Transcript Tree Basics - Milan Area Schools

Tree Basics
• Basic Description: Woody plants with
single stems.
• Consist of toots, trunk and crown
Roots
• Roots – used to anchor and support tree,
take in water and nutrients, store food, and
hold soil in place.
• 4 types of roots in a complete root system
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Tap root (get water)
Deeply decending root (get water)
Lateral root (get nutrients)
Fibrous root (get nutrients)
Roots cont..
• Roots grow in both length and diameter.
• Rapid cell division just behind the root cap
on each root.
• Root hairs – absorb water and nutrients
• Behind the growing tip of each root
Trunk
• Supports the crown of the tree, transports sap
(water and dissolved nutrients)
• 5 parts listed from inner to outer:
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A. Heartwood – dead cells that support tree
B. Sapwood – xylem (carries water and nutrients.
C. Cambium – cell growth occurs here
D. Inner bark – phloem (take food made in leaves to
rest of tree)
– E. Outer bark – protects the tree from insects and
disease.
Tree growth
• Trunk, branches and roots all grow in
diameter by means of cell division in the
cambium layer.
• Tree grows in length by means of rapidly
dividing young cells in the terminal bud on
each branch and twig.
Trunk cont..
• Growth occurs in cambium faster in spring
and slower in summer. This makes the tree
have an annual growth ring.
– Soil moisture is plentiful in spring (creates a
wide ring)
– Dry years, disease, fire, insects can cause
narrow rings.
Crown
• Includes branches, twigs, buds, and leaves
• This is where photosynthesis takes place
• Leaves take in CO2 from air, water from
roots and sunlight to make sugar for food.
– Oxygen is a waste product given off.
Excess water is given off through stomata
through transpiration.
Growth in the crown
• 1. New growth of twigs increases length of
branches
• 2. Each branch and twig grows in diameter.
Light Requirements
• Shade tolerant: grow well without sunlight
(Dogwood, Maples)
• Moderately shade tolerant: require some
direct sunlight. (Ponderosa Pine)
• Shade-intolerant: Need sun for atleast part
of the day. (Douglas Fir)
The Forest Canopy
• Ceiling of the forest : made up of crowns of
taller trees. 4 relationships:
– Dominant : crown extends above general
canopy level.
– Codominant : crown on the general canopy.
– Intermediate : crown in general canopy, little
direct light from side.
– Suppressed: Poorly developed crown below
the canopy.