Chapter 6 (Part 2): Natural Regeneration
Chapter 6 (Part 2): Natural Regeneration
Vegetative Methods, Regeneration Surveys and Species-Specific Techniques
1. Key Concepts
Vegetative Regeneration
The renewal of a forest crop using vegetative parts of existing trees, primarily through stool coppice, root coppice, pollarding, or root suckers.
Coppice
A shoot arising from an adventitious or dormant bud on the stump (stool) or root of a felled or killed tree.
Stool Coppice
Shoots arising from the stump at or near ground level.
Root-Collar Coppice
Shoots originating specifically from the root-collar junction.
Pollard
A tree whose stem is cut back at a height of 2 to 3 metres above ground level to produce a crown of shoots out of the reach of browsing livestock.
Root Sucker
A shoot arising from an adventitious bud on a root above or below ground level.
Advance Growth
Young tree regeneration (seedlings, saplings, or poles) established naturally in a forest stand prior to the commencement of main regeneration fellings.
Regeneration Survey
A quantitative sampling survey carried out to assess the presence, density, composition, and spatial establishment of young forest regeneration.
Cultural Operations
Silvicultural tending treatments such as weeding, climber cutting, cleaning, and girdling of undesirable species carried out in young regeneration areas.
2. Important Points
A. Natural Regeneration by Vegetative Parts
1. Coppicing Physiology and Season
- Optimal felling season: Late winter to early spring, before bud-break, when food reserves are concentrated in the root system and stump.
- Cutting technique: Stumps should be cut low to the ground with a smooth, sloping surface to prevent water accumulation and fungal rot.
- Root-collar shoots: Low shoots develop independent root systems rapidly.
- Age and stump diameter: Coppicing vigour declines with increasing tree age and stump diameter. Younger stems with thin bark possess maximum dormant/adventitious bud activity.
2. Root Suckers
- Root suckers are generated naturally or induced artificially by digging trenches around trees to sever lateral roots near the surface.
- Important examples include Diospyros melanoxylon, Dalbergia sissoo, Ougeinia oojeinensis and Salmalia malabarica (Bombax ceiba).
Exam point: Coppicing is associated with shoots from the stump or root-collar, whereas root suckers originate from adventitious buds on roots.
B. Regeneration Survey Methods and Stocking Metrics
- Sampling unit: Standard square record plots, such as 2 m × 2 m or 4 m × 4 m.
- Layout: Record plots are laid out along systematic grid lines.
- Indicator status: Seedlings are classified as unestablished, partially established or fully established.
- Stocking percentage: Represents the proportion of sample plots containing stocked regeneration.
Stocking Index (%)
(Number of stocked indicator plots ÷ Total number of sample plots surveyed) × 100
C. Species-Specific Natural Regeneration Conditions
1. Sal (Shorea robusta)
- Requires canopy manipulation through the shelterwood system.
- Side light is admitted while ground frost is moderated.
- Fire protection combined with periodic controlled burning clears leaf litter.
- Controlled burning stimulates bacterial nitrification and helps taproot penetration into mineral soil.
2. Teak (Tectona grandis)
- Strong light demander.
- Requires complete overhead light for sapling establishment.
- Seeds require alternate wetting and drying (weathering) to break the hard, woody endocarp.
- Ground fires help clear competing undergrowth and induce uniform germination.
3. Deodar (Cedrus deodara)
- Requires partial canopy shade during early seedling stages, followed by gradual canopy opening.
- Heavy leaf litter accumulation retards germination.
- Light grazing or controlled raking exposes raw mineral soil.
4. Chir Pine (Pinus roxburghii)
- Strong light demander.
- Regenerates abundantly on burnt mineral soil and exposed slopes.
- Protection from heavy summer fires is vital during the early sapling stage despite its thick adult bark.
Memory Trick: Species and Regeneration Requirements
- Sal: Shelterwood + controlled burning.
- Teak: Full light + seed weathering.
- Deodar: Partial shade initially + exposed mineral soil.
- Chir: Full light + protection from heavy summer fire.
3. Classifications: Types of Vegetative Regeneration
| Method | Origin / Mechanism | Key Species Examples | Silvicultural Applications |
|---|---|---|---|
| Stool Coppice | Shoots arising from dormant buds on the felled stump. | Tectona grandis, Shorea robusta, Anogeissus latifolia, Eucalyptus spp. | Main mechanism in Coppice-with-Standards and Simple Coppice systems. |
| Pollarding | Stem cut back at 2–3 m height to produce a high crown of shoots. | Hardwickia binata, Salix spp., Morus spp. | Fodder/fuelwood production safe from livestock browsing. |
| Root Suckers | Shoots arising from adventitious buds on shallow roots. | Diospyros melanoxylon, Dalbergia sissoo, Stereospermum, Ailanthus excelsa. | Soil conservation, erosion control and Tendu leaf production. |
| Root-Collar Coppice | Shoots originating at the root-stem junction. | Shorea robusta, Dalbergia latifolia. | Produces wind-firm trees by forming independent adventitious root systems. |
4. Important Tables
A. Coppicing Power Classification of Major Indian Trees
| Coppicing Capacity | Representative Forest Species |
|---|---|
| Strong Coppicers | Tectona grandis, Shorea robusta, Dalbergia sissoo, Anogeissus latifolia, Albizia lebbek, Acacia catechu, Ougeinia oojeinensis. |
| Moderate Coppicers | Terminalia tomentosa, Terminalia arjuna, Adina cordifolia, Pterocarpus marsupium. |
| Poor / Non-Coppicers | Most conifers: Pinus roxburghii, Cedrus deodara, Picea smithiana, Abies pindrow; also Casuarina equisetifolia. |
B. Natural Regeneration Problems and Management Remedies
| Species | Primary Regeneration Bottleneck | Silvicultural Remedy / Operation |
|---|---|---|
| Sal (Shorea robusta) | Dieback, light competition and raw litter accumulation. | Controlled burning, canopy manipulation, weed/climber cutting. |
| Teak (Tectona grandis) | Hard seed coat dormancy and dense shade. | Seed weathering, complete canopy clearance and controlled ground fires. |
| Deodar (Cedrus deodara) | Thick humus accumulation and intense weed competition. | Light grazing/soil working to expose mineral soil and shelterwood felling. |
| Chir Pine (Pinus roxburghii) | Uncontrolled summer fires destroying young poles. | Controlled winter burning and fire-line maintenance. |
5. Flowcharts and Diagrams
A. Stages in a Standard Forest Regeneration Survey
Boundary Demarcation of Area
↓
Grid Line Layout (Systematic Parallel Transects)
↓
Sample Plot Assessment (2 m × 2 m or 4 m × 4 m)
↓
Seedling Classification (Unestablished vs. Established)
↓
Stocking Index Calculation (%) and Mapping
↓
Decision: Natural Regeneration Adequate OR Supplement via Artificial Planting
B. Vegetative Propagation via Root Suckers
Parent Tree Lateral Root (Near Surface)
↓
Root Severance / Soil Trenching Exposure
↓
Adventitious Bud Activation on Severed Root
↓
Vertical Shoot Emergence Above Ground
↓
Independent Root System Formation and New Tree Establishment
6. Important Scientific Names
| Common Name | Scientific Name | Vegetative / Regeneration Trait |
|---|---|---|
| Tendu / Kendu | Diospyros melanoxylon | Profuse root-sucker producer; managed for bidi wrapper leaves. |
| Shisham | Dalbergia sissoo | Strong coppicer and active root-sucker producer. |
| Sandan | Ougeinia oojeinensis | Excellent root-sucker producer on exposed banks and cuttings. |
| Willow | Salix spp. | Classic pollarded species for cricket bat wood and wicker baskets. |
| Anjan | Hardwickia binata | Pollarded for fodder and fibre production. |
7. Important One-Liner Facts
- Conifer coppicing exception: Most conifers are non-coppicers, but Taxus baccata and Redwood (Sequoia) exhibit coppicing ability.
- Optimal stool height: Stumps should be cut below 15 cm height with a sloping cut to avoid water pooling and stump rot.
- Pollarding height: Stems are cut at 2–3 metres above ground level to keep young shoots safe from browsing animals.
- Tendu leaf harvesting: Periodic burning and root-sucker stimulation are used to yield high-quality Diospyros melanoxylon foliage.
- Supplementing regeneration: When natural regeneration stocking falls below threshold limits during a survey, it is supplemented by artificial planting (beating up/enrichment planting).
Remember: Most conifers are non-coppicers, but Taxus baccata and Sequoia are the stated exceptions.
8. Formulae and Metrics
A. Stocking Percentage
Stocking (%) = (Number of Stocked Record Plots ÷ Total Number of Survey Plots) × 100
Example: If 35 out of 50 sample plots are stocked:
Stocking (%) = (35 ÷ 50) × 100 = 70%
B. Weighted Regeneration Value Index
Assigns higher numerical weights to established advance growth over unestablished seedlings when calculating total regeneration readiness.
9. Mnemonics and Memory Tricks
1. Strong Coppicing Species – T-S-D-A-A
- T – Teak (Tectona grandis)
- S – Sal (Shorea robusta)
- D – Dalbergia sissoo
- A – Acacia catechu
- A – Anogeissus latifolia
Recall: Teak, Sal, Dalbergia, Acacia and Anogeissus are the five species to remember as strong coppicers in this mnemonic.
2. Root Sucker Producers – D-D-O-S
- D – Diospyros melanoxylon
- D – Dalbergia sissoo
- O – Ougeinia oojeinensis
- S – Salmalia malabarica
3. Coppice, Pollard and Root Sucker
- Coppice: Cut stump → new shoot.
- Pollard: Cut high → shoots above browsing height.
- Root sucker: Root bud → new shoot.
4. Species-Specific Regeneration Recall
- Sal: Shelterwood and controlled burning.
- Teak: Full light and weathered seeds.
- Deodar: Partial shade in early stages.
- Chir: Light-demanding; protect young regeneration from summer fire.
10. Previous-Year Exam Focus Areas
- Stool Coppice vs. Root Sucker: Stool coppice arises from the stump/stool; root suckers arise from adventitious buds on shallow roots.
- Purpose of Pollarding: Executed at 2–3 m height to produce shoots above the reach of browsing livestock.
- Advance Growth Value: Pre-existing established advance growth significantly reduces the conversion period during shelterwood regeneration fellings.
11. Quick Revision Box
- Coppice: Shoot from stump/stool dormant bud.
- Pollard: Stem cut at 2–3 m height to prevent browsing.
- Root sucker: Shoot from root adventitious bud (Diospyros, Dalbergia).
- Conifers: Generally non-coppicers.
- Advance growth: Natural pre-established regeneration prior to main fellings.
- Regeneration survey: Systematic sampling to quantify stocking percentage.
- Enrichment planting: Supplemental artificial planting in understocked natural regeneration areas.
- Stool height: Below 15 cm, with a sloping cut.
- Pollarding height: 2–3 m.
12. Interactive MCQ Quiz
20 questions. Tap an option to see the correct answer and explanation straight away, then go to the next question.
Your score
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