Tree Story: The Life of a Douglas Fir Tree

ObjectivesStudents will…

  • Learn about the life-cycle of a Douglas fir tree
  • Be able to identify the interconnections between forest organisms
  • Learn about forest structures and changes over time

Grade Level Expectations:for grades 6-8: 1.3.10 Understand how organisms in ecosystems interact with and respond to their environment and other organisms.

Procedure:

1)Make a copy of the tree story. Decide whether to use the in-depth (left hand) or easier (right hand) version. A full tree timeline is also included in this link.

2)Students will be reordering the story after you cut the cards up. It is easier to check their work if you print a letter on the card backs so you can check your work. There are 14 cards, so, you can write one letter of the words “See Spotted Owls” on each card back.

3)Shuffle the cards.

4)Shuffle the cards. Do step 1-4 ahead of time.

5)To accommodate your whole class, you can work with half your class, you can have students work in teams, or you can make two sets of cards.

6)With students, pass out the 14 cards randomly. Ask students to cooperate in rebuilding the story of a Douglas fir tree. You can give students the hint that it will be easier if they sub-divide into the early, wound stage, and later stage of the trees life, and work from there.

7)If you want to check and make sure they got it right, you can have them turn over the cards and see if they spell “See Spotted Owls.” Or, you can have them discover any mistakes as they read.

8)Have the students stand in order in a circle and read the story and check their work.

9)Discuss anything surprising that the students learned from this story. Collect vocabulary words new to students. (See forest vocabulary below.)

References:

Franklin, J.F., Cromack, K., Denison, W., McKee, A., Maser, C., Sedell, J., Swanson, F., Juday, G., Ecological Characteristics of Old-Growth Douglas-Fir Forests.U.S. Dept of Agriculture, General Technical Report PNW-118, Feb, 1981.

Forest Vocabulary

Bole: The bole is the trunk of the tree. Foresters look for straight unblemished boles to make good boards.

ClimaxForest: Most Western Washington forests naturally convert to western hemlock as the dominant species as they age. Alder, Douglas fir and Sitkaspruce generally dominate forests after a disturbance such as a fire. As these trees mature, they block out much of the light in a forest. Western hemlocks are able to grow in low light, and eventually they out-compete Douglas fir and spruce in these low light conditions. These older forests are called climax forests. Forests constantly cycle through different life stages; climax is not stasis.

Crown: The top portion of a tree is referred to as the crown. In older trees, crowns are frequently damaged by insects, high winds, or lightening. These damaged crowns can grow wider platforms as a result of their damage. These are important nesting habitats for marbled murrelets, bald eagles, and osprey among others.

Disturbance: A fire, landslide, development, wind-fall, or something similar that changes the forest composition.

Dog Haired: “The most sterile succession stage for diversity of plants and animals is a dense, rapidly growing young conifer forest” (Franklin et al., 1981, p. 4).

Epiphytes: Epiphyte is the term for a plant that lives on another plant without taking from its host. Old-growth dependent crown lichens such as Loberia oregana produce 6-9 pounds of nitrogen each year per acre. Nitrogen is the limiting growth factor in old-growth forests (Franklin et al., 1981 p. 7).

Decadent: As forests mature, a tree’s growth of wood slows down. At the same time, heart rot and other factors speed up the relative decay of wood. This does not create a net loss of living biomass, but it does represent less productivity in terms of tree growth (Franklin et al., 1981, p. 2 & 6).

Saprophytes: “All or part of their energy [comes] from decomposition of dead organic materials rather than photosynthesis—most vascular plants characterized as saprophytic have fungal associations essential to their survival (Furman & Trappe, 1971)” (Franklin et al., 1981, p.4).

Woody Debris: “18-35% of all woody debris in streams is flushed downstream, leaving 82-65% to form the base of stream food chains, protection for young fish. Woody debris also changes the structural flow of rivers and streams” (Franklin et al. 1981, p. 8).

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