The document summarizes the coniferous plant life found in the Lake Tahoe basin. It identifies the main conifer families of pine and cypress that are native to the area. Key pine species discussed include white fir, red fir, Jeffrey pine, and lodgepole pine. Incense-cedar is also examined as part of the cypress family. The importance of these conifers to the local ecosystem is addressed, as well as their evolutionary history and adaptations. Tree core samples were analyzed to determine tree ages and growth patterns. Granite and volcanic rock formations are also briefly described.

1. Coniferous Plants of the Lake Tahoe Basin
Michael A. Maguire
Lake Tahoe Community College

2. Abstract
The focus of this lab/field assignment was to gain insight into the coniferous
plant life of the Lake Tahoe basin. Each of these plants is an essential
component to the biological productivity of this delicate ecosystem. This
presentation seeks to identify and analyze these elements and construct an
intricate understanding of how this ecosystem benefits from their presence.

3. Native Coniferous Plants of the Lake Tahoe Basin
• The Pine Family
- Evergreen, needled trees with unisexual reproductive structures (cones)
occurring on the same tree (monoecious).
- Male Pollen cones are non-woody and deciduous.
- Female seed cones (pine cones) are woody with bracts and persistent
scales.
• The Cypress Family
- Evergreen trees
- Opposite, four ranked or whorled, scale like leaves
- Fleshy seed cones, become hard at maturity
(Rost, T.L., Barbour, M.G., Stocking, C.R., & Murphy T.M., 2006)

4. The Importance of Coniferous Plants in the Lake
Tahoe basin
• Conifers in the Lake Tahoe basin are of immense ecological importance.
They represent the dominant class of plant life that inhabits the Lake
Tahoe Basin.
• Without their presence, the ecosystem would suffer to sustain its survival.
• Erosion would decrease drastically, the biological productivity of the
terrestrial landscape would be greatly inhibited, and the clarity of the lake
would be greatly impacted.
• Animals, birds, and beneficial micro-organisms would as well lose an
essential resource that they need to survive.

5. The Evolution of Coniferous Plants
• The earliest conifers in the fossil record date to the late Carboniferous
period, about 300 million years ago. (Pinophyta, 2012)
• An important adaptation of these gymnosperms was allowing plants to
live without being so dependent on water. (Pinophyta, 2012)
• Another adaptation is the development of pollen, which allows the
embryo to be transported and developed elsewhere. (Pinophyta, 2012)

6. The Pine Family
A. White Fir (Abiesconcolor) [Piss Fir]
1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order
(Pinales), Family (Pinacaea), Genus (Abies), Species (AbiesConcolor).
2. 0 to 120 feet tall
3. Late season
4. Semi-moist to dry, cool habitats
a. Mostly found below 7,500 feet in elevation
b. Smooth White-gray bark in young trees
c. Deeply furrowed dark-gray bark on mature trees
d. Single, unbundled needles
i. Longer needles than red fir
ii. Flattened
iii. Twisted 180° at the base
e. Seed cones grow in single season (about 4 inches in length)
f. Tend to die from the top down
(Graf, 1999)

7. The Pine Family
B. Red fir (Abiesmagnifica) [Silver Tip]
1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order
(Pinales), Family (Pinacaea), Genus (Abies Mill), Species (Abiesmagnificana)
2. 60 to 180 feet tall
3. Late season
4. semi-moist, cool habitats
a. Abundant on cool exposures in deep soils
b. Found between 7,000-9,000 feet in elevation
c. Mature red fir distinguished from white fir by
i. Deeply furrowed, purplish red bark
ii. Tightly needled
iii. Jigsaw-puzzled branch orientation that project out horizontally
from the trunk
d. Young red fir distinguished by
i. Smaller, untwisted, rounded needles
e. Cones may be over 8 inches long (twice the size of white fir cones)
(Graf, 1999)

8. The Pine Family
C. Jeffrey Pine (Pinusjeffreyi)
1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order
(Pinales), Family (Pinacaea), Genus (Pinus), Species (Pinusjeffreyi)
2. 2 to 160 feet tall
3. Late season
4. Dry, open to semi-open habitats
a. Common on drier soils from lake level to 8,000 feet in elevation
b. At lower elevations, on exposed rocky slopes and in the drier regions of
the basin, it is the most abundant conifer.
5. Recognizable by its three long grayish-blue needles
6. Reddish-brown, deep furrowed bark, gives off a vanilla-like smell
7. Large, oblong seed cones with recurved scales
8. Ranges from southern tip of Oregon to Baja California
(Graf, 1999)

9. The Pine Family
D. Lodgepole Pine (Pinuscontorta)
1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order
(Pinales), Family (Pinacaea), Genus (Pinus), Species (PinusContorta)
2. 1 to 120 feet tall
3. Mid to late season
4. Diverse habitats
a. Able to survive and prosper over a wide range of elevations
b. Most abundant in most areas along lake and meadow edges, aided bya
root system that, unlike that of other conifers, is able to tolerate
waterlogged, anaerobic environments.
c. Commonly found on thin, rocky soils that overlay granitic bedrock in
higher elevation watersheds.
d. Flourish in soggy to dry soils by controlling rates of water uptake and loss
from transpiration.
5. Two needled bundles, corn flake-like bark, and small spherical, pointed
cones
6. The common name, lodgepole, comes from Native Americans’ use of the
young trees as poles for their teepees.
(Graf, 1999)

10. The Cypress Family
A. Incense-cedar (Calocedrusdecurrenes)
1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order (Pinales),
Family (Cupressaceae), Genus (CalocedrusKurz), Species (Calocedrusdecurrens)
2. Habitat
a. Large range of soils
b. Elevations below 7,000 feet in the Sierra Nevada’s
c. Found in California, Oregon, Washington, and sometimes in Nevada
3. 60 to 150 feet tall
4. Needles
a. Small, ovate, oblonged, and opposite
b. orientated in whorls of four
5. cones
a. Two types of cones, pollen cones and seed cones
i. Yellowish pollen cones
ii. Woody seed cones
6. Bark
a. Young trees
i. Purplish red color
b. Mature trees
i. Cinnamon-red color
(Graf, 1999)

11. Core Samples
• Taxonomic classification, growth patterns, bark characteristics, needle/leaflet
arrangement, and natural habitats were utilized in the identification of these trees.
• Tree Core samples where obtained with the use of an increment borer and a measurement of
the circumference of each tree was also documented.
• An increment borer is a tool used to take a core sample of a tree’s annual rings.

12. Core Samples Data
1. White fir (Abiesconcolor)
a. Sample 1
i. 2 feet 3 ¼ inch circumference
ii. 53years ± 3 years
2. white Fir (Abiesconcolor)
a. Sample 2
i. 4 feet 5 inch circumference
ii. 100 years ± 3 years
3. Jeffrey Pine (Pinusjeffreyi)
a. Sample 1
i. 4 feet 4 ½ inch circumference
ii. 70 years ± 5 years
4. Jeffrey Pine (Pinusjeffreyi)
a. Sample 2
i. 5 feet 6 inch circumference
ii. 112 years ± 5 years
5. Lodgepole Pine (Pinuscontorta ssp. Murrayana)
a. Sample 1
i. 5 feet ½ inch circumference
ii. 100 years ± 3 years
6. Lodgepole Pine (Pinuscontorta ssp. Murrayana)
a. sample 2
i. 5 feet 3 ¾ inch circumference
ii. 100 years ± 10 years

13. White Fir

14. Red Fir

15. Jeffery Pine

16. Lodge Pole Pine

17. Incense Cedar

18. Granite
• Granite is an igneous rock that that is composed of minerals that crystallized from
cooling molten rock matter.
• This process is known as intrusive igneous activity
• Granite is a major component to the structure of the Sierra Nevada Mountains, which
solidified under ground and was later “exposed at the surface following uplift and
erosion.” (Monroe &Wicander, 2012, p. 86)
• The following image is a
picture taken of granite
boulders resting along the
waters edge just past Sand
Harbor on the north east
shoreline, looking towards
Crystal Bay.

19. Volcanic Rock
• A volcanic rocks is, “an extrusive igneous rock that forms when lava flows
cool or when pyroclastic materials become consolidated , which then
become extruded onto the surface.” (Monroe &Wicander, 2012, p. 87)
• Volcanic rocks grade into hypabyssal and metamorphic rocks and compose
an important element of some sediments and sedimentary rocks.
(Volcanic Rock, 2012)

20. Reference List
Graf , M. (1999). Plants of the Tahoe Basin (First ed.) CA: Phyllis M.
Faber, CNPS Press.
Monroe, J.S., &Wicander, R. (2012). The changing Earth: Exploring Geology
and Evolution (6th ed.). Belmont, CA: Brooks/Cole, Cengage Learning.
Rost, T.L., Barbour, M.G., Stocking, C.R., & Murphy T.M. (2006). Plant Biology.
(Second ed.). CA: Thomson Brooks/Cole.
Pinophyta. (2012). In Wikipedia. Retrieved July 29, 2012, from
http://en.wikipedia.org/wiki/Conifer#Evolution
Plant Evolution Timeline. (2012). Evolution of Plants. Retrieved July
29, 2012, from
http://botanistbackyard.blogspot.com/2012/03/evolution-of-plants.html
Volcanic Rock. (2012). In Wikipedia. Retrieved July 29, 2012, from
http://en.wikipedia.org/wiki/Volcanic_rock