The drive back to the camp went through a mixture of woody savanna and open fields and I saw for the first time the dynamics of the shifting agriculture or swidden as it is sometimes known – all aspects were on show en route. We would see the heavily forested river valleys, generally untouched by this form of landuse, and the long stretches of woody savanna; this is fairly thickly wooded land but able to survive the harsh dry season between November and May. It had a lot of herbaceous grasses and other plants that grew vigorously in the wet season – as much as 3m high by the time the rain stopped. This would then seed and dry out and thick scratchy material was left behind as the trees lost their leaves and were reduced to knobbly skeletons. The mixture of leaves and grass became a tinder box as the dry season progressed and natural fires from lightning strikes in particular might ravage through the understory, leaving a black and white scar across the landscape. Most of the trees would survive as would the seeds, rhizomes and bulbs in the soil ready to rejuvenate the grassy layer the next wet season. One or two trees here or there, weak from age or damage, might succumb to the fire and their ashy imprint left on the ground would be all that remains after all their years of life.
Many fires are started deliberately. Indeed the first step to shifting agriculture would be the chopping down of many standard trees and lighting the bush. If done correctly it could be controlled within a tight area to be prepared for cultivation, but so often it would spread dangerously into the surrounding shrubs.
The herbaceous layer of these forests are vigorous and if the ground is not tilled and weeded before the dry season, they will grow back more strongly the following year. Along our route back to the camp, there were lots of examples of patches of ground in various stages of clearance. Eventually though people would plough or build mounds of soil, and dryland rice would be cultivated in these patches. The goodness in the soil, however, without further inputs from manure, compost or fertiliser, would dry up quickly and the fields would be abandoned and left to regenerate first into herby fields, then shrubs and given time in to small trees and back to woody savanna. As you went round the countryside you would see this checkerboard of clearance, cultivation, abandonment and natural regeneration, but it would be hard to determine exactly which stage it was at.