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Big trees, bark beetles, goshawks, and timber

Date: August 21, 2019

The creation and maintenance of stand and forest structures dominated by large ponderosa pine trees resistant and resilient to bark beetles and wildfires can be accomplished


Ponderosa pine thinning on the Black Hills Experimental Forest in 2004.
One of 12 thinning densities established on the Black Hills Experimental Forest in 1962. They were followed through 2010 when the trees in the study were killed by mountain pine beetles (photo credit: Lance Asherin).

Throughout the Rocky Mountains over the last century, large ponderosa pine trees provided lumber for growing cities and towns, along with fuel and timber for the mining and railroad industries. Most of these forests are now occupied by dense young and mid-aged forests highly susceptible to being killed by bark beetles and burned by wildfires. These conditions have been exacerbated by fire suppression and urban encroachment. As a result, knowledge is needed to inform management actions directed at restoring and conserving ponderosa pine forests. 


Forest development research has been conducted for over 100 years. In 1960 research on the development of ponderosa pine forests was started both in northern Arizona and western South Dakota. Intensive bark beetle research commenced in 1980 in western South Dakota adding to work started in 1910. These lines of research followed individual trees and different stand structures. Similarly, northern goshawk and its prey’s habitat research started in 1990 adding knowledge on the importance of large ponderosa pine trees in the goshawk’s conservation. Combined, this research and resulting publications have transformed how ponderosa pine forests are viewed, valued, and managed throughout western North America. 

Key Findings

  • Stand thinning is suggested early in the life of a forest to create conditions that produce large trees.
  • Moderately low tree densities with open understories and irregularly tree spacing are recommended.
  • Young to old forest structures irregularly arranged within stands and over landscapes of low-density trees are resilient and resistant to bark beetles and wildfire.

Such conditions provide habitat for the northern goshawk and its prey as well as many other wildlife species.

Mountain pine beetle caused tree mortality in the Black Hills
Millions of ponderosa pine trees were killed in the central Hills from 2000 through 2012. The thinning and bark beetle studies provide knowledge to ameliorate this damage (photo credit: 2011 Black Hills National Forest aerial flight).

Featured Publications

Graham, Russell T. ; Asherin, Lance A. ; Jain, Terrie B. ; Baggett, Scott ; Battaglia, Mike A. , 2019
Graham, Russell T. ; Asherin, Lance A. ; Battaglia, Mike A. ; Jain, Terrie B. ; Mata, Stephen A. , 2016
Graham, Russell T. ; Bayard de Volo, Shelley ; Reynolds, Richard T. , 2015
Graham, Russell T. ; Rodriguez, Ronald L. ; Paulin, Kathleen M. ; Player, Rodney L. ; Heap, Arlene P. ; Williams, Richard , 1999

Forest Service Partners: 
Blaine Cook, Black Hills National Forest
Sandy Boyce, Washington Office
Kurt Allen, Forest Health and Protection, Region 2
Ron Rodriguez, Dixie National Forest
Research Location: 
South Dakota, Utah, Arizona, Idaho