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An issue has come up within our local homeowners association regarding some of the evergreen trees in our common areas. The issue is that about 20 or so trees have "deformed tops" - the tree has grown straight, but in the course of nature, the top has either broken off in a storm, or the tree has grown irregularly, developing a "hook" or "lever" at the top of the tree. This has lead to considerable discussion and (unfortunately) argument within our association. A tree service was hired by our association and they recommended "topping" the evergreens with the "lever" on the top. They stated these "levers" become "sails" in the wind and weaken the trees. One side believes these trees are hazardous and should be topped for safety, the other side believes they should be left as they are.
Searching through resources on the internet has led me to believe that topping these trees is the worst thing that could be done for the future health of the trees, not to mention the effect on property values due to the unsightliness "topping" causes.
I am interested in obtaining any information on the subject and would be open to discussing this with an arborist if possible, preferably someone who is very familiar with northwest evergreens.
You are right to be concerned about topping. The discussion probably should be whether to remove the trees if they pose a true hazard, or leave the trees if they do not pose a hazard. A damaged leader can be remedied, but do not take my word for it! You need a CERTIFIED arborist. If the arborist is hired as a consultant he will not have any incentive to recommend work that is unnecessary (this is why I am suspicious of the tree-service company).
Here are two organizations to contact for referrals:
Plant Amnesty: www.plantamnesty.org
PNW Chapter of the International Society of Arboriculture (the organization that grants certification) www.pnwisa.org or www.isa-arbor.com
You want someone who has experience with tree hazard evaluation. Another source is Arboriculture by Harris, Clark and Matheny that discusses what to do when a conifer loses its leader.
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We recently bought a house on San Juan Island with lots of beautiful madronas (Arbutus menziesii) on the property. Two of them show no signs of life... others have the occasional dead branch here and there. We have been advised that this is likely caused by a fungus and that it can spread rapidly. We have been shown blackened excavated areas on the trunks of the dead trees.. and similar though less extensive areas on some of the others. What can be done to save our beautiful madronas?
It is possible your trees are suffering from canker fungus (Nattrassia mangiferae), or some other type of fungal disease. Here is a link to a file called "The Decline of the Pacific Madrone" edited by A. B. Adams (from a symposium held here at the Center for Urban Horticulture in 1995): http://soilslab.cfr.washington.edu
You may want to call a certified arborist to look at the trees, determine the extent of the disease, and help you decide whether the trees can be salvaged. (Search the Pacific Northwest Chapter of the International Society of Arboriculture for a local arborist.)
Below is a response to a question similar to yours from the
University of British Columbia Botanical Garden and Centre for Plant Research:
"What you describe are the classic symptoms of 'Arbutus decline,' which is postulated in the literature as being caused by mostly naturally-occurring, weakly pathogenic fungi, made more virulent by the predisposition of Arbutus to disease, caused by urban stresses, especially root disturbance." (see also: "Arbutus Tree Decline" from Nanaimo. B.C.'s Parks, Recreation and Culture department)
Nevertheless, I am convinced that much of the die-back we are seeing on established Arbutus trees stems not from disease, but primarily from the complications of damage, competition, shading and especially, drought stress (we have had a run of very droughty summers). Typically, the most affected natural stands of Arbutus are very dense, with poor air-circulation, internal shading and intense competition for resources (characteristic of rapid growth after clearing). And because this region is becoming increasingly urbanized, with more vehicular and marine traffic (marine traffic evidently accounts for a huge proportion of the pollution in the Fraser Basin air-shed), I would not discount atmospheric pollution as a contributor to the decline (one more stress).
I think the reason your shaded trees are not as affected is that their roots are probably deeper and less exposed, and there is reduced evaporative demand on the leaves. However, as the shade increases, these plants, or at least their shaded branches, will succumb.
What to do? I do not think there is anything you can do to save the existing trees, except, perhaps, to minimize human influence around them. You should avoid both disrupting roots and damaging above-ground portions of the trees (with pruning, for example), as any wound is an open invitation to disease-causing micro-organisms. Interestingly, a friend of mine who kayaks has seen black bears foraging for fruit in the tops of Arbutus trees on Keats Island (he should have told them they are not helping the situation any).
Irrigation of established plants is nearly always counter-productive because it encourages surface rooting (which is typically short-lived and considerably less resilient than deep rooting), and summer irrigation is worse, as Arbutus are well adapted to our conditions (at least, where we find them growing naturally) and normally somewhat dormant in summer. You can plant more Arbutus, as a previous correspondent in this thread has, to replace what you are losing, but there is no guarantee that these plants will survive the next drought or indeed, your well-intentioned meddling. (I suspect his plant was lost for the same reason most young Arbutus are lost--by root damage from saturated or compacted soil conditions). The natural succession on your island is probably (as elsewhere in similar places along the coast) tending toward open Douglas fir forest with a few scattered Arbutus in the more inhospitable places. In other words, you can plant what you will, but the larger the Douglas firs, the fewer Arbutus will be able to survive around them. Neither species is particularly shade tolerant and resources are pretty limited on rocky ground, where both prefer to grow locally. Expect change.
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I live in a condo that is surrounded by land owned by the condo association. The conifers on the site have now grown to a height that is beginning to obstruct the view of the neighbors. We have a covenant with these neighbors not to exceed a height of 25 ft with our trees. Last year several of the conifers were topped and others removed. Our concern now is that we may have to either top or remove more trees. In addition to not wanting to block the view of our neighbors, our association does not want to destabilize the ground - we all live on a hillside. What can we do over the next 5, 10, 15, 20 years to decrease the number of conifers and replace them with other trees that will be neighbor-friendly and keep our hill stable?
The short answer is to plant shrubs and groundcovers.
The long answer is that slope stabilization is a serious concern and deserves expert advice. Get started in your research by reading the articles on the WA Dept. of Ecology site:
Controlling Erosion Using Vegetation.
Your condo association may want to hire a consulting arborist and/or a civil engineer ("To locate technical experts such as experienced registered engineers specializing in geotechnical and/or drainage projects, use local telephone directories or call the Seattle or Kitsap branch of the American Society of Civil Engineers (ASCE) for membership references." from DOE site)
For an arborist referral try:
The Pacific Northwest chapter of the International Society of Arboriculture has information about hiring an arborist.
The following site can help to narrow the search to your area: www.isa-arbor.com
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April 19 2012 16:02:30