What symbolism can be found in the oak trees that are planted at the 9/11 memorial in the novel, Towers Falling?

The oak trees planted at the 9/11 memorial symbolize American grown and prosperity. New oak tress will sprout up over the years just from the small acorn that happens to fall and get embedded.

The trees also symbolize strength and adaptability. There is a saying: "From the tiniest acorn grows the mightiest oak." Oaks are known for their ability to grow without much fuss, right from where an acorn falls. The symbolism implies that the towers fell right there and in their place grows something just as mighty and strong, the memorial to honor the victims. It also symbolizes that the two falling towers made America stronger by planting the seeds that began the nation's war on terror.