1. Alpine Vegetation Some slides courtesy of Bill Bowman
reference: Körner, Ch Alpine Plant Life. Springer Verlag, Berlin
Some slides courtesy of Bill Bowman
Mountain Research Station, INSTAAR

2. MOUNTAINS Have the highest plant species diversity
High mountain environments have a high percentage of endemic plants
Alpine areas have a much high plant diversity than forested areas

3. Regional scale plant diversity in S
Regional scale plant diversity in S. Rockies; the influence of mountains:
Weld County: ~600 species
Boulder County: species
(50% of flora of Colorado)

4. Nival
Alpine
treeline
Subalpine
Montane

5. Mixed Aspen - Lodgepole Pine Forest : 8,500 to 10,000 feet
yellow - green color
foliage
dense trees
straight, pole-like
Used by humans since prehistoric times
light construction, finishing lumber, poles

6. Lodgepole pine needles attached to twigs in bunches paired, twisted
long, green

7. Aspen only deciduous tree at this altitude
grow in a variety of soil conditions from wet to dry

8. Subalpine Forest: 10,000 -11,000 ft spruce and fir dominate.
narrow crowns
dark green color
cool,dark, humid
E.g. Engelmann Spruce
Humans have seldom used these forest due to their remoteness

9. Engelmann Spruce short needles attached to twigs rounded, spiky
Spruce bark is reddish and outer layer flakes off

10. Rocky Mtn. Douglas Fir short needles attached to twigs; flat needles
smooth bark

11. Forest- Tundra Transition: CLIMATE
Situated between timberline and treeline
(lower) (upper)
Windier and colder
mean annual soil temps ~ 0 deg.
Snow covered

12. Forest-tundra transition: VEGETATION
Wind
snow
"Krummholz”: crooked wood
slow growth (few inches trunk)
”Flag trees”

13. Forest-tundra transition: TREE ISLANDS
Trees grow into bands
form microsites -- reproduction occurs
Lee side:
snow
Windward side:
wind

14. World’s highest tree?
Quenual, up to 4,800m

15. Nival
Alpine
Subalpine
Montane
treeline

16. Elevation of treeline corresponds with:
1) minimum growing season temperature around 6 °C
2) wind zone
3) geomorphic disturbance- avalanches

17. Global distribution of treeline
from Körner, 1999
large variation in altitude at mid-latitudes
associated with continentality- treelines lower in moist, maritime locations

18. Nival
Alpine
treeline
Subalpine
Montane

19. Alpine Tundra: 11,200 to 12,000 ft Definition:
windswept, treeless area found at highest altitudes in the mountains
Niwot Ridge in May

20. Alpine environmental conditions: CLIMATE
cold (<0 deg C)
temperatures may change rapidly
windy (mainly temperate zone)
100 mph at Niwot Ridge!
Precipitation as snow

21. Alpine environmental conditions: SOIL
low nutrients in soil
Rocky
Thin soil cover
low soil temperature
ice present in the ground --
creates periglacial features
“polygons”

22. Alpine Tundra distribution

23. Alpine is a globally distributed biome-
plants have similar
"growth forms:"
graminoids
(grasses, sedges)
forbs
(broad leaved
plants)
prostrate shrubs
flowers

24. Major life forms of alpine vegetation

25. Incas used them as
fuel source
Cushion plants – Coropuna, Peruvian altiplano

26. Note the leaves
Puya Raimondi, Pastoruri (Peru)
Blooms evey 40 years!

27. Alpine environment summarized:
Cold + windy
snowy!
short growing season
low nutrient availability
High UV radiation
How do plants survive in these conditions?

28. Plant adaptation to alpine environment
(1) evolutionary adaptation
(2) ontogenetic modifications, which are non-reversible during the life of an individual
(3) reversible adjustment, often termed “acclimation”

29. 4 things plants need: Liquid water nutrients warmth light
Limiting factors in alpine and arctic tundra
Limiting factor in arctic tundra only

30. Adaptations to cold 1) Cushion plants: grow in small, rounded humps
conserve heat
reduce wind chill

31. Adaptations to cold 2) Develop a blanket of white hairs
protect them from cold at night
White to reflect radiation during the day
e.g. Giant Lobelia, in Kenya

32. Adaptations to cold 3) Keep dead leaves on the stem
prevents ground from freezing
e.g. Groundsel

33. Adaptations to cold 4) Grow short and small
to avoid harsh winds and crushing snow
the air temperature is warmer 10-15cm above the soil.

34. Adaptations to cold
5) Grow in balls that roll around w/frost heave, eg. Kenya moss
deal w/expansion and contraction
of soil due to freezing and thawing.
Stone circles

35. Adaptations to cold 6) Rosette plants cabbage-like
leaves surround a central bud
winter: central bud is protected by the remaining vegetation.

36. More adaptations to cold
high investment into belowground biomass (high root:shoot ratio)
tolerance to low temperatures
(= intolerance of high temperatures)

37. Cold-tolerant species examples
Heaths: hard evergreen leaves that can withstand drying winds and cold temperatures.
Common heaths: cranberries, blueberries, and rhododendrons

38. II. Adaptations to dry conditions
Many high mountains plants are succulents, with water stored in thick leaves;
minimize evaporation
E.g. cactus

39. Adaptations to High UV irradiance
Cover their leaves with white hairs (reflect the suns rays).
Some plants contain a red pigment called anthocyanin which absorbs UV sunlight before it has a chance to damage the leaves.

40. Short growing season Cold nights short daylight hours 180 days/year
Adaptation:
start to grow as soon as the snows melts
store food during the summer months
pollination strategies?
The Fireweed's seeds are plume-
shaped. This allows them to ride
on the wind before falling to the ground
where they can take root.

41. Summary LIMITATIONS ADAPTATION Cold - grow short, close to ground
- grow horizontally
-cushion trees
wind - grow in clumps (island trees)
low nutrients -carnivorous
UV -white hairs; antocyanin
low growing seasons - grow fast; store nutrients;
-pollination strategies
dry -wax leaves