Rows of long nails were found hammered into trees at Estes Drive and Martin Luther King Jr. Boulevard, where a landowner will start clear-cutting the land this week.
Property owner Kathryn Butler began planning for the 14.7-acre timber harvest earlier this year. She has town permits for the work, which is scheduled to begin Monday, June 11.
Butler's representative and Emily Cameron, a town landscape architect, found trees skewered with between 30 and 50 long rusty nails each during an inspection of the site last week.
"I've been walking in the woods in Orange County for 32 years, and I've never seen anything like it," Cameron said. She turned over photos and information about the vandalism to the Chapel Hill Police Department.
Whit Rummel, who owns an adjacent wooded tract, visited the site this weekend after hearing about the nails.
Butler's "timber cutting company had found 30 to 40 trees with substantial spiking; nails driven in the tree vertically at one inch intervals for about two feet," he said.
Police think the vandalism may be old, public safety spokesman Ran Northam said. A woman was charged with a misdemeanor after hammering nails in a similar pattern to trees in 2016 at Southern Community Park.
But Tom Colhoun, a commercial Realtor who represents Butler, said he thinks the nails are more recent. The vandal used discolored nails so they wouldn't be as obvious, he said.
"They have not been there for a long time, because typically, if you put a nail in a tree, if it's been there a long time then the tree will 'bleed' from that injury. The sap will come down and run down the tree," Colhoun said. "These have no bleeding. [The nails] have just been put in."
Colhoun said they have asked police to make more frequent patrols of the area. Northam said police encouraged the property owner to install cameras.
Tree spiking, in which a nail, spike or other metal or ceramic rod is hammered into a tree, has been common form of eco-terrorism since the early 1980s, especially in Western states where timber and wood products are major industries. If the nail or spike is placed high enough, it can be missed during logging but cause damage and injuries after the tree is taken to a sawmill.
Vandals also have been known to damage equipment in an attempt to stop a timber harvest. Police Chief Chris Blue confirmed a report that someone spraypainted construction equipment at the site of the new Chapel Hill Retirement Center a few weeks ago.
Colhoun said the biggest concern is the potential for injury to a worker or a bystander.
"When you go in there with a big piece of equipment, you're not going to be able to see those at the bottom of the tree where they placed them," he said. "But when [the nail] hits that blade, you're talking about possibly shattering the blade and parts start flying everywhere, and somebody is going to get hurt."
The Butler harvest is one of two planned for Chapel Hill and Carrboro this year. Rummel, contrary to a recent post in the Chapel Hill Alliance for a Livable Town email listserv, said he does not have a plan to harvest his trees.
The other coming harvest involves about 40 acres of a roughly 70-acre between Bolin Creek and Seawell School Road. Landowner P.H. Craig Jr. has said he needs to replace the aging, damaged pine trees with new pines to mitigate the risk of beetle infestations and fires.
The harvest also will allow him to meet the requirements of the state's present use value program, which has provided him with property tax cuts for about 50 years. Craig has never made the timber harvests required by state law.
Forester Bill Dryman said he would be checking Craig's trees after hearing about the vandalism on Butler's property. He also will ask police to increase patrols in the area once logging starts this fall.