Chapter 13 Forests, Parks and Landscapes

Modern Conflicts over Forest Land and Forest Resources Silviculture: the the professional growing of trees Forests benefit people through public service functions: functions performed by ecosystems for the betterment of life and human existence Ex) cleansing of air by trees

The Life of a Tree How a Tree Grows – Photosynthesis, Transportation Systems, Evapotranspiration Tree Niches – Determined by Water content in the soil Forest tolerance of shade – There is no single best set of conditions for a forest

A Forester’s View of a Forest Old-Growth Forest: a forest that has never been cut Second-Growth Forest: has been cut and re-grown Foresters group trees into: - Dominants, Codominants, Intermediate and Suppressed Sites are classified by site quality: the maximum timber crop the site can produce in a given time

Clear-Cutting The cutting of all trees in a stand at the same time 4 types: 1. Shelterwood-Cutting 2. Seed-Tree Cutting 3. Selective Cutting 4. Strip-Cutting

Slash and Burn Agricultural Practices

Plantation Forestry Plantation: a stand of single species planted in straight rows Properly managed plantations can relieve pressure on forests

Sustainable Forest Def: Efforts to manage a forest so that a resource in it can be harvested at a rate that does not decrease the ability of the forest ecosystem to continue to provide that same rate of harvest indefinitely. Three are few examples of this. The “certification of sustainable forestry” developed. This involves: – Determining which methods appear most consistent with sustainability – Comparing the management of a specific forest with those standards

4 Ways Vegetation Can Effect the Atmosphere: 1.Changing color of the surface and the amount of sunlight reflected and absorbed 2.Increasing the amount of water transpired and evaporated from the surface to the atmosphere 3.Changing the rate at which greenhouse gases are released from the Earth’s surface into the atmosphere 4.Changing the “surface roughness,” which affects wind speed at the surface

Deforestation History Causes World Firewood Shortage Indirect Deforestation

Countries with the largest forested areas

Parks, Nature and Wilderness Wilderness: an area undisturbed by people Managing parks for biological conservation is a relatively new idea. Parks that are too small or in the wrong shape may not be able to sustain their species

Chapter 14 Wildlife, Fisheries and Endangered Species

Traditional Single-Species Wildlife Management Assumptions Maximum Sustainable Yield: The population size that yielded maximum production Minimal Viable Population: The goal for a threatened or endangered species

Threats to Fisheries Overfishing – Bottom Trawling Bottom Trawling Ocean Acidification Pollution – Sediments/silt – Nutrient – Other Invasive species Habitat destruction

The Logistic Growth Curve Def: The S-shaped growth curve that is generated by the logistic growth equation In the logistic, a small population grows rapidly, but the growth rate slows down, and the population eventually reaches a constant size Logistic Carrying Capacity: The population size at which birth equals deaths and there is no net change in the population Optimum Sustainable Population: The population level that results in an optimum sustainable yield. The level is in some way best for the population, its ecological community, its ecosystem or the biosphere

Classic Cases of Wildlife Management or Mismanagement The American Grisly Bear The American Bison A common goal in wildlife conservation is to “restore” the abundance of a species Adequate information of the abundance of a species is very rare

Improved Approaches to Wildlife Management Time Series and Historical Range of Variation - Time Series: an estimate of a population over a number of years - Historical Range of Variation: the known range of abundances of a population over some past time interval Age Structure as Useful Information Harvests as an Estimate of Numbers – Catch per Unit Effort: estimates previous animal abundance. Assumes same effort by hunters.

Fisheries The Decline of Fish Populations Can Fishing Ever Be Sustainable? – Past experience suggests that economically beneficial sustainability is unlikely for most wild populations

The Current Status of Endangered Species The Red Book Endangered vs. Threatened How a Species Becomes Endangered or Extinct Local Extinction: Occurs when a species disappears from a part of its range Global Extinction: Occurs when a species cannot be found anywhere

The Good News Many species have been successfully restored to an abundance Success is achieved when the habitat is restored to conditions required by a species The conservation of wildlife offers great rewards of long-standing and deep measure to people