Deforestation: land demand and ecological effects
הוצג| English | משמעות |
|---|---|
| biofuel/ˌbaɪəʊˈfjuːəl/ | דלק ביו-אנרגטי |
| deforestation/diːˌfɒrɪˈsteɪʃn/ | כריתת יערות |
What would explain this observation?
- Replacing a forest with a crop can increase one useful product while removing many habitats. Food or fuel output is only one part of the decision.
Build the model
- The specification identifies tropical forest clearance for cattle, rice cultivation and biofuel 生物燃料 crops.
- Forest removal destroys habitat and can reduce biodiversity.
- Burning cleared material releases carbon dioxide; later decay can also release carbon.
- Fewer trees can reduce photosynthetic uptake compared with the original forest, although replacement plants also photosynthesise.
- deforestation 森林砍伐: Removal of forest for another land use.
- biofuel: Fuel produced from biological material.
Which evaluation includes both a benefit and a biological cost?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Evaluation weighs benefit against cost: crop output or timber value against habitat loss, carbon release and biodiversity decline. Price or machine counts alone see only one side.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- The result depends on the replacement system, what happens to the wood and the time interval.
- A claim that every biofuel has no emissions ignores land-use change and production.
- Evaluate food, income and energy benefits alongside habitat, carbon and other environmental consequences using the supplied evidence.
In the lab: Compare a fictional land-use proposal with retained-forest and alternative-site options. Use area, production and stated carbon-transfer records separately, avoiding double counting carbon released from the same material. Explain the biological mechanism rather than writing only deforestation is bad.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a supplied 150-hectare region retains 105 hectares of forest after clearance.
- Cleared area = 45 hectares, or 30%.
- This describes that region; it is not a current global deforestation statistic.
- A biodiversity conclusion also needs information about which habitats and species were affected.
Your turn: A supplied region has 240 hectares of forest and retains 168. Find the cleared percentage.
A supplied region has 240 hectares of forest and retains 168. Find the cleared percentage.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 30 %. Known: 240 hectares of forest; 168 retained. Cleared = 240 - 168 = 72 hectares. Cleared percentage = 72/240 x 100 = 30%. This describes one supplied region, not a global statistic.
Check the conclusion and its limits
- Trees do not store carbon only while alive: dead wood and soil can also be stores.
- Carbon dioxide release and reduced future uptake are different terms.
- A new crop’s photosynthesis does not automatically replace all original habitat or carbon storage.
Not true: Growing a biofuel crop guarantees no environmental cost from land clearance. A biofuel crop still replaces the cleared habitat, and its photosynthesis is far below the original forest's carbon storage. "Biofuel" on the label does not erase the land-clearance cost.
- The specification identifies tropical forest clearance for cattle, rice cultivation and biofuel crops.
- The result depends on the replacement system, what happens to the wood and the time interval.
- Watch for: trees do not store carbon only while alive: dead wood and soil can also be stores.
Growing a biofuel crop guarantees no environmental cost from land clearance.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
A biofuel crop still replaces the cleared habitat, and its photosynthesis is far below the original forest's carbon storage. "Biofuel" on the label does not erase the land-clearance cost.
Removal of forest for another land use: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
deforestation means Removal of forest for another land use.