Biology STANDARD V: Objective 3: Title: Tree Key
Description: In this activity students will use a dichotomous key to identify native Utah conifers.
Background Knowledge: None
Equipment and Supplies: Student sheet, collected samples of conifere from the following: Limber, Ponderosa, Lodgepole, or Pinyon Pines; Douglas, Sub-Alpine, or White Firs; Englemann or Blue Spruces; Common, Utah, or Rocky Mountain Junipers.) dichotomous key (below) and tree pictures (below)
Safety Issues: None
Duration: 1 ½ class periods (70 min.)
Procedures for Teachers:
1. Collect samples of a few native Utah conifers. You may want to collect multiple samples of each conifer if you have a large class. Label them with numbers or letters. 2. Make copies of the tree picutres and protect in plastic. Make at least one for each tree or two to make sure students can get a new one when they are ready. 3. Pass out the student sheet, keys and a picture to each group of 2 students. 4. Read the introduction with the students and have them begin the identification. Check their work as they start. 5. Tell students they are now to identify the 12 samples using their key 6. When the students are done, hand out the real samples and ask them to identify them. 7. Go over the correct names and make sure students understand where they got off track.
Key to pictures: 1. pinyon pine 2. lodge pole pine 3. blue spruce 4. white fir 5. ponderosa pine 6. common juniper 7. Engleman spruce 8. Limber pine 9. Utah juniper 10. subalpine fir 11. Rocky Mt. Juniper 12. Douglas Fir Student Sheet Name______Period______
Title: Tree Key
Introduction: A key is necessary to find the names of plants and animals. Keys are written with different levels of scientific vocabulary various ways, depending on the age and background of the reader. If you find yourself with a key that has too many words you do not recognize, find a new key. The key you will use in this activity should contain mostly words you know. A couple of hints:
needles in bundles single needles scales on a cone scales on a leaf of two
In this activity, you will use pictures of trees and real tree branches. See how well you can use the key to identify them.
Procedure: 1. Use the pictures your teacher provides to identify each tree by name. 2. Write the characteristics of each tree and steps you follow to get to the trees name in your data. 3. Use the real trees and find their names after you have practiced with the pictures.
Data:
Tree Characteristics Key numbers Name number 1 2 3 4 5 6 7 8 9 10 11 12
Real Trees:
Tree Characteristics Key numbers Name number 1 2 3 4
Analysis:
1. How many names did you get correct?
2. Pick a vocabulary word off the key that you did not know. What is it and what do you think it means (you can draw it if that is easier)?
3. What characteristics seem best to identify coniferous trees?
4. Why is it important to be able to name trees? Describe at least two reasons.
Conclusion:
KEY TO NATIVE CONIFERS 1. a. Leaves are needle-like: cones are woody or papery and brown in color. ..……………...... 2 b. Leaves have overlapping scales, cones are berry-like and blue in color…………………….………….9
2. a. Needles arise in bundles or packets of 2,3, or 5: cones scales are woody…………………...... 3 b. Needles do NOT arise in bundles or packets but are singular: cone scales are thin and papery...... 5
3. a. Needles arise in bundles of 5: branches are exceptionally flexible, cones have even diamond shaped scales...... …………………………….………………………..Limber Pine b. Needles arise in bundles of 3 and are unusually long: cones occur in groups of three with a center stamen...... ……………………………………………………………………………..…...... Ponderosa Pine c. Needles arise in bundles of 2: cones are small ………………...... ………….……...... 4
4. a. Needles are twisted in appearance: cones are on underside of branch: trunk grows straight and tall...... ………………………………..………….……...... Lodgepole Pine b. Needles usually less than 2 inches long: cones are short with large edible seeds: trunk is short and tree is bushy in appearance...... …………………………………..…………...Pinyon Pine
5. a. Needles are flat and blunt: not sharp to touch...... …………...... 6 b. Needles are NOT flat, but are square in cross section: sharp to touch……………….…….…….…,8
6. a. Needles point outward from twig: cones with leafy bract extending from the cone scales, trees are tall and straight…………….....……………………………………….……………..…………...Douglas Fir b. Needles arise from twig on all sides but bend upward: cones without leafy bracts extending from cone scales...... ……………...... …………...... 7
7. a. Needles usually less than 1 inch in length: cones cluster on bottom of branch……..Subalpine Fir b. Needles have whitish tinge; cone scales look like stacks or layers…………….………..…...White Fir
8. a. Bark is gray in color: cones have rounded cone scales: mature trees are rounded in shape…………………………………………………………………………………………...Englemann Spruce b. Young twigs and branches are stiff, growing outward in flat layers: cones have flattened cone scales: trees are bushy and have a blue shade...... ………..……………………………Blue Spruce
9. a. Leaves have a white color on tips: mature tree grows as a low lying bush……...Common Juniper b. Leaves are have small scales…...... ……………..……….....10
10. a. Berry-like cones are small, rarely to ¼ inch in diameter: trunk usually forked and bark is papery and sheds off in sheets...... ………………………………………...... Utah Juniper b. Scaly leaves are smooth: trunk usually with a central stem...……..…...Rocky Mountain Juniper