HUMBOLDT COUNTY (CBS / AP) — Authorities say unemployment and drug addiction have spurred an increase in the destructive practice of cutting off the knobby growths at the base of ancient redwood trees to make lacey-grained coffee tables.

They say the practice — known as burl poaching — has become so prevalent along the Northern California coast that Redwood National and State Parks have closed a popular road at night to deter thieves.

READ MORE: Oakland Ties 2020 Homicide Total in First 9 Months of 2021

Law enforcement Ranger Laura Denny said Tuesday that the size and frequency of thefts have been on the rise.

READ MORE: Advocates for Immigrant Rights March From Santa Rosa to Healdsburg

Park interpreter Jeff Denny says a redwood tree can survive the practice, but the legacy of the organism that could be 1,000 years old is threatened, because the burl is where it sprouts a clone before dying.

MORE NEWS: Pelosi Expects House to Pass Infrastructure Bill This Week

© Copyright 2014 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.