Indian Forest Service Examination Principles of Silviculture: practice questions

1 · Site factors: climatic, edaphic, physiographic, biotic · hard

Shelford's law of tolerance holds that:

1. Each species has a range and optimum for each factor; excess limits as much as deficiency
2. Each species tolerates any value of a factor provided the other factors are optimal
3. Trees tolerate shade better as they grow older, whatever the site conditions
4. A species' tolerance range is the same for all factors and at all ages

2 · Site factors: climatic, edaphic, physiographic, biotic · hard

Afforestation of a long-treeless grassland with an exotic pine fails even though climate and soil appear suitable. Which biotic factor is a well-known cause?

1. Excess soil nitrogen from the grassland, which pines can never take up at all
2. The grass's high albedo, which reflects light away from pine seedlings
3. Absence of the mycorrhizal fungi the pine needs, supplied by inoculation
4. Lack of root nodules, since all pines depend on nitrogen-fixing bacteria

3 · Site quality and its assessment · hard

Why is the height of dominant trees, rather than stand volume, used as the main tree-based index of site quality?

1. Stand volume cannot be measured at all in natural forests, only in plantations
2. Dominant height is the same on all sites, so it shows the effect of management alone
3. Stand volume depends only on site, so it would give the same answer anyway
4. Dominant height reflects site and is little changed by density or thinning from below

4 · Light and shade tolerance; crown classes · medium

Which observation in a closed stand indicates that a species is shade intolerant?

1. Live lower branches persist for many years down to the ground
2. Seedlings survive and grow slowly beneath the parent canopy
3. Lower branches die and fall early, giving long clean boles
4. Suppressed trees remain alive under the canopy for decades

5 · Light and shade tolerance; crown classes · medium

Kraft's 1884 classification of trees in a stand has how many main classes?

1. Four: dominant, codominant, intermediate and suppressed
2. Three: upper, middle and lower canopy
3. Six, each subdivided by bole quality
4. Five, from predominant to wholly overtopped

6 · Natural regeneration: seed supply, germination, establishment · hard

Why do open-grown trees usually begin seeding earlier and more heavily than trees of the same age in dense stands?

1. Their roots are shallower, which triggers early flowering under drought
2. They are genetically different from trees in dense stands of the same species
3. Their bark is thicker, which protects the developing flowers from frost
4. Their large, well-lit crowns produce more carbohydrate for flowering and fruiting

7 · Regeneration by coppice and root suckers · hard

A disadvantage of repeated short-rotation coppice over many cycles is that:

1. Each cycle produces larger timber than the last, flooding the market
2. Stools decline, genetic gain is impossible and nutrient removal is high
3. Coppice cannot be harvested by hand and needs heavy machinery
4. Coppice shoots are always slower than seedlings in the first years

8 · Choice between natural and artificial regeneration · hard

Planting seed of a provenance from a distant, warmer region on a cold site carries which main risk compared with natural regeneration?

1. Poor adaptation, such as frost damage or mistimed growth
2. Faster growth and better form than local trees in every case
3. Inability of planted trees to produce any seed later
4. Guaranteed resistance to all local pests and diseases

9 · Stand structure: even-aged and uneven-aged stands · medium

In a balanced uneven-aged stand with q = 1.5 and 10-cm diameter classes, there are 30 trees per hectare in the 50-cm class. How many trees per hectare are expected in the 40-cm class?

1. 45
2. 20
3. 31.5
4. 60

10 · Stand dynamics: stand initiation, stem exclusion, understorey reinitiation, old growth · medium

Which feature characterises the stem exclusion stage?

1. Abundant new seedlings establishing in a fully open site
2. Large old trees, snags and logs in a multi-layered canopy
3. A new layer of tolerant seedlings under small canopy gaps
4. A closed canopy, no new trees establishing and a sparse understorey