INFORMATION NOTE 2: SPECIES SELECTION
TREAT’s replanting and restoration efforts are focussed on the Atherton and Evelyn Tablelands, in the Wet Tropics of Far North Queensland. The predominant vegetation type here is rainforest, although there are also areas of wet sclerophyll and heath. These notes are written for restoration of rainforest habitat by TREAT members on the Tablelands.
For further information download: ‘Repairing the rainforest’ (2013) 2nd ed by S Goosem and N Tucker. WTMA & Biotropica.
The aim of rainforest restoration is to generate a forest that is self-sustaining, with intact ecological processes, and that creates a habitat for the organisms that naturally occur in the area. There is no single or simple technique to achieve this aim, not least because there is still so much that we don’t know, and because environmental factors are in a state of flux. However, there is much that TREAT/QPWS has discovered in its forty years of operation — things that work and things that don’t work.
What is certain is that you will need to start preparing before planting season — controlling weeds and preparing the site (see INFORMATION NOTE 1: SITE PREPARATION AND MAINTENANCE). A minimum of 18 – 24 months is need to source and grow tubestock. TREAT members can apply for up to 300 trees and applications should be submitted before the beginning of the wet season.
Seek guidance from TREAT, the TRC nursery or specialist consultants based on the Tablelands. Even if you have revegetation experience elsewhere, you will find that conditions here are different, and you will avoid the mistakes and frustrations experienced by others if you are open to local advice.
1. IDENTIFY REGIONAL ECOSYSTEM AND FOREST TYPE
It is important to choose only those species that occur in your area and forest type. Rainforest is not just rainforest! Different rainforest types (and different species) are found, depending on the altitude, rainfall and soil type.
If you are applying for trees from TREAT, QPWS staff will select appropriate species according to the information you have supplied on the application form.
You can work out your regional ecosystem by asking TREAT nursery staff, from a map (<link>) or by referring to <link>. The most common regional ecosystems catered for at the TREAT nursery are in Group 7, described as moist (rainfall 1600 - 2000 mm) highlands and uplands (altitude > 400 m) on basalt.
Simple-complex mesophyll to notophyll vine forest on moderate to poorly-drained alluvial plains of moderate fertility
Complex mesophyll vine forest. Lowlands and foothills, on krasnozem soils derived from basalts and basic volcanic parent material. Very wet and wet rainfall zone.
Complex mesophyll vine forest. Ridgelines and exposed areas may support stunted, wind-sheared notophyll vine forest. High rainfall, cloudy uplands on basaltic krasnozem and euchrozems.
Mabi Forest (Endangered) Complex semi-evergreen notophyll vine forest. Uplands on basaltic krasnozems, euchrozem-krasnozems and prairie soil types.
Simple to complex notophyll vine forest. Uplands and highlands on basaltic krasnozems, of the cloudy wet rainfall zone.
2. IDENTIFY SPECIES IN YOUR REGIONAL ECOSYSTEM
Each regional ecosystem has its own characteristic species, with a few species common to more than one. Make a list of the more common species found in your regional ecosystem. These are the species you should plant. The next stage will be to find seed from these species in your area. Plants grown from these seed will do better because they are adapted to local conditions.
3. MATCH SPECIES TO ENVIRONMENTAL CONDITIONS
Different species have different growing requirements. Pioneer species are those that grow fast and provide canopy cover earlier. They can cope with the open paddock situation of a new planting — with wind, high light levels and moisture stress. They grow fast but are also short lived. They help ameliorate the environment for other species, fruit earlier and die younger, providing woody debris that is essential for healthy forest development. However, higher proportions of pioneer species can slow down restoration and achieving biodiversity. TREAT has found that 10 – 15 % pioneer species works well on the Tablelands.
Some species are useful to plant along the edge, helping to ‘seal’ it against weed incursion. Some are more useful in erosion gullies, others in waterlogged areas. Figs are particularly palatable to pademelons, and will need to be protected. Other species need to be protected against frost. Some species do not do well in an open paddock planting and are best added later in an infill planting. Only certain species are able to compete when planted adjacent to existing forest.
4. FiND OUT MORE ABOUT YOUR TARGET SPECIES
Rainforest is very diverse — this means that the species list for your area will be long. It may be more efficient to narrow down the list, and learn to identify a smaller number of species. Target species that reliably produce viable seed, are easy to grow and survive well in restoration plantings. Choose species that are hardy — for wind, sun, frost or inundation depending on your site conditions. Less resilient species add diversity but may not survive —requiring in-fill planting.
The number of species you should plant is determined by the site’s distance from existing forest or regrowth — if it’s close enough, birds and flying foxes will carry in seed. That said, aim for some diversity. Trees (such as figs) that grow fast and produce copious fruit that brings in seed-dispersing birds and flying foxes will also assist in increasing the diversity of the forest. These are sometimes referred to as ‘keystone species’. Vines and shrubs are not usually included in restoration plantings because vines will smother young trees and shrubs require some shade.
Examples of target species — resilient and easy to grow
Ficus (especially Ficus obliqua)
fruits when young
grows very fast
small fruit eaten by everybody
grows very fast
small fruit eaten by everybody
Edge species are those such as Alstonia scholaris, Atractocarpus fitzalanii or Melicope rubra that retain lower branches, thus helping to exclude weeds but which can withstand drying winds and sun exposure. ‘Repairing the Rainforest’ suggests more edge species.
Suitable species for riparian zones include Agathis robusta, Syzygium australe, Ficus congesta and Melaleuca viridiflora. QPWS can advise further.
W & W Cooper (2004) ‘Fruits of the Australian Tropical Rainforest’ Nukomis Editions, Melbourne.
Repairing the rainforest
TREAT fruit collection diary published in each newsletter.