4 DISCUSSION
4.1 Causes of deforestation in Zhejiang
Province
Zhejiang Province has experienced massive deforestation since 2000,
representing a significant land use change in the region. During the
study period, remote sensing data showed a decrease in forest area in
Zhejiang Province between 2000 and 2020.
According to satellite-based land
use and land cover products, we detected a substantial decrease in
forest area in the early 2000s (Figure 2b). While data on forest decline
are not uniform, inconsistent definition of forest may be a plausible
reason for explaining the different rates of forest loss among various
land cover products (H. Chen et al., 2020; Zeng et al., 2018). The
Hansen’s forest dataset show that extensive deforestation occurred in
Zhejiang Province in the early 2000s (Xiong et al., 2020). However, the
GlobeLand30 (30 m) imagery, which has a higher resolution, showed less
deforestation compared to the Hansen’s dataset. The GlobaLand30 dataset
was produced with a globally trained machine learning algorithm. This
algorithm, less suitable for detecting irregularly shaped mountain crop
fields, may account for its underestimation of forest loss. The
resolution of the ESA-CCI (300m) product requires a classification
scheme to use mosaic classes, which might result in mixing cropland with
other land cover types. These mosaic categories may also underestimate
the area of agricultural land (Ozdogan & Woodcock, 2006), and thus may
also have underestimated forest loss. Yet, despite the inconsistent
changes in forest loss area, we believe that remotely sensed land data,
not relying on government statistics, are more likely to show objective
patterns with relatively high reliability (Zeng et al., 2018).
Forest transition theory assumes that forest in a country or a region
will shift from a net loss to a net gain along with socio-economic
development (Meyfroidt, Rudel, & Lambin, 2010). However, it has also
been shown that if a country or region is engaged in cross-region trade
flows (e.g., South America soybean), then deforestation may positively
correlate with the growth of urban population and agricultural exports
(DeFries et al., 2010). Some studies also show that forestland tends to
be lost as China’s GDP per capita rises (Vina, McConnell, Yang, Xu, &
Liu, 2016). The accelerated urbanization in Zhejiang Province from 2000
to 2020 has resulted in conversion from agricultural land to urban land
(Figure 4). Besides, we also observed a large amount of forest loss
(i.e., land converted to arable land) (Figure 4) and continued forest
fragmentation in Zhejiang Province, which might arise from reclamation
of agricultural land (Xiong et al., 2020). Such large-scale and rapid
deforestation should be of concern to governments and the scientific
community.
4.2 Policy evolution on the Balance of Arable Land System
(BALS)
The establishment and implementation
of the BALS policy, established to play a dual role of guaranteeing
economic development and protecting the environment, might have achieved
this goal (Long et al., 2012; Xin & Li, 2018). However, this policy
also attracted great debate and was changed several times.
China’s
BALS policy can be roughly divided into three stages (Figure 8). The
initial stage was for systematic policy construction. China first
proposed the arable land acquisition and compensation system in 1997.
The BALS policy was formally written into the new Land Management law in
1998. To protect arable land, China amended the Land Management Law to
maintain the amount of arable land with a new arable land replenishment
mechanism, giving rise to the “occupy one ha and replenish one ha”
policy in 1999. In 2001, all provinces (including autonomous regions)
basically achieved a balance in the amount of arable land, ensuring that
the total area of arable land was not in decline. The focus of land
consolidation during this period was to increase the amount of arable
land, provide space for urbanization and industrialization, ensure food
security, and increase farmers’ income (Wei Song & Pijanowski, 2014).
Figure 8. The Balance of Arable Land System (BALS) policy evolution
The second stage featured systematic policy improvement. From 2004
onwards, Chinese government has been focusing on the quality of newly
created arable land, issuing a series of policies. In 2004, the
government introduced measures to control the quality of land during
land conversions, assuring that the quantity and quality of newly
created arable land should meet national standards. The year of 2005 saw
a shift of focus to administrative accountability, starting to implement
an accountability target assessment and chief executive responsibility
system. In 2006, several specific institutional assessment mechanisms
were introduced, which issued several pilot projects demanding that
decreases in rural construction land be linked to increases in urban
construction land (Long & Li,
2012). In 2008, China proposed to
designate permanent basic cropland to ensure that the quantity of arable
land would not be reduced and its quality would be improved. In 2009,
arable land was required to be fully replenished before land occupation,
and subsequent operational rules were issued to strengthen the quality
and management of replenished arable land. At this stage, the quantity
and quality of arable land was protected, and the productivity of arable
land was relatively ensured (Long, 2020).
The third stage was characterized by a “Trinity” of quantitative,
qualitative, and ecological policy. The Chinese government authorities
have further improved their management approach by emphasizing a policy
of balancing land occupation and compensation between provinces. To
ensure the quality of replenished arable land, a decree was issued in
2012 to strengthen the management of arable land and maintain land
quality. In 2014, the Chinese government proposed that the occupation of
high-quality land and paddy land should be compensated;
in 2016, a combination of quality
improvement and remediation was proposed. In 2018, China formed the
Ministry of Natural Resources to strengthen the unified integration and
management of natural resources. In 2018, the Ministry of Natural
Resources issued a national coordinated management decree to establish
the inter-provincial replenishment of arable land along with a
management scheme for construction land transfer between rural and urban
areas in different provinces. This provides a clear direction for the
unified management of arable land resources, focusing more on the
ecological functions of land use (Long, 2020; Long et al., 2018).
Zhejiang
Province, the first province to implement the BALS policy in China,
needs to evaluate its consequences and effectiveness. It is easy to
focus on assessing the quantitative balance and difficult to assess the
qualitative and ecological balance (Lin et al., 2017). As cropland
varies greatly over spatial and temporal dimensions, the policy needs to
be further adjusted in the future to effectively protect high-quality
cropland resources and support national food security and ecological
safety. In Zhejiang, for example, the conversion of forestland to
agricultural land has occurred in parallel with the BALS policy
implementation, inevitably leading to loss of forestland (Xiong et al.,
2020).
4.3 Telecoupling and the no net loss of cropland
policy
The
telecoupling framework can explain
the long-range land change mechanisms (Jianguo Liu, 2017; Sun Jing et
al., 2020), which may apply to this particular deforestation phenomenon
in Zhejiang Province. The expansion of arable land, although able to
satisfy market demands and conform with policies, may lead to ecological
problems such as deforestation (Henders, Ostwald, Verendel, & Ibisch,
2018). Our study shows that the largest source of urban construction
land in Zhejiang Province is arable land, and the largest source of
arable land is through converting forest land (Figure 4). In the context
of the BALS policy, the balance of cropland quantity needs to be
guaranteed, which inevitably leads to converting forest land to arable
land in Zhejiang Province. In China, large municipalities like Hangzhou
are often blamed for the massive loss of high-quality arable land (Hu et
al., 2020). The largest land change in Hangzhou is the conversion of
arable land to urban land; while in Lishui, the major changes feature
mutual conversions between arable land and forest land with the area of
forestland loss larger than that in Hangzhou (Figure 5). The
less-urbanized Lishui municipality also has the most deforested area in
Zhejiang Province (Xiong et al., 2020). A stable or depopulated
landscape may face a higher deforestation pressure largely because
distant urbanization processes would demand increases in arable land in
surrounding places. In contrast, the BALS policy allows for the
deployment of land resources within the province. In this context,
Lishui municipality becomes the place that supplies land resources for
other cities and towns because of its lower level of urbanization. As a
result, Lishui will likely experience land degradation and ecosystem
loss.
Figure 9. Mutual relationships between productive, living, and
ecological land
The simultaneous demand of land for urban development, ecological
conservation, and rural revitalization is a challenge for China’s policy
and planning for land and other related resources (R. Chen, Ye, Cai,
Xing, & Chen, 2014). A rational
land planning and management system needs to reconcile the balance among
productive land, living land, and ecological land (Figure 9).
However, many land use policies
implemented in China for more than 20 years are irrational in some
aspects as they do not coordinate well with each other. These policies
have either failed to ensure the productivity of arable land, or
resulted in ecological land degradation, which clearly contradict
China’s strategy for sustainable development (Bryan et al., 2018).
Moreover, appropriate land use policies must be in line with
socioeconomic development (Xin & Li, 2018). With urbanization, the
continuing migration of rural population to cities will inevitably lead
to the emergence of hollow villages and the abandonment of large amounts
of arable land in rural areas (Zhang, Song, & Chen, 2018), which will
further challenge the effectiveness and efficiency of BALS (S. Li et
al., 2018).