https://extension.psu.edu/tree-of-heaven
Tree of heaven is very difficult to control because of its tendency to send suckers up from its extensive root system and  because of its heavy production of seeds each year.  The above website provides some helpful information on the recommended herbicides and the timing of their application.  For the tree in your picture, it should be cut down and then be prepared to apply herbicide to any regrowth or additional growth from other suckers in your landscape.  The above website recommends using either Glyphosate (Round-up) or Triclopyr (brush killer) to the young plants in July.  Glyphosate will kill grass as well as broadleaf plants so care must be used to keep from killing your lawn.  Triclopyr does not kill grass and it is best used in lawns where the suckers are present.  Cutting off the young Tree-of-Heaven will not usually kill the plant but it will cause the plant to send up new suckers which are more sensitive to the herbicides than larger plants are.