Trees come and go in the park whether they are felled by old age, ice or by the latest foreign invader, new ones rise up and take their place. Many of the new ones are foreign invaders themselves.
Norway Maples have become ubiquitous in Eastern Canada – even to the point of having their leaf on our currency. They have been in Canada for hundreds of years and are able to grow more quickly and produce leaf earlier in the season than native trees. In addition, their shallow roots and dense shade have a smothering effect on native tree seedlings. As for Siberian / Chinese Elm, I can honestly say I must have killed thousands of saplings in their attempts to establish a beachhead in my back yard.
This old Norway Maple provides wonderful summer shade to cars in the Raymore parking lot but its age is showing and its hollowing interior has become home to more than a few squirrels. It drops the occasional limb now and then and will soon become a victim of old age. Unfortunately its replacement (if any) will take many years to provide the same cover. Hopefully the replacement will be from a native species.
Across the path from the parking lot attempts have been made to mass plant native trees and shrubs with varying degrees of success. Part of the problem is that the saplings (thanks to the availability of student labour) are planted at the hottest time of year. Last summer, a substantial batch of saplings was delivered to the planting site and left in plastic bags for a day in hot sunshine before being carefully planted. Needless to say, thanks to bad planning, only a tiny fraction survived, wasting a whole lot of time, effort and money.