FIRE EFFECTS
SPECIES: Rhamnus purshiana | Cascara 



IMMEDIATE FIRE EFFECT ON PLANT : 
Cascara is usually top-killed by fire [29].

Preburn and postburn measurements of cascara in central Idaho were as
follows [17]:

           Avg. Live     Avg. Live    Avg. Crown  Avg. Dead    No.  Avg. Sprout
         Crown Diameter Crown Height  Below 7ft.    Crown     Basal    Height
             (ft)           (ft)          (%)        (%)     Sprouts    (ft)
------------------------------------------------------------------------------
Preburn       4.0            8.0          95.0        95.0      1.0      1.5
Postburn      3.0            4.5         100.0       100.0     18.0      3.0
------------------------------------------------------------------------------
1.  Preburn measurements were taken in March, 1965.  Postburn measurements
    were taken in August, 1965.  
2.  Postburn measurements were taken on the part of the plant which
    existed before treatment.
3.  All cascara's aboveground parts were completely killed by the fire.

 


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Change in cascara measurements after prescribed burns in northern Idaho
were as follows [16]:

                          1965    1970    1975     1966   1971   1976
                          -------------------------------------------
Avg. Preburn
Crown Height (cm):        244     ---      ---      ---    ---    ---

Avg. Preburn
Crown Diameters (cm):      91     ---      ---      ---    ---    ---
 
Avg. No. Basal
Sprouts per
Plant:                     18      12       7       ---    ---    ---

Avg. Sprout 
Height (cm):               91      76      76       ---    ---    ---

Max. Crown Height
2 Years After Burn (cm):   ---     ---     ---      183     137   122

Max. Crown Diameter
2 Years After Burn (cm):   ---     ---     ---      137     107   107


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Fire intervals on southern Oregon sites where cascara occurs range from
30 to 60 years, to longer intervals of 100 to 320 years.  These
understories are generally free from heavy fuels, giving rise to
low-intensity fires.  In some plant associations that include cascara,
however, high-intensity, stand-replacing fires occur approximately every
60 to 150 years [2].

Related categories for Species: Rhamnus purshiana | Cascara