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"'What are my parasites to me? May they live and prosper! I am strong enough for it.'" -- F.W.N. Eastern Red Cedar (Juniperus virginiana), photographed January 5, 2018 |
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In 2018, we identified a problem: the plant disease known as cedar-apple-rust prevented the arboretum's four mayhaws from producing fruit. A fungus, Gymnosporangium juniperi-virginianae, had made itself at home in a particular eastern red cedar (Juniperus virginiana), pictured above, and this fungus seasonally infected the mayhaws. While this organism can be observed on many cedars, this tree has supported a particularly virulent and aggresive population. Since it was deemed more practical to treat the mayhaws rather than the cedar, all four mayhaws were sprayed with a fungicide. You can read about that project on a blog post (here).
Spraying the mayhaws with a fungicide proved ineffective at breaking the cycle between cedar and mayhaw. Each spring, the mayhaw twigs were thoroughly covered in rust and could not produce fruit. Subsequently, our one wild crabapple (Malus angustifolia), which stands between the cedar and the mayhaws, lost its vigor and looked near death. Upon examination, rust was discovered here too. Furthermore, for the past two years, five other species of Crataegus have been infected with rust, and, perhaps coincidentally, the hog haw (Crataegus brachyacantha) died last summer.
Since the rust is deleterious to the health of so many trees, I, the arboretum curator, decided to remove the primary host of the rust, i.e., this eastern red cedar. There are four other eastern red cedars in the arboretum collection. One tree lives in near isolation on an island in the Mickle Hall parking lot, which you can read about here; it does not appear to have any parasites. The other three trees are in a cluster on the north side of the arboretum; these trees have parasites each year, but only a negligible amount. The only cedar that is thoroughly parasitized is the individual pictured above, located at the southern edge of the arboretum near the Fitness Center. You can read about it here. This beautiful, vigorous 'bad apple' was chopped down this week.
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A handsaw and a chainsaw were used to remove the middle and lower branches, leaving a triangular green crown.
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With the foliage removed, we see ascending branches and a slight curve in the trunk.
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Trunk bark is rough and peeling.
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The heartwood is a beautiful color and fragrant.
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Amber-colored sap bleeds from where the branches were cut. This sap is very sticky and stains clothes.
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While cutting branches, we were thoroughly reminded of the reason for removing this particular tree. Among the leaves we see numerous round objects. From a distance, they resemble mature bald cypress fruits.
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They are not fruits of the tree. This is a fungus that lives as a parasite on the eastern red cedar. Pictured above are old, inactive galls of the plant disease Gymnosporangium juniperi-virginianae.
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When smashed, the old galls crumble and turn into dust.
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Right now, in the spring, the fresh galls are activated by rainy weather. From seemingly inert, dark-brown bulbous blobs, they transform into ooey-gooey orange tentacled monsters. Haws certainly have nightmares about it. Will you, too?
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While sawing off branches, there was plenty of opportunity to get up close and personal with these jelly-like fungi. It appears that the central gall extrudes tentacles of orange slime though dozens of nodules. Perhaps upon drying, wind spreads the spores.
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So, the cedar has been stripped to the trunk. Removing all that material is a large and dirty job; watch out for the sap. Since the fungus feeds on living branches, it will no longer spread from this tree. Enjoy the trunk, which makes a handsome pillar. It's quite fragrant and will serve as a fine lookout post for birds, squirrels, insects, and the rest of the arboretum's mobile inhabitants.
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