B.F. Bachelor of Forestry Forest Soils 3

Question 1

What is the primary reason forest soils experience much lower erosion rates than adjacent agricultural soils?

Accepted Answer

Organic matter and root networks bind soil and absorb raindrop impact energy

Answer

Higher clay content in forest soils traps sediment particles

Answer

Forest soils have higher mineral content that resists physical weathering

Answer

Tree canopy reduces wind speed at the soil surface

Question 2

How does prescribed fire generally affect soil nitrogen in the short term?

Accepted Answer

It causes a net loss of nitrogen through volatilization of organic nitrogen compounds

Answer

It increases available nitrogen by converting organic matter to ash

Answer

It has no measurable effect on soil nitrogen pools

Answer

It stimulates nitrogen fixation, increasing total soil nitrogen

Question 3

Which practice is most effective for maintaining soil productivity on a timber harvest site?

Accepted Answer

Retaining slash and organic debris on the harvest site

Answer

Deep tillage to break up compacted layers and improve aeration

Answer

Applying herbicides to eliminate all competing vegetation

Answer

Burning all harvest residues immediately to release nutrients rapidly

Question 4

Which soil property does pH most directly affect in forest soils?

Accepted Answer

Nutrient availability and soil microbial activity

Answer

Bulk density and resistance to compaction

Answer

Soil texture and particle size distribution

Answer

Water-holding capacity and internal drainage

Question 5

What is a soil catena in the context of forest soils?

Accepted Answer

A sequence of related soil profiles across a hillslope reflecting changes in drainage and soil development

Answer

A type of mycorrhizal network linking multiple tree species across a stand

Answer

A field method for classifying soil texture by ribbon length

Answer

An instrument used to measure resistance to soil compaction

Question 6

Which statement correctly distinguishes ectomycorrhizae from arbuscular mycorrhizae (endomycorrhizae)?

Accepted Answer

Ectomycorrhizae form a fungal mantle around roots without penetrating cells, while arbuscular mycorrhizae penetrate root cells

Answer

Ectomycorrhizae penetrate root cells, while arbuscular mycorrhizae form a mantle around roots

Answer

Both types penetrate root cells but differ in the fungal phyla they belong to

Answer

Ectomycorrhizae are restricted to tropical forests, while arbuscular mycorrhizae dominate temperate forests

Question 7

What does a high C:N ratio (above 30:1) in forest litter indicate about decomposition rate?

Accepted Answer

Slow decomposition because nitrogen is insufficient relative to carbon for microbial metabolism

Answer

Rapid decomposition because carbon provides energy for microbial growth

Answer

No effect on decomposition because only temperature and moisture control decay rates

Answer

Accelerated decomposition because high carbon soils have greater microbial diversity