NEED HELP AND RECOMENDATIONS THAT THERE IS A Leylandii (CONIFER) TREE ABOUT 12 METERS HIGH ONLY ABOUT 1.75Mtr. FROM WHERE THE FOUNDATION IS TO BE EXACAVATED. THE SOIL IS LAND FILLED WITH SOME CLAY.HOW CAN I KEEP THE TREE AND WHAT DEPTH I NEED TO GO UP TO FOR FOUNDATION AND WHAT PRECAUTIONS I...