Forest and Watershed Geology Documents

​Timber Harvest Plan Geologic Review Documents

CGS staff conduct engineering geologic field reviews of select Timber Harvesting Plans (THP) as part of a multi-agency review team led by the California Department of Forestry and Fire Protection (CAL FIRE). Upon completion of the field reviews, CGS staff prepare memoranda that summarize pertinent observations and recommendations made during the field review. These memoranda are submitted to CAL FIRE, the lead agency for timber harvest plan approval, for consideration as part of the THP review process.

THP engineering geologic review memoranda prepared by CGS staff are available for viewing on the CalTREES website. If you cannot find a particular CGS memorandum, please send an email with the THP number to and we will email a PDF if available (THPs beginning in 2002) or direct you to CAL FIRE for a hard copy. For more information on the THP review process, visit CAL FIRE's webpage.

NOTE: As of April 30, 2019, CGS THP documents are only available via CalTREES. To start using the CalTREES system immediately, click the CalTREES logo below.

CalTREES logo 

ABOUT CALTREES: Timber harvest permitting in California is moving into a new era with the launch of CalTREES by CAL FIRE and the AB 1492 Timber Regulation and Forest Restoration Program. The CalTREES system streamlines the submission and review processes for timber harvesting plan (THP) documents. For more information, please visit the CalTREES Information Portal, the CalTREES FAQ web page, or email CalTREES Support.

Post-Fire Erosion and Slope Stability Documents

California Geological Survey staff provide advisory services to the Department of Forestry and Fire Protection regarding geologic and slope stability concerns associated with wildfires and vegetation management plans in mountainous areas of California. The results of some of this work are presented below.

Document Description
ArticleCalifornia Fires, Floods, and Landslide, 2005
PowerPointCalifornia Debris Flows & The Effects of Fire, 2005
California Geology ArticleFire and Rain Equal Mudflows, Big Sur 1972
California Geology Article
Hazard Evaluation Following the Tunnel (Oakland Hills) Fire, Oct 19-23, 1991
Burn Site FormCalifornia Geological Survey Burn Site Evaluation Form

Misc. Documents Prepared by the CGS Forest and Watershed Geology Program

Document Description
SR 217Special Report 217
Geologic Compilation of Quaternary Surficial Deposits in Southern California. Contains report and a complete GIS digital database for all 16 maps.

Review of July 2002 EPA Analysis Impacts of Timberland Management on Water Quality. Dated November 27, 2002.

MemorandaRegional Geologic Information and Preliminary Geomorphic Characterization of Bear Creek at Quigley Grove, Humboldt County, California. Dated February 24, 2003.

Geologic Consequences of Tree Removal Under the National Resources Conservation Service (NRCS) Sponsored Southern California Tree Mortality Emergency Watershed Protection Program. Dated November 28, 2006.
Appendix 1 - Inventory Sheet
Appendix 2 - Photos

SP 120
SP 120 Errata

Special Publication 120
Index to Published Landslide Maps, California Coast Ranges, Monterey County and North for Use in Timber Harvesting Plan Preparation on Non-Federal Land, 1999.

Vegetation Island Review, Oceano Dunes SVRA

Geologic review of shape, size, and geomorphology of 20 vegetation islands in Oceano Dunes SVRA. Describes geologic conditions and sand sample analyses, dune processes, sediment transport, sedimentation and moisture retention, historical changes over more than 60 years, and suggested management practices.

Phase 2 Study

At the request of California State Parks, CGS prepared this evaluation of the San Luis Obispo County Air Pollution Control District’s “South County Phase 2 Particulate Study” dated February 2010.