1 Phenology By: Lynn Vaughan

2 Phenology Is Watching For… changes in animals, people or plants

3 Phenology is not… watching everyday events, like when we eat, sleep or play. watching everyday events, like when we eat, sleep or play. Scientists are interested in when leaves appear in the spring and how quickly they Scientists are interested in when leaves appear in the spring and how quickly they expand and how quickly they change and expand and how quickly they change and disappear in the fall. disappear in the fall.

4 The rate of fall leaf changes, such as color changes and leaf drop, is important.

5 Why is it Important?

6 Many scientists use NASA sensors to monitor seasonal changes. Many scientists use NASA sensors to monitor seasonal changes.

7 Green-up/Green-down data from GLOBE students is a consistent method to verify the accuracy of these satellite products.

8 Phenology is about watching for changes in plants and animals because of changes in the SEASONS and climates.

9 These seasonal changes are related to how long the sun shines each day, how much rain, sleet, or snow falls during the These seasonal changes are related to how long the sun shines each day, how much rain, sleet, or snow falls during the season, and how hot or cold the air season, and how hot or cold the air temperature. temperature.

10 For example: watching when birds fly south for the winter, when animals grow thick fur to keep warm, when trees shed their leaves in the fall or when plants bloom in the spring.

11 Plants Have Roots Roots Stems Stems Leaves Leaves

12 What Do Trees Do For Dinner? Leaves are Nature’s Food Factories. Leaves are Nature’s Food Factories.

13 Plants make their own food. They take water from the ground through their roots.

14 Then, they take a gas called carbon dioxide from the air. They turn water and carbon dioxide into food with the help of the sun and something called chlorophyll.

15 During the summer, the days are filled with lots of sunshine. So the plants are busy making and storing food and growing.

16 green Chlorophyll is a special chemical that gives plants their green color.

17 When it gets colder and the days get shorter in late summer leaves cannot make much food.

18 The trees shut down their food-making factories and the chlorophyll disappears.

19 We begin to see yellow, red, and orange colors. These colors were in the leaves all summer, but the bright green covered them up.

20 Why Do Some Leaves Turn Red?

21 The red color is made in the fall from food trapped in the leaves.

22 Why do some leaves turn brown?

23 Brown is made during the fall from the waste left in the leaves.

24 What about yellow and orange ?

25 Scientists do not know the exact role of yellow and orange, but think they may be involved in the food making process.

26 How does a deciduous tree know when to lose its leaves?

27 As the days get shorter and nights get longer, a special chemical in the tree called phytochrome tells the tree to stop growing.

28 The leaf makes less and less food and green chlorophyll each day.

29 Special cells between the branch and the leaf stem begin to break down making a weak spot on the stem.

30 The leaf is only holding onto the branch by a thread-like vein.

31 Then the wind blows and breaks the leaf off.

32 The leaf floats to the ground.

33 The branch forms a hard covering called a “leaf scar” to heal the spot where the leaf fell off.

34 When you see a twig look for the leaf scar.

35 Is it Goodbye for Mr. Leaf?

36 No, NO, NO, The leaf is eaten by insects, worms, or animals. The insect’s and animal’s waste is broken down and returned to the soil for another plant to use.

37 For Help Lynn Vaughan AMSTI-GLOBE Resource Specialist Jerry Cobbs AMSTI-GLOBE AMSTI-GLOBE/Technology Specialist www.amsti.org/globe