N.M. Admin. Code § 20.11.21.19

Current through Register Vol. 35, No. 23, December 10, 2024

Section 20.11.21.19 - EMISSIONS REDUCTION TECHNIQUES

Emissions reductions techniques (ERTs) are control strategies that help reduce smoke from prescribed fires. ERTs are used in conjunction with fire and do not replace fire. In addition to department-approved ERTs, other ERTs are included below.

A. Reducing the area burned.

(1) Burn concentrations - Sometimes concentrations of fuels can be burned rather than using fire on 100 percent of an area requiring treatment. The fuel loading of the areas burned using this technique tends to be high.

(2) Isolate fuels - Large logs, snags, deep pockets of duff, sawdust piles, squirrel middens or other fuel concentrations that have the potential to smolder for long periods of time can be isolated from burning. Eliminating these fuels from burning is often faster, safer and less costly than mop-up, and allows targeted fuels to remain following the prescribed burn. This can be accomplished by several techniques including:

(a) constructing a fireline around fuels of concern;

(b) not lighting individual or concentrated fuels;

(c) using natural barriers or snow;

(d) scattering the fuels; and

(e) spraying with foam or other fire retardant material.

(3) Mosaic burning - Landscapes often contain a variety of fuel types that are noncontinuous and vary in fuel moisture content. Prescribed fire prescriptions and lighting patterns can be assigned to use this fuel and fuel moisture non-homogeneity to mimic natural wildfire and create patches of burned and non-burned areas or burn only selected fuels. Areas or fuels that do not burn do not contribute to emissions.

B. Mechanical treatments - Mechanically removing fuels from a site reduces emissions proportionally to the amount of fuel removed. Treatments may include but are not limited to the following methods.

(1) Firewood sales - Firewood sales may result in sufficient removal of woody debris making on site burning unnecessary. This technique is particularly effective for piled material where the public has easy access.

(2) Whole tree harvesting - Whole trees can be removed through harvesting or thinning techniques and virtually eliminate the need for burning.

(3) Mulch/chips - Mechanical processing of dead and live vegetation into wood chips or shredded biomass is effective in reducing emissions if the material is removed from the site or biologically decomposed.

(4) Fuel for power generation - Vegetative biomass can be removed and used to provide electricity in regions with cogeneration facilities.

(5) Biomass utilization - Vegetative material can be used for many miscellaneous purposes including pulp for paper, methanol/ethanol production, wood pellets, garden bedding, furniture, specialty crafts, compost, mulch and fiberboard/particleboard.

C. Chemical pre-treatments - Broad spectrum and selective herbicides can be used to reduce or remove live vegetation, or alter species diversity respectively. Herbicides can be applied before burning to kill vegetation, which can create a much drier fuel, which in turn burns more efficiently.

D. Site conversion - Natural site productively can be decreased by changing the vegetation composition.

E. Land use change - Changing wildlands / shrublands / rangelands / croplands to another land use category may result in elimination of the need to burn and vice versa.

F. Reduce fuel loading - Some or all of the fuel can be permanently removed from the site, biologically decomposed, or prevented from being produced. Overall, emissions can be reduced when fuel is permanently excluded from burning.

(1) Mechanically removing fuel - Mechanically removing fuels from a site reduces emissions proportionally to the amount of fuel removed.

(2) Burn more frequently at low intensity - This method prevents the fuels from building up and causing greater emissions.

(3) Schedule burning before green up - Burning in cover types with a grass or herbaceous fuel bed component can produce fewer emissions if burning takes place before these fuels green-up for the year.

(4) Under burn before fall leaf drop - When deciduous trees and shrubs drop their leaves, this ground litter contributes extra volume to the fuel bed.

(5) Ungulates - Grazing and browsing live grassy or brushy fuels by sheep, cattle or goats can reduce fuels prior to burning or reduce the burn frequency.

(6) Isolating pockets of fuel - See explanation under reducing the area burned.

G. Reduce fuel consumption - Emission reductions can be achieved when significant amounts of fuel are at or above the moisture of extinction, and therefore are unavailable for combustion.

(1) Having high moisture content in non-target fuels - This can result in only the fuels targeted being dry enough to burn.

(2) High moisture in large woody fuels - Burning when large-diameter woody fuels (three- plus inch diameter or greater) are wet can result in lower fuel consumption and less smoldering.

(3) Moist litter or duff - The organic layer that forms from decayed and partially decayed material on the forest floor often burns during the inefficient smoldering phase. Consequently, reducing the consumption of this material can be effective at reducing emissions.

(4) Mass ignition/shortened fire duration/aerial ignition - "Mass" ignition can occur through a combination of dry fine-fuels and rapid ignition, which can be achieved using a helitorch. The conditions necessary to create a true mass ignition situation include rapid ignition of a large open area with continuous dry fuels.

(5) Burn before large fuels cure - Living trees contain very high internal fuel moistures, which take a number of months to dry after harvest. If an area can be burned within 3-4 drying months of timber harvest, many of the large fuels will still contain a significant amount of live fuel moisture.

(6) Rapid mop-up - Rapidly extinguishing a fire can reduce fuel consumption and smoldering emissions somewhat, although this technique is not particularly effective at reducing total emissions and can be expensive.

(7) Burn before precipitation - Scheduling a prescribed fire before a precipitation event will often limit the consumption of large woody material, snags, stumps, and organic ground matter, thus reducing the potential for a long smoldering period and reducing the average emission actor.

H. Minimizing emissions by minimizing the emission factor - Using burning techniques that create a more efficient burn.

(1) Burning fuels in piles or windrows - Keeping piles dry and free of dirt and other debris generates greater heat and therefore, the piles burn more efficiently. The piles or windrows can be made mechanically or by hand.

(2) Utilizing a backing fire - Flaming combustion is cleaner than smoldering combustion. A backing fire takes advantage of this relationship by causing more fuel consumption to take place in the flaming phase than would occur if a heading fire were used.

(3) Rapid mop-up - See above.

(4) Mass ignition/shortened fire duration/aerial ignition - See above.

(5) Dry conditions - Burning under dry conditions increases combustion efficiency and fewer emissions may be produced.

I. Air curtain incinerator (ACI) - Use of an air curtain incinerator improves combustion and reduces emissions by introducing high velocity air into a combustion environment. As the air continuously rotates in and over the environment, a "curtain" is created over the fire thus trapping smoke and particulate matter. Constant airflow into and over the combustion environment allows temperatures to remain high, resulting in relatively complete combustion of all emission products. ACIs can burn a wider variety of materials from green fuel to red slash and produce lower smoke emissions as compared to pile or broadcast burning. They also reduce risk of an escaped fire since the fire is contained and can be quickly extinguished if necessary.

N.M. Admin. Code § 20.11.21.19

20.11.21.19 NMAC - N, 12/31/03; A, 7/11/11