The uncertainties of the development of swidden agriculture and
its dynamics
Many facets limit our understanding of swidden agriculture. The lack of
geographic and demographic data and information on their corresponding
dynamics across the tropical regions undoubtedly further aggravate the
uncertainties surrounding above questions(Heinimann et al., 2017; Mertz
& Padoch et al., 2009; Padoch et al., 2007). Ever since the first
appeal of the eradication of shifting cultivation by the FAO in the late
1950s(FAO Staff, 1957), in situ anthropological, ethno-ecological
and/or ethno-biological studies dominated for a long time(Brush, 1975).
The launch of Landsat satellites in the 1970s offers the feasibility and
marks the beginning of periodically observing this ancient farming
system(Conant & Cary, 1977). However, research progress in the
algorithms for mapping swiddening or shifting cultivation is not
prominent, if not retarded or stagnant(Li, Feng, Jiang, Liao, & Zhang,
2014). So far, the only thematic map of global shifting cultivation,
largely speculative and conspicuously old-fashioned, was firstly
reported in 1980(Hurtt et al., 2011), although a few new attempts have
emerged recently at regional scale, e.g. montane mainland Southeast
Asia(Li, Feng, Xiao, Boudmyxay, & Liu, 2018; Li & Feng, 2016). In
addition, the annually-changing and spatially-random dynamics of swidden
agriculture mean that it is seldom included in existing classification
maps of land cover and land use(Padoch et al., 2007), plus prevailing
governmental eradication policies. The report of shifting cultivation
maps in South and South East Asia, China, Africa, and South America
based on the SPOT-VGT based Global Land Cover 2000 (1km) can be consider
an early attempt via remote sensing at large scale(Silva, Carreiras,
Rosa, & Pereira, 2011). However, the question about the accuracy of the
1km-resolution regional maps always persists as tropical swidden
agriculture belongs to small-scale farming systems with small-sized
plots (about 0.01km2)(Li et al., 2014). Even worse,
longitudinal dynamics of the evolution or transformation at a coarse
resolution increases greater uncertainty. Unsurprisingly, few studies
have been involved the spatiotemporal dynamics(Li et al., 2018). Lately,
the contributions of shifting agriculture and other four factors to
global deforestation were quantitatively for the first time(Curtis,
Slay, Harris, Tyukavina, & Hansen, 2018). However, the fact that
shifting cultivation is still practiced in many extra-tropics regions
including Europe, North America, Australia, North China and many other
countries is problematic and unconvincing. Since shifting cultivation is
one of the main causes of tropical active fires(Cochrane, 2003; Li,
Xiao, Feng, Li, & Zhang, 2020) and shifting cultivators are typically
poor ethnic minorities in remote uplands with limited
accessibility(Mertz & Leisz et al., 2009), the estimation of greenhouse
gas emissions and achievement of the SDGs will be impacted without
accurate figures and maps for the land coverage of swidden agriculture.
Shifting agriculture as well as commodity production, forestry and
wildfire are the leading drivers of global forest loss(Curtis et al.,
2018). Among them, the first two were preeminent in tropical regions
particularly in the past two decades, which are always accompanied by
frequent fire occurrence or biomass burning especially during the dry
season. Anthropogenic fires not only occur in tropical upland and
lowland agriculture, but also in tropical agriculture-forest frontiers
(TAFF)(Li et al., 2020). In the uplands, vegetation fires are generally
related to traditional practice of slash and burn(Cochrane, 2003), which
acts as a key part of swidden agriculture. In the past, the words of
“slash and burn” meant primitive and backward, or the stumbling block
of national economic development. By the same token, the
overgeneralization of describing swidden system as old as the hills
could make us bet on the wrong horse(Pham Thu, Moeliono, Wong,
Brockhaus, & Dung, 2020). Conversely, this becomes more necessary as
increasing evidence are connected with social and ecological outcomes of
this farming system(Downey, Gerkey, & Scaggs, 2020; Ziegler et al.,
2012). The positive effects of swidden agriculture are gaining ample and
convincing evidence in the aspects of carbon fixation, biodiversity
maintenance, livelihoods risk and cultural identity(Dressler et al.,
2020). Then, why should we still stick to the one-sided views of swidden
systems?