Forests
план-конспект урока английского языка (9 класс) по теме

Forests

The effects of climate change on forests in the U.S. and other parts of the world will depend not only on climatic factors but also on stresses from pollution (e.g., acid rain); future trends in forest management practices, including fire control and demand for timber; and land-use change. It is difficult to separate the influence of climate change from these other pressures.

Climate change effects on forests are likely to include changes in forest health and productivity and changes in the geographic range of certain tree species. These effects can in turn alter timber production, outdoor recreational activities, water quality, wildlife and rates of carbon storage.

In general, forests are sensitive to climatic variability and change. Climatic factors that influence forest health-temperature, rainfall, atmospheric levels of carbon dioxide (CO2) and other greenhouse gases and extreme weather and fire events—are changing and are expected to continue changing due to human activities.

The following climate factors are likely to play an important role in determining future forest conditions:

1. Air temperature
2. Atmospheric CO2 concentrations
3. Climatic variability
4. Indirect effects on pollution levels such as tropospheric ozone

Changes in temperature and precipitation are expected to change forest location, composition, and productivity. Climate change is likely to drive the migration of tree species, resulting in changes in the geographic distribution of forest types and new combinations of species within forests. 

Free-Air CO2 Enrichment experiments suggest that tree growth rates may increase with increasing levels of atmospheric CO2, but these effects are expected to saturate over time as tree communities adjust to increased CO2 levels.

Changes in forest disturbance regimes, such as fire or disease, could also affect the future of forests and the market for forest products, such as timber. Increased temperatures could increase fire risk in areas that become drier due to climate change. These changes could compound existing fire risks. Climate change could also promote the rapid increase of diseases and pests that attack tree species. Such disturbances may be detrimental to forests themselves, but may have a lesser impact at the market level due to salvage operations that harvest timber from dying forests.