (municipality) County of Volusia (county government) Florida Dept. of Transportation (state government) Glatting Jackson Kercher Anglin Lopez Rinehart, Inc. (community planning) Glenn Acomb Associates (landscape architect) Gray I Robinson (attorneys) Greater Construction, Inc. (real estate development and construction) Regency Professional Management, Inc. (real estate management) Rumberger, Kirk & Caldwell (attorneys) State Farm Insurance Co. (insurance) Walt Disney Imagineering (theme park and timeshare development) Wilson, Leavitt & Small (attorneys)