San Francisco State University
Department of Geography
Geography 316: Biogeography
The Biogeography of Monterey Pine (Pinus radiata)
By Saverio G. Trinchese, Student in Geography 316, Fall 2000
.
Figure 1. Monterey Pine Needles.
Kingdom: Plantae
Phylum: Pinophyta
Class: Pinapsida
Order: Pinales
Family: Pinaceae
Genus: Pinus
Species: Pinus radiata
Description of Species:
The shape of the tree has a pointed top, which is
commonly seen on young trees. When located in dense and sheltered communities the shape of
the trees are usually straight bold. When isolated in exposed sites they are prone to
irregular shapes, caused by wind and salt spray most of the time (Bakker, 1984). The
needles are a shiny green color bundled into groups of three. They are 4-6 inches in
length (Figure 1). The bark of the tree is thick, and deeply furrowed into scaly ridges,
and is dark reddish brown in color. The cones are 3-6 inches in length and exhaled with a
pointed tip (Figure 2). The cones are shiny brown in color and grow clustered in rings on
short stalks and turned back. "The scales of the cones are raised and rounded, larger
on the outer sides and ending in tiny prickle: small, long winged seeds (Little,
1980)". Height of the Monterey pines range from 50-100 feet tall.
Figure 2. Monterey pine cone
(Picture taken by the author 2000).
The diameter of the trunks run 1-3 feet. These evergreen trees can live anywhere from 60-
80 years old. Some have made it past 100 years. These trees have closed cones. This means
they need fire to reproduce, which makes them pyrophytes trees. Only two other pines are
also pyrophytes the Bishop (Pinus muricata) and the Beach (Pinus contorta).The
heat from the fire allows the cones to open up and release their seeds. The trees are
usually around the same age and are similar in height within their habitat because of this
process. Without fire they will no longer be able to reproduce and would die off as a
species.
(Picture taken by the author 2000)
Habitat:
Pinus radiata is a stenotopic (very specific
preferences & limited ecological tolerance) coniferous tree that is native to the
central California Coast & Guadalupe Island off of Baja California in Mexico. This
species like a moist climate, this is why it is found in the fog belt, up to six miles
inland in California and 1000' inland on Guadalupe Island. They like coarse soils, such as
sand, and grow on slopes. They grow very well around Monterey & Gowen cypresses and
coast live oak trees (Little, 1980).
Natural History:
The Monterey pine has been around as far back as the
Pleistocene period; about one million years ago (Evens, 1988). It once grew naturally in
the Point Reyes region of Millerton Point east of Tomales Bay (North of San
Francisco)(Evens, 1988). Fossils in that region prove this. Ornduff (1974) also states
that during the Pleistocene period; Pinus masonii was an ancestor of the Monterey pine. It
became extinct in the early beginning of the Pleistocene period. Its modern descendant
persists the same traits (Ornduff, 1974). Fossils show that the Monterey pine was more
widespread in California than now.
Evolution:
According to Murphy (1981) "Axelrod described
seven sets of dated fossils of the Pinus radiata". His descriptions note that the
cones evolve to longer lengths & wider apophyses (a natural outgrowth or process).
Axelrod also documented that there was, "an ascending sequence of mean cone lengths
among the five extant populations, increasing from 6.5 cm (Cedros Is.) to 8.2 cm
(Monterey), 11.4 cm (Ano Nuevo), and 13.9 cm (Cambria) (146)". He also suggests that,
"populations arose in a step-wise fashion, such that those with smaller cones gave
rise progressively to populations with larger cones". In other words the closer in
size the cones, the closer the trees are related to each other. Because of ecological
pressures at each habitat isolation may have changed cones lengths in different
populations (Murphy, 1981). Seed protein of the Monterey pine was also compared. This
comparison was done by "using semi quantitative agar diffusion immunochemical
techniques applied previously to seed proteins of members of the Pinacea by Prager et al.
(1976)". The data indicates that the seed protein antigens, in the five populations,
correlate closely with differences in cone length (Murphy, 1981). "Evidence that cone
lengths have changed rapidly and produced great differences in close related populations
is little; reason for a regular evolution of larger cones is not known (Murphy,
1981)". Axelrod (1980) did suggest that larger cones with large seeds show
adaptations to low summer rainfall.
Distribution:
Monterey pines grow naturally on Guadalupe Island off
the coast of Baja Cal. and Monterey & Santa Cruz coast in California. The most
abundant growth is found on the Carmel slopes next to Monterey. Because of its rapid
growth of up to 9 feet per year it is planted for reforestation projects and as paper
making. It is very commonly planted for commercial reasons in various parts of the world.
These trees have been planted in Spain, Italy, and in north African countries in the
northern hemisphere. 
(Map taken from The Calflora Database at http://www.Calflora.org/)
In the southern hemisphere it is more commonly planted in
Argentina, Chile, South Africa, Australia and New Zealand (Edlin, 1974). Some have been
planted in the tropics and failed to become successful. According to Mirov & Hasbrouck
(1976), as a species of temperate, albeit mild climate, it needs winter rest, however
short. In the tropical lowlands it is forced into continuous growth. It sprouts up a long
fox tail or rattail. These single tall tails have no branches, only needles. These tails
are very weak and are apt to break during strong winds.
Both Monterey and Bishop pines are limited to fog belt
regions, but the Bishop is found in a more northern distribution. The two trees shed their
pollen at different times; the Bishop in April and the Monterey in February. Seasonal and
geographical isolation has kept the two species from merging (Bakker, 1984). The Monterey
pine also takes more nutrients from the soil.
Other interesting issues:
The Monterey pine is prone to disease especially found
heavily in Santa Cruz County where the fungus was first discovered in the summer of 1986.
The New York Times on June 10th of 1998 published an article that said scientists fear
that 80% of the species on the Pacific coast will be gone within the next 30 years.
Scharpf (1993) describes this disease which is named the Pitch Canker of Pines. He
explains, "fungus spreads by means of spores produced in small pink fruiting bodies
called sporodochia, which are produced mostly on branches, twigs, and cones". The
spread, production, and infection occurs during rainy periods (Scharpf, 1993). It can
contaminate young seedlings as well. "Branch flagging and top kill are the most
obvious symptoms (Scharpf, 1993)". Also trunk cankers and an abundant resin flow,
especially flowing on wood of branches and trunk. Fruiting bodies may also appear on
younger dead tissues. Tissues must be taken to a lab for positive diagnosis (Scharpf,
1993).
Bibliography:
Axelrod, D.I. 1980. "History of the Maritime
Closed-Cone Pines, Alta and Baja California". Univ. Calif. Publ. Geol. Sci.
120:1-143.
Bakker, Elna. 1984.An Island Called
California. Berkeley, CA. University of California Press.
CalFlora: Information on California
plants for education, research and conservation. [web application]. 2000. Berkeley,
California: The CalFlora Database [a non-profit organization]. Available: http://www.calflora.org/. (Accessed: Dec 05, 2000)
Edlin,Herbert L. and Maurice Nimmo. 1974.
The World of Trees. London, England. Orbis Publishing Limited.
Evens, Jules G. 1988. The Natural History
of the Point Reyes Peninsula. Point Reyes, CA. Point Reyes National Association.
June 10,1998. "Lowly fungus poses
direct threat to the majestic Monterey pines." The New York Times pA18(L) col 1(10col
in).
Little, Elbert L. 1980. The Audubon
Society Field Guide To North American Trees: Western Regoin. New York, NY. Alfred A.
Knopf, Inc.
Mirov, Nicholas T. & Jean Hasbrouck.
1976. The Story of Pines. Bloomington. Indiana University Press.
Murphy, Terence M. Feb 1981.
"Comparing seed proteins from pinus radiata populations." Bioscience v31 p146
(2).
Ornduff, Robert. 1974. Introduction to
California Plant Life. Berkeley, CA. University of California Press.
Prager, E.M., D.P. Fowler, and A.C.
Wilson. 1976. "Rates of evolution in conifers (Pinaceae)." Evolution 30: 637-649
Tree Guide; North American trees.
http://www.Treeguide.com (Accessed Dec. 07, 2000).
send comments to bholzman@sfsu.edu
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