Recently you’re “Ask the Arborist” editor was working in an area heavily wooded with Black Birch (Betula lenta) and noticed bad dead areas in the trunk (see first photo). This large dead area is Nectria canker (or often referred to as target canker) caused by the fungus Nectria galligena. According to literature cited from “The Missouri Botanical Garden” Nectria canker may worldwide occur in over 60 species of trees and shrubs, including Birch, Apple, Dogwood, Pear, Walnut and members of the Magnolia family. Nectria canker is generally not a fatal disease, but as you can see from our photos, can cause severe structural weakness and loss of aesthetic value. Nectria canker overwinters in the host tree callus tissue and continues growth while the host tree is dormant. During warm moist periods (like spring 2014 in Newtown, CT) fruiting structures begin to develop and once again like other fungus diseases, the spores are released into the atmosphere ready to search out other unsuspecting tree victims.
From a an arboricultural tree care stand point, my major concern with Nectria canker is the large dead areas that may cause severe structural weakness that could fail during high winds, heavy snow, excessive ice accumulation or other adverse weather conditions. Structural weak trees can easily become a potential risk target for things below, including your home and family.
Please consult with your local Yacko and Sons Tree Service staff Forester / Licensed Arborist to determine the risk factors of your trees. Forester Jeff is available for YOUR FREE LOOK-UP FROM THE TRUNK-UP! Contact Forester Jeff: jeff@yackoandsons.com or 203-733-9219
Find out what's happening in Newtownfor free with the latest updates from Patch.
