1. How to Measure & ID Week 1 Day 3
Lifecycle of Trees
It is important that students understand the biology of trees to further be aware of trees’ role in the ecosystem throughout its life.
How to Measure & ID
Week 1 Day 3
Seedling
Seed
Sapling
Mature Oak
Snag

2. Background Like all living things trees have a life cycle:
Birth
Growth
Aging
Death
As trees grow, their physical form changes as does their role in the forest ecosystem

3. Which came first - the tree, or the seed?
Seeds
Which came first - the tree, or the seed?
Seeds come in a variety of shapes,
weights, colors, and sizes, depending on the species.
Seeds develop from male and female parts of the trees producing fruits.
Some seeds are in a protective nut like an acorn
Others are in fleshy fruits, like the black cherry.
The fruit of a pine is a cone and the seed is winged and resembles a miniature helicopter when falling.
Wind, water, animals, and people disperse seeds to the forest floor, open fields, yards and roadsides.
Where conditions are favorable for germination, seeds will germinate and grow.

4. Seedling
The seedling grows and begins to develop woody characteristics.
The stems harden, change color, and develop a thin protective bark.
The stem may bend or develop branches that reach toward light.
Leaves or needles that develop are adapted to shade, but lean or tilt toward light.
Most roots are in the upper soil to absorb water, nutrients and air.
Seedlings compete for nutrients, water, sunlight, and space.
Threats include fire, flood, drought, disease, insect attacks, and animals.
At this stage the tree is most susceptible to being killed.

5. Sapling
When the tree is about 1-4 inches in diameter at 4.5 feet, it is considered a sapling.
standard height where tree’s diameter is measured – diameter at breast height (DBH).
As the tree starts to get taller the trunk thickens and branches develop.
A sapling is the size of a tree growing in a nursery.
In this juvenile state, the tree is not mature enough to reproduce.
Growing rapidly, the sapling has the same competition and threats as seedlings.

6. Mature
What does DBH mean?
With favorable conditions, a sapling will grow into a mature tree (>4 inches DBH).
During this stage, each tree will grow as much as its species and site conditions will permit.
In addition, flowers develop, reproduction ensues, fruits form, and seed dispersal can now occur.
Trees provide the maximum environmental benefits to people during this stage.

7. What plant in the picture would you say is a mature tree?

8. Decline
The life span of a tree is a wide-range, yet death is inevitable.
A combination of factors overcome a tree and causes it to die.
Injury, drought stress, followed by disease, rot, root dieback, coupled with a lightning strike or insect infestation contribute to tree decline.
Sometimes a single factor is serious enough to cause mortality.

9. Dead Tree
Standing dead trees, called snags, play vital roles in the life cycle of many organisms.
A snag slowly breaks down and returns nutrients as limbs, bark, and branches fall. It provides habitat and food for wildlife and insects.
Animals, insects, and fungi help break down the tree.
Eventually, the snag will fall and return nutrients to the soil where they are taken up by other trees.
And, the cycle begins anew.

10. What stage of the lifecycle are these trees in currently?
SEEDLING 

11. What stage of the lifecycle are these trees in currently?
SNAG 

12. What stage of the lifecycle are these trees in currently?
SAPLING 

13. Have you ever measured anything? WHAT? HOW? WHY?
Why do people measure things?
In what ways do people measure things?

14. A little Practice
How many finger lengths is your book?
1. Use the length of your index finger to measure the width of you textbook.
2. Use the length of your forearm to
measure the height of your desk.
Record the results in your packet.
Why did people get different measurements?
Compare your index finger with your neighbors.
How can we make sure our measurements are accurate?

15. Why would we want to measure trees?
Plan harvesting
Make forest management decisions
Monitor forest health

16. DBH
Tree diameter is an important forestry measure and is used to indicate how well a tree is growing over time.
It is also one of the standard measures of timber volume used to estimate the commercial value of a forest stand.
By convention, the diameter is measured at a height on the trunk that is 1.35 m (4.5 ft) above ground level.
This height above the ground is used because uneven swelling and irregular growth at the base of the tree and upper roots could mask the true growth of the trunk.
What would happen if people measured tree circumference at different heights?

17. What is the crown spread of this tree?
Tree’s Crown Spread
What is the crown spread of this tree?
2.5 feet
This is a horizontal measurement:
leaf tip to leaf tip of the shortest spread
leaf tip to leaf tip of the longest spread
through the main mass of the tree canopy 
Add the two numbers together, and divide by two for the average crown spread
Crown spread is difficult to measure when branches are high. Have 2 people stand where the tips of the farthest branches are directly overhead. A 3rd person can measure the distance at ground level.
3 .5 feet
1 .5 feet

18. What is the crown spread of this tree?
9.5 feet
11 feet
8 feet

19. How do you think you use a book like this to identify trees?
Identifying Trees
What characteristics would you use to identify trees? Look at the twigs on your desk for ideas.
Look at several different features
Leaves
Bark
Twigs
Flowers
Fruit
Seeds
Shape
How do you think you use a book like this to identify trees?

20. Needles or Broad Leaves
In the simplest sense we have 2 types of trees:
Conifers (coniferous) :
seeds develop in cones, have needle shaped leaves
don’t lose leaves each year so stay green = evergreens
Pines, spruces, hemlocks and firs
Broad-leaf (deciduous) :
broad, flat leaves that they lose each year
Oaks, maples, beeches and aspens

21. Leaf Shape Differ in many ways and help identify trees
Tips may be pointed, rounded, tapered…
Bases may be squared, rounded, heart-shaped…

22. What are the shapes of these 3 leaves?1
PALMATE!
HEART-SHAPED! 2 3
ROUND OR OVAL!

23. Margins Edges or margins of leaves give clues to tree identity
Teeth (serrated)
Lobed
Smooth (toothless)

24. What type of leaf margin do these leaves have?
LOBED!

25. Textures Completely hairy Hairs on one side Completely smooth
Thick, thin, rough or waxy

26. Simple & Compound Simple leaves have only one piece to them
Maple, oak, aspen and sycamore
Compound leaves are made-up of several leaflets
Ash, walnut and sumac trees

27. Are these leaves simple or compound?3 2 1 5 6 4

28. Leaf Arrangements The way the leaves are arranged on the twigs
Alternate, opposite, whorls

29. What kind of leaf arrangements are these?
ALTERNATE!

30. Twiggy Clues Even leafless twigs can help identify trees.
Look for the leaf scars (leaves used to be there) or buds on the twig to see if leaves grow alternate, opposite or whorled.
Size, color, texture, and shape of buds also help identify trees.
Spines, thorns, prickles and other surface features also help.

31. What type of leaf scar pattern do these twigs show?2
OPPOSITE! 1
ALTERNATE!

32. Fruit and Flowers Various tree species produce characteristic fruits.
Deciduous tress produce berries, winged samaras, nuts, or drupes. Some have unique names (acorns, walnuts, and chestnuts).
Conifers produce different cones that vary in shape, size, and arrangement of scales.

33. Bark Identify with the color and texture
Shaggy, smooth , rough or deep furrows
Example: Paper Birch – white, paper-like
Use bark on trunk, not branches
Paper Birch

34. Crown Shape Characteristic shapes can identify trees
Rounded, weeping, vase-to Funnel, tabular and conical
Some people are able to look at a tree in the distance and know what kind it is