This year the Polly Hill Arboretum’s annual David H. Smith Memorial lecture features Coastal Maine Botanical Gardens plant curator Bill Cullina, who will discuss the environment via a long-term geological view. His talk is called The Web of Life: Taking the Long View.

Mr. Cullina believes that to think only in terms of life relating to our own lifespan, while quite common, does a disservice to the idea of permanence. Far better to contemplate the world of living things that survive over much longer intervals. For example, a Douglas fir that has lived for 1,000 years is considered quite old to us, but in geological time 1,000 years is roughly equivalent to 10 minutes in our own lives.

Mr. Cullina’s talk will take place on Wednesday, August 10 at 7:30 p.m. at the arboretum in West Tisbury. The cost is $10 or $5 for PHA members. For more details, call 508-693-9426.