Workshop Report: Poplar and willow planting for Land Overlay 3A, Gisborne, East Coast region
Why there was a need for this workshop
The workshop was designed to bring current practitioners, with significant experience in soil conservation and forestry practices, together with scientists knowledgeable in the causes and solutions for erosion types typical of this region, to explore whether a consensus could be reached on the process of selecting the most effective and practical erosion control solution for different types of erosion feature.
Irrespective of tree species, close-planted stands of forest and space planted poles (poplar and willow species) are both useful erosion control options with their own strengths and weaknesses and when applied in appropriate situations, established correctly and maintained1, each treatment can be as equally effective as the other. However, there is no clear cut process for deciding which treatment or combination of treatments is the most appropriate for all situations likely to be encountered in the field.
One of the earliest decisions to be made is whether the current land use in the immediate vicinity of each erosion feature is appropriate and viable in the long-term or if genuine land use change through conversion to forest/retirement would be a more sustainable option.
There are a host of economic and social factors that can influence the landowner’s choice of treatment and often these will override the most appropriate “one off” treatment option based on the physical evidence at sites requiring erosion control. Historically, the ultimate decision on whether, what and where to plant has rested with the landowner. Much unplanted land has remained so because the most feasible option has not been acceptable to landowners.
Furthermore, for each of the erosion types being considered there is a continuum of size of feature, degree of current activity, slope and specific site criteria that ultimately needs to be factored into deciding the most appropriate treatment. Though generally backed with experience, scientific studies and training, the selection of a treatment for a particular location is often partially subjective and tempered by successes and failures.
The unique combination of the ECFP incentive and RMA rule ensure only effective soil conservation solutions will be promoted to the landowner. There will be no scope for partial implementation, inadequate maintenance or doing nothing (unless nothing is physically the only option, for example, vertical river gorges and much of class eight mountain land identified at a property scale).
That is not to say landowners will have little input. On the contrary, it is essential that proffered solutions are able to accommodate landowner’s desires where effectiveness is not unduly compromised and solutions become accepted. A regulation that does not have the vast majority of its community (in this case farming community) behind it is doomed to failure.
The aim of the workshop was to develop of a set of written guidelines outlining specifications for the treatment of eroding areas where poplar/willow pole planting could result in a successful erosion control outcome. Discussions at this workshop focused on the appropriateness of poplar and willow regimes on Land Overlay 3A.
Land Overlay 3A is classed as the worst eroding land in the Gisborne District and comprises land defined in the text descriptions of Land Use Capability Units (1st ed. NZLRI) VIIe12–16,18 and 20, VIIIe 1–6; and (2nd ed. NZLRI) VIIe18–19, VIIe21–25, and VIIIe2–9.
The key elements of the workshop were:
- a field visit where participants could view a range of erosion forms falling within Land Overlay 3A;
- a desktop exercise that required participants to prescribe treatment options for 11 gullies, 10 earthflows and 6 slip/slump complexes depicted on aerial and oblique photographs and a 3D digital elevation image of each site.
1 It should be noted the notified rule on the District Plan and the modified ECFP include a maintenance requirement.
Contact for Enquiries
East Coast Forestry Project
Ministry of Agriculture and Forestry
Cnr Grey St & Childers Rd
1st Floor ZGFM Building
PO Box 2122
Gisborne 4040
Tel: +64 6 986 8691
Fax: +64 6 986 8697
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