FIRE EFFECTS
SPECIES: Betula alleghaniensis | Yellow Birch 



IMMEDIATE FIRE EFFECT ON PLANT : 
Yellow birch seedlings and saplings are killed by even low-severity
fires [32].  Small trees were killed by fire that left large trees in a
northern hardwoods forest unharmed [105].  Large trees usually survive
fire; Martin [85] mentioned the presence of large, old yellow birch that
predate a fire that initiated a red maple-paper birch stand in Ontario.

A subjective ranking of tree fire resistance compiled by Starker [106]
listed yellow birch as twelfth out of twenty-two species rated.


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Yellow birch is a poor sprouter following top-kill by fire.  Seed
germination and seedling establishment are enhanced by fire disturbance.
Yellow birch frequently forms pure patches following fire.  In Wisconsin
northern hardwood forests it often comprises 60 percent of the hardwood
thickets [80].  Most of the research on yellow birch regeneration is
associated with logging regimes, so it is not clear what role fire plays
in yellow birch regeneration in unmanaged stands.  It is likely that a
low-intensity, patchy fire would create conditions that favor yellow
birch regeneration by reducing the hardwood leaf mat and exposing
mineral soil, but leaving mature trees as a seed source [1].

In northern hardwood forests, postfire regeneration is likely to include
at least a small proportion of yellow birch.  Major postfire species in
this area are paper birch, gray birch (Betula populifolia), aspens, red
spruce, and pines (Pinus spp.) [32,89].  In the Laurentian Highlands of
central Quebec, yellow birch is present in low numbers in early postfire
succession on well-drained sites in montane mixed forests. The main
colonizers are balsam fir and paper birch [22].  In North Carolina
spruce-fir forests, which rarely burn, yellow birch was important in
postfire regeneration [103].  Gibson [42] reported that former Atlantic
white-cedar (Chamaecyparis thyoides) swamps developed into red maple or
red maple-yellow birch stands following fire.  In northwestern
Pennsylvania, a ridge that supported a dense stand of eastern hemlock
and mixed hardwoods was converted by fire to a stand composed of red
maple, black cherry, yellow birch, and water birch (B. occidentalis) [54].

In northern hardwood types in Wisconsin, low-severity surface fires seem
to favor sugar maple over yellow birch and beech.  Severe fires,
however, destroy existing sugar maple reproduction and create openings
in the canopy, favoring yellow birch.  The composition of a northern
hardwood stand was traced to three distinct fires, each of which was
followed by an increase in the proportion of yellow birch [80].  Birches
(yellow birch, sweet birch, and paper birch) exhibited a pulse of
reproduction after a surface fire in Connecticut, peaking in density
around 25 years.  By 55 years after the fire birch density on burned and
unburned stands was similarly low [117].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Regression coefficients relating bark thickness to diameter at breast height
have been published for yellow birch [51].

The moisture content of the inner bark of yellow birch ranges from 44 to
65 percent, depending on season of sampling.  The heat of combustion
of dry yellow birch bark is 9,200 Btu [129].

Site Preparation:  Fire has been used to create suitable seedbed
conditions for yellow birch regeneration [1].  In New York, the number
of yellow birch seedlings was higher on postharvest plots that had been
prescribed burned and scarified than on plots that had either been
prescribed burned or scarified, or on control plots [11].  Prescribed
fires have been used for yellow birch seedbed preparation in Ontario.
The fires were conducted in late fall, after sugar maple and beech leaf
and seedfall and before the major portion of yellow birch seeds were
dispersed.  Low-intensity surface fires consumed litter and killed
advance regeneration of sugar maple.  These fires did not significantly
reduce the number of stems (all species) greater than 0.6 inch (1.5 cm)
d.b.h., though basal scarring was evident.  Fire-prepared plots resulted
in higher stocking of yellow birch than unburned plots, and reduced the
development of sugar maple [6,16].

Related categories for Species: Betula alleghaniensis | Yellow Birch