Some aspects of natural revegetation in southern New Zealand : In partial fulfilment of the National Diploma in Horticulture of the Royal New Zealand Institute of Horticulture

In partial fulfilment of the National Diploma in Horticulture of the Royal New Zealand Institute of Horticulture.

The past and present awareness of a decline in the extent and quality of New Zealand's native flora and fauna has resulted in a proliferation of reserves, National Parks and Forest Parks. The aim of these is to preserve in perpetuity their natural features, while generally making them accessible to the public. The management of reserves and National Parks to conform with these aims is not always without conflict. Public use can cause destruction of the vegetation on a large scale especially when roading is involved. Occasionally mining, tourism, and recreation can have similar devastating effects. Where damage to the natural environment has been done, or is intended, allowances in project costs are usually made to repair damage in keeping with the natural setting. In these endeavours horticulturists are frequently expected to play a role, usually involving the production and planting of plants. Their ability to do this is usually adequate, but difficulties sometime arise in decisions on what species to grow, how many, and where to plant them. Often their directives define some vague natural order, and to clarify this some definite planning system is needed. In the multi-discipline planning team approach which is often the case, well defined and justified plans must be proposed. In order to conform with nature, nature must be used as a guide. Planning of repairs, especially revegetation, must be based on careful observation of nature so that appropriate species, locations and densities can be determined. To expect clear answers using the complexity of natural vegetation as a guide is unrealistic, but this does not give a licence to dispense entirely with nature-based planning. A reasoned approximation must be made to conform with nature and thus enable a long term plan to be written which will help bridge staff changes, aid informed comment and pooling of knowledge, and give environmental pressure groups definite proposals on which to base their follow-up watch-dog functions. In this study an attempt will be made to examine revegetation planning using naturally occuring vegetation as a model. By using existing ecological studies some planning possibilities will be presented. The validity of some proposals could be debated but they are offered as starting points in situations where few alternatives exist. Short trials were conducted to investigate some practical possibilities and these are reported in Chapter IV. Some past attempts at natural revegetation are described to illustrate other potential methods. Examples have been restricted to southern South Island forests in an effort to restrict this topic to manageable proportions.