The phrase "noble trees" in the poem "A Heritage" by David Horsburgh symbolizes the enduring strength, resilience, and longevity of nature, particularly in the context of the poet's ancestral heritage. These noble trees represent the deep roots and enduring legacy that connect the speaker to his family's past and serve as a source of inspiration and pride for him.
Additionally, the trees may also symbolize the interconnectedness of all life and the harmony between nature and humanity, reminding the speaker of the importance of preserving and cherishing the natural world that has been passed down to him as a heritage.