Environmental impacts of harvesting forests

Permitted harvest activities

If you harvest more than 1 hectare you must comply with requirements of the National Environmental Standards for Commercial Forestry (NES-CF).

Red and orange zone activities

Orange zone (high risk) or red zone (very high risk) land is more likely to erode during and after harvest, particularly under high rainfall. This means extra care is required in planning your harvest and harvesting. You need to:

• ensure the land is stabilised after harvest
• monitor the land until vegetation is re-established.

If your land is in a red zone, you need resource consent to harvest. Some activities on orange zone land may also require consent, but even where an activity is permitted you must plan for and meet a range of conditions.

Contact your local council to find out your resource consent requirements.

Green and yellow zone activities

Green (low risk) and yellow (moderate risk) land is less likely to erode. Harvesting is a permitted activity in green and yellow zone land, but you must plan for and meet a range of conditions.

What you need to do

You need to:

• if you’re doing earthworks before harvesting, or as part of harvesting, tell your regional and district councils. You’ll need to prepare a forestry earthworks management plan to the requirements of Schedule 4 of the NES-CF
• notify your regional and district councils when you will start and end harvesting, and where the harvesting is happening
• prepare a harvest plan according to the requirements of Schedule 6 of the NES-CF
• consider how you will manage the environmental impacts of harvest.

Environmental impacts you need to think about

You need to consider how you will:

• protect freshwater such as rivers and wetlands by stopping sediment and slash reaching them and causing damage to the waterways, surrounding vegetation and coastal marine areas
• protect biodiversity such as nesting birds and any significant natural areas within or beside your forest
• minimise damage to vegetation outside the forest.

You will need to manage:

• earthworks, such as building tracks, roads and landings. These activities can cause erosion if not carefully planned, and any bare earth can result in sedimentation of waterways and must be carefully managed
• river crossings must be built to withstand flood conditions and to allow for fish passage. Erosion and sediment control are required in construction and during use.

Harvest management

During harvesting you need to protect the environment. For example, you must:

• fell away from waterways and significant natural areas
• extract logs without damaging waterways and significant natural areas
• manage slash.

Slash needs to be managed on the cutover (the harvested site) and landings to minimise erosion and sedimentation. It is important to prevent it getting into waterways and significant natural areas, and stop it causing a hazard for downstream infrastructure and communities.

Post-harvest management

Soil is most vulnerable to erosion for the period following harvest as the:

• tree canopy is no longer available to intercept rain
• tree roots will rot over several years. Until a new root system is established the slope will be less stable
• earthworks needed to construct roads, tracks and landings require soil exposure and can result in slope instability if not carefully constructed.

When the site is decommissioned you need to minimise erosion and sedimentation effects while new forest or vegetation is being established. This includes roads, tracks, landings, river crossings and the cutover.

Replanting

When you replant after harvest you can learn from any difficulties during the harvest. For example, if an area was difficult or unsafe to harvest it could be retired into permanent vegetation. Hazards and difficulties could be documented so a record is available when you plan the next harvest.

You must comply with conditions under the NES-CF if you are replanting. These include requirements for:

• setbacks to protect waterways and significant natural areas
• wilding tree risk control
• mechanical land preparation.

Forest practice guides

The Forest Owners Association's forest practice guides assist forest owners, managers and contractors to meet the legislative requirements of the Resource Management Act 1991 and the NES-PF.

The guides provide options and information on a range of practices and methods to manage the effects of forestry operations on the environment.

Changing land use after harvest

If you are not going to replant your forest, check with your local council if they have any land use requirements for your proposed land use. Some land uses will require resource consent.