Sustainable Resources Sustainable Resources 11/1211/12

Forestry Unit Forestry Unit

Introduction to TreesIntroduction to Trees

Structure and Function of PlantsStructure and Function of Plants

BotanyBotany

Botany: is the science of plantsBotany: is the science of plants

Plants have the following Plants have the following characteristics:characteristics:

1. cell wall1. cell wall 2. photosynthesize (breath in CO2. photosynthesize (breath in CO22, ,

breathe out Obreathe out O22, make their own food – , make their own food –

sugar)sugar) 6CO6CO22 + 6 H + 6 H22O + Energy O + Energy 6O 6O22 + C + C66HH1212OO66

Introduction to TreesIntroduction to TreesTrees:Trees: are perennial woody plants with apical are perennial woody plants with apical

dominance. dominance.

Apical dominance: Apical dominance: a single main stem a single main stem (trunk) that is (trunk) that is dominant over dominant over all other stems. all other stems.

Trees are VascularTrees are Vascular

VascularVascular: : vascular tissue is complex, formed of more than one vascular tissue is complex, formed of more than one

type of cell. The primary components of vascular type of cell. The primary components of vascular tissue are the tissue are the xylem and and phloem.. These two tissues These two tissues transport fluid and nutrients internally. transport fluid and nutrients internally.

Vascular plants tend to be tallVascular plants tend to be tall

Types includeTypes include::

a) cone bearing (gymnosperms = evergreens)a) cone bearing (gymnosperms = evergreens)b) flower bearing (angiosperms)b) flower bearing (angiosperms)

Seed-Bearing PlantsSeed-Bearing Plants

1.1. GymnospermsGymnosperms: :

conifers or conifers or cone-bearing cone-bearing

evergreens.evergreens.

2. Angiosperms2. Angiosperms: : Flowering plants, Flowering plants, enclosed seeds.enclosed seeds.

TreesTrees1.1. ConifersConifers: : Are cone-bearing woody trees with vascular Are cone-bearing woody trees with vascular

tissue. tissue. Evergreen plants with needle-like leaves.Evergreen plants with needle-like leaves. Dominate the boreal forest making them the Dominate the boreal forest making them the

largest carbon sink (a natural reservoir for largest carbon sink (a natural reservoir for the storage of carbon). the storage of carbon).

Examples of ConifersExamples of Conifers

A: Pine A: Pine TreesTrees

B: CedarB: Cedar

C: Douglas FirC: Douglas Fir

D: HemlockD: Hemlock

2. Deciduous trees:2. Deciduous trees: ‘‘falling off or tending to fall off’; these trees falling off or tending to fall off’; these trees

have true leaves that fall off during the colder have true leaves that fall off during the colder and shorter days of the yearand shorter days of the year

Trees lose their leaves to conserve water and Trees lose their leaves to conserve water and prevent against insect damage.prevent against insect damage.

Examples of Deciduous TreesExamples of Deciduous Trees

A: Maple treeA: Maple tree

B: Fruit TreesB: Fruit Trees

C: Alder TreesC: Alder Trees

D: Birch TreeD: Birch Tree

E: Willow TreeE: Willow Tree

Plant PartsPlant Parts

1.1. Vascular tissuesVascular tissues

2.2. LeavesLeaves

3.3. StemsStems

4.4. RootsRoots

5.5. Flowers Flowers

6.6. ConesCones

Stem

roots

Major Organs of Plants

LeavesFlower

Fruit/Seed

1. Vascular Tissue1. Vascular Tissue

Leaves, flowers, stems and roots are all Leaves, flowers, stems and roots are all interconnected with a phloem-xylem network.interconnected with a phloem-xylem network. Xylem: mainly water and nutrients from Xylem: mainly water and nutrients from

roots.roots. ““Xy” to the skyXy” to the sky

Phloem” mainly sugar and water from Phloem” mainly sugar and water from leavesleaves

Xylem and PhloemXylem and Phloem

2. Leaves2. Leaves

Purpose: where photosynthesis occurs Purpose: where photosynthesis occurs (actually inside little, green organelles (actually inside little, green organelles calledcalled chloroplasts ). ).

CuticleCuticle (waxy layer): keeps water in so leaf (waxy layer): keeps water in so leaf doesn’t dry out.doesn’t dry out.

EpidermisEpidermis: protection and strength: protection and strength Guard cells = StomataGuard cells = Stomata: air exchange and : air exchange and

control of water loss (“doors” that open when control of water loss (“doors” that open when there is lots of water, close when not).there is lots of water, close when not).

Palisade LayerPalisade Layer: contains chloroplasts to do: contains chloroplasts to do

Spongy LayerSpongy Layer: also contains : also contains Loose packing of mesophyll (middle) cells Loose packing of mesophyll (middle) cells

facilitates gas exchangefacilitates gas exchange

chloroplasts;photosynthesis

Conifer LeavesConifer Leaves

The leaves of many conifers The leaves of many conifers are long, thin and are long, thin and have a needle-like have a needle-like appearance.appearance.

Some have flat, Some have flat,

triangular scale-like triangular scale-like leaves. leaves.

3. Stems3. Stems

Functions:Functions: 1. support leaves1. support leaves 2. movement of materials*2. movement of materials*

3. gas exchange and some photosynthesis (green 3. gas exchange and some photosynthesis (green stems)stems)

xylem

phloem

phlo

em

*Water moves up stems because of *Water moves up stems because of “transpiration”.“transpiration”.

Transpiration:Transpiration: water loss from the plant water loss from the plant through the stomata. through the stomata.

Water molecules are held together by a Water molecules are held together by a cohesive force known as hydrogen bonding. cohesive force known as hydrogen bonding. This is an attractive force that holds water This is an attractive force that holds water molecules close together, thus when molecules close together, thus when transpiration occurs water is pulled up the transpiration occurs water is pulled up the stem.stem.

Fact!Fact!

Giant redwoods have Giant redwoods have been measured around been measured around the trunk and they actually the trunk and they actually have a smaller diameter on have a smaller diameter on hot summer days when hot summer days when lots of water is drawn up. lots of water is drawn up.

Types of Stems:Types of Stems:

A. “Herbaceous” (soft and A. “Herbaceous” (soft and greengreen):):

i) i) Monocot:Monocot: bundles of xylem and phloem are bundles of xylem and phloem are scattered throughout the stem.scattered throughout the stem.

No vascular No vascular cambiumcambium (cambium layer of (cambium layer of cells that produce vascular tissues), therefore cells that produce vascular tissues), therefore diameter is fixed (stem is long and thin)diameter is fixed (stem is long and thin)

Epidermis

Cuticle (waxy): prevent water loss

Cortex: some photosynthesis

Pith: food storage

Vascular bundle xylemphloem

Monocot

Epidermis

Cuticle (waxy): prevent water loss

Cortex: some photosynthesis

Pith: food storage

Vascular bundlexylem

phloem

ii) Dicot: vascular bundles arranged in a circle

Vascular cambium: reproduces X & P tissue

B. “B. “Woody DicotWoody Dicot” (hard, long-lived) i.e. trees.” (hard, long-lived) i.e. trees.

Vascular cambium: meristematic = produces X & P tissue

Sapwood : outer (living)

Heartwood : inner (dead)wood = xylem

pith

Inner bark = phloem

Outer bark = cork (dead): contains suberin, waterproof

Ray: transport system between phloem and xylem from bark

Functions of Woody Dicot StucturesFunctions of Woody Dicot Stuctures

Vascular CambiumVascular Cambium: : meristematicmeristematic tissue, here tissue, here new xylem and phloem are produced.new xylem and phloem are produced.

SapwoodSapwood: :

The wood that is formed first. Sapwood is the The wood that is formed first. Sapwood is the younger, outermost wood; in the growing tree younger, outermost wood; in the growing tree it is living wood, and its principal functions it is living wood, and its principal functions are to conduct water from the roots to the are to conduct water from the roots to the leaves (xylem). leaves (xylem).

Functions of Woody Dicot StucturesFunctions of Woody Dicot Stuctures

HeartwoodHeartwood: Dead wood located in the center : Dead wood located in the center of the tree. of the tree.

Here it is the Here it is the darker wood.darker wood.

Functions of Woody Dicot StucturesFunctions of Woody Dicot Stuctures

Inner BarkInner Bark: part of the periderm (epidermal : part of the periderm (epidermal meristem) consists of phloem.meristem) consists of phloem.

Outer BarkOuter Bark: Part of the outer most periderm, : Part of the outer most periderm, dead waterproof bark.dead waterproof bark.

PithPith: center of the stem, trunk or branch.: center of the stem, trunk or branch.

4. Roots4. Roots

Functions: Functions: Support the plant and anchor it in the Support the plant and anchor it in the

soilsoil Uptake of nutrients and waterUptake of nutrients and water Storage of foodStorage of food

5. Flowers5. Flowers part of plant which is specialized for part of plant which is specialized for

sexual reproduction.sexual reproduction.

6. Cones6. Cones

Reproductive structure in a conifer. Reproductive structure in a conifer.

Assignment /30 marksAssignment /30 marks Create a vocabulary list for all of the words Create a vocabulary list for all of the words

that you have learned during this lesson. that you have learned during this lesson. Lots of these words are from the Greenhouse Lots of these words are from the Greenhouse Unit, put a star beside words that appear in Unit, put a star beside words that appear in both the Greenhouse Unit and the Forestry both the Greenhouse Unit and the Forestry Unit. You will have a Vocabulary Test in a Unit. You will have a Vocabulary Test in a few days. In order to write the vocabulary few days. In order to write the vocabulary test you must do a vocabulary list separate test you must do a vocabulary list separate than the notes. I will be looking for both. than the notes. I will be looking for both.