These planters landed on Morse in 2011 or 2012. Ordinarily plants or trees do not grow so far above ground. Below is a quoted quote from HGTV regarding the drawbacks of being planted in artificial containers.
"Essentially any type of container exposes the roots to ambient temperatures," says Dr. Hannah Mathers, assistant professor in nursery and landscape extension at Ohio State University in Columbus. Mature roots can gradually get used to the cold, but young, immature roots can't. In containers, young roots grow on the outer part of the rootball. When exposed to the cold, young roots are unable to acclimate and die back.We just had one of the coldest winters on record. These small pines never had a chance. If the built in sprinklers still work then the city should replace these dead shrubs soon.