Pines and the pinetum
Notes on the introduction to pines
The pines are part of the Pinaceae, which contains the spruce, larch, Douglas fur, cedar and hemlock plus others.
It is primarily a Northern Hemisphere group. The Southern Hemisphere equivalent is the podocarps.
Pinus was the Roman name for pine.
The largest tree in the Pinaceae is the Douglas Fir, the oldest Pinus longaeva.
The great botanist Carolus Linneaus established the Pinus genus in 1754.
There are some 120 pine species. Some 30 species of pine were originally planted in the Garden, with 20 species
(including species planted more recently) remaining.
About 30 of the 120 total species produce edible nuts.
Pinus pinea was the first pine used and cultivated by man, its edible seeds having been harvested for perhaps
half a million years or more. Prehistoric man has used its seeds for food, shells being found at many prehistoric
It is the dominant forest of large regions, and many of the species are commercially cultivated throughout the
world, producing most of the world's softwood timber.
Pulpwood, naval stores (tar, pitch, turpentine) and essential oils are also produced from various species, and
food especially from the seeds is a significant food source for some indigenous cultures.
It was initially an important shelter and firewood tree in pioneer New Zealand. Pines have long been a principal
source of timber for all purposes, and continue to be a leading genus in agroforestry production
From many pines vanillin, a vanilla flavouring used in the manufacture of 'artificial' vanilla, is obtained as
a by-product of other resins that are released from pulpwood.
Most species are fire adapted; the recurrence of fire permits the pines to maintain a dominant role in forest successions.
Fire may kill the tree, but the seeds are protected in the cones. Over subsequent months the cones will open and
there can be a prodigious seed fall onto ground that the fire has left in a state securing the maximum seed germination.
Their quick growth allows re-establishment before other competitive plants can become established. Architecture
of pine lead to rapid fire spread-and of course, conifers are very flammable. Protected buds lie beneath the bark
and are stimulated by loss of photosynthetic area. Young individuals better able to regenerate crowns than old
ones . Some cone scales open and release seed, while others remain closed until exposed to heat. The resin that
holds scales of jack pine closed melts at 60oC. The thick woody scales spring open and the seeds are shed in the
days following the fire. Seeds remain viable in cones exposed to 200oC for 10 minutes and 370oC for 1 minute. Crown
fires are of short enough duration and the seeds are protected enough within the cones to remain viable. Seeds
in this aerial "seed bank" retain viability for many years, but do not have the long viability of seed
from species that specialise forming soil seed banks.
Heat stimulated germination in species with thick hard seed coats that are cracked by heat allowing water penetration.
In some cases sunlight is enough-but in others, temperatures associated with breaking physical dormancy (cracking
seed coats) is best achieved by fire. After fire, shade is removed that would otherwise inhibit seedling success.
Chaparral species thus replace themselves after fire.
Germination in pine is enhanced by short-term exposure to heat as in a cone opened by a fire. The mechanism by
which pines have more successful germination after being exposed to heat is unknown-but is probably a physiological
mechanism rather than physical. Mechanically opened pine cones are by no means dormant and the effect of heat is
only a minor enhancement.
Most plants do not germinate well in organic matter. Removal of leaf litter by fire is not so much an adaptation
as an environmental change brought on by fire. Removal of rubbish brings seeds into intimate contact with soil
and allows the seed to absorb water-not possible with seeds in organic matter. Fire assists in the removal of the
alleopathic germination inhibitors, which are very common in decaying organic material.
Rapid early growth: enables re establishment before other plants.
Most conifers will exude resin if wounded. Others will exude resin spontaneously from branches and cones. Several
genera of conifers produce resin in copious quantities, which are then harvested and put to a wide variety of uses.
These have made resin one of the most important non-wood products from conifers. The resin harvested from various
species of Pinus is undoubtedly the oldest and most important of the non-wood products from conifers
Resin products from pines are commonly called naval stores. This term dates back to the days when the British Royal
Navy used large quantities of resin products from pines to waterproof ships. Three produces are involved. From
the resin the volatile turpentine is extracted. Tar is then removed, and pitch remains.
Pine resin has been an important commodity at least since biblical times, as attested to by the story of Noah receiving
instructions from God to "pitch the ark within and without with pitch". Dates of 20,000 to 50,000 years
ago for that flood have been suggested.
The Roman statesman and poet Ausonius wrote about the tapping of pines for resin in Aquitania in the southeastern
part of France. The pine he referred to is Pinus pinaster.
Oleo-resins are present in the tissues of all species of pines. Turpentine consists of an average of 20% of the
oleo-resin and is separated by distillation. Turpentine has a wide range of uses including as a solvent for waxes
etc, for making varnish, medicinal etc. Rosin is the substance left after turpentine is removed. This is used by
violinists on their bows and also in making sealing wax, varnish etc. Pitch can also be obtained from the resin
and is used for waterproofing, as a wood preservative, adhesive and diluted, even as a protective surface coating.
The needles contain a substance called terpene, this is released when rain washes over the needles and it has a
negative effect on the germination of some plants.
When sail tied the world together, pines often assumed strategic importance providing naval stores, influencing
the pattern of Western colonisation. When oak started to become scarce in Britain, the availability of pine and
other good ship building trees in North America was an important reason for early colonisation. They were the first
timber resource exploited in North America.
Pine resin was very important to the British shipbuilding industry during the fifteenth and sixteenth centuries.
When America was a series of British Colonies, the capacity of two indigenous pines: Pinus elliottii and P. palustris,
to produce resins of excellent quality and quantity was recognised and naval stores became an important export
commodity from the South Carolina and Georgia colonies. The tapping of resin from these pines was, until recently,
a major industry in southeastern United States when high labour costs reduced its profitability.
In 1652 the first New England pine trees were felled for British ship masts. Before the end of the century, British
warships were being built in North America because suitable timber supplies were in short supply in Britain.
The pine tree was used as one of the symbols on the first American-made coins, issued in Boston
.1761 By this year British land grants in New England required that pine trees, most notably white pine (Pinus
strobus - Eastern White Pine, also known as Northern White Pine), that were suitable as ship masts be conserved
- to be cut only under license from the crown. Appointed surveyors marked trees to be protected with the "king's
broad arrow," a triangular scar. This decree, among many others, greatly perturbed American colonists.
The first flag used by Revolutionaries bore the image of a single white pine - representing the state of Massachusetts.
P. strobus was a valued source of naval stores in the 1700's, and large tracts were once reserved for exploitation
by the Royal Navy . Vast stands were logged in the 1700's and 1800's for masts, buildings, and furniture. Because
of extensive lumbering, few uncut stands remain
Eastern white pine is the provincial tree of Ontario and the state tree of Maine and Michigan
1772 An uprising against British authority in New England, the Pine Tree Riot, resulted from the levying of fines
on a New Hampshire man for cutting what were determined to be the King's pines. This was one of the precursor events
leading to the Boston Tea Party in the following year.
The Boston Tea party 1773 Americans were displeased by a 3% tax imposed by the English Parliament on tea and other
products. That small tax added to a 100% import duty that all English subjects already paid on tea, and led to
an increase in smuggling of tea from Holland. Loss of business for the London-based John Company resulted in the
Tea Act of 1773, which eliminated the 100% tax - meaning the Dutch would be undersold. Even though this change
represented savings for American tea drinkers, the monopoly granted to the John Company continued to carry a 3%
tax for colonists who had no representation in Parliament. The uniting of American colonists resulted in some ships
being turned away at their ports, but for others (in Boston, Greenwich, Charleston, Philadelphia, New York, Annapolis,
and Edenton), boarding parties threw consignments into the sea.
By 1775 easy sources of wood for masts had been stripped from Eastern North America.
Let us now move to the West Coast of America.
Pine resin was used in California by Indians and the Spanish, long before the territory became part of the United
States, again as an essential element of Spanish shipping.
The origin of the name "California" may be linked to pine trees and the resin they produced. Padre Arroyo,
one of the early priests who converted the Indians of California to Christianity and ultimately wrote a vocabulary
of the California Indian languages, told an officer of Captain Beechey's expedition in 1826 that the word "California"
was a corruption of the Spanish word colofón meaning "resin". He indicated it was suggested by
the numerous pines, primarily Pinus radiata, that produced resin around the old Spanish city of Monterrey.
In south-western United States, the Pueblo and Navajo Indians used the resin of various species of piñon
pines to give their stone griddles a non-sticking surface, something like the Teflon of today. The Hopi Indians,
of American southwest, used resin to repair broken ceramic pottery. In Asia there are numerous records of the use
of pine resin for medicinal purposes.