Planting trees is not equal to improving biodiversity

We hear a lot about large tree planting projects these days, and while we love trees and we’re always cheering on scale, there is an enormous misconception that planting trees is equal to improving #biodiversity.

In fact, some tree planting projects are #ecological ‘traps’, where animals are lured into #revegated areas because they seem advantageous, but ultimately harm them in the long term.

We want people to keep planting trees, but we also want to bust the myth that you'll always get a big biodiversity benefit. Here's why:

1. Shout out for the understorey: We LOVE trees and we understand how important they are.  But often the greatest diversity is in the grasses, flowers and shrubs of understorey plantings.  This is also where loads of Australian insects and animals live, so if you only plant trees you’ll have much poorer biodiversity outcomes than restoring a complexity of species.

2. Go with the flow: If you plant trees without restoring the processes that trigger their recruitment cycle, such as floods, cultural burns or animal species, the trees might look good for a while but they won’t have the capacity to replace themselves over time.  When this happens, you are likely to find yourself in the very expensive cycle of replanting rather than regeneration, and you’ll ultimately lose the species that depend on these plantings for their survival.

3. How far apart you plant trees matters for the movement of plants and animals, and ultimately the biodiversity benefit you'll receive. Animals need different planting densities or ‘patchiness’ for movement, nesting and accessing food resources.  Depending on the types of species living in the landscape, you need to change the spacings of the plants so animals can easily and safely get around and hide from predators.

4. Trees don’t belong everywhere, and when they are planted in the wrong places they can reduce biodiversity.  We’re looking at you, grasslands, wildflower meadows and herbfields.

So what should we be doing instead? If you’re investing in a biodiversity project, complexity in planting design and delivery is your friend.  It might cost more up front, but it will likely save you a lot of money in the long term through reduced interventions, and is likely to have a much better biodiversity outcome.