1. The Solution to the Willow Problem
"The Longstem Story"
In the 1950s when the seriousness of the damage to our river systems first became properly understood by authorities, funding was initiated to carry out urgently needed engineering and riparian revegetation work. These initiatives have become ongoing programs of repair and restoration.
Although native trees were used in the revegetation of the stream environs, greater use was made of the willow because it lent itself to deep planting as a hardwood cutting. The willow was capable of fast growth and had strong resistance to wash away in flood conditions as a result of the deep planting of the cuttings.
Although the Willow was particularly effective in stabilising the stream banks, it ran counter to the desirability to restore the natural native stream bank ecology which had been destroyed in earlier clearing of trees and under-story plants along our rivers and streams.
The desire to find an alternative to the willow, initially because it was environmentally out of place and ecologically damaging, has been heightened in recent years by the increasing trend for willows to extensively self propagate in stream beds from the germination of seed . In some river systems this has reached serious proportions and the enormous willow population is threatening the integrity of the river channels.
As a result of this problem many willow species are now being declared noxious and are therefore no longer an option, even if their violation of the ecology could be tolerated.
At the National Stream Management Conference, it was conclusively adopted by river management authorities from across Australia, that willows should no longer be considered as a tool in stream management programs.
2. Difficulties Lead to the Solution for the Willow Problem
It is not possible to plant Australian native trees as large hardwood cuttings. Historically, when native trees were used in riparian revegetation programs, it was generally carried out using tubestock, i.e. plants grown for about six to seven months in 50mm x 130mm plastic forestry tubes. These trees when planted out would be in the order of fifteen centimetres long.
However experience had shown that tubestock is vulnerable to washaway from floods and also subject to heavy losses as a result of drying out in hot dry periods. This then created a serious dilemma, how to reliably replace willow plantings with appropriate native species.
The answer turned out to be LONGSTEM NATIVE TUBESTOCK, a new and innovative method of growing native trees to replicate all the advantages previously attributed only to willows.
3. Overturning Established Concepts
Over a number of years, Bill Hicks, an electrical engineer, with a lifelong interest in the ecology and in the propagation of Australian native plants, had been independently working on developing a system of growing and planting native trees which would replicate all the favourable characteristics of willows, particularly the ability to be deeply planted in riparian environments.
Longstem tubestock is a tree, or under-story shrub, grown in the same standard 50mm square tree tube used in the growing of standard tubestock. But in the case of Longstem tubestock the plant is grown to a length similar to that of an average willow cutting, a length of one metre or more. Being developed within the dimensions of the 50mm tube, the plant root-ball is small enough to be inserted into a deep hole not dissimilar to that provided for the deep planting of a willow cutting. About three quarters of the length of the plant is placed below the soil surface.
In achieving this result two traditional horticultural
principles have been overturned.
Both of these assertions have been proven incorrect by the Longstem system developed by Bill Hicks. By developing a special fertiliser regime with particular emphasis on trace elements the Longstem plants grow to the required size within the small container with an ideal, undistorted, root structure. Additionally the deeply immersed plant stems are totally unaffected by the deep planting.
Becoming aware of the Longstem system, the Hunter Catchment Management Trust and the Department of Land and Water Conservation in the Hunter Region, decided to adopt the technology for their major revegetation programs in the Hunter valley.
4. Success and Advantages of the New Method
Over the past few years tens of thousands of Longstem trees have been planted along the Hunter River and its subsidiaries. These plantings have achieved outstanding results in growth and reliability and of course have set in train the restoration of the original native ecology throughout the Hunter. Following the success in the Hunter region, Longstem tubestock is now being used in many other areas throughout Australia.
Although the Longstem system was proposed as a means of achieving the same deep anchorage as the willow, a number of additional advantages have been observed. The deep immersion of the root ball has the effect of placing the root structure below the hot, dry strata in the immediate surface area of the soil, a condition which is damaging to surface planted standard tubestock.
It also protects the root structure from the frosty, sometimes frozen surface soil, in winter. It is very often the freezing of the root that causes the plant to die, rather than the freezing of the plant superstructure. The protection of the root system enables the plant to re-shoot when the growing season re-commences.
The deep immersion also places the root system below the area of weed competition and allows accelerated growth compared with the alternative planting procedures.
Longstems are now also being used for arid region plantings and for use in re-vegetation of areas affected by a high level of salinity and are also used in rainforests plantings and Sand dune restoration. Although developed using Australian native plants, the Longstem technology is equally applicable to plants from other regions and it is now being used areas outside of Australia.
However the most immediate outcome of the Longstem technology is that there need never be another willow planted along Australias river system.
Root inspection example Eucalyptus
Top tie shows level of soil when planted.
Bottom tie shows level of soil when plant was in the pot.
Original roots in the pot extend to form the tap root system while the stem form the main adventitious roots.
5. Successes With Different Soil Types.
The use of Longstem Native Tubestock in the re-vegetation of areas subject to high salinity is now being closely examined as a means of achieving more effective results in these programs.
The significant loss of plants used in salinity re-vegetation projects using conventional tubestock techniques has been very disappointing. These losses have been generally due to the hot salt crust destroying the shallow planted root structure of the standard tubestock plants.
The use of deep planted Longstem Tubestock removes the root ball from the hostile, hot, crusty surface environment and places the roots in a cooler sometimes moist situation sixty to ninety centimetres below the surface.
6. New Concept Still Holds True
Two long held horticultural principles have been overturned. Firstly that plants must never be planted more deeply than the soil surface level of the container in which they are growing otherwise they would be subjected to fungal diseases of the submerged stem. Secondly, that large plants could not be grown in small containers without causing permanent damage to the plants root system and thus inhibiting its future healthy growth.
The reversal of both of these principals were, however, necessary to achieve the requirements for willow replication. After some years of trials with deep planting, this long accepted principal of tissue disease proved to be simply not correct and in fact Longstem plants, deeply planted, not only survived, but progressed far more satisfactorily than conventional surface planted standard tubestock.
The ability to achieve a healthy plant grown to about a metre in length in a container of very limited size without root damage was achieved through the development of special fertiliser regime which enabled the plant to achieve this substantial size without the need for significant root development.
There are now close to two hundred thousand Longstem Native Tubestock plants growing across Australia in riparian revegetation programs. Their survival success has been outstanding and growth rates have significantly outstripped standard tubestock. In many areas the use of Longstem plants has now entirely superseded conventional surface planted tubestock.
The Longstem system was originally developed to use deep planting as a mechanism to ensure survival against wash-away in riparian environments. It has since been shown that deep planting can be even more important in non-riparian situations. By having the plant root placed in a deeper, less hostile environment than the immediate top few centimetres in dry situations the survival rate is dramatically improved.
Following its successful use in arid conditions, it became obvious that this same deep planting technique could have benefit in overcoming problems being experienced in re-vegetation programs in areas of high salinity. These problems arise from the impact of the hot crusty surface soil on the plants sensitive root ball when surface planted.
The feeling was that deep planting would place the root ball in a more benign soil structure with minimum damage to the plant in its early growing period. It must be emphasised that the trees and shrubs being planted must be salt tolerant species capable of sustaining growth in the saline soil conditions.
7. Successful Results of Species Tested
A number of limited test plantings were carried out and results were most encouraging. As a result of these successes, a dry land saline affected area in the Upper Hunter Valley was planted progressively with 2500 salt tolerant trees in late 2001. The survival success and growth rates have both been outstanding and seems to confirm that this will be a major application of plants grown and planted employing the Longstem Tubestock system.
It should be emphasised that these trees have not only survived a period of record drought and above average maximum temperatures, but also frosts which were the worst in living memory. This is of course in addition to surviving the saline environment on their sensitive young root system. Species included in initial testing projects and in the Upper Hunter Project include Eucalyptus robusta, E. camaldulensis (three salt tolerant provenances), E. botrioides, E. tereticornis; Melaleuca styphelioides, M. liliariifolia, M. quinquinerva, M. bracteata, M. nodosa; Acacia binerva, A. saligna; Casuarina glauca, Casuarina cunninghamiana (seed collected from saline tidal margins).
These species were selected purely to prove the effectiveness of Longstem Tubestock for this application and were not especially chosen to preserve site bio-diversity. The selection of species for saline revegetation would depend upon the local situation and available tree and understorey varieties which were known to have salt tolerance.
Re-afforestation trials at Katandra Reserve, on the Central Coast, using rainforest species have proved to be successful. See Trial Reports in "Katandra" section of this website.
Trials that are being carried out on the sand dunes at Copacabana and Patonga Beaches have shown pleasing results with the trial species; Acacia sophorae var. sophorae and Banksia integrifolia producing adventatious roots.
Experience in growing and planting Longstem Native Tubestock over a number of years has shown that most, if not all, native species will effectively grow as longstem and subsequently prosper when deep planted. This ensures that the use of Longstems grown from seed appropriate to the area will provide the opportunity to use this technique universally for saline affected re-vegetation programs and is not location or species specific.
Trials carried out at Katandra Reserve using rainforest species have proved to be successful. (See Trial Reports in "Katandra" section of this website)
8. Technique for Using Longstem In Riparian Projects
One successful method has been the use of lancing jets. However in other areas petrol driven augers and even a hand drill have been equally successful in the drilling of holes.
See the pictures below showing alternate or smaller scale methods.
It might be best to consider which drilling processes suit the particular site best. Consideration would be in the size of the project, costs and personnel involved as well as the type of soils and water supply. These last thoughts are now most important as the concept of longstem planting has now broadened beyond the original "Willow Problem"
Water Lancing Jet Use
Alternate Successful Drilling Methods
Petrol Driven Auger
Note the depth to which the Longstem Plant is buried.
9. Longstem Native Tubestock Fertilising procedure