Hence, β measures the fraction of decrease in agricultural product per capita
indirectly caused by one percent increase in the area of forest destroyed that raises the
mortality rate through disasters. For example, the estimated coefficient of LnDEKIL in
Panel (5a) is - 0.0033, implying that there is a 0.0033% decrease in agricultural product
per capita indirectly caused by one percent increase in the deforestation that raises the
mortality rate from disasters. The interpretations for LnDEAFF (= lnAFF*lnDEFOR)
and LnDEDAM (= lnDAM*lnDEFOR) are in the same manner.
Table 5 also shows that there are positive effects, in spite of being still limited, of
reforestation on the production per capita levels. For example, one percent increase in
reforestation raises forestry production by 0.027%, and the p-value of 0.020 implies that
the effect is statistically significant. Since there are negative effects of deforestation and
positive effects of reforestation, having some knowledge on forest development in the
future is important.
The Food and Agriculture Organization of the United Nations (2014) shows that the
growth rate of reforestation in Vietnam was 1.1% while the rate of deforestation due to
illegal exploitation and fires combined was 0.8% during 2005–2013. Modifying the
theoretical framework for GDP growth suggested by Thirlwall (2003), we provide
forecasts for the forest development in Vietnam.
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42 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
Natural Disasters and Rural Vietnam:
Estimations and Forecasts
TAM BANG VU
University of Hawaii-Hilo, tamv@hawaii.edu
ERIC IKSOON IM
University of Hawaii-Hilo, eim@hawaii.edu
ARTICLE INFO ABSTRACT
Article history:
Received:
Dec. 10 2014
Received in revised form
Dec. 21 2014
Accepted:
Dec. 30 2014
Using disaster data from the emdat.be website and data for six regions
in Vietnam, this paper investigates the impacts of natural disasters on
the gross product per capita of the three rural sectors that have been
affected the most by disasters―agriculture, fishery, and
forestry―over the period 1995 to 2013. The preliminary tests reveal
endogeneity and contemporaneous correlations among these three
sectors. Hence, a combination of instrumental variable (IV)
estimations and system seemingly unrelated regressions (SSUR) are
employed. The results reveal that disasters have different impacts on
different sectors of the rural Vietnam with agriculture suffering the
heaviest losses, fishery second, and forestry suffers the least. We then
analyze the effects of reforestation as a disaster prevention measure
and provide forecasts on the forest development in Vietnam.
Keywords:
Vietnam, natural
disasters, rural areas,
deforestation,
reforestation.
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 43
1. Introduction
The economic reform in Vietnam has brought on rapid economic development in
rural Vietnam. Together with the positive impacts such as higher GDP per capita,
infrastructure and human capital improvements, and access to new technology, are a host
of negative effects, including deforestation and pollutions that cause suffering for most
residents, especially the ones who live in the remote areas. To some extent, the negative
consequences of disorganizing development exacerbate the negative impacts of natural
disasters on rural production. This paper looks into the effects of natural disasters in the
presence of deforestation and reforestation in rural Vietnam.
In contrast to the earlier papers by Vu and Im (2014), who analyze the impacts of
natural disasters on household income using data on 64 sub-regions, and Noy and Vu
(2010), who estimate the effects of natural disasters on aggregate outputs in Vietnam,
this paper focuses on the impacts of natural disasters on three sectors that are the most
vulnerable to disasters - agriculture, forestry, and fishery - using data for six large regions
in Vietnam. The research uses a combination of instrumental variable (IV) estimations
and seemingly unrelated regressions for a system of equations (SSUR) with different
dependent variables and different explanatory variables introduced by the University of
California at Los Angeles (2014).
Different from data for households and firms in Vietnam, which are organized into
eight regions, aggregate data for economic sectors are divided into six large regions: Red
River Delta, Northern Midlands and Mountain Areas, North Central and Central Coastal
Areas, Central Highlands, South East, and Mekong River Delta. In general, disasters
often occur in a whole region or sometimes multiple regions at the same time. To reflect
this fact, the data provided by the Center for Research on the Epidemiology of Disasters
(CRED) from its website, emdat.be, are for each occurrence instead of for each of the
64 sub-regions in Vietnam. These characteristics justify our use of the panel dataset for
six large regions in this paper.
Researches on the macroeconomic impact of natural disasters, such as Albala-
Bertrand (1993), generally show evidence for positive impact on GDP but adverse
effects on the trade and current accounts. The intuition is that the destruction reduces the
stock of goods available, while it also leads to increase in the flow of spending
investment for reconstruction. Skidmore and Toya (2002) call this phenomenon the
“creative destruction” evidence, which is related to the concept introduced by
44 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
Schumpeter (2008). Paxson (1992) investigates the effect of natural disasters in the
mostly rural least developed countries. Employing time-series data in combination with
cross-sectional data, the author examines the impact of regional rainfall on household
transitional income. The result shows that sudden rainfall affects household income but
not consumption. Hence, the household income affected by regional rainfall is only
considered a measure of transitory income that has a negligible effect on household
permanent income.
There are also papers on a single country. Horwich (2000) analyzes the impacts of
the Kobe earthquake of 1995 in Japan and emphasizes that human capital is the most
crucial factor of production in any economy. Selcuk and Yeldan (2001) examine the
August 1999 earthquake in Turkey. Using general equilibrium computation, they
estimate the transition path of the Turkish economy to its new equilibrium after the
earthquake and offer the best policy as a negative indirect tax in form of a subsidy
financed by foreign aid to individual sectors to recover their capital losses. Halliday
(2006) examines the impact of the 2001 earthquakes on net migration from El Salvador
to the United States. He shows that unfavorable agricultural conditions in El Salvador
raises both migration to the United States and remittances sent back to El Salvador. He
finds that the 2001 earthquakes reduced net migration to the United States.
Regarding the nexus between deforestation and natural disasters, Hammill, Brown,
and Crawford (2005) point out that the severe damage caused by the powerful cyclone
that hit India’s Orissa coast in October1999 was a consequence of deforestation that
exaggerated the impact of the disaster. Most damage occurred in the vastly-deforested
new settlement areas along Orissa’s coast when the storm surge ripped through a 100-
km long barren stretch, the Ersama block, killing thousands of people within minutes.
Brown, Crawford and Hammill (2006) also show that the Indian Ocean tsunami of 2004
that took the life of more than 300,000 people were an indirect consequence of the
deforestation in the area. In Vietnam, Ngoc Cam (2011) reports that the devastating
floods of 2010 that caused severe damage to people and property were a direct
consequence of the deforestation along the upper streams.
Pham Thi Thanh Thuy (2010) indicates that the forest covering rate of Vietnam was
43.2% in 1943 but dropped to 27.7% in 1990. On the other hand, Meyfroidt và Lambin
(2008) show that this rate went up from 27.7% to 39% during 1990–2005. From the
United Nations Food and Agriculture Organization website, we find that the current
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 45
covering rate is 44%, slightly higher than that of 1943. This is a big improvement thanks
to rigorous forest planting rate of 2.2% during 1995–2005. Although this rate dropped
to 1.1% during 2005–2013, it was not serious enough to reduce the forest covering rate
in Vietnam. However, deforestation is still a problem with the rate of forest destroyed
due to both illegal exploitations and fires at 0.8% during 2005–2013.
To incorporate these concerns on the forest development and its effects, this research
aims at making an assessment of the three disaster impacts―the number of people killed,
the number of people affected, and the monetary damages―in the presence of
deforestation and reforestation. Different from the aforementioned authors, we examine
all disasters in Vietnam during 1995–2013 instead of a single event and focus on the
rural area of Vietnam. Also in contrast to the above papers, we combine IV estimations
with SSUR to control for the endogeneity and contemporaneous correlations among the
cross-sectional residuals. Moreover, we use data for three typical sectors in rural
Vietnam―agriculture, forestry, and fishery―instead of only farming sector as in Paxson
(1992) or aggregate macroeconomic data as in Albala-Bertrand (1993).
Section two of this paper provides details on the data used in the research. Section
three introduces methods for estimating the effects of the natural disasters. Section four
analyzes the estimation results regarding the impacts of natural disasters on the
production in the three economic sectors. Section five discusses the reforestation versus
deforestation and provides alternative forecasts on the forest development in Vietnam.
Section six offers policy suggestions and conclusions.
2. Data
The issue of which dataset we are going to use is important because it affects the way
we build the model for this paper. As discussed in Vu and Im (2014), there are two
datasets on disasters. The first dataset is available on the Disaster Inventory
System/Disaster Information Management System website (desinventar.net) provided
by United Nations Office for Disaster Risk Reduction. This dataset is for 64 provinces
and municipal cities (64 sub-regions) in Vietnam but does not report the onset month of
each incident. The second dataset is available from the Emergency Events Database
website (emdat.be) provided by the Center for Research Epidemiology of Disasters
(CRED) and Office of U.S. Foreign Disaster Assistance (OFDA). This dataset is for
each incident that affects large regions and reports the onset month of each disaster.
46 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
Since we examine the macroeconomic effects of the disasters on three sectors in the rural
areas using data for six large regions in Vietnam, utilizing this dataset is rather
appropriate.
We use three reported measures of the magnitude of the disasters in emdat.be divided
by the population of each region to form the impact measures (IMM) mostly similar to
Noy (2009): (i) the fraction of population killed (KIL); (ii) the fraction of population
affected (AFF); and (iii) the total damages per capita in US thousand dollars (DAM). For
any incident that affects more than one region, we sum the total population of the
affected regions, divide the impact measure by this sum, and then assign this value to
each region. Table 1 provides a summary of these three impact measures for the
estimation period from 1995 to 2013. This table reveals that the disasters in Vietnam
during this period were distributed quite evenly although the North Central Area and
Central Coastal Area suffer the most damage in two out of the three impact measures.
Table 1
Impact measures of disasters in Vietnam during 1995–2013
Region Killed Affected Damages
Unit (Persons) (Persons) ($US thousands)
Red River Delta 941 51,187,233 458,210
Northern Midlands and Mountain Areas 704 396,495,093 253,162
North Central Area and Central Coastal Area 3,640 917,486,486 4,475,682
Central Highlands 518 9,064,388 139,163
South East 521 11,477,790 596,403
Mekong River Delta 5,043 76,715,007 1,142,425
Source: emdat.be
Using the emdat.be dataset also has the advantage of calculating the weight of each
impact measure on the economy depending on the onset time. Different from Noy
(2009), who use a monthly weight based on the onset months, we use quarterly weight
based on the onset quarters (OQ) because there are numerous incidents occurred in
different months that call for grouping them into four quarters per year. Also different
from Noy (2009), who assigns a zero value to an incident occurring in December of a
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 47
current year, we spread the effects out into two years (eight quarters). Thus, the current
impact (IMt) based on the impact measures (IMM) is:
IMt= IMMt*(8-OQ)/8 (1)
The lagged impact in the following year (IMt-1) is:
IMt-1 = IMMt*OQ/8 (2)
For example, a disaster which occurs in the fourth quarter of 2012 will have one half
of the impact on 2012 and the other half on 2013, whereas a disaster which occurs in the
first quarter of 2012 will have 7/8 of the impact on 2012 and the remaining 1/8 on 2013.
Table 2 reports the number of disasters occurring in the six regions of Vietnam during
1995–2013. This table, in combination with Table 1, reveals that the North Central and
Central Coastal Areas suffered the most from disasters. Although the Northern Midlands
and Mountain Areas experienced higher numbers of disaster, they endured less severe
impacts than the Mekong River Delta did as shown in Table 1. Nationwide, there were
867 disasters reported by the CRED during 1995–2013.
Table 2
Number of disasters in Vietnam during 1995–2013
Region Number Mean Standard Deviation
Red River Delta 42 2.2 1.4
Northern Midlands and Mountain Areas 229 9.0 6.8
North Central Area and Central Coastal Area 362 11.1 7.0
Central Highlands 55 2.9 2.5
South East 78 4.1 2.8
Mekong River Delta 102 5.4 3.7
Total 867 51.4 35.8
Source: emdat.be
Data for most of the other variables are from GSOV’s Statistical Yearbooks. Data
for agricultural (AGRI), forestry (FOREST), fishery (FISH), and industrial production
(INDUS) are divided into two periods: the ones for 1995–2011 use 1994 constant price,
the one for FOREST in 2012–2013 use 2010 constant price whereas for INDUS during
2005–2013 use current prices. We use the comparative period from 2005 to 2013 and
the producer price index for industrial production to adjust all values to 1994 constant
price. Data for AGRI and FISH are not available for the period 2012–2013. The retail
48 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
sale values (SALE) are converted into the 1994 constant price using the consumer price
index. For a proxy on education (EDU), we calculate the sum of primary, secondary,
vocational, technical schools and college enrollments in each region. Data on the
number of medical staff are used as a proxy for available health care (HEAL). Data on
freight traffic on road (ROAD) and water way (WATER) in millions of tons.km are used
as proxies for infrastructure. All these variables are divided by population to obtain per
capita measures. Data on the areas of forest destroyed/deforestation (DEFOR), forest
planted/reforestation (REFOR), and aquaculture (AQUAA), are in hectare (ha). Data on
wood production (WOOD) are in cubic meter (m3). Data on aquaculture production
(AQUAP) are in tons, and data on poverty level (POVER) are already in percentage of
the population.
Table 3 displays types of disasters in Vietnam. The table shows that all regions have
storms and floods as the most frequent disasters whereas epidemics often occur in the
large urban areas.
Table 3
Types of disasters in Vietnam during 1995–2013
Region Storm Flood Epidemic Drought Land Slide Other Total
Red River Delta 13 11 12 2 2 3 42
Northern Midlands
& Mountain Areas
89 94 9 8 21 8 229
North Central &
Central Coast
Areas
161 136 18 11 20 16 362
Central Highlands 16 21 4 3 5 6 55
Southeast 19 24 17 2 6 10 78
Mekong River
Delta
21 42 9 8 12 9 102
Total 319 328 74 34 64 52 867
Note: other consists of hailstones, extreme weathers, and miscellaneous events.
Source: emdat.be
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 49
Data on household per capita income (PERCA) are from Vietnam Household Living
Standards Survey provided by General Statistics Office of Vietnam (GSOV). Data are
for even years from 2002 to 2012. We project the data for odd years using a combination
of averaging and trending methods to obtain yearly data from 2001 to 2013. Data are for
monthly per capita income in current Vietnamese Dong, so we multiply the data by
twelve months to obtain per capita income per year and use the consumer price index to
convert current values to real values. Since our estimation period is from 1995 to 2013,
we have an unbalanced panel, for which we use binary dummies to control. Data on the
real interest rate (RINT) for Vietnam are from the International Monetary Fund’s
International Financial Statistics. We use the regional indicator variables to account for
the regional differences in financial markets.
3. Methodology
Based on the variables formed in equation (1) and (2), we estimate a system of
equations in logarithmic form:
, 1 2 , 3 , 1 ,t ,ln ln ln lni t i t i t i i tAGRI IM IM X (3)
, 1 2 ,t 3 , 1 ,t ,ln ln ln lni t i i t i i tFOR IM IM Y f (4)
, 1 2 , 3 , 1 ,t ,ln ln ln lnZi t i t i t i i tFISH IM IM g (5)
where AGRI, FOR, and FISH are annual gross product per capita in agricultural,
forestry, and fishery sectors, respectively. IMs are the weighted impacts of KIL, AFF, or
DAM, all in per capita forms, to be estimated in three separate systems. X, Y, and Z are
vectors of control variables, i is the regional index, and t the time index.
To examine the indirect impact of deforestation (lnDEFOR) in addition to its direct
impact on the three typical sectors in rural areas, we also form the following interaction
variables:
LnDEKIL = lnKIL*lnDEFOR,
lnDEAFF = lnAFF *lnDEFOR, and
lnDEDAM = lnDAM *lnDEFOR
We use a downward piecewise process to avoid omitted variables, starting with all
available variables and performing the Variance Inflation Factors test to detect the
multicollinearity as discussed in Kennedy (2008). Table 4 displays the results for two
50 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
possible combinations of variables where log of industrial production per capita can be
used alternatively with poverty level.
Table 4
Final results of VIF tests with two possible combinations of variables
First Combination Second Combination
Variable VIF 1/VIF Variable VIF 1/VIF
Poverty Level 5.72 0.17 Industrial
Product
6.64 0.15
Aquaculture
Product
4.26 0.23 Aquaculture
Product
3.81 0.26
Road Traffic 3.35 0.29 Road Traffic 3.12 0.32
People
Affected
2.95 0.34 People
Affected
3.02 0.33
Forest
Destroyed
2.61 0.38 Forest
Destroyed
2.87 0.34
Forest
Planted
2.14 0.47 Education 2.18 0.45
People Killed 2.11 0.47 Water-Way
Traffic
2.18 0.46
Total Damage 2.01 0.49 People Killed 2.10 0.48
Water-Way
Traffic
1.94 0.52 Total Damage 2.04 0.49
Education 1.51 0.66 Forest
Planted
1.95 0.51
Real Interest
Rate
1.19 0.84 Real Interest
Rate
1.11 0.90
Mean VIF 2.71 Mean VIF 2.82
The p-values for the White tests on the heteroskedasticity are all greater than 0.10,
implying no serious heteroskedasticity problem for all three equations (3), (4), and (5).
The p-values for the Arellano-Bond tests on the autocorrelation of AR(1) and AR(2)
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 51
processes are also all greater than 0.10, implying no serious autocorrelation problem.
The p-values of the Modified Hausman tests reveal that two disaster impact measures,
lnKIL and lnDAM, have endogeneity problems. Hence, Instrumental Variables (IVs)
estimations are needed for these two variables.
To see whether or not the economic development exacerbates disaster damage we
conduct Granger-Causality tests. We perform a regression for each of the disaster
measure variables on product per capita lags, together with all control variables for each
sector, and test the significance of the product per capita lags. The t-tests for single
coefficients and the F-tests for joint significances (at any lag structure) all indicate that
the product per capita in each sector does not Granger-cause the disaster damages.
Hence, the system does not have a simultaneous bias problem.
Finally, we perform the Breusch-Pagan Lagrange Multiplier test on the system and
discover that there are contemporaneous correlations among the residuals with the p-
values all smaller than 0.05. This is understandable because all three sectors are in rural
Vietnam with similar local customs and rules of law as well as under similar central
government policies and economic conditions. They also share overwhelmingly similar
types of disasters, especially storms and floods. Therefore, it is likely that the impacts of
any omitted factors on the production of the agricultural sector will be similar to the ones
on the other two sectors.
Since there are endogeneity problems for lnKIL and lnDAM, a combination of IV and
SSUR estimations for the systems involving these two variables is appropriate, whereas
the system involving lnAFF needs only SSUR estimation. SSUR estimations assume
that the residuals of the systems are not serially correlated over time. This condition is
satisfied through the aforementioned Arellano-Bond test results. The basic SSUR
estimation, which is a system generalized least squares (SGLS) procedure, can be
performed in three steps as follows:
(i) Estimate the three equations separately using ordinary least squares.
(ii) Use the residuals from the OLS estimation in step (i) to estimate
2 2 2
(3.1) (3.2) (3.3), , , and
2
(3.1),(3.2),(3.3) and
(iii) Use the estimates from step (ii) to regress the three equations jointly within a
GLS framework.
52 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
In this research, step (i) is modified slightly by using fixed effect (FE) estimations
instead of OLS to control for the regional differences. We try lnAFF as the instrumental
variable for lnKIL and lnDAM. A reduced form estimated on each separate equation―(3)
with lnKIL as the dependent variable and (5) with lnDAM as the dependent
variable―shows that lnAFF in (3) is highly correlated with lnKIL (with the p-value =
0.000), and lnAFF in (5) is highly correlated with lnDAM (with the p-value = 0.032).
Since the estimated equations have similar control variables and lnAFF is exogenous, it
is not correlated with the residuals. Hence, lnAFF is a valid instrument. We perform two
separate (FE) regressions, one with lnKIL as the dependent variable, and one with
lnDAM as the dependent variable, on lnAFF and the other control variables. We then use
the predicted value of lnKIL (lnKILH) and that of lnDAM (lnDAMH) as instrument in
the SSUR regressions.
4. Effects of disasters on gross product per capita in three sectors
Table 5 shows regression results for effects of the three impact measures on the gross
product of the three sectors that are affected the most by disasters in rural Vietnam. Due
to the characteristics of SSUR regressions that might produce coefficient estimates that
are highly insignificant in themselves but jointly significant with other variables, we
only eliminate any variable with the p-value greater than 0.90. When this occurs, we
either drop this variable or replace it with an equivalent variable in the available list that
was eliminated due to multicollinearity problem. As discussed in Greene (2003) and
Wooldridge (2003), an adjusted R-squared in a IV estimation does not have a meaningful
interpretation. Instead of an adjusted R-squared, we provide the root mean square error
(RMSE). A small RMSE implies a good fit in addition to a p-value of the model smaller
than 0.05.
Panel 5(a) reports the results for agriculture. Since there are the current and lagged
values involved, we calculate the sums of these values to form a composite impact
measure and perform tests on the significance of the composite impact. For example,
summing up current and lagged values of “lnKIL” yields – 0.0543, this implies that for
one percent increase in the ratio of people killed to population, there is a decrease of
agricultural product per capita by 0.0543%, and the p-value of 0.0019 indicates that the
composite impact is significant. The same method of calculation should be applied for
the other variables. From this panel, one can see that all three disaster measures─lnKIL,
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 53
lnAFF, and lnDAM─affect agricultural product per capita negatively and the sums of
their individual values are also negative and significant. Although lnINDUS is only a
control variable, it is noteworthy that its estimated coefficients are negative and
significant in all three columns, implying the industrialization process does cause a
reduction in the agricultural production in rural Vietnam. However, effects of the
industrialization process on forestry and fishery are highly insignificant with p-values
greater than 0.90 and so are omitted in Table 5.
Table 5
Results from SSUR estimations on three typical sectors in rural Vietnam
Panel (5a) Dependent variable: Log of gross agricultural product per capita
Variable LnKIL LnAFF LnDAM
Current Impact -.0390** -.0104*** -.0251***
(.016) (.007) (.010)
Lagged Impact -.0153*** -.0032*** -.0064**
(.002) (.001) (.041)
Composite Impacts -.0543*** -.0136*** -.0315***
(.0019) (.0004) (.0011)
LnDEKIL -.0032*
(.078)
LnDEAFF -.0092**
(.041)
LnDEDAM -.0018*
(.100)
LnINDUS -.1104** -.0999** -.1602***
(.018) (.012) (.001)
LnDEFOR .0214 -.0099
(.157) (.296)
LnROAD .1180*** .1598*** .2577***
(.000) (.000) (.000)
54 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
Table 5 (continued)
Variable LnKIL LnAFF LnDAM
RINT -.0104*** -.0077*** -.0049*
(.000) (.000) (.080)
LnAQUAP .0511 -.0016 -.0252
(.137) (.954) (.518)
LnEDU 1.0976*** 1.2019*** 1.1991***
(.000) (.000) (.000)
Panel (5b) Dependent Variable: Log of Gross Forestry Product per Capita
Current Impact -.0011 .0029 -.0145**
(.932) (.320) (.050)
Lagged Impact -.0020 .0028 .0052
(.878) (.253) (.453)
Composite Impact -.0031 .0057 -.0093**
(.8807) (.1507) (.0486)
LnDEFOR -.0062 -.0081 -.0061
(.570) (.343) (.550)
LnREFOR .0267** .0197 .0309**
(.020) (.149) (.033)
LnROAD .0960*** .0495 .0023
(.008) (.236) (.143)
LnPERCA .0533
(.132)
RINT -.0102** -.0146*** -.0062
(.031) (.002) (.292)
LnAQUAP .1476*** .1287
(.000) (.123)
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 55
Table 5 (continued)
Panel (5c) Dependent Variable: Log of Gross Fishery Product per Capita
Current Impact -.0356*** -.0001 -.0200**
(.004) (.945) (.019)
Lagged Impact -.0228* -.0012 -.0110
(.067) (.428) (.247)
Composite Impact -.0584** -.0013 -.0310***
(.028) (.662) (.0046)
LnDEFOR -.0206** -.0061 .0533***
(.046) (.243) (.000)
LnREFOR .0112 .0075
(.175) (.676)
LnROAD .2243*** .0723**
(.000) (.011)
LnWATER .0330*** .0602*** .0448***
(.009) (.000) (.008)
LnAQUAP .5616***
(.000)
LnAQUAA .7613*** 1.168***
(.000) (.000)
LnEDU .3434*** .4201***
(.002) (.007)
Average RMSE for the system: .0659; average p-value for the model: 0.0000
Notes: ***, **, * indicate the significant levels at 1%, 5%, and 10% respectively, with p-values in
parentheses.
Panel (5b) reports the results for forestry. The results show that all individual and
composite impacts of “lnKIL” and “LnAFF” are not statistically significant, whereas
the current and composite impacts of “LnDAM” are negative and statistically significant.
56 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
Pane (5c) reports the results for fishery and reveals that all individual and composite
impacts of “LnKIL” are negative and statistically significant. All individual and
composite impacts of the variable “LnAFF” are not statistically significant, whereas the
current and composite impacts of “LnDAM,” are negative and statistically significant.
5. Deforestation versus reforestation and forecasts of forest development in
Vietnam
From Table 5, we also see that the deforestation affects the gross product per capita
negatively most of the time, either directly or indirectly. To interpret the indirect effect,
we solve for the estimated coefficient of each interaction variable. For example, for
LnDEKIL = lnKIL*lnDEFOR, holding other variable constant:
Ln Ln * Ln
Ln / Ln
Ln
AGRI DEFOR KIL
AGRI KIL
DEFOR
Hence, β measures the fraction of decrease in agricultural product per capita
indirectly caused by one percent increase in the area of forest destroyed that raises the
mortality rate through disasters. For example, the estimated coefficient of LnDEKIL in
Panel (5a) is - 0.0033, implying that there is a 0.0033% decrease in agricultural product
per capita indirectly caused by one percent increase in the deforestation that raises the
mortality rate from disasters. The interpretations for LnDEAFF (= lnAFF*lnDEFOR)
and LnDEDAM (= lnDAM*lnDEFOR) are in the same manner.
Table 5 also shows that there are positive effects, in spite of being still limited, of
reforestation on the production per capita levels. For example, one percent increase in
reforestation raises forestry production by 0.027%, and the p-value of 0.020 implies that
the effect is statistically significant. Since there are negative effects of deforestation and
positive effects of reforestation, having some knowledge on forest development in the
future is important.
The Food and Agriculture Organization of the United Nations (2014) shows that the
growth rate of reforestation in Vietnam was 1.1% while the rate of deforestation due to
illegal exploitation and fires combined was 0.8% during 2005–2013. Modifying the
theoretical framework for GDP growth suggested by Thirlwall (2003), we provide
forecasts for the forest development in Vietnam.
Define the following variables:
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 57
CT = targeted rate of forest covering
Rd = current rate of deforestation (= 0.8% in the year of 2013)
Cc = current rate of forest covering (44% in the year of 2013)
RR = current rate of reforestation (= 1.1% in the year of 2013)
T = the time it takes Vietnam to reach a targeted rate of forest covering
The model can be presented as follows:
CC (1 + RR)
T = CT (1 + Rd)
T (6)
Taking the natural logarithm of equation (6) yields:
ln ln(1 ) lnC ln(1 )
[ln(1 ) ln(1 )] lnC lnC
C R T d
R d T C
C T R T R
T R R
Solving for T to obtain:
ln
ln(1 ) ln(1 )
T
C
R d
C
C
T
R R
Suppose Vietnam wishes to increase its forest covering rate from 44% to 50%, then:
ln(50 / 44)
43
ln(1.011) ln(1.008)
T
Thus, it takes Vietnam 43 years to increase the forest covering rate from 44% to 50%
if the reforestation rate remains at 1.1% and the deforestation rate remains at 0.8%.
Suppose Vietnam wishes to increase its forest covering rate from 44% to 48%, then:
ln(48 / 44)
29
ln(1.011) ln(1.008)
T
Thus, it takes Vietnam 29 years to increase the forest covering rate from 44% to 48%.
if the reforestation rate remains at 1.1% and the deforestation rate remains at 0.8%.
The second question is how fast the reforestation rate should be so that the targeted
rate of forest covering will be reached in T years. This is similar to the question raised
in Thirlwall (2003) concerning GDP growth rate. However, we present a solution that is
more accurate than the relative approximation by Thirlwall. From equation (6):
58 Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61
1/
C (1 )
(1 )
(1 )
1
T
T T d
R
C
T
T
T d
R
C
R
R
C
C R
R
C
1/
(1 ) 1
T
TT
R d
C
C
R R
C
(7)
Suppose Vietnam plans to reach the target rate of 50% forest covering in 2020, which
is seven years from 2013, substituting T = 7 into equation (7):
1/7
7(50 / 44)(1 0.008) 1 0.027 2.7%RR
Hence, the required rate of reforestation is 2.7% if the rate of deforestation remains
at 0.8%.
If Vietnam wishes to reach the target rate of 48% forest covering in 2020, then:
1/7
7(48 / 44)(1 0.008) 1 0.021 2.1%RR
Thus, the required rate of reforestation is 2.1%, which is achievable, as Vietnam
already reached the reforestation rate of 2.2% during 1995–2005, although this rate
dropped to 1.1% during 2005–2013.
If Vietnam is able to reduce the deforestation to 0.6% and wishes to achieve the
targeted rate of 48% forest covering by 2020, then:
1/7
7(48 / 44)(1 0.006) 1 0.019 1.9%RR
Thus, the required rate of reforestation is only 1.9% if the rate of deforestation falls
from 0.8% to 0.6%. This target is even easier to achieve.
6. Policy suggestions and conclusions
Based on the research results, we recommend the following policies:
First, tighten the government-people linkage, especially between the local
government and the farmers who usually have little access to the newest information.
This will increase the dissemination of the information to the faraway areas, raising the
Tam Bang Vu & Eric I. Im. Journal of Economic Development 22(1), 42 – 61 59
awareness of and preparedness against the coming disasters. Second, improve local
infrastructure, including telephone lines and broadcasting system in addition to road and
water way to raise the level of damage prevention in the rural area. Third, encourage and
enable rural households to send children to schools, help the rural adults attending
evening classes to foster knowledge of disaster impacts and effective prevention
measures. Fourth, reduce impacts of disasters in advance by stocking up emergency
supplies, including food, water, first aid kits, water purification units, medical supplies,
temporary shelters, and generators. Fifth, strengthen activities against deforestation to
reduce the area of forests destroyed by fires and illegal exploitations. Finally, mobilize
all rural households to plant new forests. Most trees, especially mangroves, reduce the
frequency and harmful impacts of flash floods and storms. Many regions have been very
successful in planting mangroves and utilize mangrove forests in saving the residents’
lives and properties. This activity needs to be encouraged in the whole nation.
In sum, this paper investigates the effects of disasters on the three sectors that endure
the most from disasters in rural Vietnam. The results reveal that agricultural sector
suffers the most severe impacts of disasters, the fishery second, and the forestry the least.
Forecasts for alternative plans are then offered that shows that a target of 48% forest
covering rate in 2020 is achievable if the deforestation remains at 0.8% and even easier
to reach if the deforestation rate falls to 0.6%.
As in any research, this paper has certain limitations. First, data on several variables
are not comprehensive and might render inaccurate magnitudes of the estimated
coefficients. Hence, it is better to pay attention to the signs of the estimate coefficients
instead of the specific values of the point estimates. Second, since data obtained from
emdat.be are for each incident that affects a large region, we believe that using data on
six large regions of Vietnam reflects these regional impacts more precisely. However,
this causes some losses of detailed information that might be available if sub-regional
data are used. Finally, we only focus on the three sectors that suffer the most from the
disasters. It is also important to examine the effects of the disasters on the gross product
per capita of several other sectors in Vietnam, which is left for future research
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