Vityakon (2001) has concluded, based on her own long-term
observations, that the number of trees in fields in farming
systems in Northeast Thailand has been declining over time
as farmers cut down more trees to meet their needs for timber
and firewood and as some remnant forest trees, especially
those located in lower paddy fields, die naturally as a consequence of the transformation of their natural habitats or
senescence. Cutting of trees has been accelerated by the
recent increase in the use of four-wheel tractors and combine
harvesters, which have difficulty in working efficiently in
fields with many trees (Praweenwongwuthi 2009) as well as
by the planting of sugarcane in many paddy fields, especially
upper paddies. Sugarcane is vastly more profitable for the
farmers, but also much less shade tolerant than rice, leading
to cutting down of more trees (field observations of authors).
If this trend continues, then the vast ‘‘invisible forest’’ represented by trees in paddy fields may truly disappear, with
negative consequences for the livelihoods of the villagers,
loss of biodiversity, and reduced ability of the rural ecosystem to sequester carbon. Finding ways to help reverse this
decline is an important priority if land degradation, which is
widespread in the Northeast, is to be countered and the sustainability of agricultural production enhanced.