BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus glabra | Spruce Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Spruce pine is a medium-sized, native, evergreen conifer.  It usually
grows to 90 to 100 feet (27.4-30.5 m) tall and 24 to 36 inches (61-91
cm) in d.b.h.  The national champion tree is 125 feet (38.1 m) tall.
The needles are borne in bundles of two and are 1.6 to 4 inches (4-10
cm) long [3,22].  The bark is relatively thin (0.25 to 0.375 inch
[0.64-0.95 cm])[2].  The bark is smooth on young trees, later developing
close ridges with flat plates on the lower trunk of older trees.  Upper
branches and trunks maintain the smoother bark [3,23].  The branches are
drooping [17].  Spruce pine develops a moderately deep taproot, with
numerous moderately deep lateral roots.  It is obligately mycorrhizal;
seedlings that fail to develop mycorrhizae usually do not survive [2,9].

Longevity is approximately 113 years; the relatively short life span is
probably a result of the high frequency of good seed crops [12].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Spruce pine is sexually mature by 10 years of age; peak cone production
occurs between 20 and 40 years of age.  Good seed crops occur frequently
[12].  The small, winged seeds are released upon maturity and
disseminated by wind.  Seedling establishment does not appear to require
a mineral seedbed [8,12].  Seedlings develop well in the shade of
hardwoods or other pines, forming widespreading lateral roots near the
surface before penetrating deeper into the soil [9].


SITE CHARACTERISTICS : 
Spruce pine grows in limited numbers in rich bottomland woods, swamps,
and on hammocks and riverbanks.  It occurs on the Coastal Plain where
summers are long, hot, and humid; and winters are mild.  Average
rainfall is approximately 50 inches (1,270 mm) per year and generally
evenly distributed, although fall tends to be the driest season [9].

Spruce pine is generally found on acidic sandy loam soils that are
intermediate between dry sandy soils and alluvial bottomland soils
[2,12].  Spruce pine grows well on moderately to poorly drained sites
that may have a high water table or are intermittently waterlogged [12].
Soil orders tend to be Spodosols or Entisols [9].


SUCCESSIONAL STATUS : 
Obligate Climax Species

Spruce pine is very shade tolerant.  Seedlings and saplings can grow
where available light is as low as 250 foot-candles (2,778 lux) and are
common in many parts of the southern mixed-hardwood forest where light
intensity is less than 1000 foot-candles (11,111 lux) at noon on a
summer day [2].  It is usually only found in late succession hardwood
stands of magnolia, beech, or other climax species.  In these stands, it
is represented by all stages of growth [2,15,16].  Where it is found in
younger seral stands, it has usually become established in the shade of
loblolly or shortleaf pines [9,16].  According to Platt and Schwartz
[24], however, spruce pine appears to capitalize on large-scale
disturbance caused by hurricanes.  They state that advance recruits in
localized light gaps that are capable of rapid growth at high light
intensities will capture space in the canopy following large-scale
disruption by hurricanes.  Hirsh and Platt found that age structures of
spruce pine tend to consist of discrete age classes corresponding to
dates of hurricanes [25].


SEASONAL DEVELOPMENT : 
Spruce pine pollen is released in February and March in Mississippi.
Seed cones ripen in October of their second year, and seeds are dispersed
in October and November [10].

Related categories for Species: Pinus glabra | Spruce Pine