Appendix J-3

Marking Guidelines Alternative 3 Fuels Reduction 

Introduction 

The thinning from below marking guidelines are designed to implement Alternative 3 of the Kings River 

Experimental Watershed (EIS). Alternative 3 is designed to respond to design criteria consistent with 

the 2001 Framework. 

Alternative 3 contains three landscape treatment prescriptions, the Old Forest Emphasis Thin, General 

Forest Thin and Defense Zone Thin:

1. Old Forest Emphasis Thin: This treatment applies to any stand area with pre-settlement 

characteristics (CWHR size classes 5M, 5D, 6) including high levels of horizontal and vertical diversity at 

the stand-scale. Old forest (CWHR size classes 5M, 5D, 6) and other sensitive habitat areas would be 

thinned with an upper tree diameter limit of 12 inches DBH. This prescription is focused on removal of 

ladder fuels in dense patches. The treatment removes 90 percent of trees less than 12 inches DBH. 

These areas are patches found within stands. Markers should use vegetation maps developed for the 

project to identify 5M, 5D and 6 CWHR size and density patches.

2. General Forest Thin: This prescription is designed reducing the potential for severe wildfire. General 

forest would be thinned with an upper diameter limit of 20 inches DBH to 50 percent canopy cover or no 

more than a 20 percent reduction in canopy cover. Maintain portions of stand above 50 percent canopy 

cover with medium size trees above 5O percent. This prescription will leave approximately 200 square 

feet or reduce existing stand basal area by approximately 20 percent. When existing canopy cover is 

below 50 percent, focus removals on ladder fuels up to 20 inches DBH. When trees less than 16” 

dominate canopy cover, reduce tree densities to achieve crown fire objectives. 

3. Defense Zone Thin: Stands that lie within the first 0.25 miles around structures in the WUI would be 

thinned more aggressively to minimize fire danger. This thinning strategy responds to a desire in the 

2001 SNFPA to reduce fire severity while maintaining dense canopy conditions in the WUI. It treats 

ground fuels, ladder fuels and only limited crown fuels. Stands that lie within the WUI would be thinned 

with an upper diameter limit of 20 inches to 50 percent canopy cover. Alternative 3 applies a more 

aggressive approach to fuels reduction in the Defense Zone. Basal area retention will vary based upon 

the size of trees and existing basal area. Generally basal area reduction will be less than 35 percent. 

Marking Guideline

Thinning from below is a forest treatment that seeks to reduce stand density by removing trees 

beginning with trees in the most subordinate position. Trees that are of sufficient size can be used to 

produce structural lumber products. Trees to small for lumber are removed as biomass to generate 

electricity or piled and burned. Marking guidelines for thinning is based on meeting the project 

objectives and desired conditions. Tree removal occurs to reduce the potential for crown fire. Trees 
that remain are selected on their ability to make use of increased site resources and reduce vertical and 

horizontal fuel continuity. 

Criteria used in determining trees to remove and trees to leave are listed below:

 Species- healthy black oaks are given first priority for leave trees. Ten percent of 

dominant oaks will be provide .25 acre opening for crown expansion. This meets 

the LRMP objective of providing oak canopy cover. Healthy Sugar pine are second 

priority, Leaving sugar pine resistant to White Pine Blister Rust is consistent with 

the Districts Sugar Pine Strategy. Ponderosa Pine is given third priority. It is the 

dominant tree species. Incense cedar is given last priority. Incense cedar has 

encroached in the understory. It is over represented and falls outside the range of 

variability.

 Disease-During thinning understory trees (12” or 20” DBH) with mistletoe are 

discriminated against. Trees with less mistletoe or those with mistletoe in the 

lower third or where the mistletoe is found on the outer crown are favored over 

those with high amounts of mistletoe and infections close to the bole or in the 

upper two thirds of the crown. Mistletoe infections are lowered in intensity and in 

the total number of trees infected with mistletoe are reduced. 

 Crown position-Trees in the lower crown layers are removed to provide space 

for trees in the upper crown layers. Crown position is a strong indicator of a trees 

ability to make use of site resources

 Fuel ladders-Trees that provide fuel ladders to larger trees are removed to create 

conditions suitable for underburning. Protecting larger trees from underburning

maintains stand structures that will contribute to future habitat diversity.

 Spacing- In the General Forest and Defense thinning trees are spaced apart to 

provide room for crowns and root expansion and meet objectives to reduce tree 

stress and reduce potential for sustained crown fire.

The number of trees or the basal area of trees remaining following thinning treatment varies based on 

the size of existing trees and the objectives for each stand. Alternative 3 proposed to thin from below 

remove trees up to the canopy cover limits and size limitations prescribed in the 2001 SNFPA.