What is the difference between a redwood, a sequoia and a cedar? And yes, I know that a sequoia is a type of?

Question

redwood, but how many types of redwoods are there and how do you tell them apart?

Answer 1

Here are a number of pictures for each of the types.  

Redwoods:  http://images.google.com/images?um=1&hl=...

Sequoia:  http://images.google.com/images?um=1&hl=...

Cedar:  http://images.google.com/images?um=1&hl=...

Cedars are the easiest to tell because their leaves are modified flat scale.  Sequoias needles are tiny, overlapping, and similar to Juniper.  Redwood needles are flat and the branches look kind of like fans in that they are very flat.

Answer 2

Different trees are named "redwood":

3 Angiosperms:

Trochetiopsis erythroxylon, fam. Sterculiaceae - St Helena Redwood

Caesalpinia sappan, fam.Fabaceae - East Indian Redwood

Caesalpinia echinata, fam. Fabaceae - South American Redwood

5 Gymnosperms:

Sequoia sempervirens - Coast Redwood

Sequoiadendron giganteu - Giant Sequoia or Sierra Redwood

Metasequoia glyptostroboides - Dawn Redwood

Cryptomeria japonica - Japanese redwood, also named Japanese cedar

all fam. Cupressaceae

The processed wood of Scots Pine (Pinus sylvestris, fam. Pinaceae) - not the tree - is called redwood.

Cedar, genus Cedrus, fam. Pinaceae has a lot of species; this site lists 170:

http://zipcodezoo.com/Key/Cedrus_Genus.a...

The common names redwood and cedar are used in a haphazard way and the differences incidental.

Fazit:

"Redwood" is an imprecise name for different trees and wooden material.

Some species of genus Sequoia are named redwood

Genus Cedrus, cedar covers more than 170 species, but the name "Japanese cedar" is another common name for "Japanese redwood", a Cupressacea.

The only precise and international understood classification to characterize one specific tree/plant is the binomial taxonomy.

PS

Exactly that is the problem:

Looking at the trees you can see: it`s a cedar, a sequoia, a pine or a cypress, they have different leaves/needles.

But you can`t see, if anybody decided to call it "redwood" because it has a red stem. There are trees with red stems but not named redwood, f.e. redstem willow, red spruce trees or red maple.