Answers to Hone Your Problem-Solving Skills Questions
1. At the base of the mountains on the western slope, the biome type would be temperate evergreen forest (using the 12°C annual average temperature and 120 cm annual average precipitation).
Using the environmental lapse rate of 4.5°C per 1,000 m, the annual average temperature will drop to -1.5°C by the summit ridges and peaks. With an annual average precipitation of 180 cm, this puts the trajectory of biome (vegetation) change through temperate deciduous forest, boreal forest, tundra, and finally into a gray area of ice and snow year-round. In fact, several coniferous forest bands are encountered, but the deciduous forest biome analog is generally missing.Descending on the east slope, the temperature warms more quickly. Using an environmental lapse rate of 6.5°C per 1,000 m, the average annual temperature at the base of the mountains (2,700 m lower) would be 16°C. With an annual average precipitation of 50 cm, shrubland vegetation would occur at the base of the mountains. Between the alpine ridges and the shrubland at the base, vegetation zones of tundra, boreal forest (subalpine forest), deciduous forest, grassland, and shrubland would be encountered.
2. The starting point on the western slope would have average annual temperature and precipitation of 16°C and 84 cm, respectively, with future climate change projections. The summit ridges would have annual average temperature and precipitation of 2.5°C and 126 cm with climate change projections. The vegetation transition from the base of the western slope to the summits would include grassland, deciduous forest, and boreal (subalpine) forest.
3. With projected climate change, annual average temperature and precipitation at the base of the western slopes of the Cascades would be 20°C and 35 cm. Descending the eastern slopes, the transect would encounter boreal (subalpine) forest, deciduous forest, grassland, shrubland, and finally desert.