Two Stories on Washington Square's Dying Trees Around the Fountain

Updated —

DNAinfo covers the dying trees around the Fountain and has the city’s response (and mine!) with this story: City Getting to Root of Washington Square Park Tree Deaths (August 25, 2011)

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Local Ecologist Blog notes how the latest tree is dying and researches what this signifies:

Strolling through the park yesterday morning I was struck by the bronze foliage of one of the remaining Zelkovas (Zelkova serrata, Japanese zelkova; Ulmaceae (elm family)) around the fountain. Bronze is a color typical of fall foliage; this tree is not exhibiting the dark green typical of summer.

The bronze (brown) color indicates leaf scorch. The entire canopy appears scorched.* Also, there is some dieback in the center of the canopy. What are the causes of scorch? From The Ohio State University “Disease Control in the Landscape” (Bulletin 614):

These diseases commonly result from winter damage as well as from poor root function coupled with high temperatures and moisture shortage. In some cases, bacterial infection of the plant is involved. Scorched leaves are brown around the edges and sometimes between the veins. Leaf yellowing and wilting may occur in late summer. Dieback and decline is often mistaken for Verticillium wilt. No wood streaking is present, however. Girdling roots may also cause these symptoms.

When I looked into the tree well I noticed that someone (or an animal) had dug near the trunk and at the edge of the basin. Looking into the cleared soil next to the trunk I did not see the root flare. Planting a tree so that its root flare is at the soil surface is important — for gas exchange, disease control, and to prevent girdling roots.

Read more at A bronze Zelkova in August.

See WSP Blog coverage posts on the dying trees.