VitaminAir

Rewilding · Planting pilot

VitaminAir Forest Restoration Pilot

Testing planting density to understand forest growth, survival, and fire resilience.

VitaminAir is testing three planting densities on approximately one hectare of land. The goal is to understand how different densities affect tree survival, growth, canopy development, ground vegetation, and the long-term cost of restoring a diverse native forest.

  1. Plot A20,000trees/ha
  2. Plot B30,000trees/ha
  3. Plot C40,000trees/ha
Pilot land
approximately 1 hectare
Saplings
20,000
Assumed sapling price
US$1 each (saplings may be free)
Initial sapling budget
US$20,000 (sapling purchase only)

Planned trial This is a plan. Nothing on this page has been planted yet.

The planting layout

A conceptual way to divide about one hectare: three equal strips on two thirds of it, and the rest kept for firebreaks, tracks and access.

Conceptual layout of the planting pilot A square site of about 100 m by 100 m. Three strip plots, A, B and C, each 26.7 m wide and 83.3 m long, stand side by side at 20,000, 30,000, 40,000 saplings per hectare. A 5 m firebreak and buffer runs round the edge, 5 m access tracks run between the plots, and an access strip runs along one end. A 20,000/ha 4,444 B 30,000/ha 6,667 C 40,000/ha 8,889 5 m buffer and firebreak Access strip 26.7 m 83.3 m ≈100 m No compass: the orientation is not known.
Conceptual drawing, not a surveyed site plan. It assumes a square 100 m × 100 m site. The real boundary, slope, drainage, access and fire risk will set the final layout. Each dot in a plot stands for one sapling, in the row layout shown under “Marking out the plots”.

  1. Plot A

    Density
    20,000 trees/ha
    Area
    0.2222 ha · 2,222 m²
    Size
    26.7 m × 83.3 m
    Saplings
    4,444
    Spacing
    0.71 m

  2. Plot B

    Density
    30,000 trees/ha
    Area
    0.2222 ha · 2,222 m²
    Size
    26.7 m × 83.3 m
    Saplings
    6,667
    Spacing
    0.58 m

  3. Plot C

    Density
    40,000 trees/ha
    Area
    0.2222 ha · 2,222 m²
    Size
    26.7 m × 83.3 m
    Saplings
    8,889
    Spacing
    0.50 m

  4. Remaining land

    About 0.33 ha: a 5 m firebreak and buffer around the edge, 5 m tracks between the plots, and an access strip along one end. Not counted as planting land. A reference area left to regenerate on its own would need to sit outside this hectare.

Three plots · about 0.67 ha · 20,000 saplings

Three densities, side by side

Most dense native plantings use two to five saplings per square metre. We want to see, on our own soil and through our own dry seasons, what changes between two, three and four.

MeasurePlot A · 20,000/haPlot B · 30,000/haPlot C · 40,000/ha
Trees per m²234
Approximate square spacing0.71 m0.58 m0.50 m
Field layoutRows 0.50 m, trees 1.00 m, shiftedRows 0.50 m, trees 0.67 m, shiftedGrid 0.50 m × 0.50 m
Pilot plot area2,222 m² (0.2222 ha)2,222 m² (0.2222 ha)2,222 m² (0.2222 ha)
Saplings allocated4,4446,6678,889
Sapling purchase cost$4,444$6,667$8,889

What we think may happen

These are ideas to test, not results.

  • Denser planting may push trees to compete and grow upward faster.
  • Faster canopy may shade out grasses and other competing plants.
  • Less dry grass may, in time, mean less fine fuel to carry a fire.
  • Thinning may give us healthy young trees to move to other cleared areas.
  • Higher density also means more competition for water, nutrients and space. More saplings may die, and each plot costs more to plant.

Marking out the plots

Trees per square metre is an average across the plot, not a number of trees around each square. A tree standing on a corner is shared by the four squares that meet there. The drawings show a corner of each plot, to scale, with every distance the team needs.

Plot A: a 3 m by 2.5 m corner patch with rows every 0.50 m and trees every 1.00 m in a row, every second row shifted 0.50 m. A 1 m² box holds 2 trees. Corner Plot edge Plot edge 1.00 m 0.50 m shift 0.50 m 0.71 m 1 m² = 2 trees
Plot A · 2 per m²The same as a 1 m grid with one extra tree in the centre of every square.
Rows every
0.50 m
Trees every
1.00 m
Shift every 2nd row
0.50 m
Whole plot
167 rows × 27 = 4,509, planned 4,444
Plot B: a 3 m by 2.5 m corner patch with rows every 0.50 m and trees every 0.67 m in a row, every second row shifted 0.33 m. A 1 m² box holds 3 trees. Corner Plot edge Plot edge 0.67 m 0.50 m shift 0.33 m 0.60 m 1 m² = 3 trees
Plot B · 3 per m²
Rows every
0.50 m
Trees every
0.67 m
Shift every 2nd row
0.33 m
Whole plot
167 rows × 41 and 40 = 6,764, planned 6,667
Plot C: a 3 m by 2.5 m corner patch with rows every 0.50 m and trees every 0.50 m in a row. A 1 m² box holds 4 trees. Corner Plot edge Plot edge 0.50 m 0.50 m 1 m² = 4 trees
Plot C · 4 per m²A plain 0.5 m × 0.5 m grid.
Rows every
0.50 m
Trees every
0.50 m
Shift every 2nd row
none
Whole plot
167 rows × 54 = 9,018, planned 8,889
Whole plotPlot A · 20,000/haPlot B · 30,000/haPlot C · 40,000/ha
Rows167167167
Trees per row2741 / 4054
Trees if the whole plot is filled4,5096,7649,018
Planned4,4446,6678,889

Filling each whole plot this way takes about 1.5% more trees than planned (20,291 instead of 20,000), because the first row and first tree sit on the edge. Either order about 1.5% more, or leave the last row of each plot short. Decide before ordering. Count each row as it is planted and write down the real number.

Step by step

  1. Peg the four corners of each 26.7 m × 83.3 m plot. Check it is square: both diagonals should measure 87.5 m.
  2. Along both long edges, put a peg every 0.50 m. Each peg pair is one row.
  3. Stretch a string across the plot between the first pair of pegs. Mark it at the tree spacing: every 1.00 m in Plot A, 0.67 m in Plot B, 0.50 m in Plot C.
  4. Plant at each mark, starting on the corner.
  5. Move the string to the next pair of pegs. In Plots A and B, start every second row shifted: 0.50 m in A, 0.33 m in B. Plot C is not shifted.
  6. Count the trees in each row as they go in, and write the number down.

Tools: a 100 m tape (or a 50 m tape used twice), string, pegs, and sticks cut to 1.00 m, 0.67 m, 0.50 m and 0.33 m.

The starting budget

20,000 saplings · US$20,000 estimated purchase cost

  • Plot A$4,44422.2%
  • Plot B$6,66733.3%
  • Plot C$8,88944.4%
ItemQuantityEstimated cost
Plot A seedlings~4,444~$4,444
Plot B seedlings~6,667~$6,667
Plot C seedlings~8,889~$8,889
Total20,000$20,000

US$1 per sapling is a planning assumption, not a confirmed supplier quotation. We may be able to get the saplings at no cost. Nothing is confirmed, so the plan keeps the full purchase cost until it is. If the saplings do come free, this part of the budget falls away and every other cost stays. This budget covers sapling purchases only. Transport, site preparation, planting labour, maintenance, fire management, replacements, monitoring, and long-term protection are additional costs to be estimated.

What we are trying to learn

The pilot is for gathering real evidence before deciding whether to plant more of the cleared land, and how.

  1. Survival. Which density keeps the most saplings alive?
  2. Growth. How fast do trees grow in height and settle in?
  3. Canopy closure. Which density makes useful shade soonest?
  4. Fire exposure. How does dry grass and fine fuel change as the trees grow?
  5. Thinning. Can healthy young trees be moved to other cleared areas and survive?
  6. Cost. What does each surviving tree cost to establish and look after?

Monitoring schedule Planned trial

Proposed. None of this has happened yet.

  1. Month 0

    Record site conditions, species, initial seedling counts and planting costs.

  2. Month 3

    Check establishment, early losses, and watering or maintenance needs.

  3. Month 6

    Record survival, height, grass cover and maintenance effort.

  4. Month 12

    First-year review of survival and growth.

  5. Month 24

    Compare growth, canopy, ground cover and cumulative costs.

  6. Every year after

    Keep monitoring and write down major changes.

  7. When thinning starts

    No fixed date

    Record how many trees were removed and their condition, transplant attempts, and transplant survival.

Thinning and transplanting

As the dense plots grow, some trees will probably need thinning. We want to find out whether some of the healthy young trees can be moved to other cleared areas instead of being thrown away.

That depends on the species, the size of the tree, the season, how much the roots are disturbed, and whether moved trees survive. We will thin when growth and competition in the plots show it is time, not on a fixed year. The first moves would be a small trial, timed to the rainy season.

Important considerations

Same species mix in every plot

The three plots should use the same native species mixture in similar proportions, as far as nursery supply allows. Species follow local suitability, confirmed provenance and what nurseries can supply.

Record site differences

Soil, slope, drainage, moisture, existing vegetation and sun exposure, for each plot, at the start.

One plot per density is not a controlled trial

If plots sit on different parts of the land, site differences may affect the results. With a single plot per density, we cannot fully separate the effect of density from the effect of place. We will say so when we report.

Long, narrow plots

Strips have more edge than squares. Trees on the edge get more light and more grass around them, so record the outer rows separately from the inside of each plot.

Judge more than tree count

Compare survival, canopy growth, fire exposure and total cost, not how many trees went in.

Fire

Keep access tracks and firebreaks clear, manage dry vegetation, and have a dry-season fire plan before planting.

Transplanting

Only in suitable conditions, preferably early in the rainy season, and first as a small trial.

This plan will change as we learn the land. Results, including what doesn't work, will go in the journal.

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