For nearly five years the arboretum has been plagued by a fungal epidemic: cedar-apple rust. The wild crabapple, mayhaws, and several different hawthorns have suffered from this fungus, which depends on the eastern red cedar for its lifecycle. At first, in 2018, we treated the mayhaws with an anti-fungal spray. This labor intensive job resulted in no noticeable effect: the following spring, the mayhaws were still thoroughly infected with the fungus, potentially threatening their longevity.
The next step was to remove an eastern red cedar, which was both growing in proximity to the mayhaws and exceptionally ornamented with the developing fungal galls. The decision to cut down a healthy tree was not easy; its removal occurred in April 2021. You can read about the process here. Within a year of its removal, there was a noticeable improvement in the arboretum's lone wild crabapple. While the mayhaws were still infected with the fungus, their overall health improved.
Then, in 2022, one of the parsley hawthorns showed signs of a terrible infection. The remaining eastern red cedars were examined, and two cedars were shown to be harboring the fungal galls. They were removed in late 2022.
Two eastern red cedars remain, and today one is on the chopping block. Galls were discovered on this cedar last winter, and over the summer the hawthorns growing on the grass slope near Cline Hall looked pitiful from the rust. So, with the aim of eliminating the cedar-apple rust in the arboretum, we are removing yet another eastern red cedar.
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| An established, volunteer eastern red cedar (Juniperus virginiana) is pictured center. This is one of our two remaining eastern red cedars. Its age isn't documented, but we know with certainty that this individual germinated here prior to 2012. It's a happy tree, doing well in this area, although it would be larger and stouter with more sunlight. A mature white oak (Quercus alba) looms above it. |
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| Due to the existence of cedar-apple rust galls developing in its canopy, this eastern red cedar was marked for removal. Today, the process began. The first step was to climb the tree and cut off as many branches as possible. This will make the tree less messy when it is taken down. |
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| These are the removed branches. A few of them carry the developing cedar-apple rust galls, currently hard and dry. |
The trunk and remaining branches will come down this weekend. Then there will be one remaining eastern red cedar in the arboretum catalogue, which can be found in the Mickle Hall parking lot. You can read about it on an older blog post, found here. As of right now, that cedar does not have any visible galls. It, however, suffers from being confined to a small growing space, so it too will most likely have to be removed for poor health. The fate of the eastern red cedars in the arboretum is unfortunate, but this tree is very common in our area and can be enjoyed elsewhere. We have many important species in the arboretum to look after, and this one was simply too dangerous to its neighbors.
