Tree id please

im located in chicago,All the time in the summer i see tiger swallowtails flying around these 3 trees i dont know if they are host plants for them..if so i would like to get some because they are always on there. im not sure if 2 of these are the same ones because one is older then to other. here are the pics of the 3 trees. anyone have any idea?

Tree 1: <a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree1.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree1.jpg" border="0" alt="Tree 1"></a>

<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree2.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree2.jpg" border="0" alt="tree 2"></a>

Tree 2:<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree3.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree3.jpg" border="0" alt="Tree 3"></a>

<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree4.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree4.jpg" border="0" alt="Tree 4"></a>

Tree 3:<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree5.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree5.jpg" border="0" alt="Tree 5"></a>

<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree6.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree6.jpg" border="0" alt="tree 6"></a>

<a href="http://s932.photobucket.com/albums/ad164/frankiebf/?action=view&current=Tree7.jpg" target="_blank"><img src="http://i932.photobucket.com/albums/ad164/frankiebf/Tree7.jpg" border="0" alt="tree7"></a>