I’m almost 3 months into clearing steep hillside of invasive trees .making check log terraces planted with vetiver along contour with sweet potatoes.I back filled terraces with decaying wood and leaves ,brown longon leaves and guinea grass leaves .im also planting fruit trees papayas ,soursop ,banana etc I’ve bought a small chipper that chips 3 inch branches.theres a huge supply of hau bush that chips real small also cutting banana stalks in half for water .my problem is how to get rid of umbrella tree and invasive gauge from growing back ?