For more than 24 hours last week, Cody Lee Miller perched in a giant sequoia tree in downtown Seattle, pelting people and cars with pine cones and tearing off branches to throw like spears into the street below.

Investigators said Mr. Miller harmed the 90-foot tree, and they have come up with a figure for the damage, using a complicated formula that goes far beyond the value of natural beauty.

A Seattle tree expert, Darren Morgan, said Mr. Miller caused $7,800 in damage, according to court documents released this week. Investigators took into account the tree’s age, its potential life span and how much of its lush foliage was denuded.

The formula, created by professional foresters, goes like this. The trunk is 34 inches in diameter at breast height, an investigators’ report said. The tree has a “95 percent species rating,” a “100 percent condition rating” and a “100 percent location rating,” Mr. Morgan was quoted as noting in his calculations.