Agroforestry Chapter 7 (Part 2): Management of MPTs and Agroforestry Nursery
Agroforestry Notes · Chapter 7 · Part 2
Chapter 7 (Part 2): Management of MPTs and Nursery
Managing trees in space and time; thinning, pruning, pollarding, lopping, coppicing, bending and training; nursery definitions, importance, types and site selection.
1. Management strategy
The key factor in managing MPTs is the relationship between the overstorey trees and the understorey crops. The manager decides which resource is limiting and manages along that dimension.
| Dimension | When used | Tools |
|---|---|---|
| Horizontal | Water and nutrients limiting | Spacing; zonal (macro/micro) arrangement; mixed cropping |
| Vertical | Light limiting | Species of different heights; smaller ones maturing before the tallest; extra light by leaf fall or pruning |
| Time | Seasonal resource peaks | Choose species by phenology; staggered and relay planting |
- Initial spacing depends on growth rate.
- Final stocking depends on the relative values of trees and crops, site, latitude and aspect, machinery and preference.
2. Tree management operations
ThinningFelling made in immature stand for the purpose of improving the growth and form of the trees that remain without permanently breaking the canopy.Source: ICAR e-course, Introductory Agroforestry
PruningRemoval of live or dead branches or multiple leaders from standing trees for the improvement of the tree or its timber.Source: ICAR e-course, Introductory Agroforestry
- Thinning improves hygiene (removes dead, dying and diseased trees), wood quality and net financial return.
- Natural pruning is the death and fall of branches in close stands; artificial pruning uses sharp tools.
- Pruning close to the trunk gives a small knotty core and clear timber; late pruning enlarges the knotty core; over-pruning slows growth.
- In agroforestry, pruning also cuts shade on crops and gives fodder, fuel and mulch.
PollardingPollarding consists of cutting a sapling or pole tree at some height above the ground level so that it produces new shoots from below the cut. Pollarding is done at a height of 2- 2.5 m above ground level; e.g. in Salix spp., Hardwickia binata, Grewia optiva, Morus alba, etc.Source: ICAR e-course, Introductory Agroforestry
Pollarding (glossary)It is defined as a’ tree whose stem has been cut off in order to obtain a flush of shoots usually beyond the reach of browsing animalSource: ICAR e-course, Glossary
Pollarding (Nair)Cutting back the crown of a tree in order to harvest wood and browse to produce regrowth beyond the reach of animals and/or to reduce the shade cast by the crown.Source: Nair (1993), Glossary
LoppingRemoval of one year shoots or fresh growth from entire crown of the tree/plant in order to get sufficient fodder for livestock is known as lopping. Lopping is extensively done in Morus, Grewia, Bauhinia, etc.Source: ICAR e-course, Introductory Agroforestry
Lopping (Nair)Cutting one or more branches of a standing tree or shrub.Source: Nair (1993), Glossary
CoppicingCutting or heading back of main stem at 20-30 cm from the ground level.Source: ICAR e-course, Introductory Agroforestry
Coppicing (glossary)Cutting back of main stem of a tree at a height of 30 cm from the ground level in order to induce new flush of shootsSource: ICAR e-course, Glossary
Coppicing (Nair)Cutting certain tree species close to ground level to produce new shoots from the stump. Also occurs naturally in some species if the trees are damaged.Source: Nair (1993), Glossary
| Operation | Height of cut | Main purpose | Examples |
|---|---|---|---|
| Coppicing | 20–30 cm (glossary: 30 cm) | New shoots from stump; fuel, poles | Eucalyptus, Acacia catechu, Albizia lebbek |
| Pollarding | 2–2.5 m | Shoots beyond reach of animals | Salix, Hardwickia binata, Grewia optiva, Morus alba |
| Lopping | Whole crown, 1-year shoots | Fodder for livestock | Morus, Grewia, Bauhinia |
| Pruning | Branches on standing tree | Clear timber, less shade | Poplar, Eucalyptus on bunds |
| Coppicing ability | Examples |
|---|---|
| Strong coppicers | Acacia catechu, Albizia lebbek, Anogeissus latifolia |
| Good coppicers | Aesculus indica, Chloroxylon swietenia, Hardwickia binata |
| Bad coppicers | Adina cordifolia, Bombax ceiba |
| Non-coppicers | All conifers |
- Bending restricts bole growth and diverts food to new leafy shoots; bending and coppicing give lots of foliage close to the ground.
- Training: agroforestry trees should be trained for vertical spread to reduce shade on crops.
Memory trick: Low–High–All: Coppice low (20–30 cm), Pollard high (2–2.5 m), Lop all of the crown. Conifers never coppice.
3. Nursery: definitions and importance
NurseryNursery is defined as an area where plants are raised for eventual planting out.Source: ICAR e-course, Introductory Agroforestry
Nursery bedNursery bed is defined as a prepared area in a nursery where seeds are sown, or into which transplants or cuttings are put.Source: ICAR e-course, Introductory Agroforestry
Nursery stockGenerally whatever is grown in the nursery for planting out is called nursery stockSource: ICAR e-course, Glossary
A nursery comprises nursery beds, paths and irrigation channels. Nursery beds are seedling beds or transplant beds; a nursery with only one kind is a seedling nursery or a transplant nursery. In India, separate seedling and transplant nurseries are seldom made.
Irregular seeding
Some species do not seed every year; nurseries store output for several years of planting.
Slow growers
Slow-growing species sown directly get swamped by weeds.
Avenues
Roadside avenue plantings need tall, sturdy plants.
Exotics
Best way to introduce tropical pines, poplars and eucalypts.
Poor sites
Planting nursery stock is the surest method on poor, barren sites.
Casualty replacement
Always done with nursery plants or stumps.
4. Types of nursery and site selection
Dry nurseryIt is a nursery that is maintained without any irrigation or other artificial watering.Source: ICAR e-course, Glossary
Wet nurseryIt is a nursery that is maintained by irrigation or other artificial watering during the dry periodsSource: ICAR e-course, Glossary
Temporary nurseryIt is a nursery that is maintained for supplying nursery stock for a short period after which it is abandoned.Source: ICAR e-course, Introductory Agroforestry
Permanent nurseryIt is a nursery that is maintained for supplying nursery stock for a long time on a permanent basis.Source: ICAR e-course, Introductory Agroforestry
| Point | Temporary (field) nursery | Permanent nursery |
|---|---|---|
| Location | In or next to the planting area | Near a headquarters and a road; serves one or more ranges |
| Size | Small | Large |
| Manuring | Not needed: rich new soil (except Eucalyptus hybrid) | Regular manuring needed |
| Weeds and pests | Few | Build up over time |
| Supervision | Poor | Good, with irrigation and shade |
| Cost | Costlier per plant | Cheaper per plant |
Selecting a nursery site
- Close to the planting area, allowing regular supervision.
- Near or slightly below an adequate water source.
- Well-drained sandy loam; avoid clay (poor aeration, cracks in summer).
- In hills, a gentle slope not exceeding 5°.
- Western Himalaya: northern aspect; southern aspects at upper limits only up to 1200 m, beyond which western or south-western aspects are preferred.
- Within the altitudinal zone of the species; not a frost pocket.
5. Quick revision box
- Horizontal management = water/nutrients; vertical = light; time = phenology.
- Thinning: immature stand, canopy not broken permanently.
- Coppicing 20–30 cm (glossary 30 cm); pollarding 2–2.5 m; lopping = 1-year shoots of whole crown.
- Strong coppicers: A. catechu, Albizia lebbek, Anogeissus latifolia; bad: Adina, Bombax; none: conifers.
- Train AF trees for vertical spread.
- Nursery: area where plants are raised for eventual planting out.
- Temporary = field nursery, no manure (except Eucalyptus hybrid); permanent needs manuring.
- Site: slope ≤ 5°, sandy loam, water slightly above, northern aspect, no frost pocket, 1200 m rule.
6. Interactive MCQ Quiz
15 questions. Tap an option to see the answer and explanation, then go to the next question.
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