BIOL 122 Lecture 7: Biol 122 - 7th Class
Document Summary
Treeless, soil below is frozen permafrost. In the summer, ~0. 5-1. 0 m of soil thaws, allows for some growth (1-2 months) 24 hours of sunlight during this time. Soils are acidic because of high organic content. Most plants are low-lying shrubs and grasses. Densely populated by evergreen trees (tree line) Avg t <5 degrees c, precipitation between 40-1000mm. Evaporation is low, soils are always wet. Dead plants decay very slowly, creates a huge reservoir of carbon. Soils are highly acidic, most plants cannot grow. Found along pacific nw coast of na, s. chile, new zealand, tasmania. Unlike tropical rainforests, these support little species diversity. Conditions are much more variable than temperate rainforests. Photosynthesis levels in tundra and taiga are very low. Do not benefit from moderating effects of ocean currents; more inland therefore less stable. Far more land mass therefore more environment for them to exist (land: ocean ratio) Soils are slightly acidic, leached from precipitation.
