Stand-replacing crown fires appear to be consistent with historical patterns of natural disturbance in some pinyon-juniper woodlands of the American Southwest, Colorado Plateau, and Great Basin. These moderate- to high-severity fires result in the death of most or all trees across areas that range from small groups of a few trees to hundreds of acres. In some forest ecosystems, logs remaining after fire are known to reduce soil movement and increase retention of soil nitrogen. In studies of pinyon-juniper management, woody material created by tree thinning has been shown to enhance plant establishment and affect soil moisture and chemistry..

Huffman, D.W.

OpenKnowledge@NAU

Ecological Restoration 
Institute 
The Ecological Restoration Institute is dedicated to reversing declines in the condition of forested communities throughout the Intermoun-
tain West, particularly those affected by severe wildfires and insect outbreaks.  Our efforts focus on science-based research of ecological 
and socio-economic matters related to restoration as well as support for on-the-ground treatments, outreach, and education. 
Ecological Restoration Institute, P.O. Box 15017, Flagstaff, AZ 86011, 928/523-7182, FAX 928/523-0296, www.eri.nau.edu 
Fact Sheet: Pinyon-Juniper Woodland Recovery    December 2010 
Dead Wood Plays Important Roles in Pinyon-Juniper Woodland Recovery After Wildfire  
  
S tand-replacing crown fires appear to be consistent with historical patterns of natural disturbance in some pinyon-juniper woodlands of the American Southwest, Colorado Plateau, and Great Basin. These moderate- to high-severity fires result in 
the death of most or all trees across areas that range from small 
groups of a few trees to hundreds of acres. In some forest eco-
systems, logs remaining after fire are known to reduce soil 
movement and increase retention of soil nitrogen. In studies of 
pinyon-juniper management, woody material created by tree 
thinning has been shown to enhance plant establishment and 
affect soil moisture and chemistry (Stoddard and others 2008). 
Logs and standing dead trees also can be important habitat for 
various animals. It follows that this dead material may influence 
vegetation patterns over long periods of time through numerous 
effects on soils, microclimate, and wildlife habitat. Presently, 
there is extremely little information available concerning dead 
wood amounts after fire and the influence this material may 
have on patterns of vegetation development. Lack of infor-
mation leads to uncertainty in determining appropriate manage-
ment responses to severe fires in pinyon-juniper ecosystems. In 
this case study (Huffman and others in revision), we were interested in quantifying dead wood amounts and analyzing tree re-
cruitment patterns and vegetation patterns 30 years after a severe fire in a northern Arizona pinyon-juniper woodland.  
 
Research Findings 
 Numbers and sizes of dead structures suggested the site had been previously occupied by persistent woodland. Such 
conditions develop in the absence of severe disturbance over the course of centuries. 
 Thirty years after the Yellow Jacket Fire, an average of 18 standing, dead trees per acre remained and the mass of 
sound and rotten logs was 2.6 and 0.7 tons per acre, respectively. 
 Plots showed relatively high cover (8.1-8.6%) of shrubs and moderate cover (3.6-4.2%) of grasses. Tree cover averaged 
1.5%. 
 Tree-ring analysis indicated that most juniper regeneration occurred within ten years of the fire event. Pinyon pine re-
generation was minimal. 
 Correlation analysis showed strong positive relationships between number of regenerating trees, number of shrubs, and 
number of dead trees on plots.  
 Minimum distance from live tree regeneration to dead wood averaged 4.6 ft (1.4 m) and about 30% of all live trees 
were found within about 1 foot of dead wood. Similar associations were observed between shrubs and dead wood.  
 Spatial analyses suggested weak aggregation of tree regeneration and dead wood, and stronger aggregation of shrubs 
and dead wood, and live trees and shrubs.  
 
Management Implications 
 Vegetation development after fire in pinyon-juniper ecosystems is highly variable and likely depends upon the interac-
tions of pre-fire conditions, fire severity, and post-fire legacies (e.g., dead, woody material).  
 Although juniper trees may begin to reestablish soon after fire, woodland conditions may take many decades or even 
centuries to develop. 
 The amount and condition of dead trees and logs remaining on a pinyon-juniper site after fire appears to help plants 
establish by modifying microclimate, soil conditions, and providing habitat for animal seed dispersers. 
 The resilience of these ecosystems may depend upon conservation of dead, woody material.  
Juniper regeneration (green bars) displayed in five-year age classes. This pattern shows that the majority of trees 
re-established with ten years of the stand-replacing fire (1977). Also shown is average growing season precipita-
tion for the five-year periods. Processes influencing re-establishment of trees after severe disturbance are com-
plex and more work is needed to determine the role of dead woody material in modifying microsite conditions 
and facilitating tree regeneration.  
References 
Huffman, D.W., A.J. Sanchez Meador, and J.E. Crouse. In revision. Coarse woody debris and vegetation 30 
years after stand-replacing fire in a pinyon-juniper woodland. Available by e-mailing: Da-
vid.Huffman@nau.edu 
Stoddard, M.T., D.W. Huffman, T.M. Alcoze, and P.Z. Fulé. 2008. Effects of slash on herbaceous communities 
in pinyon-juniper woodlands of northern Arizona. Rangeland Ecology and Management 61:485-495. 
 
 
 
Contacts 
Dr. David Huffman David.Huffman@nau.edu 
Dr. Andrew Sanchez Meador asanchezmeador@fs.fed.us 
Joseph Crouse Joseph.Crouse@nau.edu 


Fact sheet: Dead wood plays important roles in pinyon-juniper woodland recovery after wildfire

Ecological Restoration Institute The Ecological Restoration Institute is dedicated to reversing declines in the condition of forested communities throughout the Intermoun-tain West, particularly those affected by severe wildfires and insect outbreaks.  Our efforts focus on science-based research of ecological and socio-economic matters related to restoration as well as support for on-the-ground treatments, outreach, and education. Ecological Restoration Institute, P.O. Box 15017, Flagstaff, AZ 86011, 928/523-7182, FAX 928/523-0296, www.eri.nau.edu Fact Sheet: Pinyon-Juniper Woodland Recovery    December 2010 Dead Wood Plays Important Roles in Pinyon-Juniper Woodland Recovery After Wildfire    S tand-replacing crown fires appear to be consistent with historical patterns of natural disturbance in some pinyon-juniper woodlands of the American Southwest, Colorado Plateau, and Great Basin. These moderate- to high-severity fires result in the death of most or all trees across areas that range from small groups of a few trees to hundreds of acres. In some forest eco-systems, logs remaining after fire are known to reduce soil movement and increase retention of soil nitrogen. In studies of pinyon-juniper management, woody material created by tree thinning has been shown to enhance plant establishment and affect soil moisture and chemistry (Stoddard and others 2008). Logs and standing dead trees also can be important habitat for various animals. It follows that this dead material may influence vegetation patterns over long periods of time through numerous effects on soils, microclimate, and wildlife habitat. Presently, there is extremely little information available concerning dead wood amounts after fire and the influence this material may have on patterns of vegetation development. Lack of infor-mation leads to uncertainty in determining appropriate manage-ment responses to severe fires in pinyon-juniper ecosystems. In this case study (Huffman and others in revision), we were interested in quantifying dead wood amounts and analyzing tree re-cruitment patterns and vegetation patterns 30 years after a severe fire in a northern Arizona pinyon-juniper woodland.   Research Findings  Numbers and sizes of dead structures suggested the site had been previously occupied by persistent woodland. Such conditions develop in the absence of severe disturbance over the course of centuries.  Thirty years after the Yellow Jacket Fire, an average of 18 standing, dead trees per acre remained and the mass of sound and rotten logs was 2.6 and 0.7 tons per acre, respectively.  Plots showed relatively high cover (8.1-8.6%) of shrubs and moderate cover (3.6-4.2%) of grasses. Tree cover averaged 1.5%.  Tree-ring analysis indicated that most juniper regeneration occurred within ten years of the fire event. Pinyon pine re-generation was minimal.  Correlation analysis showed strong positive relationships between number of regenerating trees, number of shrubs, and number of dead trees on plots.   Minimum distance from live tree regeneration to dead wood averaged 4.6 ft (1.4 m) and about 30% of all live trees were found within about 1 foot of dead wood. Similar associations were observed between shrubs and dead wood.   Spatial analyses suggested weak aggregation of tree regeneration and dead wood, and stronger aggregation of shrubs and dead wood, and live trees and shrubs.   Management Implications  Vegetation development after fire in pinyon-juniper ecosystems is highly variable and likely depends upon the interac-tions of pre-fire conditions, fire severity, and post-fire legacies (e.g., dead, woody material).   Although juniper trees may begin to reestablish soon after fire, woodland conditions may take many decades or even centuries to develop.  The amount and condition of dead trees and logs remaining on a pinyon-juniper site after fire appears to help plants establish by modifying microclimate, soil conditions, and providing habitat for animal seed dispersers.  The resilience of these ecosystems may depend upon conservation of dead, woody material.  Juniper regeneration (green bars) displayed in five-year age classes. This pattern shows that the majority of trees re-established with ten years of the stand-replacing fire (1977). Also shown is average growing season precipita-tion for the five-year periods. Processes influencing re-establishment of trees after severe disturbance are com-plex and more work is needed to determine the role of dead woody material in modifying microsite conditions and facilitating tree regeneration.  References Huffman, D.W., A.J. Sanchez Meador, and J.E. Crouse. In revision. Coarse woody debris and vegetation 30 years after stand-replacing fire in a pinyon-juniper woodland. Available by e-mailing: Da-vid.Huffman@nau.edu Stoddard, M.T., D.W. Huffman, T.M. Alcoze, and P.Z. Fulé. 2008. Effects of slash on herbaceous communities in pinyon-juniper woodlands of northern Arizona. Rangeland Ecology and Management 61:485-495.    Contacts Dr. David Huffman David.Huffman@nau.edu Dr. Andrew Sanchez Meador asanchezmeador@fs.fed.us Joseph Crouse Joseph.Crouse@nau.edu 

http://openknowledge.nau.edu/1269/7/Huffman_2011_ERIFactSheet_DeadWoodPJRecovery%281%29.pdf

Fact sheet: Dead wood plays important roles in pinyon-juniper woodland recovery after wildfire

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