Attempts to achieve sustainable development in the tropical forest

Overview

Sustainable development, limitations of agroforestry as a solution and selective logging.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What does sustainable development mean in the context of the tropical forest?

   Model answer

   Using the forest to meet the economic and social needs of the present population in a way that does not destroy the ecosystem's capacity to meet the needs of future generations. In practice that means generating income from the forest while keeping the biomass store, and therefore the nutrient cycle and the soil, essentially intact, protecting biodiversity and hydrology, and ensuring that the people who live in the forest share in the benefits, since a scheme that leaves them poorer will not be respected for long.

2. 2

   What is agroforestry, and why does it suit a tropical forest environment so well?

   Model answer

   Agroforestry is the deliberate growing of trees together with crops or livestock on the same land, in mixed, multi-layered plantings rather than a cleared monoculture. It suits the environment because it imitates the structure and the nutrient cycle of the forest it replaces: a permanent canopy intercepts the rain and protects the soil from rainsplash and erosion, continuous leaf fall maintains the litter store and the surface humus, deep tree roots capture nutrients that would otherwise be leached beyond crop rooting depth and return them at the surface, and nitrogen-fixing species add nitrogen. Because the nutrient capital stays on site in the standing biomass, the land does not exhaust after three to five years the way cleared arable land does.

3. 3

   How does agroforestry benefit the farmer economically as well as environmentally?

   Model answer

   It produces several products from the same hectare at different times of year and over different timescales: annual food crops between the rows for subsistence, tree crops such as cocoa, coffee, fruit, nuts, spices, rubber or oils for cash, and timber as a long-term asset. That diversity spreads risk, so a collapse in the price of one commodity or the failure of one crop does not ruin the household. Shade from the upper storey reduces heat and water stress on the crops beneath, fuelwood and fodder are available on site, and because fertility is maintained the farmer does not need to keep clearing new land.

4. 4

   What are the limitations of agroforestry as a solution?

   Model answer

   It is labour-intensive and demands considerable skill and knowledge, so it depends on training and extension services. Tree crops take years to reach first yield, so a farmer needs credit or another income to survive the establishment period. Output per hectare of any single commodity is lower than in a monoculture plantation, so it is less attractive to commercial investors and harder to market through bulk buyers. It requires secure land tenure, because nobody plants a tree that will yield in eight years on land they may lose. And it operates at the scale of a smallholding, so it can transform livelihoods over a wide area but does not by itself stop industrial-scale logging, ranching or mining.

5. 5

   What is selective logging, and what makes it more sustainable than clear felling?

   Model answer

   Removing only mature trees of chosen species, at low intensity, on a long rotation that allows the stand to regenerate before it is cut again. It is more sustainable than clear felling because the canopy remains largely closed, so the microclimate, the nutrient cycle and the soil are preserved, most species keep their habitat, and the forest regenerates naturally from surrounding seed trees. Its effectiveness depends entirely on how it is done: directional felling to control which way a tree drops, cutting lianas beforehand so neighbours are not dragged down, planning extraction trails to minimise soil damage, and enforcing the rotation and the quotas. Poorly supervised selective logging can be nearly as damaging as clearance.

6. 6

   How does timber certification work, and what is it meant to achieve?

   Model answer

   An independent body inspects a forest operation against agreed standards covering rate of extraction, regeneration, protection of watercourses and habitat, and the rights and working conditions of local people and workers. Timber from an operation that passes carries a label, and the chain of custody is tracked through processing so that the label on the finished product can be trusted. The intention is to use consumer demand in importing countries to create a price premium and a market advantage for well-managed forests, so that sustainable operators can outcompete destructive ones. Its weaknesses are that certification costs money and so favours large operators, that enforcement and verification are difficult in remote areas, that illegally cut timber is laundered into certified supply chains, and that much tropical hardwood is sold into markets where buyers do not ask for a label.

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