PINE TREES PRODUCE TURPENTINE?
My understanding is that longleaf pine was preferred over loblolly pine
for turpentine production. Is it because longleaf pines produce more
sap? Also, what explanation did you once give for why a tree that lives
in a habitat that frequently catches fire under natural conditions would
produce a highly flammable substance like turpentine? Seems like that
would be self-destructive for the species.
Turpentine, a substance characteristic of pine trees and other conifers,
is composed of a mixture of resins and volatile oils. The by-products
have been used in a wide variety of applications including caulking
for wooden ships, solvent for paint and varnish, and as an ingredient
in insecticides, cleaning agents, and shoe polish. Turpentine products
were once even used for medicinal purposes. A great turpentine industry
once flourished in the South, where pine trees, especially longleaf
and slash pine, were tapped for turpentine, the way sugar maples are
tapped for sap to produce maple syrup.
industry took advantage of pine trees' natural response to injury. If
the bark is broken, the tree begins to ooze a sticky, yellowish sap
that eventually dries and seals the wound with a covering of resin.
The material is resistant to most wood-eating insects that might further
damage the tree. The liquid can be distilled to produce turpentine.
When ship building was at its height, longleaf pine forests were abundant
in the Coastal Plain and therefore nearest the coast. Also, longleaf
reportedly produced more and thicker resin than other pine trees. Slash
pine was more commonly used in Florida but, when available, longleaf
was the preferred choice for turpentine production.
and slash pines have a characteristic that makes turpentine production
seem counterintuitive. They live in what is known as a fire climax community.
This means that, historically, trees and other plants that persisted
in a longleaf pine community had to survive periodic fires that swept
naturally through the forests, primarily as a result of summer lightning
strikes. In fact, many ecologists criticize the prescribed burning by
some forest management programs in winter because natural fires would
usually have occurred in summer. Presumably, plants and animals in regions
that experienced frequent fires evolved to tolerate warm weather fires.
pines are well adapted to survive fires at intervals of only a few years.
The early so-called grass stage of a young longleaf can be burned back
to the ground and then, unharmed, resprout the same season. The thick
bark of the pine tree is resistant to fire (and has no turpentine in
it) so that a larger tree is also immune to a fast-burning forest fire.
a pine tree that under natural conditions was sure to be subjected to
numerous fires during its lifetime be saturated with readily flammable
turpentine? One explanation is that turpentine works to the tree's advantage
after it has died.
how. A pine tree dies, and months or years later a fast-burning fire
sweeps through the area. The dead tree, especially the standing stump
where the turpentine has collected, becomes an inferno and burns up
completely, along with any dead needles or limbs on the ground. Thus
nutrients that were bound inside the dead tree are returned to the soil
and once again become available for other pine trees.
this be of advantage to the dead pine tree? The simplest answer is that
most nearby pine trees would be descendants of the burned tree; thus
the tree would be returning the nutrients to its own kin. In addition,
periodic fires would eliminate other trees that were not fire-tolerant
species and that might otherwise compete with the pine trees. So instead
of engaging in self-destructive turpentine production, pine trees have
worked out an efficient and effective mechanism to deal with periodic
fires over evolutionary time. In one of Mother Nature's paradoxes, being
saturated with a flammable material can be beneficial to a pine tree
in the long run.
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