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Sierra Nevada B

Sierra Nevada B

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Sierra Nevada B

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  1. Sierra Nevada B

  2. Sierra Nevada • 3500+ Native species • More than 50% of California plant diversity • Plant communities influenced by • Elevation • Latitude • Rain-shadow • Slope

  3. Latitude influences temperature & moisture regimes 300 miles equiv to 1000’

  4. Elevation keyed sequence forests 10 F per 1000 feet!

  5. Conifer Zones • Mixed coniferous forest • Red fir forest • Lodgepole pine forest • Subalpine forest • Alpine

  6. Subalpine • Conifer forest below treeline • 9,000-11,000 ft • Often on rocky slopes • Characterized by • Medium sized trees • 40 ft • Stunted growth

  7. Treeline • Harsh winters limit tree growth • Extreme cold & wind • 0-25 F • Winds up to 100 mph • Ice blasting creates flagging in trees near tree line • Short growing season • 6 weeks • Poor developed soils

  8. Subalpine Limiting Factors • Long cold winters • 8-12 week growing season • Moisture locked up in snow • Growing season drought • Nutrient poor rocky soils • Thin soils as result of glaciation • High wind • Blowing ice • Increased rate of evapotranspiration

  9. Adaptations for Subalpine • Photosynthesis at low temperatures • Slow growth • Evergreen • Reduces rate of leaf replacement • Beneficial with poor soils with little Nitrogen • Photosynthesis can take place in winter and immediately during short growing season • Perennials high root to shoot ratios • Growth patterns

  10. Conifer • Well adapted to cold conditions • Needles with thick waxy cuticle • Protected stomata • Evergreen • “ready to go”

  11. Grooved Surface

  12. Grooved surface contains stomata

  13. Needles in fascicles

  14. Perennials • High root to shoot ratio • Underground rhizomes store nutrient reserves for winter • Grow very fast in short growing season

  15. Shrubs Prostrate • Temperatures near ground slightly higher • Less wind • Other adaptations?

  16. Annuals mostly found on south facing slopes

  17. Krummholz • “bent wood” • Deformed trees in areas of high wind • Caused by • Snow loading • Ice • Dehydration

  18. Flagging

  19. Subalpine Pine Species • Lodgepole pine (P. ) • White bark pine (P. albicaulis) • Limber pine (P. flexilis) • Foxtail pine (P. balfouriana)

  20. White bark pine (P. albicaulis) • Most widespread subalpine tree • Occurs in pure & mixed stands • Multiple stemmed trunk • Needles in 5- 1.5-3” • Cone egg shaped • Rocky slopes soiless

  21. White bark pine

  22. Mixed Stands • Whitebark pine associated species • Lodgepole Pine • Sierra Juniper (Juniperus occidentalis) • Mountain Hemlock (Tsuga mertensiana)

  23. Whitebark Pine Cones • Dark purple at maturity • Fleshy scales • Produce large protein rich seeds • Succulent seeds • No samara • Co-evolved with Clark’s nutcracker

  24. Seed with no samara

  25. Clark’s Nutcracker • Whack cones of Whitebark pine • Also eats limber pine seeds • Seed pouch under tongue • Distribute seeds in Caches • Cache more than they will retrieve • Hides up to 38,000 of seeds per season • Up to 20 miles • Buried seeds more successful conditions • Un-retrieved caches create new stands

  26. Clark’s Nutcracker

  27. Clark’s Nutcracker

  28. Nutcracker torture!

  29. Seeds germinate in clusters

  30. Limber Pine P. flexilis • Typically grows in pure stands • Exposed rocky slopes • Dry soils • Eastern Sierra • Forms mat-like krummholz at tree line

  31. Limber Pine

  32. Exposed rocky conditions

  33. Foxtail Pine • Shallow soils • Exposed slopes • Pure stands at treeline • Replaces Whitebark pine in Southern Sierra • California endemic

  34. Exposed Slopes

  35. Foxtail Pine 2500-3000 yrs

  36. Alpine • Temperature extremes • Cold nights • Intense light • Extreme wind • Short growing season • Characterized by drought adapted perennials & annuals • Few trees

  37. Alpine zone above treeline

  38. Fast growing Perennials

  39. Alpine Fellfield • Aka pioneer zone • Stone field • Gravel & rock • High winds • Characterized by long lived perennials • Pincushion plants • Tap roots common

  40. Lots of lichen

  41. Pincushion Strategy • Low to the ground • Warmer temperatures • Avoid wind • Trap soil & organic material • Provides nutrients • Insulates • Defrays wind • Symbiotic Bacteria • Taproots for water & nutrient reserve

  42. Lots of Flowers

  43. Flowers change color to signal pollination