Dead Trees?

Question:

 I planted two sugar maples last November. Each is about 7 feet tall. It has not grown any leaves this spring. How do I determine if they are dead? The nursery told us that these are hardy maples and rarely die.

Minnesota Master Gardeners say:

 First, take a small pocket knife with a really sharp blade and gently scrape off some of the bark. If there is green tissue under the bark there is still life in the tree. If there is no green tissue, the trees are probably dead.

It's difficult to say precisely why they did not survive but here are some possibilities. First, the trees were planted too late in the fall and they were not able to get their root systems established before freeze up. Second, they may have already been dead when they were planted. Third, the trees may not have been propagated from northern grown stock in which case they were not winter hardy for USDA Zone 4. If you saved your receipt from the nursery, take the trees back and ask to have them replaced. Most reputable nurseries guarantee their stock for at least one year.