When forestry supervisor Ryan Stewart wants to check on how well Southern California Edison’s Shaver Lake forest is progressing toward being restored to its original natural state a century ago, there’s not a lot of guessing involved.

He just looks on the wall of his office at Camp Edison, which has a map by A.W. Elam called a timber cruise. It shows the native species composition of a large portion of SCE property 108 years ago when the land was still virgin forest that had never been logged.

The map is part of a timber inventory that was done in 1912 when SCE bought the land in the Sierra Nevada east of Fresno from the Fresno Flume & Lumber Co. for the utility’s Big Creek hydroelectric project. A century later, the map has become a touchstone for SCE’s ongoing forest management efforts.

SCE’s forestry staff thinks that if they can return the 20,000 acres to something akin to its original state, when wildfire was a natural part of the forest’s ecology, the forest will be more resistant to disease, bark beetles and catastrophic blazes from climate change that have become increasingly frequent and devastating.

"The map shows what it was like before it was logged in the 1940s by the Byles and Jameson Lumber Co.,” Stewart said.

For example, since those early days and the logging that followed, more shade-tolerant trees have grown on the property, crowding out the sugar pines, ponderosa pines and vegetation that need more sunlight to thrive. When a wildfire comes, it can more easily burn a dense canopy.

SCE uses a combination of prescribed burns and logging to help remove dead or dying trees and flammable undergrowth. Twice a year, the staff plants as many as 30,000 sugar pine, ponderosa pine and giant sequoia seedlings from SCE’s Auberry nursery to recreate the forest’s historic composition.

To help in the reforestation effort, SCE has restarted its own inventory, hiring forestry students from California Polytechnic University, San Luis Obispo; Humboldt State University; UC Berkeley and Reedley College in Fresno County every summer to collect the data.

Working on a one-tenth of an acre plot at a time, the students collect information using a laser tool to measure the height of the trees and a handheld data collector to record details like the species and condition of the vegetation. They can cover 40 acres per day — 1,200 acres each summer.

The SCE forestry staff can then compare that data with the 1912 map and determine what, if any, changes need to be made.

A side benefit is that by planting new trees to create a healthy forest, it will help remove carbon from the atmosphere, one of the methods cited in SCE’s Pathway 2045 analysis to help the state become carbon neutral by 2045.

For Stewart, SCE’s forest stewardship is part of the company’s legacy for California.

“We’re planting trees not for just one year or 10 years, but for 75 or 100 years for our granddaughters and grandsons,” he said.