From paint he tried out blowtorches, wetting his nude models, impressing their bodies onto cardboard, then blasting the cardboard with fire, scarring the dry areas and leaving bodily traces like ghostly outlines.
Similarly fire scarring of the tree during its lifetime appears to lead to increased impregnation of the wood material at the base of the stem (pers. obs).
What he did not expect was for the abstract piece, which was installed in 1976, to become so much a part of the environment that during the 1980s, homeless men took to sleeping under it, flames from barrel fires scarred it, and urine oxidized it before its time.
In each watershed, we sampled fire-scarred trees and tree age structure and identified fire years and cohorts of post-fire tree recruitment.
Mean fire return intervals prior to fire exclusion (1700 1900) ranged from 1 to 29 years for fires scarring >25% of the fire-scar samples.
"The Rim Fire is starting to hit all those old fire scars".
Some of the fire scars stood adjacent to stands of lodgepole pine destroyed by beetles.
Such "fire scars" in long-lived species like giant sequoias allow him to estimate the past frequency of forest fires.
The heartrot fungi gain entrance through any wound resulting from fire scars, broken limbs, or anything else that damages the tree's protective tissue.
It appears that several of the fire scars are as large as – or larger than – the surface area of that reservoir.
Here's Pyne's description of the images and their significance: The upper image shows a grove of Yosemite's Big Trees as they looked in 1890 (note the fire scars on several).
