Some common reforestation practices and some additional possibilities.
Topics include: Reforestation projects, reforestation methods, reforestation techniques, revegetation techniques, ecological restoration techniques, landscape rehabilitation techniques, conservation, succession, planting trees, direct seeding, cloud seeding.
I would like to recommend an excellent book: Goosem, S. & Tucker, N.I.J. (2013). Repairing the Rainforest (second edition). Wet Tropics Management Authority and Biotropica Australia Pty. Ltd. Cairns. (Australia).
The following may be helpful to you if you need funding for a reforestation project – I was recently contacted by Francisco Granados who informed me about crowdfunding and sponsorship for tree planting projects through http://info.tree-nations.com/planters
Below is an illustration of the natural process of succession, where plant growth and vegetation cover increase over time, as well as soils improving over time – natural regeneration, essentially nature fixing itself. Successful reforestation strategies can take advantage of, and work with this natural process. The species illustrated in this example are North American, however the phenomenon of succession is almost universal. See also the page on mixed improved fallows.
REFORESTATION METHODS – INTRODUCTION
“A society grows great when old people plant trees, knowing that they will never sit in the shade of those trees.” Based on an Ancient Greek proverb.
Reforestation on a grand scale is desperately needed in many places all around the world. I hope the information, techniques, and ideas presented on this page and web site will help.
Reforestation is generally called revegetation (and sometimes restoration) in Australia. This has merit, since for many people the word reforestation conjures up images of trees only, and perhaps a plantation of just one species (such as pines or eucalyptus trees), whereas revegetation implies restoring a cross-section of plant types and species, multi-storey vegetation, and includes different vegetation types such as grassland.
Reforestation projects can create new patches of indigenous vegetation and/or increase the size of existing remnant patches of vegetation, and provide a buffer around them, as well as create linking corridors (particularly important for the dispersal of wildlife) between vegetation patches.
The photos below show the inspiring reforestation efforts of the Salgado family and the Instituto Terra in Brazil:
Usually only indigenous plants are used in reforestation in Australia and in most other parts of the world. Ideally, propagation materials are collected from within a few kilometres, but in practice seeds, cuttings, etc. are collected from within the same catchment, or within about 15 kilometres (a largely abitrary figure, although honeyeaters will travel around 15 kilometres, dispersing pollen in the process, Lindenmayer 2012). In the USA, propagation material is collected from up to 80 kilometres away (also an abritary figure?), which provides much more flexibility (Romanowsky 2005). In some places, the nearest remnant vegetation may be further away than that, so propagation material will have to come from the nearest practical source, and perhaps a few sources to provide sufficient biodiversity, and a wide gene pool. Some suggest that as a strategy or insurance against possible climate change, seeds could be sourced from both north and south of the area.
Some non-indigenous plants which are sterile or not invasive, or perhaps only form a temporary successional stage, can be used to advantage e.g. sterile ryecorn (commonly used in mine rehabilitation), perhaps Miscanthus x giganteus (see photo further below), papaya, cassava, sweet potato, Japanese millet, Vetiver grass, etc. Sometimes volunteer exotic plants may be effective in revegetating an area (e.g. camphor laurel), and may be tolerated if they naturally only form a temporary component of the vegetation (an early seral stage of a succession).
Weeds are usually a major problem in reforestation projects, competing with the trees/plants for nutrients, light and water, reducing establishment success and growth rates. Therefore, the area to be revegetated is commonly sprayed with Roundup (glyphosate) weedkiller at a rate of around 15ml/litre, two to six weeks before planting, and usually receives two or more sprays, about two weeks or so apart, to ensure that existing weeds are killed, as well as those that germinate after the first spray.
The effectiveness of Roundup may be improved by adding a few drops of dishwashing liquid (a wetting agent, which improves coverage), and about 10ml/l of methylated spirits (which seems to help with some difficult to kill plants – perhaps the waxy leaf cuticle is disolved, aiding absorption into the leaf, and possibly dessication of the leaves). A pink dye is sometimes used so that it is easier to tell what has been sprayed. Glyphosate has, however, been implicated in having possible negative effects on amphibians and mycorrhizal fungi, and so the lowest possible effective rates are advocated.
Weeds could perhaps also be killed or largely controlled by growing a smothering groundcover (e.g. perhaps Mucuna pruriens, Lablab purpureus, Vandasina retusa in the wet tropics, or a dense covering of Sesbania or Acacia spp.), but this is largely unexplored. Spraying with pine oil or steam could be an option. In some situations, a fire or intense grazing could reduce the weeds before revegetation. Small areas, or even just a metre diameter around each planted tree, can be covered with newspaper, cardboard or similar, and then mulched with woodchips, leaves or similar on top, to control weeds.
Deep ripping of compacted degraded soils, or subsoils, can be helpful (using a tractor and ripper, or draft animals). Sometimes the soil is degraded as well as weed infested, in which case some of the species and techniques used in mixed improved fallows may be appropriate to improve the soil, shade out weeds, and kick start reforestation – see the “Fallows, Green Manure, Succession” page (click on the button at the top of this page), and the AID article on the “Articles” page. Livestock can also be used to partially control weeds and improve degraded soils – see photo below:
In the photo above, similar results could be attained with a wide range of reforestation species, and the seeds could also be fed to the livestock and dispersed by the livestock.
Degraded soils may also require inoculation with nitrogen-fixing bacteria, mycorrhizal fungi, and earthworms. In his book (Earthworms in Australia, page 91), David Murphy recommends adding 1 to 2 kilos of earthworm castings to each tree planting hole (this would not be appropriate in infertile sandy or clay soils if the intention is to maintain a naturally occuring sclerophyll “heathland” vegetation typical in Mediterranean climate regions). Earthworms can sometimes be successfully introduced to a degraded or worm-free area by digging out turf blocks (250 mm square by 100 mm thick) from an area which is rich in worms and placing the blocks upside down about 10 metres apart in the degraded area (Murphy, page 100).
It is best to try and keep on top of the weeds, to prevent them taking over. Therefore, follow up spot spraying is usually needed, and spray drift is a problem. A piece of corflute or similar can be curved around a tree to protect it from spray while spraying weeds at its base. A plastic funnel can be attached to the head of the sprayer (with duct tape of course) and placed directly over the top of small weeds to spray them.
Sometimes the weeds are providing habitat and food for native wildlife and their removal (all at once) can be detrimental to wildlife, for example, blackberries and African boxthorn in S. E. Australia, and lantana, camphor laurel and guavas in the tropics. In such cases, weed removal could be staggered, with concurrent establishment of indigenous plants that perform the same functions (of providing food and dense cover for example), or the weeds may be tolerated if they are likely to die out later (some species can be shaded out).
Planting trees – potplants/tubestock, and mulch
Nearly all reforestation projects (in Australia) involve planting mainly trees, grown in small square plastic tubes called tubestock (see photos below), into larger hand-dug holes (or an auger may be used), which are then watered in, usually with a little or no fertilizer added, and then mulched with “council” or “municipal” mulch (a composted mix of chipped wood and leaves, sourced from local government pruning of street trees, which has been at least partially composted, and which closely matches natural mulch/leaf litter in a natural forest). The mulch would normally be about 5 cm or more thick (2″ or more thick), and arranged in a circle around the plant, without touching the stem, about a metre/yard in diameter, or preferably the whole area is mulched.
An organic mulch (of leaves/twigs/woodchips for example), can help to re-establish soil life. In this area that I mulched, a bizarre fungus has grown (photo above). Another wood-rotting fungus below:
Black plastic mulch can be a very effective mulch and enhance tree growth by at least 30%, compared to bare soil, and much more compared to newly planted trees competing with weeds. Typically, squares about one metre/yard in diameter (not less than .5 of a metre – one metre wide strips which are many metres long are also an option) are used. After the tree is planted, an “X” is cut in the centre of the plastic, and placed over the tree, so that the planted tree sticks out above the plastic mulch. The plastic mulch is then kept in place by “n” shaped pieces of wire pushed through the plastic and into the soil, and/or weighed down with rocks, branches, clods of earth (or whatever is at hand). Like organic mulches, black plastic suppresses weeds and holds in moisture, however it can also collect water and direct it to the centre where the tree is (if the surface of the planting hole is shaped into a basin) which can give good results in semi-arid areas. In addition, black plastic heats up the top few centimetres of soil (and may have a partial soil solarization effect, providing partial control of soil pathogens and nematodes). Thus, black plastic could be particularly useful in cold climates (or in warmer climates if planting is at the beginning of or during the colder time of the year), and in semi-arid areas, and especially in cold semi-arid areas. The plastic mulch would normally be left in place for 6 – 12 months, or more. A disadvantage is that the plastic has to be removed later, but it can usually be re-used.
Direct seeding – utilising livestock for reforestation/revegetation
“Seeds and fruits are the chief, sometimes the only, food of many forest-inhabiting rodents,
birds, gorillas (Tutin et al 1991) and monkeys, but other mammals, even carnivores such as civets, mongooses and tigers, are said to eat fruits.” ” A very large proportion of rain forest trees have fruits or seeds attractive to mammals and birds. Roosmalen (1985) estimates that 87-90% of the woody species in the high forest of the Guianas are animal-dispersed.” (Richards 1998).
Livestock and/or wildlife can be used to disperse seeds, providing a “work smart not hard” reforestation method for large areas, with treatments repeated over time. Livestock can also be used to restore degraded soils, or enhance the fertility and structure of average soils, through their manuring and urination.
Livestock fed with seeds (seeds mixed in with supplementary fodder) will later disperse and deposit some of the seeds in their manure. Up to 90% of the seeds fed to livestock may be destroyed by chewing etc., so large numbers of small seeds fed to larger animals e.g. horses, cattle, are likely to work best (e.g. probably many species of small-seeded legumes such as Acacia spp., Sesbania spp., grasses, herbs etc.). Livestock can also disperse soil improvers (again, mixed in with supplementary fodder), such as beneficial micro-organisms, deficient nutrients, clay for sandy soils, etc., which are then deposited in their “improved” manure. In most places this improved manure will be mixed into the soil by earthworms and/or dung beetles, and in some places, termites.
Seeds can also be broadcast by hand or machine (but this is more labour and energy intensive), and then trodden into the soil by the animals, to enhance the germination and establishment of many plant species (this technique provides an opportunity to establish plant species that have large seeds e.g. Erythrina, but also small poisonous seeds). Or, a combination of the above, plus follow-up planting of potted plants and/or quickstick cuttings in bare/failed areas. See the “Animal Improved dung plus seeds” treatment on the page “Animal Improved Dung” (click on the button at the top of this page) or click here: shortaid, for a short version, concentrating on the use of livestock, but missing additional information, or click here for the full version: aid-savory-3rd
A few photos of a direct seeded hillside in Cairns, on stoney, heavy clay subsoil:
Utilising wildlife for dispersing seeds/revegetation
Piles of ripe fruit and/or seed pods from indigenous plants placed randomly in an area that needs revegetating may possibly be eaten (and the seeds dispersed) by wildlife, especially if this is done on the edge of an existing forest. This could work for some Passiflora spp., figs, guavas, Opuntia, some Solanaceae, some Cucurbitaceae, some Rosaceae, some Lauraceae, some palms, some legumes e.g. rain trees, Inga spp., etc. It may be important to avoid getting human smells on the fruit or seed pods, so it is adviseable to rub topsoil or leaflitter on hands prior to collecting and placing fruit.
Even more wildlife may be attracted to the fruit/seed pod piles if additional attractants are added. In areas that are far from the sea, salt may be deficient, and a strong natural seasalt solution poured on the piles may result in more animals being attracted to, and eating and dispersing the seeds. Also, the smell and taste of diluted molasses should attract many animals, and perhaps also diluted malt, and perhaps brewer’s or baker’s yeast. Different attractants could be added to different piles to see what works best.
Providing artificial perches and homes/nesting sites will bring in birds etc., which will deposit seeds below and near the perches (birds often defecate beneath their roosting perches, and as they take off). See the AID article for more on this technique.
“Pioneer trees such as Trema orientalis and species of Macaranga in the eastern tropics, Musanga in Africa, and many species of Cecropia, Inga, and Vismia in the Neotropics, have very wide geographical range and also effective dispersal by birds or bats.” Richards 1998.
Direct seeding – hydroseeding, seedballs and pelleted seed.
Direct seeding by hand is rare in volunteer reforestation projects. It is more likely to be mechanised and used by farmers to establish windbreaks or fodder trees, and is common in mine reclamation work and roadside cuttings. Hydroseeding/hydromulching is common on steep slopes and roadside cuttings (where seeds, organic fibres, water and guar gum or psyllium husks are mixed together and sprayed) – for more on hydroseeding/hydromulching see the excellent web site, Steinfeld et al (2007), in the references at the bottom of this page.
More research on cost-effective direct seeding techniques and the use of seed balls would be helpful (see the article on direct seeding Faidherbia albida, and the AID plus seeds article for more on seed balls), in order to revegetate larger areas at lower cost. For an article on using a modified turf industry seeder to reconstruct grassy communities, click here:
The seed ball photos below show typical seed balls, usually made of around 50:50 clay and compost, plus a mix of seeds, and typically about the size of a large marble, around 1 inch/25 mm in diameter. Shredded waste paper has also proven successful. They can be dried out and broadcast later (usually before or during the wet season), or seeds can be pre-germinated, gently mixed in just before the radicle (root) emerges from most of the seeds, and promptly broadcast after good rains, and when follow-up rain seems likely.
Both the clay and the compost hold water and provide some nutrients. In drier regions/sites, the addition of psyllium husks (available from health food stores and some supermarkets, at perhaps around 20 grams/litre, i.e. one level tablespoon/litre) or guar gum to the water leaves some free water, which would be easily available for imbibition and the early stages of seed germination, but also causes some of the water to form a gel, which may hold the water for longer, and so improve germination and increase the chances of establishment of the seeds/seedlings. However, in wet, warm climates or sites, many seedlings die because of rotting diseases, and so it may be better to use fine sand (which holds less water than clay or compost), and to add a fungicide to the mix. A tarpaulin or sheet of plastic can be moved back and forth to coat/pellet seeds with fungicide, clay, beneficial micro-organisms etc. (See: MacDonald, Edward D. “Polyethylene Tarp used in Pelleting Coniferous Tree Seed”, click here: http://www.rngr.net/publications/tpn/12-3)
The addition of topsoil may be necessary in some degraded sites to provide appropriate Rhizobium bacteria and beneficial fungi (or these can be purchased and mixed in), although compost, topsoil or manure could spread soil pests and diseases such as Phytophthora cinnamomi, and an alternative could be lignapeat (brown coal dust). Rock dusts such as basalt, rock phosphate and dolomite/lime may also be a useful minor component of seed balls (as well as deficient trace elemants).
This is just speculation, but there may be advantages to making seed balls a lot larger than is standard practice, around tennis ball size; or for practical purposes, a handfull. Larger balls or seed bombs could have the following advantages:
greater volume of water, which may be particularly important in semi-arid revegetation, so that more moisture is available for longer, giving seedlings a better chance to establish,
insulation against temperature extremes, so that seeds (and beneficial micro-organisms)near the centre or the base of the ball would be partly insulated against extreme heat and/or cold, frosts etc.
seeds deep inside a larger ball may be more likely to escape seed predation (by rodents and birds for example),
seeds of different species have different optimal depths for sowing, with some growing best if they are buried a few inches deep in the soil, while others, including many grasses and herbs, need exposure to light to germinate and so need to be on the surface. A rule of thumb when growing vegetables and grains is to sow the seed at a depth of one to two times the width of the seed. If seeds of one species, or a mixture of seeds of different species with different needs are randomly mixed in a larger seed ball, at least some of the seeds should be in the optimal position for germination.
Perhaps smaller seeds may be best in smaller seed balls, around marble to golf ball size, and larger seeds in larger seed bombs, around tennis ball size.
Direct seeding, including perhaps seed balls, can also be done using planes and helicopters, but is generally outside the budget of most reforestation projects. This method could be particularly useful for otherwise inaccessible areas. It would be helpful if the military and volunteer hobby pilots became involved in reforestation in countries around the world. Aircraft used for livestock mustering, and culling pest animals, or for just about any purpose, could also carry out aerial seeding at the same time. Aerial seeding has been very effective in some parts of the world, particularly using the nitrogen-fixing tree, Leucaena leucocephala. There are numerous other possible, preferably indigenous species, that are likely to work reasonably well with aerial seeding.
Cloud seeding and aerial seeding
Cloud seeding will probably become a fine art in the near future, making it possible to cause rain to fall in a specific area (which has just been aerial seeded or planted); or an area where it has been made to rain could then be aerial seeded/planted. Repeated and targeted cloud seeding could provide follow up rains to aid plant establishment in an area that has recently been reforested.
Cloud seeding using beneficial fungal and bacterial spores
At present, silver iodide is commonly used for cloud seeding, but in nature, the spores of many species of bacteria and fungi are important for seeding clouds. If it turns out that they work effectively as nuclei, and if it is a practical/realistic option (e.g. the spores aren’t killed by the cold, and effectively inoculate soils, etc.), it may be helpful to use the spores of beneficial micro-organisms, such as nitrogen-fixing bacteria and mycorrhizal fungi to seed clouds. This could prove useful in forestry, reforestation and agriculture, especially to inoculate areas suffering from severe soil degradation. Beneficial micro-organisms could also perhaps be dispersed during crop dusting.
In a few years time, techniques may have been refined to a point where it seems a no-brainer to combine aerial seeding operations with cloud seeding, and using beneficial micro-organisms as cloud seeding nuclei.
Many species of legume groundcover plants may succeed grown from seed balls or the AID plus seeds treatment, and would add organic matter, nitrogen, and act as a mulch, reducing erosion.
Pests and other problems
Rabbits and other browsers are often a problem, and so it is common to add a clear plastic sleeve around three wooden stakes for protection, which adds to the labour and expense, but also speeds up initial establishment and growth, especially in colder climates. Fires, weeds and vandals may also repeatedly destroy plantings.
In this reforestation project along the banks of Thomatis Creek, Cairns, Acacia mangium, Acacia holosericea, Macaranga tanarius, Elaeocarpus grandis and Homalanthus novoguineensis have all grown particularly well (as one might expect from these species).
Two species that usually grow very well in reforestation projects in North Queensland.
Reforestation methods and reforestation projects in Australia continued…
Most reforestation projects take place where most of the people are – and in Australia this is in south-eastern Australia, in suburban parks and remnant bushland. Also, most projects occur on infertile soil with sclerophyll vegetation, and to maintain this (which is usually desired) can be difficult since there are often increased inputs of nutrients, water, and weeds facilitating succession towards a wetter forest vegetation. Burning can help to volatilise nutrients and lower soil organic matter, but may also aid the establishment of fire-adapted weeds, commonly from South Africa. Similarly, in South Africa, burning may aid the establishment of Australian fire-adapted weeds, such as Acacia spp. and Hakea spp. In some projects (in Australia), topsoil has been removed by a grader to get rid of weed seeds, (click here for an article about reconstrcting grassy communities, where topsoil was removed: firstname.lastname@example.org_20141007_093512) and reduce soil fertility, or a plough is used to invert the soil (which may be followed by direct seeding in the furrows).
Waste cardboard used as a mulch to control weeds, before spreading wood chip mulch.
Same project as above – with weed problem. Dodonaea (polyandra?) on right doing well regardless.
Reforestation methods continued….
Reforestation using large cuttings (“quickstick”/stakes/truncheons or stump cuttings)
Some plants can be grown from large cuttings pushed straight into the gound (or perhaps into a rip line created by a tractor or animal drawn ripper), when the soil is moist in the wet season.
Cordyline sp. Cuttings of Cordylines and Dracaenas can be grown by cutting the base at an angle and pushing them straight into the ground. This reforestation technique is cheaper, quicker and less labour intensive than growing trees in pots, digging holes, planting them, and watering them in. However it may not be as successful as planting potted plants, and there is a limited choice of species, and there may be a limited amount of propagation material available. The flowers and fruits of Cordylines attract wildlife.
Cat’s whiskers, Orthosiphon aristarche, Lamiaceae family. This plant can be grown from cuttings placed straight into the ground. It makes a good shade-tolerant, weed-supressing ground cover. It flowers frequently, and the nectar attracts honey-eaters and sunbirds.
A female Olive-backed sunbird (or Yellow-bellied sunbird) visits an Aphelandra sinclaireana flowerhead for nectar. Like hummingbirds in the New World, sunbirds are important for pollination, and eat insects as well.
Erythrina spp. are very useful nitrogen-fixing, wildlife-attracting trees which can be grown from large cuttings pushed straight into the ground (in the wet season in the tropics). They have been used successfully as the “backbone” of reforestation projects in Sri Lanka, and should prove effective wherever they are native. Combined with one or more large, fast-growing grasses (e.g. Pennisetum purpureum, Saccharum officinale, Miscanthus) established the same way, large areas can be reforested with a minimum of cost, time, and labour. Such a combination would produce high levels of organic matter and mulch, improve soils and reduce erosion, and hopefully attract many species of wildlife for the nectar, from remnant patches of vegetation, which should bring in seeds of other species and increase the biodiversity over time.
Grasses and other monocots
Stems of some large grasses such as sugar cane and pitpit can even be placed on the soil surface, with most of the stems producing roots and shoots, if the soil is moist. The stems could be placed on the soil surface, along a contour, with each stem having perhaps three nodes. This should prove to be effective in reducing erosion, especially if combined with cuttings of sweet potato. Both species should be shaded out later by tree growth.
Roots growing from nodes on pitpit grass.
Close up of a node with roots and a bud which would grow into a shoot with leaves.
Some other plants which can be grown as large cuttings, pushed straight into the ground include:
Gliricidia sepium, Moringa oleifera, cassava, sweet potato (one of the best to reduce erosion on slopes, and is shaded out later), willows (the base of around 2 metre long willow cuttings can be cut on an angle, and thrown like spears into soft, moist river banks), some poplars, Lantana (where it is native), some grasses eg. sugar cane and Napier, many succulents including cacti, and many plants in the Lamiaceae (e.g. Plectranthus spp.), Piperaceae and Asteraceae families (e.g. Tithonia, perhaps Montanoa, Wedelia).
See the AID article, pges. 26, 27 – click here: Animal Improved Dung (AID) plus seeds treatment .
Divisions, rhizomatous plants and tubers
Similar to the large cuttings method above. Using a sharp spade or secateurs to divide up clumps, and then planting out the divisions, works for some plants such as heliconias, gingers, bananas, Jerusalem artichokes and many other rhizomatous plants.
Some plants can be grown in raised beds of friable soil/compost/potting mix. Young plants in beds can also be protected from weather extremes with palm fronds, or shadecloth, clear plastic, woven polypropylene “garden fleece”, etc.
When they are big enough, they can be gently dug up, the roots kept moist, and then planted and watered in as soon as possible (the roots can also be dipped into a solution of Rhizobium bacteria and Mycorrhizal fungi before planting out). This reduces material and labour costs (compared with growing on in pots and then planting).
There are probably many species that would be suited to this sytem. Some possibilities: mulberry, Sesbania sesban, cool to cold temperate deciduous trees/plants generally e.g. many and trees and shrubs in the Rosaceae e.g. Prunus spp., Rubus spp., some conifers, many palms, most succulents, including cacti. In West Africa, Khaya senegalensis, Senna siamea (prev. Cassia siamea), Sclerocarya birrea and some Prosopis species have been successful planted out as bare-rooted plants. See also the AID article, pgs. 26, 27.
Young plants germinating beneath a parent tree (wildlings) have little prospect of becoming established under the parent tree, and can be carefully and gently dug up and planted elsewhere. This can have a high failure rate, and may be improved if they are transplanted to a raised, protected bed first, and planted out later. This should work for many palm spp., many conifers, and most succulents.
Some plants naturally produce suckers from their roots, and usually more so if the roots are cut. This can be achieved with a tractor or draft animal and a single tyne ripper, or on a small scale, with a sharp stainless steel spade. Just a few plants that may do this: Populus spp, Robinia pseudoacacia, Ailanthus altissimus, Acacia melanoxylon, A. dealbata, A. auriculiformis, Faidherbia albida. Suckers can also sometimes be dug up and successfully transplanted.
Expect to lose few plants – it is worth having a back up of some potted plants to fill in gaps, or fill gaps with large cuttings. It is also worth having non-climbing groundcovers to fill in gaps. Sweet potato (in the wet tropics) is an option even though it is not native, as it is excellent for minimising erosion, improving structure in heavy clay soils, and will be shaded out later.
Planning and ongoing management, follow up work
Reforestation is usually not a one-off project – doing a good job generally requires careful planning and budgeting beforehand, adaptive implementation, and then follow up work is often critically important, especially weed control, but also adding more species for biodiversity/ecological complexity, e.g. climax spp. and epiphytes at a later date.
Habitat creation, attracting wildlife and natural regeneration in reforestation projects
If a habitat is created that attracts wildlife, the wildlife will aid natural regeneration by bringing in seeds (stuck to fur or feathers, or spread in their dung), although this may include weed seeds. This can be as simple as providing a perch in an otherwise open area for birds and fruitbats, which will deposit many seeds at the base of the perch, and perhaps some on their way to and from the perch. Perches can be connected using thin rope, providing more perches for wildlife to use and deposit seeds. See the AID article for more on perches, pages 32, 33 – click here: Animal Improved Dung (AID) plus seeds treatment .
A colony of Spectacled flying foxes or fruitbats. If fast-growing tall trees can be established, or artificial perches created, birds and bats will deposit seeds beneath the perches, resulting in natural regeneration and often bring in different species, adding biodiversity to a reforestation project.
What happens if you park a car under a fruitbat colony for a week or two. The seeds of various species are present, but mostly Ficus benjamina.
A Rainbow Lorikeet visits a Schotia brachypetala tree for nectar, Cairns, Australia. Many birds visit flowers for nectar but also pollinate the flowers and so increase seed set, and ensure or improve the chance of cross-pollination. More seeds equals a greater chance of more plants establishing from seed.
Plants which provide nectar followed by fruits (or edible pods, for example), are particularly helpful in attracting wildlife, and a wider variety of wildlife, which may bring in seeds and aid natural regeneration.
One of the best plants in North Queensland for attracting insects and birds with its nectar, and birds with the fruits that follow, is Premna serratifolia.
Also, (in various countries) Melicope elleryana, Rhus taitiensis, Micromelum minutum, Ixora klanderiana, Buchanania arborescens, Pittosporum spp., Schefflera actinophylla, Leea indica, Melia azedarach, Polyscias spp., Cordyline spp., Papaya, Melastoma spp., Syzigium spp., Psidium spp., Opuntia spp., Cotoneaster spp., Crataegus spp., Rubus spp., Alphitonia spp., Myoporum spp., Sorbus spp., Sambucus spp., etc.
Whole fruits or seedpods of indigenous plants containing seeds (where the fruits are not poisonous – e.g. fruits of figs, guavas, Opuntia; and seedpods of Faidherbia, Parkia, Prosopis, rain trees etc.) can be fed to livestock, or perhaps even to wildlife, to disperse the seeds in their manure.
Premna serratifolia attracts insects for nectar and then birds for fruits.
Micromelum minutum attracts insects for nectar, and later birds for the fruits, and the birds then disperse the seeds.
Micromelum minutum attracts insects which pollinate the plants.
Insects which visit flowers improve pollination and therefore seed set, and therefore increase natural regeneration because of the greater number of seeds.
A sulphur-crested cockatoo feeding on Alexandra palm Archontophoenix alexandrae fruits. Many species of birds and mammals eat fruits and seedpods and thus disperse seeds. Their natural habits can be used to advantage, to disperse seeds and encourage natural regeneration by growing plants that attract them, so they bring in more seeds.
Creating some thickets of dense, preferably thorny plants, provides a relatively safe haven
for many birds to nest in, and for various mammals, reptiles etc., (however dense thickets can also favour pests, such as rabbits, feral pigs and foxes in S. E. Australia). Choose indigenous plants, and some possibilities (depending on the location) include thorny Acacias, especially in Africa, Bursaria spinosa, Lycium ferocissimum, Grevillea rosmarinifolia, Hakea spp., Ulex europaeus, Rubus spp., some Ilex spp., Crataegus spp., Pyracantha spp., many plants in the Rosaceae family, some succulents (e.g. Aloe arborescens) including some cacti (e.g. Opuntia spp.), etc. Some of these are multi-purpose, and also attract wildlife with their flowers and fruits. The fruits or seeds of some of these could be dispersed by livestock and possibly by wildlife.
The “edge effect”
Where two or more habitats meet e.g. a grassland and a forest, a river and the sea, a forest and a lake etc., habitat is provided for animals that normally live in each of those habitats, as well as those that can only live where the two (or more) habitats meet, or prefer to live there.
It is advantageous to maximise the edge between the habitats. For example, instead of being circular, the edge of a lake surrounded by a forest, or a forest surrounded by a grassland, could be shaped more like a piece from a jigsaw puzzle, with a convoluted or wavy edge. The convoluted edge could itself also have a convoluted edge.
The “Oasis effect” – supply and demand
This is a common phenomenon, which for convenience I have termed the “Oasis effect”. It has probably been studied and already named, I am just not aware of an existing technical term.
In economics, if something is in oversupply, demand for it diminishes; and if something is in short supply, demand for it increases – it becomes more valuable. This appears to happen in nature too, in fact the words “ecology”, “ecosystems”, “economy” etc., derive from the Greek “Oikos” for a household budget.
In nature, an arid area is lacking in water, so an oasis, lake, waterhole, or swamp of water is valued and in high demand, by both plants and animals that need the water. The same applies to an island of land in the sea (for nesting seabirds for example), or an island in a lake or swamp, a grassy clearing in a forest, a patch of forest in a grassland, coral reefs and seamounts, rocky hills in otherwise flat country, etc.
There are many possibilities: an “oasis” could be an area of more or less saline water or soil, water of a different temperature, a mineral-rich patch of soil, or soil of a different PH, topographical variation with different aspects, and on a smaller scale, a tree hollow, a water-filled bromeliad, and so on.
A few personal experiences with the “Oasis effect”:
A lack of shelter/homes
In South Africa, I used to catch and keep snakes (mostly around Cape Town). I found a pond which seemed a likely habitat for water snakes Lycodonomorphus rufulus, but no logs or rocks under which one might find them and catch them. I placed a sheet of corrugated iron next to the pond, and came back a week later, and found seven water snakes under the sheet of corrugated iron!
A lack of nesting sites
In SE Australia I made some nesting boxes for birds, placed them in the trees, and the first birds were investigating them within 20 minutes.
A lack of perches (birds)
In SE Australia I made some tall wooden perches for birds and attached them to some fence posts in a largely treeless farming area. Numerous bird species used the perches, and deposited their droppings and seeds below the perches (part of the plan).
A lack of perches (dragonflies)
In North Queensland Australia, I placed some suitable perches for dragonflies on the bank of a lake where there were very few perches (just this last week). Guess how long it took for the quickest dragonfly to land on one of the perches – two seconds! (Orthetrum sabina). The second quickest was 20 seconds, and in 20 minutes, there were three species sharing one perch. Photos below:
Some wildlife species such as the birds and dragonflies below, must have open water.
Therefore, when undertaking revegetation/reforestation, providing habitats/vegetation
types/environments that are different to the dominant vegetation/environment in the area (or whatever is in short supply) is likely to be beneficial; for plants, animals and people.
These techniques (the “edge effect”, “oasis effect”, and “thickets”) can be combined – for example, a thorny thicket could be grown on a peninsula which juts out into a lake, with open grassland on the bank of the lake. This would result in an edge where water and thicket meet, another edge where water and grass meet, another edge where grass and thicket meet, and two areas where thicket, water and grass meet. In cooler climates, for example, a possible combination for a thorny thicket could be blackberries, or other Rubus spp., with an overstorey of Pyracantha and Ulex.
Bush Stone-curlews live and nest in open grassy areas. For them, an open area in a forest constitutes an “Oasis”.
Shelter, homes, and nesting sites in reforestation projects
Wildlife need shelter or protection from predation and weather extremes, places to sleep, and breeding or nesting and nursery sites.
Tree hollows: tree hollows can be a source of water, but are particularly important as nesting sites for some bird species, or simply shelter or homes for bats, reptiles, frogs etc. Some trees which form hollows include Eucalyptus platyphylla, E. camaldulensis, E. torelliana, E. tereticornis, mango trees, bamboo etc.
Hollow logs: important habitat/shelter on the forest floor, extending into the water on the banks of rivers and wetlands, and underwater.
Bromeliads, basket ferns and other epiphytes: some animals burrow into basket ferns (Drynaria rigidula) and similar plants (Australia), to live in the insulated centre of the fern. Bromeliads provide water and homes for frogs for example, in the otherwise relatively dry environment up in the trees of Central and South America.
Log and rock piles: if they are available, piles of rocks (or rock walls), logs (preferably hollow), bamboo, bark, branches, leaf litter or any combination of these will provide habitat in the form of homes, nesting sites, protection from predators and extremes of temperature, moisture/dryness etc., for many wildlife species.
Perennial tussock grasses: These include dense clumping, and hummock forming grasses, which provide a safe and protected, insulated microclimate within them for a multitude of reptile, amphibian, rodent, arthropod spp., and so on.
In the Great Victoria Desert of Western Australia, spinifex grasses provide an insulated habitat within them, and some lizard species are largely confined to this habitat, and some lizard species can only live on the edge of the grasses (and quickly disappear into the grass hummock if they feel threatened). The protection from predation and the elements provided by these hummock grasses is considered to be at least one of the factors, and perhaps the main factor, contributing to the fact that this area has the highest number of lizard species in the world (the largest population density of one species is apparently the Augrabies falls area in South Africa). Grasses also produce seeds, providing food for seed eating birds, small mammals, ants, etc. Some possible examples of “wildlife habitat” grasses:
Cortaderia spp. (Pampas grasses – an invasive weed in some areas), some Phalaris spp., some Pennisetum spp. and cultivars, Miscanthus x ‘giganteus’ and Miscanthus spp., some Carex spp., Themeda triandra, some Cymbopogon spp., Vetiveria, some Panicum spp., some Poa spp., Triodia spp., Restionaceae, etc. Also, there are plants other than grasses that provide a protected, insulated “mound”, e.g. in the Asteraceae family, such as Leucophyta brownii (prev. Calocephalus), and Santolina chamaecyparis.
A roof garden which happened by chance
Pioneer/colonising plants establish themselves, even on harsh sites. A small amount of leaf litter has collected on this roof, and birds have brought in and deposited seeds which have grown (Homalanthus novoguineensis, left, Pipturus argenteus, right) and sugar cane (background), which was probably thrown up there by someone who was eating it. From this it can be seen that making perches to bring in birds/fruitbats to deposit seeds, utilising livestock and wildlife to disperse seeds and soil improvers, and seedballs, can all be effective in establishing vegetation, even on harsh sites.
Reforestation project, Aeroglen quarry North Queensland, Australia
The following photos are of a reforestation project at Aeroglen quarry, Cairns, North Queensland, Australia. In 1996 I was in charge of a Landcare and Environment Action Program, training about 15 long-term unemployed young people. We built concrete steps up the side of a hill to provide easier access for rock climbers/abseilers (rapellers), planted trees, and built a gazebo. The site is relatively harsh with heavy clay subsoil and virtually no topsoil. The trees were mulched with woodchips, watered in well at planting, and not fertilized. They were also planted in the dry season (when the project happened) which is less than ideal. Survival and growth rates were still very good in spite of these drawbacks.
Poinciana tree, Delonix regia, self-seeded.
Terminalia sericocarpa, 16 year old tree, planted as a small potplant.
Umbrella tree, Schefflera actinophylla. This species attracts many wildlife species with its nectar (some species), followed by fruits (different species). The wildlife that it attracts may in turn bring in seeds of other species and be an aid to natural regeneration.
Eucalyptus torelliana, Cadagi gum, 16 years old, planted as a small potplant.
Noni tree Morinda citrifolia, amongst many other species, Aeroglen quarry revegetation project.
Grevillea baileyana. Reforestation project, Aeroglen quarry, Cairns.
Reforestation project, Aeroglen quarry – a wide variety of shrubs and trees.
Reforestation Around White Rock bridge, Cairns.
Some more trees:
http://reforestation.elti.org/ Tropical Native Species Reforestation Information Clearinghouse.
Buchanan, Robin A. 1989. Bush Regeneration: Recovering Australian Landscapes. TAFE NSW. ISBN 0 7240 7877 0.
Lindenmayer, David; Cunningham, Saul; Young, Andrew. (2012). Land use intensification: effects on agriculture, biodiversity and ecological processes. CSIRO Publishing. ISBN 9780643104075 (pbk). Pge. 107.
Richards, Paul W. (1998). The tropical rain forest: an ecological study. Cambridge University Press. ISBN 0 521 42194 2 (pbk). Page 109.
Ibid. Page 111.
Romanowski, Nick. 2005. Planting wetlands and dams: A practical guide to wetland design, construction and propagation. University of New South Wales Press ltd. ISBN 086840 608 2. Pg. 33.
Steinfeld D., Riley S., Wilkinson K., Landis D. L., Riley L. et al. (2007). Roadside Revegetation. An Integrated Approach to Establishing Native Plants. CTIP. http://www.nativerevegetation.org/learn/manual/ch_10_3.aspx#10_3_2/
Stork N. E. and Turton S. M. (Eds). Living in a dynamic tropical forest landscape. Blackwell Publishing. ISBN: 978-1-4051-5643-1.
Tucker, Nigel. Many excellent papers on revegetation e.g. “Restoration in North Queensland: recent advances in the science and practice of tropical rainforest restoration” in Stork and Turton above. Note that seed dispersal in rain forests in North Queensland is largely performed by birds, whereas mammals may play a relatively greater role in rain forests in Africa, Central and South America, and South-east Asia. The rain forests of Australia and Papua New Guinea are distinctively different, with, for example, the presence of the cassowary and the absence of monkeys and apes. Also, seed dispersal by animals generally, may well be less significant in other vegetation types in other climates.
Tucker, N. I. J. (2000). “Wildlife colonisation on restored tropical lands: what can it do, how can we hasten it and what can we expect?” http://www.forru.org/PDF_Files/frfwcpdf/part5/p52%20Tucker$20Wildlife%20colonisation.pdf
Tucker, N. I. and Murphy, T. M.(1997). “The effects of ecological rehabilitation on regeneration recruitment: Some observations from the Wet Tropics of North Queensland”. Forest Ecology and Management vol 99, issues 1-2, December 1997, pgs 133-152. http://www.sciencedirect.com/science/article/pii/s0378112797002004
Venning J. 1988. Growing trees: for farms, parks and roadside. Lothian. ISBN 08509 273 3.
White, E., Tucker, N., Myers, N., Wilson, J. (2004) “Seed dispersal to revegetated isolated rainforest patches in North Queensland”. Forest Ecology and Management vol 192, issues 2-3, 6 May 2004, pgs 409-426. http://www.Sciencedirect.com/science/article/pii/s03781127004000994
“It is a noble occupation to plant trees, you think of it many years after with content” Karen Blixen.
See the “Environment Posters” page for more posters.
Reforestation Methods at Reforestation.me