Started in 1998, Project Hindmarsh is the longest tree planting event in Australia.

About 13,000 trees were planted on Saturday.

Hindmarsh Landcare co-ordinator Jonathan Starks said 37 different species of plants were planted, with a focus on four local threatened species.

"We planted bulte, umbrella wattle, hairy-pipe wattle, gerang gerung wattle which is only found in Gerang Gerung in the Wimmera," he said.

Mr Starks said the event was a "big engagement of local communities" sharing the aim of restoring the environment..

"It is making a real difference to the land and the environment by associating with our long term view of biolink between Big Desert and the Little Desert in Western Victoria," he said.

Mr Starks said the event was "thoroughly successful" with volunteers travelling from Melbourne to be part of the annual event.

Meanwhile, Hindmarsh Landcare Network is working with Parks Victoria on a new three year biodiversity project.

The project will aim to re-vegetate 200 hectares of woodland along the Wimmera River, between Lochiel and Lake Hindmarsh.

The initiative aims to work with private landholders, regional government agencies, and traditional owners.

Mr Starks said Hindmarsh Landcare was seeking expressions from landholders along the river.

"As an incentive, we are offering funds to fence off their limits, if they want to fence off grazing," he said.

Mr Starks said the sites selected for the project will be used for Project Hindmarsh in 2020.

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