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ESC
200 - Spring 2003
Trees
in Our Environment
Prof: Linda Brubaker
GYMNOSPERMAE
TAXODIACEAE: Redwood Family
Family diagnostic feature:
- deciduous branchlets: leaves plus small twigs are shed as a unit
Very old family
(one member known 1st as a fossil)-- few species, one per genus
Decay-resistant
wood, not particularly strong
Some occur
in unusual ecological locations (bald cypress, coast redwood)
|
Genus |
Leaves |
Cones |
|
Sequoiadendron |
awl-shaped,
several ranked |
2-3 inches |
|
Sequoia |
linear, 2-ranked |
1 inch
|
- very large diameter-tree in Sierra Nevada's
- wood is not commercially valuable (shatters)
- important focus of conservation/preservation movement in US, played a role in establishment of National Park System (more in lab)
- very thick bark makes tree resistant to low intensity fires, but in jepardy now because years of fire exclusion has resulted in growth of tall trees in understory-- which would allow intense fires to reach crown.
- very tall tree
- restricted to in narrow fog belt along no. CA and so. OR coast-- water condensation from fog is important summer input of water to site
- wood is commercially valuable-- primarily used for siding, outdoor furniture (not for support beams)
- root-crown sprouts and sprouts from adventitious buds in trunk
ANGIOSPERMAE
SALICACEAE: Willow Family
Family diagnostic features:
|
 |
- members of this family are well adapted to grow in riparian settings where spring floods are frequent.
- Abundant small seeds are shed in spring,
- vigorous vegetative propagation from stem and branches carried by floods and deposited on river banks
|
GENUS
|
LEAVES
|
BUDS
|
|
Salix |
long, narrow
leaves with short petioles |
small, single
bud scale |
|
Populus |
broad leaves
with long petioles |
several, large
imbricate bud scales |
Salix babylonica
Salix scouleriana
Populus nigra var. italica
Populus tremuloides
Populus trichocarpa
BETULACEAE: Birch Family
Family diagnostic feature:
- preformed male aments
|
GENUS
|
MATURE
FEMALE AMENT
|
|
Betula |
bracts deciduous
|
|
Alnus |
bracts persistent
|
Contact Linda Brubaker at: lbru@u.washington.edu
[ University of Washington ] [ College of Forest Resources ]