FIRE EFFECTS
SPECIES: Garrya wrightii | Wright Silktassel 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire generally top-kills Wright silktassel.  Wildfires in Arizona
chaparral are often severe, defoliating all aboveground vegetation and
leaving only charred stems and a layer of ash over mineral soil [2,22].
Prescribed burning in September in Arizona chaparral 6 weeks following
shrub desiccation with herbicides resulted in 88.5 to 99.0 percent shrub
top-kill.  Ninety five percent of Wright silktassel shrubs were
top-killed in these fall burns [23].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
Wright silktassel is susceptible to repeated burning.  Sprouts initiated
after fire can be completely eliminated or significantly reduced if
burned again within 1 to 3 years.  Pond and Cable [25] reported that
four annual burns or two burns spaced 2 years apart killed Wright
silktassel.  Burning at 3-year intervals significantly reduced the
number of sprouts.


PLANT RESPONSE TO FIRE : 
Following top-kill by fire, most Wright silktassel plants sprout
vigorously from the root crown [3,23].

Plant recovery:  In turbinella oak-mountain-mahogany chaparral in
central Arizona, recovery of Wright silktassel following prescribed
burning in September, 6 weeks after brush was desiccated with a phenoxy
herbicide, was as follows [23]:

                         percent crown cover

                                           Post fire year
   pretreatment   post treatment      1     2     3     4     5

      6.9             0.3            0.8   1.1   0.8   0.8   1.0

Browsing by deer may have accounted for Wright silktassel's slow
recovery in this study.

Seedbanking:  Following the fire described above, Wright silktassel
seedlings emerged in late summer.  Seedling emergence and seedling
survival is summarized below [23]:

                            number of seedlings per acre
                                  Post fire year
                            1     2     3     4     5

seedlings emerging         102    86   16     0     9

*seedlings surviving at    
end of growing season      93    121   32    73    45

* For seedling survival, columns 1 and 2 were based on four annual
burns; columns 3, 4, and 5 were based on three, two, and one annual
burn, respectively.  Seedling survival data are therefore not additive
of seedling emergence data.


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Arizona chaparral often has high fuel loads (up to 40 tons/acre [89,611
kg/ha] in long-unburned stands) which can result in extreme burning
conditions during late spring and early summer [22].  In general, fall
is the best time for prescribed burning in this vegetation type [3].
Desiccation of brush with phenoxy herbicides or partial crushing allows
for prescribed burning during periods of relatively low hazard [3,22].
Repeat burning, which is sometimes desirable for suppressing or killing
shrub sprouts, is usually difficult or impossible in Arizona chaparral
because it takes several years to produce enough fuel to carry a fire
[10].

Related categories for Species: Garrya wrightii | Wright Silktassel