FIRE CASE STUDIES
SPECIES: Lycium berlandieri | Berlandier Wolfberry 



CASE NAME : 
Fire temperatures and the effect of burning on south Texas brush communities


REFERENCE : 
White, R. A. 1969 [44]

SEASON/SEVERITY CLASSIFICATION : 
March/variable


STUDY LOCATION : 
The study plot was located in Section 40, lots 7 and 8 of the Welder
Wildlife Foundation Refuge which is approximately 20 miles north of
Corpus Christi, Texas.


PREFIRE VEGETATIVE COMMUNITY : 
The regional vegetation of the area was described as Gulf prairies and
marshes.  Plant communities in the study area were dominated by mesquite
(Prosopis glandulosa), huisache (Acacia farnesiana), and seacoast
bluestem (Schizachyrium scoparium var. littoralis).  Other woody species
present included Berlandier wolfberry (Lycium berlandieri), lotebush
(Zizyphus obtusifolia), blackbrush acacia (Acacia rigidula), twisted
acacia (A. tortuosa), agarito (Mahonia trifoliolata), Texas persimmon
(Diospyros texana), and hackberry (Celtis spp).


TARGET SPECIES PHENOLOGICAL STATE : 
Berlandier wolfberry possessed a full complement of leaves at the time
of burning and 2 weeks following burning.


SITE DESCRIPTION : 
NO-ENTRY


FIRE DESCRIPTION : 
A prescribed fire was applied to a 10 acre (4 hectare) plot.  One
portion was burned March 8, 1968; the rest was burned March 12,
1968.  The following conditions were recorded at the time of burning:

                                            Date Burned
Condition                            3/8/68             3/12/68
______________________________________________________________________
Time of burning                   3:00-3:30 pm      10:00 am-4:00 pm
Air temperature (deg F)                60                  55
Relative humidity (%)                  90                  45
Wind velocity (mph)                    10                20-30
Soil moisture (%)                      40                  37
Plant moisture (%)                      9                   7
Average height of flames (ft)           7                   8
     
In subunit 1, the fuel was evenly distributed and high in loading, and
the brush was generally open.  Subunit 2 had an uneven fuel
distribution, fuel loading was moderate, and brush was dense.  There was
a low amount of evenly distributed fuel in subunit 3, and brush cover
was open.
                   


FIRE EFFECTS ON TARGET SPECIES : 
The canopy cover of all woody species, including Berlandier wolfberry,
was reduced by burning.  Overall mortality of Berlandier wolfberry was
8 percent.  Berlandier wolfberry had the following percent canopy cover
before and 3 months after the fire:

                                    Percent Canopy Cover
Subunit     Fuel load            Prefire           Postfire
--------------------------------------------------------------------------
Subunit 1 (3,686 lbs/acre)         trace              trace          
Subunit 2 (1,932 lbs/acre)         trace                1
Subunit 3 (1,970 lbs/acre)           1                trace

The extent of topkill and mortality of Berlandier wolfberry seemed to
increase with increasing fuel loads, but differences were not
statistically significant (p>.10).  Overall brush mortality was
significantly (p<.01) higher in subunit 1, where fuel loadings were
highest.  In subunit 2, where brush cover was dense, the fire was severe
enough to damage brush at the edges of clumps and significantly (p<.05)
reduce overall brush cover.  In subunit 3, with low fuel loads and open
cover, brush cover was not significantly (p>.10) reduced.


FIRE MANAGEMENT IMPLICATIONS : 
Overall, fire was an effective method for topkilling woody species but
did not result in high mortality.  Low mortality may have been due to
high soil moisture and relatively low air temperatures.  Under these
conditions, fire would have to be applied several times over a period of
years to kill many woody species.  Maximum mortality may be obtained by
burning when woody plants are small and fuel quantities are high.

Related categories for Species: Lycium berlandieri | Berlandier Wolfberry