Q.japanese lilac
My Japanese Lilac Tree did not bloom this year and I was told to fertilize it with a high nitrogen fertilizer. Should I use this fertilizer? Also, the trunk of the tree (3 years old) has a large 10″ split in the bark about 3-4″ wide and I was told to use tree wound dressing and wrap it. Does that sound correct? I live in Syracuse, New York and the tree is 3 years old and had blooms on it last spring but not at all this spring. I am also concerned about the split in the trunk. Please help!!

If you want your Japanese Lilac to bloom I recommend never fertilizing. It actually will thrive and bloom in poor soil conditions.
To much fertilizer can cause lack of blossoms and rapid growth.
Do not wrap the trunk split. Allow it to have air around it, but watch for any signs of insects or disease.
Here are a couple of links for you.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/japanese-lilac-information.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/cracking-tree-trunks.htm