The 90-year-old tree that fell over Friday afternoon and killed an Eden Prairie woman appeared healthy on the outside but was decaying inside, the city said Tuesday.

Witnesses to the freak accident that killed Nina Mackay, 56, were baffled because the basswood tree looked healthy and winds were well below the level typically needed to knock down a tree that size. But Tuesday, the city said that an investigation had found that the base of the tree had been decaying inside.

The tree, which was 30 inches in diameter, crushed Mackay as she walked with her two dogs by Mitchell Lake near George Moran Drive and Belfast Cove.

The city has a full-time forestry technician, two seasonal tree inspectors and a full-time park maintenance staff member who remove diseased and hazardous trees from city property, but with so many trees in the city, it also relies on residents' help. To report tree concerns, residents can go to

"Mackay will be deeply missed, and the city sends its deepest condolences to the Mackay family and friends," the city said in a prepared statement.

Mackay, who was a frequent volunteer and who was active in civic affairs, is survived by her husband, a 21-year-old son and an 18-year-old daughter. A memorial service is schedule for Saturday at Wooddale Church in Eden Prairie.