FIRE EFFECTS
SPECIES: Kalmia angustifolia | Sheep-Laurel 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire kills aerial portions of sheep-laurel stems.  Light fires that do
not harm the buried rhizomes do not not kill the plant.  Severe fires
that consume the organic layer or sufficiently heat the soil surrounding
the rhizomes do kill sheep-laurel [30].



DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
Sheep-laurel's ability to survive a fire depends on the survival of its
rhizomes.  Sheep-laurel rhizomes growing in forest mineral soils are
relatively shallowly buried and depend on the insulating value of the
soil and soil moisture for protection against lethal soil temeratures
[16].  On bogs or peatlants, sheep-laurel rhizomes are generally deeper.
When wet, these soils offer both insulation and protection from fire.
When dry, these organic soils themselves may be consumed, killing the
sheep laurel rhizomes [15].  On peatlands, sheep-laurel survives only
where the humus layer is not destroyed [30].



PLANT RESPONSE TO FIRE : 
The immediate postfire response of sheep-laurel is a decrease in
frequency and abundance [18].  However, it quickly responds to fire (and
cutting) with vigorous sprouting [29].  Fire stimulates the growth of
adventitious roots from the burned root stubs and rhizomes near the soil
surface [29,35].  Sprouts can be seen soon afterward.  In an Ontario
study, new shoots were 2 inches (5 cm) tall 2 weeks after a fire, and 6
inches tall (15 cm) 6 weeks after the fire [35].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Although visible on a site within 2 weeks of a fire, sheep-laurel shows
the greatest increase in frequency between postfire year 1 and 2.  Its
frequency may increase 500 precent and then remain relatively constant
for the next 40 years [31].

Regrowth after summer fires is slower than regrowth after spring or fall
fires, which shows a strong increase in sprout density.  Summer fires
coincide with a period of low photosynthate reserves that follows the
spring growth spurt [14,17].  Light spring or fall fires encourage
prolific growth [31].

In a greenhouse experiment, Mallik [29] compared sheep-laurel shrubs
that had been cut or cut and burned with control plants.  There was
no significant difference between the number and density of new sprouts
for the treatments and for the control.  Treatment sprouts were more
robust, but treatment rhizomes were smaller.  Sheep-laurel directs
photosynthates to aboveground growth at the expense of belowground
growth following disturbance.


FIRE MANAGEMENT CONSIDERATIONS : 
All but the most severe fires enhance the growth of sheep-laurel stands.
Permanent control of sheep laurel require fires severe enough to kill
the rhizomes; such fires often consume the organic layer of the soil
[31].  Managers should note that most sheep-laurel-dominated communities
in Nova Scotia are associated with frequent fires.  Logging and fire
promote heath formation [5].  The high stem density in heaths causes
severe fires when they eventually burn.  Frequent fires reduce fuel
accumulation and, consequently, are less severe [26].

Related categories for Species: Kalmia angustifolia | Sheep-Laurel