Q: In May of 2007 we added a gate and set of retractable steps to our back fence, which borders on the (unused) yard of a building owned by an educational institution. We have used this to bring in heavy items and let our dogs into the yard (many other neighbours and dog walkers use this yard). Today the educational institution planted some trees in front of the gate. Do we have any hope of a legal course (emergency exit perhaps) or are we out of luck (as I suspect)?
A: Your suspicion is correct. Unless you have a registered right-of-way over the property that abuts yours, technically your use of the lot, whether deserted or in full use, would be considered trespassing.
This does not mean that reasonable heads may still prevail. If you are providing a service to the institution by keeping an eye on the property, perhaps the powers that be may be willing to allow you to move the tree and thereby continue what appears to be harmless access to the lot. However, it is in their discretion to decide yes or no.