Plantation forestry – timber stock, CO₂ absorption and sustainable harvesting
Design & TechnologyAgriculture, Forestry & AquacultureAges 12–13
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Agriculture, Forestry & Aquaculture
One hectare of plantation forest is tracked over 30 years: the trees grow, the timber stock increases according to each species' growth pattern, and canopy cover and CO₂ absorption increase along with it. The student chooses the tree species, planting density, harvesting method (selective, progressive, or clear-cut) and harvest cycle, then clicks Run to watch the stock-over-time graph, or clicks Harvest Now and Replant. The simulation compares cumulative timber yield between sustainable harvesting and overharvesting, which degrades the forest and causes soil erosion.
Lesson: Introduction to forests; planting, tending and protecting forests; rational forest harvesting
What it shows
A plantation's timber stock follows an S-shaped, logistic curve: growth is slow while the trees are young, fastest at about half the maximum stock, and levels off as the stand matures. Fast-growing species such as acacia and eucalyptus reach harvestable volume in a few years, while pine grows slowly. Harvesting is sustainable when the average volume removed each year does not exceed the forest's annual growth; removing more depletes it. Canopy cover protects the soil, so clear-cutting without replanting leads to erosion. Growing trees also lock up carbon, about 0.9 tonnes of CO₂ per cubic metre of timber in this model.
How to use
Choose a Tree species and Planting density, set the Harvesting method and Years between harvests, then press Run and follow the timber stock graph, canopy cover and CO₂ absorbed over 30 years. Compare selective harvesting with clear-cut harvesting on a short cycle, noting the total timber harvested and any soil erosion. Use Harvest now and Replant to test what happens when replanting is delayed, and adjust Playback speed if needed.
Parameters you can change
- Tree species Hybrid acacia (fast-growing), Eucalyptus, Resin pine (slow-growing), Protective mangrove forest
- Planting density 800–3000 trees/ha
- Harvesting method No harvesting (protective forest), Selective harvesting (take 30% of the stock), Progressive harvesting (take 60%), Clear-cut harvesting (take 100%)
- Years between harvests 3–20 years
- Playback speed 0.5–5 years/second
Questions to explore
- Which harvesting method and cycle give the most timber over 30 years without depleting the forest?
- What happens to canopy cover and soil erosion after a clear-cut if the forest is not replanted?
- Why does a fast-growing species suit a shorter harvest cycle than a slow-growing pine?
