Site Preparation for Revegetation

Have you prepped your revegetation site? Site preparation is essential to any effective revegetation project.

Read on for a handy outline of some of the important things to know before you get started with your project.

Image: 2020 Revegetation Project at Laskey Plains

The following advice was prepared by Herbert Staubmann of Habitat Plants for the Landcare Tasmania Meander Valley Workshop.

Step 1: Planning

What is my vision and how am I going to get there?

Why am I growing trees? Is it for shelter, timber, biodiversity? This will impact some of the decisions you make.

What plants do I need? You want to choose the right species and quantity and order your seedlings a year ahead of your planting. It is important to get seedlings which are right for your region and site. Consider variations of topography, microclimate and soil, such as: low lying wet patches, flooding, frost hollows, waterlogging, cracking clay, dry sand / rocky knolls, exposed windy ridges etc.

It is beneficial to look at patches of remnant vegetation (native and exotic) nearby to get a 'feel' for what may grow on your site. But, be aware that soil and climatic conditions may have shifted too far to replicate what was once there (despite an existing remnant patch 'hanging in there'

How can I allocate my resources? What is the best use of time, money and human resources? Do I need a project manager? It is best to discuss certain decisions such as species selection with Landcare Tasmania, a local nursery or other specialist.

What is my capacity? Am I able to fence and control wildlife/stock? Am I able to effectively control the weeds on the property? What is my capacity for planting and erecting tree guards? Will I be able to maintain the trees?

Ideally, your site preparation will begin 12 months prior to your planned planting, usually the previous spring. Timing is important. The table below can help you plan a basic timetable for your project activities.

Image: Revegetation Projects: best practice guide for Tasmania by NRM North, Habitat Plants, Private Forests Tasmania, and the Aus Gov National Landcare Program

Step 2: Weed Control

Poor weed control accounts for most tree planting failures.

Pasture grasses are serious weeds that compete with tree establishment. This is due to competition for moisture, light and nutrients

Plants also release biochemicals which can result in a chemical warfare! Competing weeds can reduce early growth rates by 70% and decrease survival rates from an expected 90% to as little as 10%.

Do you want your seedlings to have a high chance of survival and fast growth? The answer is simple: weed control, weed control, weed control!

Each plant should have at least one square metre of clear ground, ideally 1.5-2 metre diameter to get a good start without competition. The aim of weed control is to remove competition and exhaust your weed seed bank - this is why we start at least the spring before planting. Woody weeds may need more work before planting.

You can smother grass by mulching with layers of cardboard and chipped wood, or black plastic, or a combination. Cardboard or black plastic needs to be put out and removed usually at least 2-3 times so that regrowth can occur and then be killed off. This will ensure that the seedbank is completely exhausted.

Use of herbicides is often favoured as a less labour intensive approach. Ensure you use as per label, and have the right chemical for the job. Correct timing is essential and an experienced and certified operator is recommended.

Step 3: Cultivation

Good cultivation for crops, pasture or vegetables is beneficial. Good cultivation can relieve compaction, improve aeration and improve water penetration and water holding capacity. An appropriately deep hole will allow plant roots to grow fast and deep.

"Don't plant a $2 tree in a 1 cent hole" - Herbert Staubmann, Habitat Plants

If you have used a herbicide, wait at least three weeks before preparing the soil.

Strips of plantings should be approximately 2.5m apart.

Typically, you will need a mattock, spade or ploughing machinery. Long strips of plants are usually best prepared with a mound plough or ripper. This can be followed on with a smudge to break up big lumps.

Sites that are difficult to access, have rocks or tree roots, are best prepared by loosening up the soil around each plant with a spade or mattock.

It is important to get soil conditions right - we don't want big air pockets left after ploughing and we want the soil structure intact.

Beyond site preparation

Step 4: Time to Plant

Most plantings will want to be in the ground in late winter/early spring. If there is warm weather in early autumn, and no threat from frost, April planting can be considered.

Make sure you have someone on your team who knows which plants are likely to grow where, and how to plant a plant and erect a guard properly! Give Habitat Plants' best practice guide for planting tubestock a read, found here.

Trees and shrubs should be planted 2-3 metres apart. Grasses and herbs can be clumped in between. It is sensible to plant grasses on the side of prevailing winds so that their seeds spread into the planting.

Weed mats and guards can do more harm than good, if not used properly. It is also essential to keep stock out of your plantings!

If you have prepared the planting site well, for example with a mound plough and smudge, then saplings can be planted really easily and in a short time with a Hamilton planter or Pottiputki!

Step 5: Maintain!

Image: She Oaks Hills Landcare

Make sure your hard work has not been wasted:

Inspect your plantings regularly
Maintain fences and tree guards
Help seedlings grow out of guards
Keep weed free!
Check for pests and diseases

NOTE: post planting weed control is difficult and time consuming!

Disclaimer: This guide is only a brief overview of revegetation techniques, and cannot replace the advice from an experienced person, who can assess site specific requirements. Consult Aboriginal Heritage Tasmania for a heritage assessment of your site. Depending on your site and size of the project, there may be regulatory requirements to comply with. Check with your local council and with the Forest Practices Authority.