We test an emerging theory of the forest transition using the case of Vietnam. In the early 1990s, decollectivisation of agriculture, allocation of forestry land to households, and the development of market networks transformed land use in the mountains of Vietnam, leading to an increase in forest area. We used census and geographic data covering the whole country at a fine level of aggregation to build a spatial lag regression model of reforestation. We separated natural forest regrowth from the increase in plantation forests. The forest transition theory distinguishes between the forest scarcity and economic development paths. Our study suggests that the forest scarcity path was in part at work in Vietnam: new policies allocating forestry land to households, local scarcity of forest products, and development of remote demand for timber contributed to forest cover increases. The evidence regarding the economic development path are more ambiguous, as there was no depopulation or agricultural decline in marginal regions. We propose a third forest transition path that better corresponds to Vietnam’s situation: a smallholder agricultural intensification path. In marginal regions, land scarcity associated with population growth, land degradation, and political restrictions led to, on one hand, a decline in cultivation on hillsides followed by reforestation and, on the other hand, an increase in labour inputs on the plots with the highest agro-ecological potential. The development of markets for agricultural inputs and outputs did also contribute to reforestation by raising agricultural productivity in mountain paddies and maize fields. This reinforced the concentration of agriculture on the most suitable land. r 2007 Elsevier Ltd. All rights reserved
Trang 1Land Use Policy 25 (2008) 182–197
The causes of the reforestation in Vietnam
Patrick Meyfroidt , Eric F Lambin Department of Geography, University of Louvain, Place Pasteur 3, B-1348 Louvain-La-Neuve, Belgium Received 11 December 2006; received in revised form 26 May 2007; accepted 27 June 2007
Abstract
We test an emerging theory of the forest transition using the case of Vietnam In the early 1990s, decollectivisation of agriculture, allocation of forestry land to households, and the development of market networks transformed land use in the mountains of Vietnam, leading to an increase in forest area We used census and geographic data covering the whole country at a fine level of aggregation to build a spatial lag regression model of reforestation We separated natural forest regrowth from the increase in plantation forests The forest transition theory distinguishes between the forest scarcity and economic development paths Our study suggests that the forest scarcity path was in part at work in Vietnam: new policies allocating forestry land to households, local scarcity of forest products, and development of remote demand for timber contributed to forest cover increases The evidence regarding the economic development path are more ambiguous, as there was no depopulation or agricultural decline in marginal regions We propose a third forest transition path that better corresponds to Vietnam’s situation: a smallholder agricultural intensification path In marginal regions, land scarcity associated with population growth, land degradation, and political restrictions led to, on one hand, a decline in cultivation on hillsides followed by reforestation and, on the other hand, an increase in labour inputs on the plots with the highest agro-ecological potential The development of markets for agricultural inputs and outputs did also contribute to reforestation by raising agricultural productivity in mountain paddies and maize fields This reinforced the concentration of agriculture on the most suitable land
r2007 Elsevier Ltd All rights reserved
Keywords: Forest transition; Reforestation; Vietnam; Land use change; Land allocation; Forestry; Agricultural intensification; Land abandonment; Spatial lag regression
Introduction
Forest cover conversion and modification due to land
use change impact on a range of ecosystem services
(Lambin et al., 2003) While at present these processes
mostly affect tropical and equatorial regions, it used to
take place in Europe and other now developed parts of the
world In the past, some states succeeded in stopping
deforestation and even extending their forest cover
Understanding this forest transition is attracting much
interest as it provides lessons for a broader transition to
sustainability (Mather, 1992) Vietnam is one of the few
tropical countries where a forest transition seems to be
taking place today Cases of forest transition have already
been studied on a local scale (Rudel et al., 2002; Klooster,
2003; Perz and Skole, 2003) and through cross-country analyses (Rudel et al., 2005; Ewers, 2006; Kauppi et al.,
2006) The objective of our study was to understand the causes of reforestation in Vietnam during the 1990s on a national scale and test emerging forest transition theories (FTT) at that scale It is based on census and geographic data at a relatively fine level of aggregation and relies on published case studies on the local scale to support interpretation
In historical analyses, Mather (1992) and Mather et al (1999) describe a forest transition as a broad set of interrelated economic, political, institutional, and cultural processes in the agriculture, forestry, and energy sectors Rudel et al (2005)identify two broad pathways of forest transition: the economic development path and the forest scarcity path The former is associated with industrialisa-tion and the tertiarisaindustrialisa-tion of the economy that pull the labour force away from rural areas to cities Agricultural intensification reinforces this trend by increasing food
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0264-8377/$ - see front matter r 2007 Elsevier Ltd All rights reserved.
doi: 10.1016/j.landusepol.2007.06.001
Corresponding author Tel.: +32 10472675; fax: +32 10472877.
E-mail addresses: patrick.meyfroidt@uclouvain.be (P Meyfroidt) ,
eric.lambin@uclouvain.be (E.F Lambin)
Trang 2production and profitability in the most suitable regions of
a country Market networks accelerate depopulation and
agricultural decline in the least suitable regions According
to this economic development path, the spatial pattern of
agriculture at the national scale is thus expected to match
increasingly land suitability Forests are expected to regrow
in marginal regions, especially those that are well
connected to economic centres and to agriculturally
productive regions (Mather and Needle, 1998) On a global
scale, the role of agricultural intensification in this process
is sometimes called the Borlaug hypothesis (Angelsen and
Kaimowitz, 2001) In the second pathway of forest
transition, deforestation caused by agricultural expansion
or wood extraction creates a scarcity of forest products and
decreases the ability of forests to deliver ecosystem goods
and services Increasing demand for wood products due to
economic growth may reinforce this scarcity The economic
response by landowners includes tree planting and more
intensive forest management (Hyde et al., 1996) Thanks to
forestry intensification, timber needs can be satisfied from
limited areas of forest plantations, thus saving the
remaining forests from exploitation pressure (Sedjo and
Botkin, 1997) This is similar in the forestry sector to the
Borlaug hypothesis in agriculture Forest scarcity also
arouses cultural and political responses, inducing
govern-ments to implement policies to restrict forest exploitation,
promote more sustainable management practices, and
invest in forestry research and reforestation programmes
According to this forest scarcity path, reforestation is
therefore expected to occur in regions with a low forest
cover, a poor land suitability for agriculture and good
connections to distant markets—i.e where developing
forestry is most profitable The substitution of fuelwood
with fossil fuels or other energy sources is another possible
driver of a forest transition, but with mixed empirical
evidence Recently Mather (2007) hypothesized the
ex-istence of other undefined pathways of forest transition for
China, India and Vietnam
Vietnam is a densely populated country, with large
regional differences between small but very productive
areas (the Mekong and Red River deltas) and
mountai-nous areas covering more than two-thirds of the country
(Fig 1) The deltas have long been cultivated and
mountains were still extensively covered by forests until
the mid-twentieth century (Poffenberger and Nguyen,
1998) Since then, Vietnam has experienced rapid
defor-estation, culminating in the late 1980s Forest cover was at
its lowest in the late 1980s–early 1990s, when it covered
around 25% of the territory and only 17% of the northern
mountains (Figs 2 and 3) Deforestation was mainly
caused by agricultural expansion due to increasing
population in the uplands, following both natural
popula-tion growth and migrapopula-tion (De Koninck, 1999) Policies
encouraged resettlement to relieve pressure on the already
densely populated river deltas (Lundberg, 2004) Wood
exploitation for local and urban needs also contributed to
forest clearing (McElwee, 2004), as did the collectivisation
of agriculture that was implemented in the north from 1954 onwards and in the south after 1975 but failed to generate sustainable agriculture (Castella and Quang, 2002) In the late 1980s, productivity in mountain paddies was low because the cooperatives were poorly managed (e.g unreliable fertiliser distribution) and farmers lacked incentives (paddy field production was the property of cooperatives) Farmers increasingly turned to slash-and-burn cultivation on hillsides to maximise labour returns while growing their own food Agriculture is forbidden in Vietnam on most hillsides because they are classified as
‘‘forestry land’’ due to their steep slopes whether or not they have tree cover But enforcement by local govern-ments was weak and the traditional rule of free access was prevailing on most hillsides Food shortages became severe, forests disappeared and hillsides were increasingly eroded Several authors warned of the deepening environmental and development crisis in Vietnam’s mountains (Jamieson
et al., 1998)
Since the mid-1990s, however, this trend has been largely reversed and forest cover has increased notably through natural regeneration and the extension of tree plantations, although not everywhere in the country This reforestation was accompanied by political and economic changes in favour of decentralisation and liberalisation (i.e the Doi Moi reforms initiated in the 1980s) This induced rapid economic growth and the development of the industrial and service sectors (Kerkvliet and Porter, 1995)
Agricultural and forestry policies changed dramatically
In the agricultural sector, input and output markets were
High : 3084 Elevation (m)
Low : 0 Main cities
Northern mountains
Central highlands
500 Kilometers
Hanoi
Da Nang
Ho Chi Minh City
0
N
Fig 1 Map of Vietnam.
Trang 3progressively liberalised (Pingali et al., 1997; Kerkvliet and
Porter, 1995) The ‘‘Contract 100’’ policy in 1981 allowed
farmers to keep surpluses above a fixed contracted
quantity The ‘‘Contract 10’’ policy in 1988 further liberalised rice and input prices, land rights, and crop choices Households were also allowed to own all their production after subtracting taxes and charges (Kerkvliet and Porter, 1995) Under the Land Law of 1993, house-holds were given long-term rights to use, transfer, exchange, inherit, rent, and mortgage land (Do and Iyer,
2003) In mountain areas, labour was redistributed to paddies (Sadoulet et al., 2002) and the use of fertilisers and new seed varieties of rice and maize increased, with renewed incentives for farmers to produce surpluses (Minot and Goletti, 2000; Minot, 2003) Livestock and fruit trees also increased Several local studies (Sikor, 2001;
Tachiba-na et al., 2001; Castella and Erout, 2002; Muller, 2003) have pointed to the positive role of these changes on forest regeneration, but their relative contribution is still debated
In the forestry sector, tree planting campaigns were launched via Decree 327 (in 1992) and its successor, the Five Million Hectare Reforestation Programme (started in 1998) (De Jong et al., 2006) The 1993 Land Law also introduced a system for the allocation of forestry land to households (Sikor, 1998) (we use the term ‘‘forestry land’’
to refer to land legally classified for forestry use), to make the beneficiaries assume personal responsibility for protect-ing forestry land Several authorities (forest management boards, national park administrations, state forest enter-prises) also signed forest protection contracts with house-holds, which imposed more restrictions on households rights on forestry land than for allocated land Formal implementation of these policies varied locally but, in general, participating households were given rights to allocated or contracted land, such as the right to grow crops during the first years of forest regrowth and collect
Fig 2 Evolution of forest cover in Vietnam See Meyfroidt and Lambin (to appear)
Land cover
Non forest
Forest
N
Fig 3 Forest cover in 1993.
Trang 4forest products They also received small cash payments in
return for their commitment to preserve and protect
forests, and sometimes to plant trees (Ministry of
Agriculture and Rural Development, 2001; McElwee,
2004; Sikor, 2006; Sowerwine, 2004) The impact of these
policies on forests is still under discussion According to
some studies (Tachibana et al., 2001; Castella et al., 2006),
forestry land allocation led to forest recovery by
prohibit-ing hillside cultivation However, Sikor (2001, 2006)
concludes that, because of the numerous shortcomings in
policy design and implementation, the policy largely failed
to protect uplands Forest regeneration was thus driven by
agricultural intensification Sunderlin (2006) also presents
ambiguous evidence on the impact of forestry policies
Along with agricultural and forestry policies, the
Viet-namese government also developed plans to extend
protected areas and strengthen their enforcement after
signing the Convention on Biological Diversity (
Govern-ment of Vietnam, 1994; World Conservation Monitoring
Center, 1994) At the same time, the government was still
promoting colonisation and large-scale development of
perennial crops (mainly coffee and rubber) in the Central
Highlands (Hardy, 2000; D’haeze et al., 2005), which
caused massive deforestation (De Koninck, 1999; Muller,
2003)
Materials and methods
Study design
This study analyses the influence of agricultural and
forestry changes on forests at a national scale Actually, the
forest transition theory was developed to explain change in
forest cover at the country level The units of analysis are
Vietnam’s administrative districts, which are the second
smallest administrative unit in Vietnam, just above the
communes A typical district is around 600 or 900 km2 in
mountainous regions We used two regression models to
identify statistical relations at the district level between
forest cover changes, biophysical features, and land use
variables Local or provincial case studies were used to
support interpretation of these relations Districts were
selected because they are large enough to match the
concept of region as used in the FTT, while being small
enough so that the findings at the district level can be
interpreted using case studies at the commune (around
85 km2) or village (around 10 km2) levels This multi-scale
approach allows linking in-depth knowledge of processes
acquired at the local level with a more statistically
representative analysis at the national level Such approach
has limitations, particularly given the heterogeneous
context of Vietnam’s mountains Statistical relations do
not indicate causality, and findings from case studies are
only valid for the conditions from which they were derived
The study period goes from 1993 to 2002, corresponding
to two forest inventories and close to two exhaustive
agricultural censuses (in 1994 and 2001) that provide data
about rural households, agricultural, and forestry land uses This period corresponds broadly to the initial years of reforestation Policies regarding decollectivisation and liberalisation of agriculture were largely in place in the late 1980s, but their implementation continued during the early 1990s, especially in the remote mountain regions (Minot, 2003) The consequent agricultural developments progressed throughout the 1990s Although it was initiated earlier, forestry land allocation accelerated after the 1993 Land law This time scale is short compared to historical studies of forest transition that often extend over several decades Therefore, some driving forces identified in the FTT, such as slow demographic changes, are expected to figure less prominently in this study However, by studying
an ongoing transition, we were able to rely on more detailed data and disentangle multiple causes and pathways
of this transition
Data
We assembled data from several sources in a geographi-cal information system (GIS) to perform multiple regres-sion analysis Data were collected for the 542 districts of Vietnam Due to missing values, we used only 344 districts
in the regression analysis for natural forests, and 345 for planted forests The following variables were included (Table 1): forest cover and forest cover change, land suitability for agriculture, accessibility to markets and population centres, agricultural intensification, agricultural and economic diversification (livestock, perennial crops such as coffee, tea and fruit trees, and non-farm sector), activity in forestry sector and its capital intensity, degree of implementation of forestry policies (which is mainly the responsibility of district authorities,Sikor, 1998), extent of protected areas, and population density
GIS layers were obtained from the Ministry of Natural Resources and Environment (MONRE), except for the Digital Elevation Model which was extracted from the Global Land One-kilometer Base Elevation (GLOBE) model from the U.S National Oceanic and Atmospheric Administration (NOAA), at approximately 1 km resolu-tion For forest cover, we used the forest map of 1993 produced by the Forest Inventory and Planning Institute of Vietnam (FIPI) and district-level forest statistics of 2002 from FIPI and the Forest Protection Department (FPD) (Ministry of Agriculture and Rural Development, 2003) These data were produced by supervised classification of Landsat satellite images supported by field assessment, and identify natural and planted forests The soil map was reclassified in four suitability classes, based onNguyen et
al (2002) We calculated the percentage of a district area covered by soils from the two lowest suitability classes Accessibility of a district was measured by the road density and the distance to the main population centres (markets and/or administrative centres) The densities of unpaved and paved roads were used as indicators of internal communication within a district
Trang 5The main data sources on rural households and land use
were the 1994 and 2001 Rural, Agricultural and Fishery
Censuses conducted by the General Statistical Office of
Vietnam (GSO) (General Statistical Office, 1995, 2003),
covering the whole rural population The implementation
of the forestry land allocation policy was measured by the
percentage of land allocated to households as forestry
lands No data on forest protection contracts were
available Forestry sector activities were proxied by the
proportion of households whose main activity was in the
forestry sector The capital intensity of this sector was
proxied by the number of chainsaws per person
Agricul-tural intensification was measured by the rate of increase of
rice and maize yields (the two main crops), the change in
the percentage of area under irrigated crops, and the
change in rice cropping frequency (the number of times a
plot of land is cultivated each year or, similarly, the
proportion of land that is under multi-cropping) The censuses contained no district level data on rice and maize yields, livestock, and cropping frequency in paddies For these variables, we used data at the provincial level, assuming that all districts in a province had the same value This is likely to introduce spatial autocorrelation in our analysis, as discussed below Data sources were Statistical Yearbooks published by the GSO (General Statistical Office, 1994, 2004), the Agricultural Census of
1994, and the General Land Census and Statistical Yearbook of 2000 (partial results were published by the Ministry of Agriculture and Rural Development, 2002)
Regression models
We first computed linear correlations to describe the spatial pattern of forest cover changes We then performed
Table 1
List of variables
Biophysical and accessibility variables
Dtown Distance to the nearest provincial capital, in km GIS layer from MONRE Dcity Distance to the nearest large city (Ha noi, Ho Chi Minh City or Da Nang), in km GIS layer from MONRE
Plateau Index of presence of plateau, calculated as mean altitude/mean slope NOAA-GLOBE
Forest cover, forestry and forest policies variables
Natforchg Change in % of land covered by natural forest FIPI and MARD (2003) Plaforchg Change in % of land covered by planted forest FIPI and MARD (2003)
Allocfor94 % of area allocated to households as forestry land in 1994 GSO (1995)
Allocfor Change in % of area allocated to households as forestry land GSO (1995, 2003)
Forhh94 % of rural households for which forestry is the main activity in 1994 GSO (1995)
Forhh Change in % of rural households working primarily in forestry GSO (1995, 2003)
Saw Change in number of chainsaws by 1000 rural households GSO (1995, 2003)
Agricultural sector and other variables
Freqgr Growth rate of paddy rice cropping frequency (%) GSO (1994), MARD (2002)
Nagrhh Change in % of rural households working primarily in non-agricultural sector GSO (1995, 2003)
Popden94 Rural population density in 1994 (people=km2 ) GSO (1995, 2003)
Interaction terms
Allocslop Interaction between forestry land distributed to households and mean slope
Allocfreq Interaction between forestry land distributed to households and growth rate of paddy cropping frequency
Allocmysl Interaction between forestry land distributed to households, growth rate of maize yields, and mean slope
Freqslop Interaction between growth rate of rice cropping frequency and mean slope
Yldslop Interaction between growth rate of rice yields and mean slope
MYldslop Interaction between growth rate of maize yields and mean slope
Perenplat Interaction between change in % of area covered by perennial crops and plateau
All variables are measured at the district level (unit of observation) Growth rates are annual All change and growth rate variables are measured between
1994 and 2001, except for forest cover where the period is 1993–2002.
Trang 6multiple linear regressions, using a spatial lag model with a
maximum likelihood estimator (MLE) (Anselin, 1988) with
the Geoda software (Anselin, 2005), to account for spatial
dependency in our data We built two models where the
dependent variables were specified as differences in,
respectively, natural and planted forest areas between
1993 and 2002 Independent variables representing land use
were also expressed as differences between 1994 and 2001,
to measure how land use changes affected changes in forest
cover However, some variables were not specified as
differences: biophysical and accessibility variables were
assumed to be unchanged during the 10-year period of
study, and initial forest cover in 1993 was included as a
measure of forest abundance In some cases, we included
the variable measuring initial values along with the
2001–1994 difference: the forestry land already distributed
in 1994 measured the implementation of the policy for
1993–1994, and population density and percentage of
households living mainly from forestry activities in 1994
were proxies for the demand in forest products and land
The spatial lag model is expressed as
y ¼ rWy þ X b þ ,
with N being the number of observations and K the
number of independent variables, y is a N 1 vector of the
dependent variable, W a N N spatial weights matrix, r
the spatial lag coefficient, X a N K matrix of independent
variables, b a K 1 vector of coefficients for independent
variables, and a N 1 vector of the disturbance term
This model was chosen after a diagnostic procedure
whose full results are not presented here We started with
ordinary least square (OLS) regression The presence of
spatial dependency was detected by a series of Lagrange
Multiplier (LM) tests (Anselin, 2005) This issue can be
dealt with either by a spatial lag or a spatial error model
(Anselin, 1988) Spatial error models introduce a spatial
autoregressive error term This is appropriate when error
terms are spatially correlated, which is theoretically due to
an unspecified variable affecting the dependent variable
similarly in neighbouring locations (e.g a provincial-level
policy) LM tests rejected that model, suggesting that
spatial dependency in our data was not mainly due to a
misspecification Spatial lag models are appropriate when
values of the dependent variable in one location influence
values of this dependent variable in neighbouring locations
(e.g due to imitation strategies of neighbouring farmers)
The dependent variable in one place can be affected by
surrounding values of the dependent or independent
variables A spatial lag model identifies the variables
contributing to spatial dependency by verifying which
parameters are affected by inclusion of the spatial
autoregressive term Parameters from spatial lag models
indicate the marginal effect of a variable in one district
while parameters from OLS regression indicate the
aggregate effect of a variable, including contributions from
the neighbourhood The explanatory power in the spatial
lag model can be estimated by a pseudo-R2, calculated as
the squared correlation between observed and predicted values of the dependent variable It is not directly comparable to the OLS R2 Log-Likelihood (Log-L.) values are also used to compare alternative models, including the OLS: a higher value indicates a better fit of the model Diagnostic tests showed that the spatial lag model represented our data correctly and took the spatial dependency into account
In our implementation of the spatial lag model, we used
a spatial weight matrix based on distance between district centres, provided these distances were less than 67 km Larger distances were assigned a weight of zero This threshold was the minimum to ensure that every district had at least one neighbour A sensitivity analysis revealed that results were robust to other thresholds (100, 150, 300, and 600 km) and that these larger thresholds did not improve the model fit based on the Log-L criterion We also verified that results were robust to heteroscedasticity
in residuals by using HC0 standard error estimates (Long,
2000) in OLS regression As this did not modify OLS results, we assumed it was also valid for the MLE spatial model
Several interaction terms were computed To analyse the differential impact of agricultural intensification and the distribution of forestry land on districts more or less suitable for agriculture, we computed the product between,
on the one hand, mean slope and, on the other hand, rice cropping frequency, rate of increase of rice and maize yields, and percentage of forestry land distributed To measure a possible synergy or redundancy between new forest policies and agricultural intensification, we com-puted the product between, on the one hand, the percentage of forestry land distributed and, on the other hand, first the cropping frequency and then the rate of increase of rice yield For maize, we computed the product between percentage of forestry land distributed, rate of increase of yield, and mean slope, as this crop is mainly found in mountains To test whether new forest regulations were less effective in remote areas due to weaker government enforcement capacities, we computed interac-tion terms between allocated land and, respectively, mean slope, distances to cities, and road densities None of these latter terms were significant and they were therefore not used Finally, we measured whether a district terrain could
be characterised as a plateau by dividing mean altitude by mean slope (after adding 1 to slope to avoid division by zero) This index was multiplied by the change in area under perennial crops to evaluate the differential impact of the development of these crops in the Central Highlands as opposed to the rest of the country
Some variables introduced notable collinearity in the model, e.g rate of increase of rice and maize yields, and especially their interaction terms with slope and forestry policies In each case, only one of the collinear variables was significant It was thus retained in the regression models Change in agricultural mechanisation and in rural population density, and the interaction term
Trang 7between change in perennial crops and the presence of a
plateau were also collinear All three variables represent
agricultural colonisation in the Central Highlands We
retained the interaction term and removed the two other
variables For the same reason, we did not include the
accessibility variables for the model of natural forest
change
Results
Natural and planted forests displayed different spatial
patterns of forest cover change during the study period
(Figs 4 and 5, and Tables 2 and 3) Natural forest
regeneration occurred mainly in the northern and central
coastal mountains, in districts with high slope and thus low
suitability for agriculture, and far from urban centres
Districts close to cities and in river deltas, where agriculture
is most profitable, and in the Central Highlands region
were less affected by reforestation or even still affected by
net deforestation Tree plantations were more scattered
geographically and located mainly in midlands and along
coasts, where the road network is more developed, with no
relation to the slope of districts Few forest plantations
were observed in peri-urban areas and in river deltas
Regression models for both natural and planted forests
had a high explanatory power (Table 4) Log-L values
% Change in natural forests
< 0 0
0 - 10
10 - 20
> 20
N
Fig 4 Natural forest cover changes.
% Change in planted forests
< 0 0
0 - 10
10 - 20
> 20
N
Fig 5 Planted forest cover changes.
Table 2 Forest cover in 1993 and 2002 for selected regions Region Natural forests Planted forests All forests
1993 2002 1993 2002 1993 2002 Country 23.99 29.99 0.64 5.83 24.63 35.82 All mountains 29.96 40.55 0.45 5.44 30.40 45.99 Central Highlands 52.83 50.72 0.27 2.41 53.10 53.13 Northern Mountains 16.79 33.15 0.62 6.26 17.40 39.40
In % of area ‘‘All mountains’’ refers to districts with mean slope above 2:5 Sources: FIPI and MARD, 2003.
Table 3 Pearsons’s correlations between forest cover change and geographical variables
Variable Changes in natural forests Planted forests
*, p o0:05; **, po0:01; ***, po0:001; ***, po0:0001.
Trang 8indicated that the spatial lag models had a better fit than
the OLS models The model for change in natural forests
showed no direct influence from accessibility and
biophy-sical variables at the district level The area of remaining
forest in 1993 was positively associated with forest
recovery However, increased tree planting was associated
with a decline in natural forest cover The other variables
regarding forestry economy were not significant
Concern-ing forestry policies, the amount of land already allocated
to households in 1994 had no explanatory power but the
area of forestry land distributed during the study period
was significantly associated with natural forest regrowth
The interaction term between forest allocation and rate of
increase in mountain maize yields was marginally
signifi-cant and negative Protected areas were not signifisignifi-cant Natural forest regeneration was not affected by change in rice cropping frequency and affected negatively by change
in maize yields However, in both cases, the interaction terms associating these variables with mean slope were highly significant and positively associated with increases in natural forests The net effect of increases in maize yields and cropping frequency is positive for mean slopes steeper than 2:5(for maize) and 1:4(for rice cropping frequency) The interaction term associating the change in area covered
by perennial crops with the index measuring the presence
of plateau in a district terrain was negatively associated with forest cover change The rate of increase in cattle was marginally positive and change in rural non-farm sector
Table 4
Descriptive statistics and results of the spatial lag regressions for forest cover change between 1993 and 2002
Variable Descriptive statistics (units see Table 1) Spatial lag regression
change Estimate
Planted forest cover change
Estimate
*po0:05, **po0:01, ***po0:001, ****po0:0001 NI: variable not included in the model but non-significant (see text) ND, no determination; –; dependent variable.
Trang 9was not significant Finally, population density in 1994 was
negatively related to change in natural forests and the
spatial lag variable was positive and highly significant
In the model for planted forests, accessibility measures
were significantly associated with positive change Planted
forests increased more rapidly in districts with higher
densities of unpaved roads and highways, close to
provincial capitals Distance to the main cities was not
significant Only the density of main roads had a negative
effect, perhaps as it is highest in peri-urban areas where the
land rent is higher than the returns of forest plantations
Biophysical conditions were not significant Results also
showed that forests were more likely to be planted in areas
with a low forest cover in 1993 and where the share of
population working in forestry had increased—both a
cause and a consequence The mechanisation of forestry
practices was not significant The areas allocated to
forestry already distributed to households in 1994 were
related to increases in planted forests, as well as the areas of
newly allocated forestry land However, the latter effect
was reduced in mountains and in districts with a higher rate
of increase in rice cropping frequency The rate of increase
in paddy yields was associated with an increase in planted
forests but this effect was weaker in mountain areas The
rate of increase in rice cropping frequency was negatively
but very marginally associated with change in plantations
In districts with steep slopes, this association became
positive and more significant The increase in perennial
crops had a positive relationship with increases in forest
plantations, while an increase in cattle density had a
negative one Population density, non-agricultural
popula-tion, and spatial lag parameters were related with changes
in plantations in the same way as with changes in natural
forests
Discussion
Methodological issues
Our results are robust to the model specification
However, their reliability depends on data quality Official
forest cover statistics in Vietnam have been criticised for
several reasons (Lang, 2001) In a quantitative,
compara-tive analysis of forest statistics and land cover maps from a
variety of sources,Meyfroidt and Lambin (to appear)show
that: (i) the area and spatial pattern of forest cover on the
FIPI maps used in this study is consistent with the most
reliable data, and (ii) these data for Vietnam indicate a
turning point of forest cover around the first half of the
1990s, followed by an increase in forest cover of a similar
magnitude as represented on the FIPI maps Forest cover
change was measured as the change in the percentage of
land covered by each type of forest between 1993 and 2002
We did not use rates of forest cover change as they are
sensitive to the base level (the forest cover in 1993), which
was close or equal to zero for a number of districts
Changes in percentage are also more comparable with
other variables, such as percentages of land allocated for forestry to households, of land classified as protected areas, etc However, by counting only the net change in forest cover, the destruction of old-growth forests was aggregated with changes in secondary regrowth and therefore the quality of the new forests cannot be assessed Similarly, it was not possible to test whether the factors decreasing deforestation were different from those promoting refor-estation (as suggested by Grainger, 1995) Finally, large negative forest cover changes can only be measured where large forest areas were present in 1993 This may partly explain why changes in natural forests were more associated (negatively) with 1993 forest cover than changes
in planted forests These problems did not arise for planted forests, as the percentage of planted forest cover in 1993 was negligible and very few districts experienced a decrease
in planted forest
In a regression analysis of the distribution of forestry land against biophysical features, accessibility, population, and land use variables (in 1994), only the slope of the terrain was significant and positive Actually, forestry land
is mainly defined by its steep slope As we controlled for slope in the regression models of forest cover change, we assumed that the residual effect of the forestry land variable represented the policy implementation Changes
in perennial crops and in plantation forests were not correlated (Pearson’s R: 0:01, p ¼ 0:76) There was thus no overlap between these two land uses (e.g fruit trees that may have been included in both categories) Cropping frequency was computed by combining several methods, given the high heterogeneity of farming systems in Vietnam For the northern part of the country and the Central Highlands, with shifting cultivation and two rice cropping seasons, one being dominant, the total area sown during the year divided by the maximum area sown during one season was computed, as in Minot (2003) For the other regions with little shifting cultivation and up to three rice cropping seasons without necessarily a dominant one, the total area sown divided by the area under rice cultivation was computed, as in Minot and Goletti (2000) Results were also consistent with those of Castella and Erout (2002) The variable for change in irrigated area accounted mainly for two rather localised changes: dykes and irrigation infrastructures were built in the southern Mekong Delta, allowing for a second crop in areas reclaimed from seasonal seawater invasion, and significant areas of irrigated agriculture were replaced by perennial crops in the eastern Red River Delta In the rest of the country, changes in irrigated surfaces were included in the cropping frequency variable Protected areas were initially represented by two variables: areas already protected before 1993 and newly created natural reserves between
1993 and 2000 As they displayed similar patterns, they were aggregated The lack of explanatory power for protected areas therefore cannot be imputed to a time lag after the creation of parks The variable on the percentage
of households working primarily in the non-farm sector
Trang 10was strongly correlated with the share of household income
coming from non-agricultural sources (for 2001, Pearson’s
R: 0:74, po0:0001), which increases confidence in this
indicator The soil quality variable may be more
question-able as the binary categorisation in poor versus good
quality soils might be too simplistic Finally, we lacked
adequate data to measure changes in firewood
consump-tion, and hydropower dams and reservoirs
Although the results suggest distinct regional dynamics
(between uplands and lowlands, between northern
moun-tains and Central Highlands), the analysis did not include
regional dummy variables Instead, we used continuous
biophysical variables (slope and plateau) that are more
relevant to our hypotheses and that allow interpretations
based on physical rather than administrative regions
Policy and economic responses to forest scarcity
The main policy response to forest scarcity was the
forestry land allocation to households, which restricted
slash-and-burn cultivation on hillsides and provided
incentives for a sound management of allocated land
Sikor (2001; 2006), in a study of the actual allocation
system in a northwestern commune, argued that the policy
largely failed to reduce slash-and-burn cultivation because
it conflicted with customary land tenure systems, thus
inducing non-compliance by villagers Local authorities
were inclined to let local people, often members of their
kin, cultivate their plots illegally rather than strictly enforce
the rules of a physically and politically distant (due to
ethnic background) government (Sikor, 2001)
Investiga-tions by Nguyen (2006)andThanh and Sikor (2006) also
describe how social differentiation and the discrepancies
between legal rights and actual entitlements attenuated the
impact of this policy However, despite these shortcomings,
our results suggest that this policy had a positive impact on
natural forest cover
Our results also suggest that forestry land allocation
largely failed to stimulate the expansion of planted forests
We suspect that the association between forestry land
already distributed in 1994 and the expansion of
planta-tions might be spurious: districts that first started the
allocation procedure were perhaps districts with more
developed forestry activities in the first place For an
average district, the impact on plantations of forestry land
distribution after 1994 is negligible, as this impact
decreases in mountains where most of the allocated
forestry land is situated and in areas where rice cropping
frequency rose the most This intensification occurs where
growing rice is the most profitable, especially in the
south-eastern region around Ho Chi Minh City Labour was less
likely to be allocated to forestry there In mountains, the
limited expansion of planted forests could be due to the
absence of adequate sylvicultural knowledge and
proces-sing infrastructure, and to the few market opportunities for
timber compared to lowland districts A study in hoa Binh
province showed that, except for the richest farmers, tree
planting was not an economically feasible option (Clement
et al., 2007) In the midlands, where the infrastructure is more developed, allocated forestry land could provide profitable returns by planting trees Other authors have also commented on the difficulty of stimulating forestry activities in remote regions because of their poor infra-structure (Lang, 2002; Ohlsson et al., 2005; Sunderlin,
2006) Actually, better accessibility contributed to an increase in forest plantations, which was also associated with an increase in the population working in forestry Thus, in line with the forestry intensification argument (Hyde et al., 1996), demand from remote markets stimulated the growth of the forestry sector and of forest plantations in economically suitable places However, this was not the case for natural forests
At the local level, the positive effect of lower forest cover
on reforestation might be due to scarcity-induced increases
in forest stands and the better management of natural forests by households to meet their needs, as was observed elsewhere (Hyde et al., 1996; Foster and Rosenzweig,
2003) Our results do not support the argument that the development of plantations relieves pressure on natural forests (Sedjo and Botkin, 1997) Actually, at the local level, natural forests and plantations compete for space, considering that increases in the latter were partly at the expense of the former At an aggregated level, the reverse might be true, but our model does not allow drawing conclusions on that point
Forest regrowth was positively correlated with protected areas (Pearson’s R ¼ 0:26, po0:0001) but this association was not significant in the multiple regression Zingerli
et al (2002) argue that, around the Ba Be park in the northern mountains, the reforestation observed could be attributed to agricultural changes and forestry policies rather than to park regulations that were weakly enforced
By contrast, in the study by Muller (2003)in the Central Highlands, protected areas did contribute to forest regrowth Sowerwine et al (1998) conclude for Ba Vi, another park in the north, that it has not been truly effective so far, but improvements in park management and better cooperation with local people might prove more successful Cropper et al (2001) argue that in Thailand, areas set aside often have a low suitability for agriculture and thus their status does not really increase the likelihood
of their being cleared for agriculture This may explain the positive correlation between protected areas and forest regrowth as the latter happened mostly in areas with
a low suitability for agriculture And it may also explain why protected areas are not significant in the multiple regression
In conclusion, reforestation in Vietnam fits several aspects of the forest scarcity path of forest transition New policies were implemented to address the perceived degradation of forest resources Economic responses driven partly by urban and remote markets and probably also by
a perception of local scarcity by rural households also contributed to reforestation (Mather et al., 1999; Foster