Vatican City, November 29 - A walnut tree given to Pope Benedict XVI as a gift by the Italian Forest Guards and nature foundation Sorelle Natura was planted in the Vatican gardens on Thursday. The plant was given to the pontiff to mark the anniversary of the appointment of Saint Francis of Assisi as patron of ecologists on November 29 1979, and also to commemorate the official day of the safeguarding of creation. The walnut tree, planted in an area located between the heliport and the Tower of Saint John, was blessed by Bishop Giuseppe Sciacca, secretary-general of the governatorate of Vatican City State. Present at the ceremony were Roberto Leoni, president of the Sorella Natura foundation, and Cesare Patrone, chief of the Italian Forest Guards. A commemorative plaque made of a characteristic red stone found in the Assisi area was placed near the tree.