BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Melaleuca quinquenervia | Melaleuca 



GENERAL BOTANICAL CHARACTERISTICS : 
Melaleuca is a relatively fast-growing evergreen tree reaching a height
of about 90 feet (27 m), but more commonly 50 to 70 feet (15-21 m).  It
grows in typically dense monocultures.  It is self-pruning, tall and
slender, and generally lacks branches on the lower two-thirds of its
bole.  The branches are slender and moderately short.  Trees grown in
the open have a broader, columnar form with dense branches extending
from near the soil surface to the top of the tree.  Some have multiple
trunks, often more than a dozen that originate close to the soil surface
and diverge outward, giving it a shrublike form.  The white flowers are
borne on spikes with an average of 30 sessile capsules per flower spike.
A branch may bear 8 to 12 of these seed-bearing sections, often
alternating with foliage, along a single axis.  The hard, woody capsules
are aggregated along the branches.  The thick, low-density bark contains
multiple layers of paperlike material that retains both considerable
moisture and abundant small air spaces.  The leaves are simple and
arranged in five spiral rows.

The root system of melaleuca is adapted to fluctuating water tables.
The surface root network is characterized by abundant vertical sinker
roots that extend at least to the water table's deepest annual level.
During periods of surface flooding, "water roots" proliferate from
permanent surface roots and submerged portions of the stems [8,9,12].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Seed production and dissemination:  Melaleuca's primary mode of
reproduction is sexual.  It produces an abundance of small, lightweight
seeds and can begin seed production as early as 1 year of age, although
most trees do not flower that young.  Viable seeds are present in
capsules that are 15 years old, but viability of seeds declines with
age.  Some capsules apparently open constantly, releasing a continous
light rain of seeds.  Most capsules are serotinous.  They do not open
until the conductive tissue connecting them to the tree is disrupted by
shoot growth and bark production, or by stress, such as fire, frost,
mechanical damage, or herbicide treatment.  Following stress, a massive
seed release may begin within a few hours and occur over several days.
Melaleuca has no adaptations that aid in seed dispersal.  The seed is
not dispersed by any native birds or mammals.  Most seeds fall close to
the parent tree, with wind dispersal affected by the height of the seed
release and wind speed.  The seeds will also float on water if the
surface tension is maintained.  In spite of the small size, the seeds
are surprisingly long-lived, remaining viable up to 10 months.  When
submerged in water, the seeds will live up to 6 months. [5,8,10]

Seedling development:  Germination is epigeal.  Dense reproduction
occurs when trees shed millions of seeds.  Seedlings averaging 6.5 feet
(2.0 m) tall may be as dense as 1.4 million per acre (3.5 million/ha).
If seedlings are submerged by water for several months, they may survive
and resume growth.  Seedling growth may occur every month of the year,
but growth is most rapid from spring to early fall.  Natural seedlings
can grow more than 3 feet (1 m) tall during the first year, while
seedlings planted at a density of 4,050 per acre (10,000/ha) on drained
muck soils grew 6.5 feet (2.0 m) in 6 months [8].

Vegetative reproduction:  Melaleuca stumps sprout readily.  The tree has
the ability to generate adventitious buds on its roots and shoots.  This
characteristic results in coppicing below a cut or when the apical bud
is destroyed.  A tree that is uprooted and on the ground may develop
into a row of trees as a result of branches on the upper side of the
bole becoming individual trunks.  Broken branches that fall on suitable
soils may root and grow.  The adventitious buds generate a collar of
"water roots" in the water column above the sediment where there is
prolonged flooding [10].


SITE CHARACTERISTICS : 
Melaleuca tolerates a broad range of site conditions.  It becomes
established more readily on sand than on marl but can survive on almost
any soil in south Florida.  It tolerates extended flooding, moderate
drought, and some salinity [5,24].

Soils supporting melaleuca include the suborders Psammaquents, Aquods,
and Saprists of the orders Entisols, Spodosols, and Histosols,
respectively.  Many of these soils are shallow and underlain by
limestone [8].

In Hawaii, melaleuca is found from sea level to 4,500 feet (1,400 m).
In grows fairly well on Hawaiian soils, especially on Inceptisols,
Ultisols, and Oxisols developed on basalt ash or lava rock of pH 4.5 to
5.5 [1,8].

Some common associates of melaleuca not previously listed in
Distribution and Occurrence include cabbage palmetto (Sabal palmetto),
Brazilian peppertree (Schinus terebinthifolia), southern bayberry
(Myrica cerifera), cocoa plum (Chrysobalanus icaco), and buttonbush
(Cephalanthus occidentalis) [1,8].


SUCCESSIONAL STATUS : 
Obligate Initial Community Species.

Melaleuca rarely has to compete directly with other tree species in
Florida because it mainly invades sparsely vegetated ecotones, prairies,
marshes, and fire-damaged forests.  Mature trees are classed as
intolerant, although some germination and seedling development does
occur in shade.  Massive seed release typically follows disturbance such
as fire, allowing melaleuca to invade the site and form an almost pure
stand.  Pure stands with a closed canopy will inhibit the development of
understory vegetation, including melaleuca seedlings [8,16].


SEASONAL DEVELOPMENT : 
Flowering occurs in every month except February, March, and April.
After flowering, twigs continue to elongate from the ends of spikes to
produce leaves or more flowers.  Individual trees bloom from two to five
times a year.  In Hawaii melaleuca flowers throughout the year [8].

Related categories for Species: Melaleuca quinquenervia | Melaleuca