Download TREES

What is a Tree?
• A tree is a large, woody plant that has a
single, sturdy stem, or trunk, and that
grows taller than most other plants.
What About
Shrubs & Bushes?
• Shrubs and bushes are much smaller and
have several stems instead of a single
trunk.
Basic Parts of a Tree
• Crown
• Gathers sunlight, makes food
for growth, helps filter air,
produces oxygen.
• Trunk
• Supports crown, carries water
and nutrients to crown,
carries food back to roots.
• Root
System
• Anchors tree, collects water
and nutrients from soil, helps
hold soil in place.
CROWN
• Leaves
– breathing pores
• Takes in carbon
dioxide and releases
oxygen during
photosynthesis.
– solar panels
• Takes in light energy
and heat in order for
photosynthesis to
occur.
TRUNK
• Inner Bark
– Phloem (arteries)
• Carries food from the
leaves down to the stem
and roots.
• Cambium
– Phloem & xylem cells are
made in this single cell
layer.
• Sapwood
– Xylem (veins)
• Transports water,
minerals and food upward
from the roots to the
leaves and horizontally
across the stem.
ROOTS
• Root Tips & Hairs
– absorb water and
minerals from the
soil that are used in
photosynthesis
Classifying Trees
• Angiosperm
– angeion – “case”
– sperma – “seed”
• Deciduous (hardwood)
– Flowering Trees
• wide, flat leaves
– fall off in autumn
• Gymnosperm
– gymnos – “naked”
– sperma – “seed”
• Coniferous (softwood)
– Cone-bearing Trees
• needle-like leaves
• scale-like leaves
– most stay green all
year
How Old is That Tree?
• Every year a tree’s trunk grows wider, and each
year’s growth appears as a ring.
• The approximate age of the tree can be
determined by counting the annual growth rings.
• Springwood – wider, lighter part of the ring made
up of cells that are added in the spring, when the
tree grows rapidly.
• Summerwood – thinner, darker part of the ring
formed during the rest of the year, when the tree
grows more slowly.
Counting Growth Rings
• Start at the center ring
(first year of growth) and
count outward towards
the bark.
• Close rings
– Slow growth
• Dry year
• Limited water
• Wider bands
– Faster growth
• Wetter year
• Optimal growing
conditions
The Value of Trees
• Can you identify 4 reasons why trees should be valued
as one of our most important natural resources?
Recreational use
Habitats for wildlife
Filters air
Products and by-products