powerpoint - tree life cycle

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

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Page 1: Powerpoint - Tree Life Cycle

How to Measure & ID

Week 1 Day 3

It is important that students understand the biology of trees to further be aware of trees’ role in the

ecosystem throughout its life.




Mature Oak


Page 2: Powerpoint - Tree Life Cycle

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

Page 3: Powerpoint - Tree Life Cycle

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.

Which came first - the tree, or the seed?

Page 4: Powerpoint - Tree Life Cycle

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.

Page 5: Powerpoint - Tree Life Cycle

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.

Page 6: Powerpoint - Tree Life Cycle

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.

What does DBH mean?

Page 7: Powerpoint - Tree Life Cycle

What plant in the picture would you say is a

mature tree?

Page 8: Powerpoint - Tree Life Cycle

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.

Page 9: Powerpoint - Tree Life Cycle

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 takenup by other trees.

And, the cycle begins anew.

Page 10: Powerpoint - Tree Life Cycle

What stage of the lifecycle are these trees

in currently?


Page 11: Powerpoint - Tree Life Cycle

What stage of the lifecycle are these trees

in currently?


Page 12: Powerpoint - Tree Life Cycle

What stage of the lifecycle are these trees

in currently?


Page 13: Powerpoint - Tree Life Cycle

Have you ever measured anything? WHAT? HOW?


Why do people measure things?

In what ways do people measure things?

Page 14: Powerpoint - Tree Life Cycle

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.

How many finger lengths is your book?

Why did people get different measurements?

Compare your index finger with your


How can we make sure our measurements are


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Plan harvesting Make forest management decisions Monitor forest health

Page 16: Powerpoint - Tree Life Cycle

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?

Page 17: Powerpoint - Tree Life Cycle

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

What is the crown spread of this tree? 2.5 feet

Page 18: Powerpoint - Tree Life Cycle

What is the crown spread of this tree?

11 feet

8 feet

9.5 feet

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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?

Page 20: Powerpoint - Tree Life Cycle

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

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Differ in many ways and help identify treesTips may be pointed, rounded, tapered…Bases may be squared, rounded, heart-


Page 22: Powerpoint - Tree Life Cycle

What are the shapes of these 3








Page 23: Powerpoint - Tree Life Cycle

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

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What type of leaf margin do these

leaves have? LOBED!

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Completely hairyHairs on one sideCompletely smoothThick, thin, rough or waxy

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Simple leaves have only one piece to them Maple, oak, aspen and


Compound leaves are made-up of several leaflets Ash, walnut and sumac


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Are these leaves simple or






5 6

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The way the leaves are arranged on the twigs Alternate, opposite, whorls

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What kind of leaf arrangements are


Page 30: Powerpoint - Tree Life Cycle

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.

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What type of leaf scar pattern do

these twigs show?





Page 32: Powerpoint - Tree Life Cycle

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.

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Identify with the color and textureShaggy, smooth , rough or deep furrowsExample: Paper Birch – white, paper-likeUse bark on trunk, not branches

Paper Birch

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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