This winter, Council has been busy in the Maitai and Marsden valleys, tackling erosion and protecting waterways through large-scale restoration planting.

Contractors have made the most of good weather to plant 35,350 trees in Marsden Valley and 38,600 in the Maitai. Around 80% are natives, including tōtara, kānuka and manuka, with fast-rooting exotics added to speed up slope stabilisation.

“As these trees mature, their roots will bind and stabilise fragile hillslopes, and their foliage will act like an umbrella protecting erodible soils during heavy rain events,” says Forestry Systems Manager, James Griffiths.

“Trees aren’t the only line of defence. Deep-rooted grass species are being hydroseeded by helicopter to hold topsoil in place on slips, and we are spreading fast-growing shrubs and groundcover across bare slopes to further increase slope stability and reduce erosion.”

“In time, newly established forests will act like a living shield, reducing the likelihood of slope failure and sedimentation rates.”

Glider Road Closure

A recent geotechnical report has confirmed ongoing concerns about Glider Road in the Marsden Valley and indicates that the area continues to be vulnerable to slope instability. The report also highlights the hazard posed by frequent rockfall events to road users.

Restoring the road to a safe standard would require significant investment—estimated at up to $1.7 million for reinstatement and around $150,000 per year in maintenance. To manage both safety risks and costs, Council will keep the road closed for the foreseeable future while recent extensive plantings take root and stabilise the slopes. An extended closure is anticipated and could be up to 5 years, with re-assessment taking place regularly.

In the meantime, we're pleased to note that walkers and cyclists have several great alternative options in the area, including the Involution and Scout tracks, as well as the Marsden Valley Walkway. There's also convenient nearby access through the Silvan Forest Mountain Bike Park for walking and cycling (www.silvanforest.co.nz/mtb-park).

What’s Next

Further planting is planned next winter, along with continued monitoring of soil stability, plant health, and stream conditions. Animal pest control will also be undertaken periodically to protect new plantings from browse. The long-term vision for these valleys is to create permanently forested, biodiversity-rich landscapes that provide safe, scenic walking and cycling access that forms a beautiful natural backdrop to Nelson. Community drop-in sessions in Marsden this month will share progress and invite feedback.