Forestry and the environment
Reports on forestry and the environment, following 2017 Cyclone Cook slash investigation.
Design of Debris Slash Traps: Considerations for NZ Plantation Forestry Operating - April 2020.
Prof. Rien Visser and Campbell Harvey (Canterbury University)
Design of debris slash traps [PDF, 3.1 MB]
Best practices for reducing harvest residues and mitigating mobilisation of harvest residues in steepland plantation forests - July 2018
Rien Visser (Canterbury University)
This report outlines the ways in which forestry slash is generated and the various methods and techniques available in steepland forests to reduce the amount of slash produced and the risk of it being mobilised into streams.
Best practices for reducing harvesting residues [PDF, 3.7 MB]
A risk matrix for storm-initiated forestry related landslides and debris flows in the Gisborne region - February 2017
Chris Phillips, Michael Marden, Les Basher, Nick Spencer (Landcare Research)
A risk matrix designed to be used by forest land managers to assess the risks associated with storm-initiated landslides and debris flows within plantation forests.
Risk matrix for storm initiated forestry related landslides [PDF, 1.1 MB]
Storm-initiated debris flows and plantation forestry: protocols for monitoring & post storm data capture - 2016
Chris Phillips, Michael Marden, Les Basher, Nick Spencer
A discussion document outlining an appropriate set of fit-for-purpose data to evaluate the impacts of future storm-induced debris flow/landslide occurrences (hereafter referred to as events) related to forestry.
Storm-initiated debris flows and plantation forestry: protocols for monitoring [PDF, 707 KB]
Research and monitoring advice on environmental impacts of forestry in the Gisborne-East Coast region – February 2016
Chris Phillips, Les Basher, Michael Marden (Landcare Research)
This report was prepared by Landcare Research to provide input and advice to develop a 'research and investigation programme' to meet a range of council, community, Government and forestry needs.
Research and Monitoring Advice on Environmental Impacts of Forestry [PDF, 2.7 MB]
Cyclone Cook slash investigation
Plantation forestry is a significant land use in Tairawhiti, providing a number of environmental and economic benefits. However, there are also a number of associated issues particularly during the harvest and post-harvest period. A key issue and the one at focus in the report is slash mobilisation events after high intensity rain events.
Ex tropical Cyclone Cook struck Tairawhiti on 12 April 2017. The duration of peak rainfall intensities was a key driver during the event with rainfall of 80mm+ over 3 hours causing woody debris to mobilise. The area of maximum rainfall was in the headwaters of the Uawa and Waiapu catchments. The impacts of the storm were exacerbated by rainfall from Cyclone Debbie occurring just over a week earlier.
Cyclone Cook Slash Investigation Report [PDF, 14 MB]
Appendix A and B of the Report [PDF, 8.5 MB]
Appendices include helicopter flight photos and Tolaga Bay Slash Identification Guide
Limitations - this report compiles and analyses data acquired primarily by Gisborne District Council staff after Cyclone Cook. While it is as comprehensive as possible, resources did not allow to a helicopter overflight over the entire district. Nonetheless, the details obtained are considered to accurately reflect the impacts of Cyclone Cook.