Coniferous Plants of the Lake Tahoe Basin

Michael A. MaguireLake Tahoe Community College

AbstractThe 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.

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)

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.

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)

The Pine Family

A. White Fir (Abies concolor) [Piss Fir]1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida),

Order (Pinales), Family (Pinacaea), Genus (Abies), Species (Abies Concolor).

2. 0 to 120 feet tall3. Late season4. Semi-moist to dry, cool habitats

a. Mostly found below 7,500 feet in elevationb. Smooth White-gray bark in young trees

c. Deeply furrowed dark-gray bark on mature treesd. Single, unbundled needles

i. Longer needles than red firii. Flattenediii. 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)

The Pine Family

B. Red fir (Abies magnifica) [Silver Tip] 1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida),

Order (Pinales), Family (Pinacaea), Genus (Abies Mill), Species (Abies magnificana)

2. 60 to 180 feet tall3. Late season4. semi-moist, cool habitats

a. Abundant on cool exposures in deep soilsb. Found between 7,000-9,000 feet in elevationc. Mature red fir distinguished from white fir by

i. Deeply furrowed, purplish red barkii. Tightly needlediii. Jigsaw-puzzled branch orientation that

project out horizontally from the trunk

d. Young red fir distinguished byi. Smaller, untwisted, rounded needles

e. Cones may be over 8 inches long (twice the size of white fir cones)

(Graf, 1999)

The Pine Family

C. Jeffrey Pine (Pinus jeffreyi)1. Kingdom (Plantae), Division (Coniferophyta), Class

(Pinopsida), Order (Pinales), Family (Pinacaea), Genus (Pinus), Species (Pinus jeffreyi)

2. 2 to 160 feet tall3. Late season4. 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 needles6. Reddish-brown, deep furrowed bark, gives off a vanilla-

like smell7. Large, oblong seed cones with recurved scales8. Ranges from southern tip of Oregon to Baja California(Graf, 1999)

The Pine FamilyD. Lodgepole Pine (Pinus contorta)

1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order (Pinales), Family (Pinacaea), Genus (Pinus), Species (Pinus Contorta)

2. 1 to 120 feet tall3. Mid to late season4. Diverse habitats

a. Able to survive and prosper over a wide range of elevationsb. 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 cones6. The common name, lodgepole, comes from Native Americans’ use of

the young trees as poles for their teepees.

(Graf, 1999)

The Cypress Family

A. Incense-cedar (Calocedrus decurrenes) 1. Kingdom (Plantae), Division (Coniferophyta), Class (Pinopsida), Order (Pinales), Family (Cupressaceae), Genus (Calocedrus Kurz), Species (Calocedrus decurrens)2. Habitata. Large range of soils b. Elevations below 7,000 feet in the Sierra Nevada’sc. Found in California, Oregon, Washington, and sometimes in Nevada3. 60 to 150 feet tall4. Needles a. Small, ovate, oblonged, and oppositeb. orientated in whorls of four

5. conesa. Two types of cones, pollen cones and seed conesi. Yellowish pollen conesii. Woody seed cones6. Barka. Young treesi. Purplish red colorb. Mature treesi. Cinnamon-red color

(Graf, 1999)

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.

Core Samples Data

1. White fir (Abies concolor) a. Sample 1

i. 2 feet 3 ¼ inch circumference ii. 53years ± 3 years

2. white Fir (Abies concolor) a. Sample 2

i. 4 feet 5 inch circumference ii. 100 years ± 3 years

3. Jeffrey Pine (Pinus jeffreyi) a. Sample 1

i. 4 feet 4 ½ inch circumferenceii. 70 years ± 5 years

4. Jeffrey Pine (Pinus jeffreyi) a. Sample 2

i. 5 feet 6 inch circumference ii. 112 years ± 5 years

5. Lodgepole Pine (Pinus contorta ssp. Murrayana)a. Sample 1

i. 5 feet ½ inch circumferenceii. 100 years ± 3 years

6. Lodgepole Pine (Pinus contorta ssp. Murrayana)a. sample 2

i. 5 feet 3 ¾ inch circumference ii. 100 years ± 10 years

White Fir

Red Fir

Jeffery Pine

Lodge Pole Pine

Incense Cedar

Granite

• 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.

• 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)

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)

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, fromhttp://en.wikipedia.org/wiki/Conifer#Evolution

Plant Evolution Timeline. (2012). Evolution of Plants. Retrieved July 29, 2012, fromhttp://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