DANVILLE, Va. -

A year-long effort to clone a 150-year-old, iconic tree at Virginia International Raceway has come to a close.

The White Oak tree collapsed last July, and researchers at the  Institute for Advanced Learning and Research in Danville hoped to clone it.

Researchers say the tree's old age might have made it more difficult to clone.

Two different cloning methods failed. One was by inducing roots from the tree cuttings and the second was to induce shoot regeneration through tissue culture.

The tree was a symbol of VIR.