"把部分草地铺砖" most likely will against By law of city of ottawa. You'd better check with by-law office of city of ottawa before you do something like that.
Most of time the tree in the front of your house is NOT CITY property!!!
Check the distance between tree and road shoulder, if it is more than 5 meters. Then it very likely has nothing to do with City.
Could you cut any tree in your property then? Answer is NO.
If diameter of the tree is larger than 50cm then you couldn't cut it.
For most of tree, it means about 30 years old. I bet it isn't your case.
Any smaller tree than that, just cut it.