When planning a restoration project, one of the first and most critical steps is determining how many plants are needed. The success of a project depends heavily on getting this calculation right. Planting too few may leave the area vulnerable to invasive species and erosion, while over-planting can unnecessarily inflate costs and require more labour than needed. Accurate calculations not only save resources but also optimise labour and ensure the long-term success of your restoration efforts.
This guide will walk you through three main restoration approaches, exploring how they influence plant numbers and the resources needed. Whether you’re restoring a degraded landscape, re-establishing native vegetation, or enhancing biodiversity, understanding these methods will help you effectively calculate how many plants you will need.
3 Main Restoration Approaches
We come across 3 main restoration approaches and the reason they relate to calculating plant needs is because each approach uses a different amount of nursery grown plants. So depending on what approach you take, will determine how many plants you will need.
- Plant everything
- Plant a bit, let birds, wind do the rest
- Fence off and leave it to nature
Approach 1: Plant Everything
This method involves planting nursery-grown plants densely across the entire area, leaving little to chance. It's often used for highly degraded sites where natural regeneration alone cannot establish a thriving ecosystem in a reasonable timeframe. This method is best for areas where rapid restoration is required, or where natural regeneration is unlikely to succeed, such as on exposed, degraded land with poor soil health.
Pros | Cons |
Fastest way to restore land: Planting everything gives you full canopy cover within a shorter period compared to other methods. This can be critical for projects where speed is a priority, such as erosion control, carbon sequestration, or biodiversity offsetting. | Most expensive approach: Planting at high densities requires a large number of nursery-grown plants, significantly increasing upfront costs. |
Greater control over species composition: You can choose specific plants to create a balanced ecosystem or prioritise certain species for ecological or aesthetic reasons. | Labour-intensive at the start: Establishing plants on such a scale requires considerable manpower for planting, irrigation, and initial care. |
Less maintenance in the long term: Once the plants establish, weed suppression and other maintenance requirements are significantly reduced due to dense vegetation. |
Approach 2: Plant Some, leave birds and wind to do the rest.
In this approach, nursery-grown plants are used to establish a starting point, with natural dispersal mechanisms like bird activity and wind carrying seeds to fill in the gaps. It's a middle-ground strategy, balancing cost, speed, and labour intensity. This approach works well for sites that already have some natural seed sources nearby or for projects with moderate budgets.
Pros | Cons |
Reasonably fast: While slower than planting everything, this approach still achieves canopy cover in a reasonable timeframe, particularly if bird-attractive species are used strategically. | Higher maintenance requirements: Without dense planting, weeds and grasses are more likely to compete with seedlings. Regular control measures are necessary during the early years. |
Cost-effective: Using fewer nursery-grown plants reduces the upfront costs of the project. | |
Approach 3: Fence off area, let it regenerate naturally.
This is the least interventionist approach, relying entirely on natural regeneration. Fencing off the area prevents livestock and other disturbances, allowing seeds from nearby native areas to regenerate the land naturally. This method is suitable for projects where time is not a constraint and where a hands-off approach aligns with conservation goals.
Pros | Cons |
Most natural method: Seeds from nearby trees and shrubs are distributed through bird droppings and wind, creating an ecosystem that reflects the surrounding environment. | Slowest method: It can take decades to achieve full canopy cover, especially in areas with poor seed dispersal. |
Minimal initial labour and cost: There’s no need for nursery-grown plants or extensive planting activities, reducing upfront costs significantly. | Proximity to mature native vegetation is essential: This approach only works if there’s a nearby seed source. |
Ongoing weed and grass control required: While fencing protects the area from livestock, weeds and non-native grasses may still hinder natural regeneration in the early years. |
Calculating Required Plant Numbers
The number of plants required varies greatly depending on the restoration approach and the specific goals of the project. Below are general guidelines for calculating plant numbers based on the three approaches.
Planting everything requires high-density planting to establish quick coverage.
- Cover crop species: Approximately 1,100 plants per hectare. These fast-growing species provide initial soil stabilisation, suppress weeds, and create favourable conditions for slower-growing native species.
- Infill plants: Around 500 plants per hectare. These species are added later to diversify the ecosystem and fill in gaps as the cover crop matures.
For example, if you’re restoring a 5-hectare site, you’d need 5,500 cover crop plants and 2,500 infill plants.
Approach 2: Plant Some, Let Birds and Wind Do the Rest
This approach requires significantly fewer plants, with an emphasis on species that attract birds or disperse seeds widely.
- Bird-attractive/cover crop species: Depending on the site, 300–500 plants per hectare may be sufficient to kick-start the natural regeneration process.
For instance, for a 10-hectare project using this approach, you might need between 3,000 and 5,000 plants, significantly reducing costs compared to the "plant everything" method.
Approach 3: Fence Off the Area and Let Nature Take Over
No nursery-grown plants are needed if the site is near an established native forest or bush area. Natural seed dispersal can provide sufficient regeneration over time. However, some sites may benefit from planting a handful of key species to accelerate the process or ensure biodiversity.
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Choosing the right restoration approach depends on your project’s goals, budget, and timeline. Whether you opt to plant everything, let birds and wind do the work, or allow nature to regenerate the area unaided, each method has its pros and cons. Accurately estimating plant numbers is a critical step in planning, ensuring efficient use of resources and the best possible outcome for the environment.
For further advice on restoration projects or to source eco-sourced native plants, contact our team at Riverside Horticulture—we’re here to help you bring your vision to life.