Upload
damian-ramsey
View
218
Download
0
Tags:
Embed Size (px)
Citation preview
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
• Trunk
• Root System
• Gathers sunlight, makes food for growth, helps filter air, produces oxygen.
• Supports crown, carries water and nutrients to crown, carries food back to roots.
• 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
• Gymnosperm– gymnos – “naked”– sperma – “seed”
• Coniferous (softwood)– Cone-bearing Trees
• needle-like leaves• scale-like leaves
– most stay green all year
• Angiosperm– angeion – “case”– sperma – “seed”
• Deciduous (hardwood)– Flowering Trees
• wide, flat leaves– fall off in autumn
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?
Habitats for wildlife
Recreational use
Products and by-products
Filters air