Hello all, I'm glad to find this wonderful resource and this is my first post. We recently moved to an acreage in central Manitoba and we have several of these huge trees in the yard. Someone here suggested they may be poplars, but I've never seen a poplar with this type of leaf. The leaves are also relatively small - about 1.5" across. Also of note is that we haven't seen them as part of shelter belts or natural tree forests in this area. Perhaps they were brought here by a previous owner. Thanks. Debbie
White Poplar Populus alba. Native to Europe and Asia, invasive in some parts of Canada (not sure if that applies to Manitoba).