Fuel Concepts - Wildland Fuel Fundamentals and Applications - page 173

stand inevitably does burn, it may have a higher probability of experiencing exten-
sive fire-caused mortality because it is composed of fire susceptible species.
Mastication is a mechanical treatment that uses specialized equipment to shred,
chip, or break apart dead and live trees to raise CBH, decrease CBD, and reduce
fuelbed depth. This treatment is amenable to many managers because it is rela-
tively cheap and poses little risk when compared with prescribed fire. However,
the tremendous amount of shattered fuel left on the forest floor may cause adverse
ecological consequences to the treated stand, such as increased rainfall interception,
reduced plant regeneration, altered nutrient cycling, and increased soil insulation
(Kane et al. 2010 ). Moreover, plant mortality may be high when masticated stands
eventually burn in wildfires because of deep soil heating from smoldering combus-
tion of the thick duff and litter layers and high fire intensities from burning the
dense surface fuels (Kreye et al. 2014 ). Short-term decreases in fire hazard may be
eventually overwhelmed by long-term declines in ecological integrity for those fuel
treatments that don't address ecological concerns.
Current efforts in the restoration of fire-prone ecosystems often design treat-
ments to create stands that, when burned by wildfire, will experience fire effects
that were common historically and that will leave the landscape with much of the
prefire character. Restoration actions in frequent-fire ecosystems, such as ponder-
osa pine forests, often retain large, relic individuals that are able to survive future
wildfires (Agee and Skinner 2005 ). Retaining large trees that have survived many
disturbances and have lived through many climate fluctuations will ensure high
survival rates for future disturbances and offer the best genetic sources for the fu-
ture. Ecosystems with long fire return intervals, such as the Canadian boreal or the
Rocky Mountain lodgepole pine forests, experience primarily high-intensity crown
fires so the goal of keeping large trees may not be a concern. Instead of emphasizing
reducing fuels, an approach that balances what can survive a wildfire with what fire
behaviors and effects are acceptable both ecologically and socially will often result
in both fuel reduction and beneficial ecological restoration.
Another important factor in designing fuel treatments is the condition of the
vegetation being treated. Most fire-prone ecosystems need fuel treatments because
fire has been excluded from them for decades. As a result, plants are highly stressed
because competition for light, water, and nutrients has been amplified due to both
increased number of individuals and high surface fuel buildups that may have al-
tered water and nutrient cycling (Chap. 6). Moreover, trees that haven't experienced
fire in the past are not well equipped to survive fire in the future. Trees that have
been burned with low-severity fire, for example, often develop resin ducts needed
to compartmentalize injury and survive fires in the future. And because of competi-
tion for soil moisture, trees tend to concentrate fine roots in the thick duff and litter
layer that has accumulated in the absence of fire, so when fires do occur in these
fire-excluded stand, trees may experience high root and plant mortality. Fuel treat-
ments that fail to recognize initial stand health in their design may cause additional
mortality that result in even greater posttreatment surface fuel loadings and unsus-
tainable ecosystems.