AP Environmental Science › Forests
Swidden agriculture is used mostly in rainforest areas. Plots that are made in this way are typically abandoned in only a few years due to poor soil quality.
Swidden agriculture is also known as __________.
slash and burn agriculture
terracing
intensive agriculture
desertification
Slash and burn describes the process of clearing forested areas of vegetation and burning to provide cropland or rangeland. Terracing is the process by which a hill is converted into large "steps" of land, which are easier to farm. Intensive agriculture describes the large-scale, systematic production of food for distribution to heavily populated areas. Desertification, as the name suggests, involves land degradation in which an already dry area becomes increasingly dry, usually resulting in a decrease in biodiversity.
Oak is very profitable as a firewood, but oak stands take long periods of time to mature, often hundreds of years. Oak saplings aren't very shade-tolerant and soil erosion from over-logging is a very pressing issue. Oak saplings form in the immediate area to which the parent tree drops the acorns. Which of the following harvest methods would be optimal for both the hardwood ecosystem and timber yields?
Shelterwood cutting
Seed-tree cutting
Single-tree cutting
Clear-cutting
Group-selection cutting
Clear-cutting puts the hardwood ecosystem at risk of soil erosion and depletes the resource, while single-tree cutting would reap little profit and dense stands could limit growth of shade-intolerant saplings. Seed-tree leaves too few slow-growing oaks to disperse seeds and group-selection cutting is not optimal for a tree whose saplings grow right where the acorns drop from the tree.
Shelterwood cutting thins out the forest, allowing younger, sun-loving trees to grow. This method is often preferred for slow-growing hardwoods and limits soil erosion while maximizing yield.
Skyler is a forest ranger in the Washington Parks. His job is to preserve a track of forest that has never been cut. What type of forest is this?
Old growth forest
Agroforest
Second growth forest
Native forest
None of these
The correct response is old growth forest. This refers specifically to a forest that has never been cut, or has been around for over a hundred years. Another term would be Virgin Forest. The term native forest just means that they forest contains natural vegetation to the ecosystem - it doesn't refer to whether the forest has been cut or not. Agroforest is the combination of agriculture and forest lands. Second growth forest is the regrowth of a forest after being cut down.
What timber-harvesting method involves clearing the majority of mature trees in a stand while leaving some mature trees to provide seeds to replenish the stand?
Seed-tree cutting
Clear-cutting
Shelterwood cutting
Group selection cutting
Single-tree selection cutting
Seed-tree cutting best fits this definition because most trees in this harvest method are cleared, but a few mature trees are left uncut so as to provide seeds for future stands to grow.
Clear-cutting is when an entire stand is cut for harvest. Single-tree cutting is harvesting select mature trees. Shelterwood cutting is when the forest is "thinned" of more mature trees, and a group-selected cut is when a small patch of trees is selected and cut.
From the 1930s onward, suppression of forest fires has been common practice in United States land management, particularly in the management of Western coniferous stands. Which of the following is NOT a consequence of this type of management?
When there are no regular wildfires, stands become too dense, resulting in a diminished understory of flora, which can cause soil erosion.
When fire-adapted forests are not burned periodically, the understory can become overcrowded, making it difficult for animals to migrate, travel, hunt, etc.
When forests are not burned regularly, the canopy can become too crowded for new trees to get the sunlight and precipitation they need.
Without regular wildfires, forests can become so dense that the resulting build-up of "fuel" can generate a more intense wildfire that could be more challenging to contain.
Migratory populations can be halted, hindered and even dissapear from the regional landscape due to inability to find forage.
The main concern with fire supression is the overcrowding of fire-adapted tree stands, which can be problematic for wildlife attempting to forage or migrate. A buildup of high-density wood fuel is also a high risk for a catastropic wildfire and is not befitting of a healthy ecological community. However, overgrowth of stands does not inherently pose a risk for soil erosion, as root systems from dense tree stands will likely hold the soil in place.
Which is the definition of "seed-tree cutting?"
Removing nearly an entire stand of trees, leaving only a few evenly distributed trees to regenerate the stand
A strip is clear cut, leaving a corridor narrow enough to allow regeneration within a shorter period of time
Removing all mature trees in a few cuttings over a period of ten years
Removing only mature trees individually or in small groups
Strip cutting - a strip is clear cut, leaving a corridor narrow enough to allow regeneration within a shorter period of time.
Shelterwood cutting - removing all mature trees in a few cuttings over a period of ten years.
Selective cutting - removing only mature trees individually or in small groups.