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A 1

why grow tropical trees?


Who are these Manuals meant for?

For anyone who is going to grow and plant tropical trees, including people working in:

  1. forestry departments;
  2. private forestry and timber firms;
  3. agriculture and horticulture departments;
  4. farming, including small-holdings;
  5. agroforestry and community tree planting projects;
  6. protecting sites from erosion by water or wind;
  7. the reclaiming of degraded land;
  8. school tree-planting and demonstration plots;
  9. parks and roadside planting;
  10. tree planting for research.

Are the Manuals only available in English?

No, they are being translated into Spanish and French, and it is hoped that arrangements may be made for other languages.

Why are they needed?

  1. much research information isn't reaching the growers of trees;
  2. a lot of tropical experience could be passed on to others;
  3. although some methods are quite well known, others are not;
  4. practical details of methods need to be explained, step by step;
  5. background ideas behind why something is done are also useful;
  6. such general tropical Manuals could encourage local publications;
  7. nowadays there are many fewer trees, but many more people;
  8. tree-planting is being recognised as very important;
  9. there's a better chance to-day to plant genetically improved trees;
  10. although growing trees is straightforward, a problem at only one of the many stages can easily prevent successful establishment.

What sorts of trees are the Manuals for?

Any kind of tropical tree.

But there are hundreds!

Yes there are. But these Manuals deal with the general principles of growing them. These apply to most species, grown for many different reasons, throughout the tropics. It is hoped that they may support and stimulate specific, local publication and translations.

Is tree planting particularly important in the tropics?

Yes, it is. Trees play vital roles in producing wood and other goods, protecting the site and providing the conditions needed for farming.

Is most tropical wood exported?

No, some timber goes for export, for making furniture, panelling, etc.
But much more is used locally for:

  1. firewood and charcoal;
  2. building houses, boats, fences, etc;
  3. making furniture and household implements;
  4. turning into paper and packaging;
  5. converting into plywood and particle board (see Manual 4).

What do trees produce besides timber?

Many different kinds of materials, sometimes more valuable than wood, that can be continually harvested without damaging the land, including:

  1. fruits, nuts, bush-meat and other human foods;
  2. medicines, spices, honey, etc;
  3. fodder and browse for domesticated animals;
  4. latex, resins, waxes and dyes;
  5. cane and vines for basket making and tying;
  6. leaves for wrapping food, etc;
  7. shading and potting soil for tree nurseries.

How do they protect the site?

  1. by not allowing the surface soil to overheat;
  2. by slowing its drying out;
  3. by preventing heavy rain-drops washing away fine particles, and even all the soil; similarly, stopping soil from being blown away by wind;
  4. by picking up and recycling mineral nutrients which would be lost;
  5. by discouraging weeds that thrive in open clearings;
  6. by providing food and shelter for animals and micro-organisms that help the plant community to function normally.

But surely one gets rid of the trees in order to farm!

Only some of them! Except on fertile land such as swamps, farm crop yields generally decline sharply if you do not keep (or plant) enough trees to preserve (or replace) ‘open woodland’ conditions. The cover needs to be sufficient to protect the soil, but not so dense that competition for light and rooting space is too great for the farm crops to grow well. Traditional farming methods have often been successful because they used:

  1. an intimate mixture of many different tree and farm crops; and/or
  2. a fallow period of 15–20 years under dense, regenerating forest or savanna.

Do trees have any effects farther away from the site?

Yes, in several different ways:

  1. making flooding less likely by reducing the rapid run-off of rain;
  2. discouraging mud-slides and the covering of lower land with eroded soil, and slowing the silting up of reservoirs and harbours;
  3. ‘combing out’ dust and particles of pollution from the air;
  4. moderating local climate, and perhaps increasing regional rainfall;
  5. helping to counteract ‘global warming’, which might alter the conditions for human societies throughout the world.

Wouldn't it all cost too much?

The Manuals describe techniques that do not require expensive equipment or materials. Replanting the large areas of former forest and savanna lands that have been degraded will certainly cost a lot, but not as much as losing the use of them altogether!

Why weren't these things thought of before?

  1. because there seemed to be unlimited numbers of trees;
  2. because they were not considered an important resource;
  3. because ecological science was not thought to be relevant;
  4. because local experience has sometimes been ignored:
  5. because advisors often thought in terms of the temperate zones;
  6. because short-term gain had replaced sustained yield value.


A 2

- overcoming the problems of growing good plants


What sort of problems may I need to overcome?

Many different things can hold up plant production, including:

  1. Accidental hazards: such as fire, unexpected storms, flooding or drought;
  2. Organisational difficulties: for example, lack of experienced staff, training opportunities, suitable workers, adequate supervision, regular finance, relevant tools, materials and information;
  3. Biological problems: including difficulties with seed supply and germination, poor rooting of cuttings, and unsatisfactory growth or death of planting stock.

Surely you can't do anything about accidents!

One can't entirely prevent the chance of damage, but the risks can definitely be lessened, for example by:

  1. thinking about and recognising what they are likely to be, before deciding where the nursery should be sited (Manual 3).
    (examples would be to avoid exposed or low-lying sites, and those near plantations liable to fire, such as teak);
  2. planting shelter- or fire-belts;
  3. training staff and workers to react quickly and effectively in emergencies.

What about organisational difficulties?

These quite often hold up progress. Indeed, without reasonable and stable working conditions, little effective tree planting may result from years of effort, training and expenditure.

The first aim of management is therefore to provide the circumstances in which good work can be done; particularly by:

  1. communicating well;
  2. planning ahead; and
  3. encouraging morale.

This can be harder to achieve in international projects if there is poor communication between the many organisations involved (see A 60).

What kinds of biological problems are important?

Many difficulties can come up in tree nurseries, any one of which can hinder or stop the production of sufficient, good planting stock, even when all the other aspects of the growing environment are perfectly satisfactory.

These manuals cover many of the important points. (See A 61 for a Check-list of problems in growing good trees, together with suggested solutions.)

But aren't some of them insuperable?

Although certain tree species have unsolved difficulties that hinder their planting, many do not. The main problems:

  1. are simple, day-to-day matters;
  2. are being studied by scientists and foresters, or are already sufficiently understood;
  3. can generally be got around (A 61).

What sort of day-to-day matters are important?

  1. Choosing suitable sources for cuttings (A 3–13) and seeds (Manual 2);
  2. Planning the nursery well (Manual 3);
  3. Avoiding unnecessary stress on nursery plants, which can easily damage, weaken or kill them;
  4. Preparing for planting so that stress is again minimised (Manual 4);
  5. Looking after planted trees until they are well established (Manual 5).

What kinds of stress can damage trees?

The commonest two types are:

  1. Water stress, caused by:
    1. too little soil moisture;
    2. too much soil moisture, preventing air reaching the roots freely;
    3. a drying atmosphere (sunnier, warmer, drier, and/or windier air); or
    4. a root system which is inadequate to replace the water lost from the shoot.
  2. Stress from light levels, either through:
    1. too sudden removal of shade, exposing plants to bright sunlight (even for a short time); or
    2. Keeping plants in very dim light for several weeks.

Others include:

  1. Temperature stress, either:
    1. too hot (above about 35°C); or
    2. too cool (below about 15°C).
  2. Nutrient stress: lack of main and/or trace elements (A 27, Manual 3).
  3. Wind stress: either mechanical damage, or through water stress.
  4. Pests & diseases: causing weakening, damage or death (A 52).

When are trees most easily damaged?

  1. When seeds are just germinating (Manual 2);
  2. When leafy cuttings are being handled (A 30–54);
  3. When plants have just been potted up (A 53);
  4. If unsuitable potting soils have been used (Manual 3);
  5. If conditions are suddenly made more stressful (A 54);
  6. If watering is not done regularly and well (A 51);
  7. If potted plants have been allowed to root freely through into the ground, because then they lose their main roots when moved (A 54);
  8. During the first week after planting (Manual 5).

But shouldn't trees be treated ‘rough’ if they are to survive?

No! This is a misunderstanding that has grown up. Tropical nursery stock need to be hardened gradually, not subjected to sudden shock treatment or abrupt changes in growing conditions.

Understanding how to grow good planting stock is the first step to successful establishment.


A 3

- vegetative propagation


What is vegetative propagation?

The production of new plants directly from vegetative parts of existing ones, not from seeds.

How is it done?

There are many different methods, including:

  1. Rooting cuttings - usually by encouraging roots to form on a piece of stem, so that it becomes an independent plant. (Occasionally leaves can be stimulated to produce both shoots and roots.)
  1. Grafting or Budding - joining a piece of stem or a bud (the ‘scion’) to another plant (the ‘rootstock’), to provide root systems for detached pieces from a selected tree.
  2. Planting shoot tubers or root tubers - these storage organs are usually separated and replanted when they are not growing actively.
  1. Taking suckers - using shoots that have been produced on roots; either treating them as unrooted cuttings, or separating them with a piece of root attached.
  2. Separating offsets - dividing up plants that form clumps or sets of buds near to the ground level.
  1. Micropropagation - growing small pieces of tissue in sterile culture in a laboratory, stimulating many plantlets to form (A 5), growing these on; them potting, weaning and hardening them (A 53–54).

Which tree species can be propagated vegetatively?

  1. Cuttings: more than 80% of tropical forest trees so far tested can be rooted as leafy stem cuttings in low-technology ‘poly-propagators’ and/or under mist (A 30–32), grown on in a nursery and planted out just like seedlings. [This Manual deals primarily with rooting leafy stem cuttings.]
    A few will root from leafless stem cuttings placed directly into the ground, as is done with cassava (manioc) and several shade, hedging and ornamental plants (see A 4 for more details).
    [Many Begonia species can be propagated from leaf cuttings].
  2. Grafting: has been successful for example with Cedrela, Cordia, Mangifera, Pinus, Tectona, Terminalia, Treculia, Triplochiton, and is likely to be possible with most tropical trees. It is used especially for seed orchards (see Manual 2).

  1. Tubers: used for agricultural crops such as potato (shoot tuber), and yam and cocoyam (root tubers with a bud).
  2. Suckers: occur in Acacia dealbata, A. melanoxylon, Chlorophora spp., Cinnamomum camphora, Cordia alliodora, Melia azedarach, Millingtonia, Ocotea usambarensis and Populus canescens.
  1. Offsets: are used in farm crops such as plantain and banana.
  2. Micropropagation: has been successfully done in Pinus and oil-palm, is easy in Nauclea diderrichii and more difficult in Khaya ivorensis (see A 5).

What's the point of vegetative propagation?

There are two very important reasons why it is done:

  1. To be free to grow a species - many tropical trees flower and fruit rarely; and/or their seeds are not easy to store.
    By rooting cuttings, plenty of nursery plants can be obtained at any time, without having to rely on seeds.
    Vegetative multiplication is also particularly valuable:
    1. if pests or diseases destroy most of the seed crop;
    2. when fruits or seeds are hard to collect, so the crop is small;
    3. with young material, before trees reach the flowering stage.
  2. To get improved trees quickly - most tree species have not undergone selection by mankind; and breeding is much slower than with annuals.
    Vegetative propagation allows more rapid genetic improvement, because:
    1. trees with desirable, inherited characters can be used directly to produce improved planting stock (A 10–13);
    2. this direct selection captures more of the desired characters than is possible by seed;
    3. with each selected clone (A 11) existing as many plants, it is easier to check which characters are strongly inherited;
    4. clonal trials (Manuals 4 and 5) can provide a more rigorous test than a progeny trial of seedlings, and the results can be used at once.

Can't rapid tree improvement come through seed?

A good start on genetic improvement can be made fairly quickly through provenance trials and seed stands (Manual 2).
In a few species, seed orchards may give good results.
In many others further progress can be slow, because:

  1. there may be long delays before the selected tree flowers;
  2. selecting trees that have large flowering crowns could lead to negative selection when the aim is to produce a vegetative yield from the main stem;
  3. the characters selected for in the female (seed) tree may have been strongly influenced by environment, competition or chance;
  4. the male (pollen) parent is usually unknown, and may be inferior;
  5. the inherited tendencies of the parent trees are mixed during reproduction, so that less favourable combinations are transmitted to some of the seedling progeny;
  6. inbreeding depression may occur, caused by crossing between closely related trees;
  7. it can often be difficult to obtain large and regular supplies of improved seed from grafted trees in seed-orchards, though in a few species flowering can be reliably stimulated (Manual 2);
  8. there can be graft incompatibility between scion and rootstock.

How do I know that cuttings will do better than seedlings?

They will only have the potential to do so if they are genetically superior. However, there are several ways to make it more likely:

  1. By planting 10–30 clones together, not just one or two;
  2. By using selected clones (A 11–13), if possible those that have been through a clonal trial (Manuals 4 and 5);
  3. By selecting for those characteristics of stem form and branching habit that show up early in life;
  4. By making sure that cuttings come from a suitable shoot (A 6, 20);
  5. By ensuring that root systems are as good or better than those of seedlings currently being used;
  6. By labelling some clonal lines, to see which do best.

Are cuttings useful for anything else?

Yes, vegetatively propagated trees are an important research tool. Because they are genetically uniform, the effects of environment and internal changes within the tree can be separated from inherent effects.

Some misleading ideas about vegetatively propagated trees:

  1. “They won't produce a vertical stem” - only true when unsuitable shoots or ‘mature’ material are used (see A 6, 21), or inferior clones.
  2. “Their root systems are no good” - only true if the cuttings were poorly rooted or had their roots badly restricted in a container. When rooting is stimulated with auxins (A 40), the root systems can be even better developed than those of seedlings. (Note that main vertical roots are seldom necessary for either (Manual 3).)
  3. “They are too expensive” - often said during the research and development stage, before it is sensible to compare either the costs of production or the benefits of species availability and genetic improvement.
  4. “Their genetic diversity is too small” - only if very few clones are used. Successful clonal tree planting harnesses the useful uniformity of the selected clone within the safety of a diverse multi-clonal mixture.

Everyone interested in growing tropical trees can now take advantage of the move away from just planting ‘wild’ trees.
Vegetative propagation offers the best prospect of growing much improved, ‘domesticated’ crops, as in agriculture.


A 4

- leafless and leafy cuttings


Are there other names for these two types of cutting?

Leafless stem cuttings are sometimes called hardwood or winter cuttings; stakes or poles.
Leafy stem cuttings have been termed softwood, greenwood, semi-hardwood, ripewood, or summer cuttings.
These terms are confusing, and some are unsuitable for the tropics.

What's the difference between the two kinds?

Leafless cuttings are larger and of firmer wood. They do not dry up fast, and can survive in moist soil until roots are formed.
Leafy cuttings are smaller and are taken from softer shoots. Because they would dry out very quickly, they need to be kept in a humid poly-propagator or under mist (A 30–32) until they root and can take up sufficient water.

Why bother with leafy cuttings, then?

Because most species of trees can be rooted with leafy cuttings, but not so many will root from leafless cuttings.

Isn't it much simpler to root leafless cuttings?

Yes it is. Propagators are not required; pieces of stem are just pushed in, or put into a hole dug in the ground, preferably in moist, lightly shaded conditions.
If necessary, coarse sand might be worked into the soil to improve rooting; and simple, temporary shading could be placed over them in hot, dry weather.

How big should they be?

Sometimes 1–2 m poles, put in to mark out plots or planting positions, will take root and produce new shoots. This capacity is used to establish “live fences” and “live poles” to support climbing crop plants, for example in Cassia siamea, Gliricidia sepium and species of Bombacopsis and Spondias.
When a tall tree is to be grown, however, the ideal length is usually 15–40 cm, with a basal diameter of about 6–30 mm.

What kinds of woody plants will root as leafless stakes?

Some other examples are Bosqueia angolensis, Ceiba pentandra, Debregeasia salicifolia, Ochroma lagopus, Pterocarpus indicus and species of Dracaena, Erythrina, Ficus, Vernonia and bamboos; agricultural crops such as cassava (manioc) and sugar-cane, and several ornamental and hedging shrubs.
Gmelina arborea has been rooted as leafless cuttings, by using the shoots removed from ‘stumped’ planting stock, without their leaves.

Does it matter when I take leafless cuttings?

  1. Adequate soil moisture: if possible plant in the first half of the rainy season, or in a place that can easily be kept watered.
  2. Inactive buds: the cuttings should preferably not have actively flushing buds, as it is better for new shoot growth to follow rooting. Lengths of older wood are often used, rather than the softest, green shoots.
    (Note: leafless cuttings of a few species can require cool storage, to make them ready to root well).
  3. Leaves: shoots that have already lost their leaves naturally are often best; if not, cut through the leaf-stalks rather than tearing them off, and leave a few very small leaves at the tip.

How should they be planted?

  1. To grow a tall tree:
    Dig a hole, and plant the cutting with only about 3 cm above ground, including a live bud.
  1. For shade trees or hedging:
    Point the stake and push it into the ground where it is to grow, leaving 0.5 to 1.5 m above ground. (In hard ground use an iron bar.)
    Near-vertical planting is likely to produce a plant with a single shoot, whereas slanting or horizontal cuttings tend to form several shoots.

What about leafy cuttings?

Most of this Manual deals with rooting leafy stem cuttings. Sheets A 20–27 explain their production, A 30–36 deal with conditions for propagating them, and sheets A 40–54 cover how they should be handled.


A 5

- micropropagation


What is micropropagation?

One of the methods of vegetative propagation (A 3), which has to be done in a special laboratory.

How is it done?

Very small pieces of a tree are washed free of all bacteria or fungi, grown on a special nutrient medium in sterile culture, and encouraged to produce many plantlets. These are then potted, grown on, weaned and hardened.

What are the main steps?

  1. Setting up the tissue culture laboratory. Two rooms without windows are needed, which can be kept very clean. One requires banks of fluorescent lights, and air-conditioning that can maintain a temperature of 25°C. The second, used for preparation, needs a sterile-air bench, and storage space. An autoclave is also required for sterilising the media on which the cultures will grow.
  2. Preparing the media. There are several different media which have given good results, and the basic chemicals can be obtained ready mixed (A 63). Distilled water and agar are added, together with specific quantities of the plant growth regulators (hormones) that determine whether shoots or roots are formed. [Note: Cytokinins tend to stimulate shoots, while auxins promote roots (A 40); but both are often needed.]
    After autoclaving - to kill spores of micro-organisms - the medium is poured into sterile tubes on the sterile-air bench, closed with cotton-wool, and allowed to set at an angle, producing a sloping surface. [Note: some heat-sensitive hormones must be added after heating, using a sterile syringe.]
  3. Taking the ‘micro-cuttings’. Small pieces of tissue are taken from the selected tree with a sharp blade, and throughly washed in a disinfectant such as hydrogen peroxide (H2O2) or a solution of hypochlorite. Success has usually been achieved with strongly juvenile material (A 6), such as parts of newly germinated seedlings, but small, active buds and even flowering parts have also been used.
  4. Setting the ‘micro-cuttings’. Using the sterile-air bench and sterilised tools, a tube is opened and a single piece of tree tissue planted on the middle of the slope. A little sterile water is added, the tube closed again and placed under the lights.
  5. Shoot multiplication. The aim of the first stage is to encourage the culture to form many small shoots. This may take a few weeks, or longer.
  1. Sub-culturing. Once the shoots on the ‘micro-stockplant’ can be handled, they should be transferred to a fresh tube containing a medium that will promote rooting. If shoot multiplication is slow, the whole culture will need transferring to a new tube each month.
  2. Rooting. In the second stage, each shoot forms a root system.
  3. Transfer of plantlets to soil. The new plantlets need to be placed carefully into a sterilised potting soil in small pots, covered with a polythene bag and allowed to grow larger under the same conditions as the cultures. [Note: At this stage they are still very delicate, and need ‘intensive care’.]
  4. Weaning. The established plantlets need to be gradually accustomed to less humid conditions and somewhat brighter lighting (A 54). It is easy to lose them if this stage is done too rapidly, particularly when they are taken to a shaded nursery bed. However, if weaning is too slow the shoot may become drawn and weak.
  5. Re-potting. During the nursery part of weaning, transfer the plants carefully to larger pots, using un-sterilised soil. The inoculum for mycorrhizas or nodules can be added to the potting mixture (A 53).
  6. Hardening. For light-demanding species, the shading can be gradually reduced after the plants have been fully weaned (A 54).

Isn't all this very difficult to do?

There are usually problems in setting up the laboratory and in finding out what conditions are needed for a new species. Once routines have been worked out for a tree species, micropropagation can become more straightforward, but it is still time-consuming.

What's the point of it, then?

Micropropagation can sometimes give certain distinct advantages:

  1. when rooting ordinary cuttings is difficult. For example, oil-palm does not produce shoots suitable for cuttings, but selected clones are now produced by micropropagation.
  2. for easy international exchange of selected clones, free from pests and diseases. (Note: viruses may still be present.)
  3. to eliminate viruses from a selected clone, as has been done with cassava (manioc), for example.
  4. if adult material from older selected trees can be re-juvenated through micropropagation, this would be of great importance (A 10).

What are the disadvantages, compared with ordinary cuttings?

  1. Propagation facilities are more complex and expensive.
  2. Knowledge of optimal conditions is little known as yet, and the research for each species can take a long time;
  3. Amount of work is greater, especially in the early stages.
  4. Staff and workers need to be more highly trained;
  5. Cultures can be lost through electricity failure or rapid spread of contamination.

Where do problems happen most commonly?

  1. In sterilising the plant material;
  2. In maintaining good growing conditions for the cultures;
  3. In obtaining shoot multiplication;
  4. In transferring plantlets to potting soil;
  5. In weaning and hardening the small trees.

A 6

- what makes a good cutting?


Won't any tree of the right species give good cuttings?

No, because there is so much variability within each species in:

  1. branching habit and stem form (the individuals may vary from tall, straight, fine-branched trees to spreading, heavy-crowned bushes);
  2. growth rate (some may grow several times faster than others);
  3. other desirable features of the tree, such as fruit yields or timber quality; and
  4. rooting ability of the cuttings (their potential could be anywhere from 0–100%).

What makes their shoots so variable?

  1. Genetics, the inherent differences that result from each individual tree getting a unique set of genes (genetic instructions) from its parents;
  2. Internal changes within the tree as it grows older and larger; and
  3. Environment, all the climatic and site factors influencing the tree, and the effects on it of animals, micro-organisms and other plants.

Can all these effects be easily distinguished?

Usually no - it is generally difficult to tell just how much each is involved (although foresters often speculate). This is partly why it is much harder to draw firm conclusions from research on trees, compared with studies on most agricultural crop plants.
Sometimes yes - particularly if clonal rooted cuttings are used in experiments in place of seedlings. The effects of genetic differences can then be largely separated out and studied, which in turn makes it easier to find out what influences the other two are having.

What can I do about genetics?

Take your cuttings from trees that are of good:

  1. provenances (or local races - A 10): already shown to be suited to the proposed planting site (Manuals 4 and 5);
  2. progenies (Manual 2): coming from parents that have produced good trees before;
  3. clones (A 11): of tested clones, if available; or from individual trees that are healthy and vigorous, and are straight with fine branches (A 12), or have other desirable features.

Genetic selection is covered in more detail on A 10–13 and in Manual 2.

Won't any shoot on a selected tree do as a cutting?

No; partly because internal changes will have made some of them unsuitable for vegetative propagation, for example:

  1. Rapid loss of rooting ability with age. Most tree species root easily from leafy cuttings taken from young seedlings, but not when these are taken from the crowns of saplings or mature trees;
  2. Branches unsuitable for propagation. In many tropical trees, the branches have a different structure from the main stems, and after rooting they give plants which may not show a normal growth habit;
  1. Vigour of growth. Leafy cuttings generally root best when the shoots were growing at a moderate rate before they were taken (A 42).
    Take leafless cuttings when the buds are not making new growth (A 4).

But all these things will stop me getting enough cuttings!

This may be a problem at first, but can be overcome by:

  1. Using nursery seedlings as a source of cuttings to start with;
  2. Using managed stockplants to produce plenty of the right sort of shoot (see sheets A 20–27 for more details).

How are stockplants managed?

Here are two ways:

  1. By felling a selected tree, and repeatedly harvesting the coppice shoots it produces. Coppice shoots from within about 1 m of the ground are usually juvenile (like shoots from seedlings), often producing vigorous shoots with a main stem structure that root easily. Coppice stumps need frequent harvesting and pruning to prevent tall shoots and those with branch structure developing (A 21).
  1. By planting clonal cutting as stockplants. These also need frequent harvesting and/or pruning to persuade them to produce plenty of the right type of shoot (A 25). Alternatively, they can be grown for 1–3 years and then coppiced.

Can I change the environment to produce better cuttings?

Yes, for the stockplant environment makes quite a difference to how the cuttings root later on. For example:

  1. Shading: moderate shading of stockplants greatly increases the subsequent rooting of Triplochiton scleroxylon. The light filtering through green leaves is best, so it is a good idea to interplant with a leguminous shrub such as Leucaena, which has many small leaflets giving a suitable kind of shading (see A 24). (Too much shade decreases subsequent rooting.)
  2. Watering: During dry weather stockplants may grow slowly or stop producing shoots altogether. If they can be watered (A 26), it may be possible to harvest cuttings all the year round, and they are more likely to be of a suitable type.
  3. Mulch and fertilisers: mulching the stockplants (Manual 5) can help them establish quickly, grow well and produce plenty of good cuttings. Adding NPK fertilisers (A 27) can help in the same way, and also replaces minerals removed by harvesting shoots, or washed away in rainfall and watering. Since fertilisers can increase or decrease the subsequent rooting of cuttings, use them in small quantities after harvesting, or do experiments with your species (A 45).

Are there some kinds of tree without all these problems?

Some species that root easily from leafless cuttings (A 4) have fewer problems, and cypresses for example often produce large numbers of easy-rooting, vertically-growing cuttings without special attention.
However, most tropical trees need stockplant management to gain the benefits of vegetative multiplication and clonal selection.

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