Lesson Plan

I'm A Tree

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Grade Level:
Second Grade-Fourth Grade
Biology: Plants, Botany, Conservation, Ecology, Environment, Visual Arts
45 minutes
Group Size:
Up to 24 (4-8 breakout groups)
National/State Standards:
Standard 7: Students examine organisms’ structures and functions for life processes, including growth and reproduction. (ASDOE Elementary Science Standards: Grade 2-4, pp. 28-42)


Most of the natural vegetation of American Samoa (present before the arrival of Polynesians about 3000 years ago) fits into the category of tropical rainforest. Tropical rainforests are found throughout the world in areas of warm climates and sufficient to plentiful year-round rainfall. The Samoan tropical rainforest originally extended from just inland of the shore up to the summits of the highest mountains.


Students will be able to:

1. Define the vocabulary terms tree and habitat.

2. Identify five species of animals that live in American Samoa's tree habitat.

3. Describe how our actions can threaten the health of our trees.
4. Learn about the role of the National Park of American Samoa in conserving trees



One of the significant characteristics of tropical rainforests is high species diversity. Tropical rainforests are home to the majority of the world’s plant species. The flora of Samoa (the sum of the plants occurring in the archipelago) comprises about 550 native flowering plants, 215 fern species, and 13 fern ally species. About two thirds of these species are found in American Samoa. They can be divided into two types: endemic species (restricted to Samoa) and indigenous species (not restricted to Samoa).

The level of endemism of the native flowering plants in Samoa is estimated to be about 30% at the species level. Areas to the west such as Indonesia and Malaysia have much larger floras, a characteristic that can be attributed to their much larger areas, older age, and to what is called a “filter effect” in which chance and distance limit the number of species successfully reaching (and becoming established in) the faraway islands of Polynesia.

Another characteristic of tropical rainforests is the presence of unusual life forms. One of the most unique is that of epiphytes, plants that grow on trees, usually in order to get closer to the sunny canopy, but which do no harm to the “host” plant. When the conditions in the forest are extremely wet, as they are in the montane forest and cloud forest, epiphytes may even cover the trees. The most prevalent group of epiphytes is the orchid family, which comprises 65 species in American Samoa (many of which are not epiphytes but grow on the forest floor). Epiphytic ferns comprise the second most abundant group of epiphytes in the Territory.

The vegetation of Samoa is not homogenous, because zones of plant combinations can be discerned. It is difficult, however, to make sense of the differences we can see in the pattern of plants, and even more difficult to determine where the boundaries are between the different types of vegetation. The vegetation can generally be divided into a number of categories called “plant communities.” A plant community is a unit of similar vegetation distinguished from other plant communities by its structure and habitat. Eight natural plant communities can be recognized in American Samoa: (1) Littoral Strand, (2) Marsh, (3) Freshwater Forest, (4) Mangrove Forest, (5) Lowland Forest, (6) Montane Forest, (7) Montane Scrub, and (8) Summit Scrub. Several other disturbed types of vegetation can also be recognized.

Littoral Strand comprises the forest, scrub, and herbaceous zones growing directly on the seashore. Its component species are seawater dispersed and widespread on Pacific shores. Marsh, Freshwater Forest, and Mangrove Forest are classified as “wetlands,” but they comprise only a small percentage of the overall land area of American Samoa. Lowland and Montane Forest together comprise the “tropical rainforest” that once covered over 90% of Samoa.

Montane Scrub and Summit Scrub are unique. Montane scrub comprises the vegetation on the summits and upper slopes and ridges of Tutuila on geologic areas called “trachyte plugs,” which have a characteristic chalky soil that appears to cause stunted vegetation. Its scattered, stunted trees are embedded in a dense matrix comprising shrubs, ferns, and lianas. Epiphytes also abound in this community, sometimes covering the stunted trees.

A plant community that is in equilibrium with its environment, when its form and flora change little with time (barring major disturbance), is called a “climax plant community.” A climax forest is often confused with “primary forest,” which is the natural and undisturbed forest in an area. However, nearly all of the mature forests in Samoa are better described as climax rather than primary forest, since in ancient times much of the interior of the islands was inhabited and cleared for cultivation before being abandoned early in the European Era (after 1830).

Native tropical forests serve several important functions in American Samoa and throughout the tropics. First, they provide protection from soil erosion, which leads to a higher quality of drinking water. Second, they are home to a majority of the world’s plant and animal species. Third, they serve as home to animals, such as pigeons and flying foxes, and plants, such as Tahitian chestnut (ifi), that have traditionally been a major part of the local diet.

Unfortunately, the forests of American Samoa are seriously threatened. The most dangerous threats, direct or indirect, are the actions of people. Due to rapid population growth, the existence of communities such as mangroves, wetlands, and some kinds of lowland forest have been nearly eliminated. Alien plant and animal species also threaten to outcompete and reduce the abundance of some native species.


1. Large piece of white paper, 15 ft. x 3 ft. wide.
2. Pencil
3. Scissors

4. Chalk or whiteboard
5. Duct tape

6. Paint
7. Paint brushes

Tasi's Gift by Tamara Montgomery



Last updated: February 28, 2015