• CASE NAME
• REFERENCE
• SEASON/SEVERITY CLASSIFICATION
• STUDY LOCATION
• PREFIRE VEGETATIVE COMMUNITY
• PLANT SPECIES PHENOLOGICAL STATE
• SITE DESCRIPTION
• FIRE DESCRIPTION
• FIRE EFFECTS ON PLANT SPECIES
• FIRE MANAGEMENT IMPLICATIONS

CASE NAME:

Colorado aspen burn

REFERENCE:

Smith, J. K.; Laven, R. D.; Omi, P. N. 1985 [116]
Smith, J. K.; Laven, R. D.; Omi, P. N. 1993 [117]

SEASON/SEVERITY CLASSIFICATION:

fall/low

STUDY LOCATION:

Miner's Road and Swamp Creek sites were located in north-central Colorado.

PREFIRE VEGETATIVE COMMUNITY:

Quaking aspen (Populus tremuloides) communities were characterized by an understory of herbaceous vegetation and common juniper (Juniperus communis). Common herbaceous species included western yarrow (Achillea millefolium), sedges (Carex spp.), Kentucky bluegrass (Poa pratensis, strawberry (Fragaria ovalis), northern bedstraw (Galium boreale), Letterman needlegrass (Achnatherum lettermanii), dandelion (Taraxacum officinale) and mountain thermopsis (Thermopsis divaricarpa).

PLANT SPECIES PHENOLOGICAL STATE:

Herbaceous vegetation was cured. Quaking aspen leaves had fallen.

SITE DESCRIPTION:

Weather conditions were described as follows:

site   dry bulb relative  wind    wind       10-hr fuel
       (oC)     humidity  speed   direction  moisture
               (%)        (km/hr)            (%)
MR1     12      25        10      SE         10.5
MR2     11      33         4      SE         10.5
MR3     13      23         7      W          10.6
SC2     17      15         3      SW          9.6

                          MR1-2          MR3
fuel depth (cm)           32(+/-7)       46(+/-10)
duff load (kg/m2)         3.52(+/-1.13)  3.01(+/-1.28)
fine fuel load (kg/m2)*   1.01(+/-0.53)  1.54(+/-0.54)
down woody fuels (kg/m2)  1.06(+/-1.53)  1.88(+/-2.82)
*mainly common juniper foliage

FIRE DESCRIPTION:

Site Name (abbreviation)  Burn Date         Ignition time
Miner's Road 1 (MR1)      October 19, 1981  14:35  MST
Miner's Road 2 (MR2)      October 19, 1981  15:27  MST
Miner's Road 3 (MR3)      November 4, 1981  12:00  MST
Swamp Creek (SC2)         November 17, 1981 13:00  MST

Burn severity varied by plot.

site   % of sample   median   estimated %
       plots burned  fraction of site
                     burned   burned
MR1     67           0.55     37
MR2     60           0.30     18
MR3    100           0.99     99
SC2    100           0.90     90 

Fire behavior was more severe in juniper clumps than in herbaceous vegetation. Fire behavior measured over the entire burns, with both common juniper and herbaceous cover, was as follows:

                             min.   max.     estimated mean            
Fire behavior    
rate of spread (m/min)       0.4    4.0      1.3
flame length (cm)            10.2   152.4    43.4
flaming zone depth (cm)      5.1    152.44   42.4
total heat release(kcal/m2)  1491   19544    6326
      
Fire behavior measured only in common juniper clumps was as follows:

average                    MR1-2          MR3
flame length*              86             62
flaming zone depth*        45             44
total heat release*        8300(+/-4326)  14021(+/-3420)  
*significantly greater than on plots with herbaceous cover

FIRE EFFECTS ON PLANT SPECIES:

Juniper was killed by fire.

FIRE MANAGEMENT IMPLICATIONS:

Flames were longer in juniper than in herbaceous cover and more fuel was consumed on juniper plots. Burned out juniper plots produced more aspen suckers than corresponding herbaceous plots. More heat may have penetrated the soil in juniper areas. Irradiance increases were especially noticeable in areas were juniper clumps had burned.

Related categories for SPECIES: Juniperus communis | Common Juniper