State Highway 38, Waiotapu
Ph (07) 366 1000
Fax (07) 366 6868

1 September 1997

Mr Lindsay Willis
13 Waters Street
PO Box 62

Wilco Spot Cultivator

To Whom it May Concern

Fletcher Challenge Forests New Zealand estate is located within the central North Island and comprises of 300,000 ha of plantation forest. The main species is Pinus radiata.

Annually we replant 11,000 ha of clearcut forest. One third of the area requires cultivation to alleviate subsurface compaction and to enhance microsite climate.

Up until 1994 all of this work was carried out suing continuous rip and mound units drawn by bulldozers. We now carry out 75% of our cultivation programme using the Spot Cultivation System.

The Spot Cultivation System arrived to meet a demand for a more consistent result than the continuous system could deliver. The main inhibitors of the continuous system being major soil destruction if blading was excessive, inability to cope with stumps without uprooting them, and inconsistent rip depth and mound height caused by slash and stump density.

The Spot Cultivation System easily achieves our prescribed requirements. Tests have verified consistent achievements of 95% or better compared to less than 50% by the continuous system.

Apart from the cultivation benefits, the spot treatment provides very accurate and extremely consistent spacing that the continuous treatment cannot achieve.

To date growth trials indicate superior survival growth and form on spot mounds compared to other alternatives.

Productivity and cost for spot work is comparable to continuous line treatment under our conditions. We plant 800 per ha on our best sites and 1200 per ha on our worst sites.

In summary, Fletcher Challenge Forests, Forest Operations Section for the Central North Island estate have identified the Spot Cultivation System as their best management practice for the cultivation of compacted clearcut sites. It provides maximum benefit for the least site impact and at a reasonable cost.

Your sincerely


Ron Reid
Forest Establishment Officer


PO Box 36
Ph (03) 204-8061
Fax (03) 204-8067

2 April 1997

Mr Lindsay Willis
13 Waters Street
PO Box 62

Wilco Spot Cultivator

To Whom it May Concern

Ernslaw One Limited is a forestry company based in Tapanui, West Otago (New Zealand).

For some time the company had a concern that our method of land preparation, which consisted of standard root-raking and windrowing logging slash, was not good enough. We knew that there had to be a better way to prepare clearfelled exotic logging areas for replanting.

We were already using a hydraulic excavator to carry out line-raking to remove slash which made the areas more accessible for planters, but our methods did nothing to assist in the establishment of new seedlings - we needed to cultivate the ground.

We knew that cultivation would provide all sorts of benefits like ease of planting, better survivals, better initial growth, etc. In June 1995 we commenced a preliminary investigation with regard to what was on the market what was available in cultivation equipment.

Sometime in late June or early July 1995 I saw an advertisment in a Forestry magazine showing what turned out to be a Wilco cultivator head. I could see that it was attached to an excavator boom, had very few moving parts and looked like it may be bulletproof. I thought at the time it was so simple it had to work. Often the best inventions are the simple ones.

Anyway, I made contact with the manufacturer Lindsay Willis. He suggested I get on a plane and fly up to Rotorua and he would take me out to Southern Kaingaroa to see one working. I took his advice and in late July 95 Lindsay met me at the motel and took me out to watch a Cat320 excavator spot mounding.

The machine was working on what was basically flat block which previously was P.nigra (Corsican pine) and had been burnt. There wasn t much slash on the ground but there were plenty of stumps.

The excavator was making easy work of ripping and pulling up a planting mound in the pumice soil. It was working 3 rows at a time and obviously the speed and success of the operation was dependent on a good competent operator. But I was sure the technique could be learnt in a few days or so.

I was impressed with its simplicity, versatility and robust construction. I was fairly sure that it would work in our situation. It would allow us to carry out a number of different land preparation functions with the same tool.

We wanted to make sure that it was going to perform in our heavy soils. Lindsay agreed to load a head on his truck and travel down from Rotorua with Danny, one of his operators, without any strings attached. We would purchase a head if we were happy with its performance. So in early August 95 Lindsay arrived in Tapanui with the cultivator head.

We trialed it over 2 days on new development and cut-over logging areas scheduled for restocking. We spot cultivated an area which was very heavy fresh logging slash. It was difficult to calculate a price for the job because the logging residue was very heavy and the operator was going through a learning curve. Danny, Lindsay s operator, said that it would take 2 weeks for a new operator to come up to full production.

The spot cultivated area was completed by the last week in September and planted immediately after. The results in the trial area have been spectacular, with excellent survival and tree growth and the added benefit of not having to spot release spray.

The Wilco spot cultivator design has been modified since we purchased our own, with a rock ripping nose and large wings being added to the ripping pick. We changed our own and have found that the modifications provide more lateral shatter and allow the shovels on the head to form up a well clutivated mound more easily.

Since the purchase of the head, we have used it extensively. It is a very versatile piece of equipment which is well suited to the preparation of logged sites for replanting. It is well constructed which means minimal maintenance (very few moving parts.) It is very versatile in that a number of operations can be performed with the same unit, ie. Ripping, mounding, windrowing or combinations of these can be undertaken.

Many of our sites were planted with minor species in the early 1900s. We now have to bust up the root mat and cultivate the compacted or wet sites. We now have no trouble getting full stocking in areas where previously we didn t.

Another positive in the use of this piece of equipment is the price from our point of view, nothing comes close. It is relatively cheap when compared to other cultivators which do a similar job.

Other forestry companies have seen the light down our way and are now using the Wilco spot cultivator head.

Your sincerely


Lance Freer
Planning Officer


PO Box 36-579, Parnell,
Auckland, N.Z.
Ph (09) 307 3841
Fax (07) 307 3842

17 November 1999


As a registered forest consultant operating throughout New Zealand, South East Asia and the Pacific over the past 37 years I have encountered numerous problems in planting a range of species in various soil conditions. Some examples of where the Wilco ripper mounder attachment has or is expected to be of great benefit to the plantation industry are given below:

1. Pinus radiata on clay soils
These include the compact clays of the Lower Northland (N.Z.) region where the Stoney Creek Forest Partnership of which I am a member, is now in its 7th year of felling our first crop of Radiata Pine and re-establishing the second. The difficult soils are damaged by the logging operations and we have encountered difficulties in successfully re-establishing sufficient trees to provide a fully stocked forest of good trees. This, in spite of very careful quality control standards being imposed on the contractors.

Beginning in 1999 we undertook a 100% coverage of our 1997/98 cut-over area using a Wilco ripper mounder. We are carefully monitoring the survival and the shoot/root growth development of the trees planted on the mounds. After 6 months we can report only an occasional death and excellent growth.

Apart from the rapid root development of roots in the mounds of topsoil we have already noted a further advantage which arises from having this new technique available. In earlier years we have planted immediately after felling. We now wait until the natural regeneration from the first crop and of gorse has struck (up to 18 months) before undertaking the Wilco operation. The ripping and mounding exposes most of the regeneration and weeds around the planting spot and eliminates the need for both ring spraying and regen. Thinning operations. As the planted trees have had an excellent start we do not expect to need to carry out any further releasing in later years. The savings in this regard will go a long way towards offsetting the cost of the ripping/mounding operation.

2. Redwoods and Eucalypt plantings on clay soils.
Plantings of both these types of trees have been very disappointing over the past 7 years when conventional planting methods have been used. However, after 12 months the success on mounds has been so good that we would no longer plant without carrying out this preparation.

3. Replanting former sugarcane fields with Eucalypts.
While not yet tested, I am convinced that the Wilco attachment will correct any problems associated with this operation in tropical climates.

After 100 years of use with constant working and in heavy rainfall areas, these soils can become impervious if a standard spade or tractor drawn ripper is used. The “smearing” of the face of the rip can inhibit the penetration of roots and slow tree growth.

In summary this environmentally-acceptable method of land preparation appears certain to become a standard tool for many users, being cost-effective and conducive of better tree growth.

Yours sincerely

John Groome
Groome Forestry Consulting Ltd