Mangrove forests in two locations in East Java Province were selected as the research setting. East Java Province was chosen because almost half of the mangrove forests had been damaged. Data by Susanto et al. [26] compared with data by Usmawati [27] show damaged mangrove from 61,700.20 ha in 2010 to 21,944 ha in 2017; this means that 35.6% of the mangrove forest in East Java was damaged within seven years.
Usmawati [27] demonstrated mangroves at the Clungup Beach absorb carbon biomass of 125.87 tons ha-1, and a litter of mangrove leaves can absorb 15.17 kg ha-1 per month. Carbon in a mangrove leaf litter absorbs 0.25 tons ha-1 per month, while the carbon stock holds 50.71 tons ha-1. Research results of Fikri [28] on the natural mangrove forest of the Lamongan Regency indicated that the carbon stock was 40.66 MgC ha-1. Rizky [29] showed that the estimated carbon stock in mangrove vegetation in Alas Purwo National Park in Banyuwangi Regency was 2,711 tons ha-1, with an average carbon stock 157.5 kg per tree. Research by Aldus [30] on carbon stock and carbon dioxide absorption in Penunggul Village, Pasuruan Regency, stated that the total estimated amount was 501.99 MgC ha-1 with a carbon dioxide absorption of 1,840.63 MgC ha-1. Also, Research by Adam [31] on the Coast of Lamongan Regency identified 251,307 tons per ha-1. These results are different from the results of Rizky [29], which show that the estimated total carbon stock in the coastal area of the Lamongan Regency is 181.3 tons C Ha-1, and the total absorption is 374.1 tons C ha-1. Based on measurements conducted by Kauffman et al. [32], measurements in Kalimantan carbon stock are 1,259 MgC ha-1. Based on this description, the average carbon sequestration and storage in East Java can be classified as moderate to low. The low carbon sequestration and storage in mangrove forests are mainly due to illegal logging that causes deforestation [8, 33].
Before conducting Analytical Hierarchy Process (AHP) and Partial Least Square (PLS) analyses, respondents in local government, society, and the private sector were surveyed. The table 1 shows the types of respondents interviewed.
Table 1 Types of respondents
No.
|
Type of Respondents
|
CCO
|
LCO
|
APP
|
PVP
|
1.
|
Local Governments
|
5
|
5
|
5
|
5
|
2.
|
Local People
|
5
|
5
|
5
|
5
|
3.
|
Private Sectors
|
5
|
5
|
5
|
5
|
4.
|
Fishermen
|
8
|
8
|
8
|
8
|
5.
|
NGO
|
7
|
7
|
7
|
7
|
|
Total Respondents
|
30
|
30
|
30
|
30
|
Note: NGO = non-government organizations; CCM = Clungup Coastal, Malang Regency; CLR = Coastal of Lamongan Regency; APP = Alas Purwo National Park; PVP = Penunggal Village, Pasuruan Regency.
There are five facets to be examined using the AHP method: irrational use, illegal logging, weak carbon sequestration, and the effect of forest damage on both carbon sequestration and law enforcement. They are stated as follows:
The first objective is to identify public opinion on irrational use (Fig. 2). The test using AHP obtained the value of 0.190 for the alternative “community does not care about the destruction of mangrove forests.” This is the basis for proposing that illegal logging causes deforestation due to the accessibility of reaching mangrove forests. Accessibility means treating everyone the same concerning the use of mangrove forests and giving them equal opportunities.
Objective 2 is to learn people’s opinions on illegal logging (Fig. 3). The AHP test found the most popular option was “Residential areas increasingly diminish mangrove forests” with a value of 0.248.
Objective 3 is to identify public opinion on the effect of forest damage on carbon sequestration (Fig. 4). The AHP test found the most popular option was “Management of mangrove forests is not optimal” with a value of 0.206.
Objective 4 is to identify public opinion on law enforcement. The AHP test found the most popular option was “Law enforcement should have limited human resources” with a value of 0.316.
Objective 5 is to identify public opinion on weak carbon sequestration. The AHP test found the most popular option was “Lack of synergy between the government and the community” with a value of 0.316.
The formulation of AHP is as follows:
- The community does not care about the destruction of mangrove forests.
- Residential areas increasingly diminish mangrove forests.
- Management of mangrove forests is not optimal.
- The community favours limited human resources for law enforcement.
- There is a lack of synergy between the government and the community.
Furthermore, the results of the PLS method are as follows. Outer model testing is conducted by testing convergent validity, discriminant validity, and reliability of each observed research variable.
Table 2: Convergent validity results
|
Original Sample (O)
|
Standard Error (STERR)
|
T Statistics (O/STERR)
|
P-value
|
Remarks
|
X1.1 <- X1
|
0.818
|
0.018
|
46.457
|
0.000
|
Valid
|
X1.2 <- X1
|
0.571
|
0.030
|
18.868
|
0.000
|
Valid
|
X1.4 <- X1
|
0.841
|
0.008
|
100.795
|
0.000
|
Valid
|
X1.6 <- X1
|
0.763
|
0.018
|
42.154
|
0.000
|
Valid
|
X1.7 <- X1
|
0.818
|
0.018
|
46.457
|
0.000
|
Valid
|
X2.1 <- X2
|
0.681
|
0.030
|
22.578
|
0.000
|
Valid
|
X2.3 <- X2
|
0.945
|
0.004
|
241.598
|
0.000
|
Valid
|
X2.7 <- X2
|
0.677
|
0.026
|
26.079
|
0.000
|
Valid
|
X3.2 <- X3
|
0.945
|
0.003
|
372.005
|
0.000
|
Valid
|
X3.4 <- X3
|
0.945
|
0.003
|
372.005
|
0.000
|
Valid
|
X3.6 <- X3
|
0.583
|
0.029
|
19.884
|
0.000
|
Valid
|
X3.7 <- X3
|
0.775
|
0.022
|
36.018
|
0.000
|
Valid
|
X4.2 <- X4
|
0.980
|
0.001
|
1062.247
|
0.000
|
Valid
|
X4.4 <- X4
|
0.980
|
0.001
|
1062.247
|
0.000
|
Valid
|
X4.5 <- X4
|
0.728
|
0.032
|
22.770
|
0.000
|
Valid
|
X5.2 <- X5
|
0.930
|
0.006
|
154.808
|
0.000
|
Valid
|
X5.3 <- X5
|
0.688
|
0.022
|
30.944
|
0.000
|
Valid
|
X5.4 <- X5
|
0.686
|
0.022
|
31.376
|
0.000
|
Valid
|
A convergent validity test on objective 1, “Irrational use,” obtained four valid indicators from the seven initial indicators used. The valid indicators are indicator X1.1, “Community utilizes mangrove forests for daily living needs”, indicator X1.2, “Community does not have awareness about the functions and roles of mangroves”, indicator X1.4, “Community access to mangrove forests is easily achieved”, and indicator X1.6, “There is no supervision from the stakeholders.” These four indicators meet the convergent validity test requirements, which have a factor loading value of more than 0.5.
The convergent validity test on objective 2, namely “Illegal logging”, identified three valid indicators out of the seven initial indicators used. Valid indicators are indicator X2.1, “People steal mangrove wood as it has a high sale value”, indicator X2.3, “Declining mangrove forests are used for agriculture, plantations, and animal husbandry”, and indicator X2.7, “The area of mangrove forests is increasingly reduced to be used for aquaculture.” These three indicators meet the convergent validity test requirements, which have a factor loading value of more than 0.5. The convergent validity test on objective 3, namely “Effect of forest damage on carbon sequestration”, obtained four valid indicators from the seven initial indicators used. The valid indicators are indicator X3.2, “Absorption of mangrove forests has weakened”, indicator X3.4, “Above-ground biomass (stems, branches, twigs, leaves, flowers, and fruit) absorption is weak”, indicator X3.6, “The tree diameter is getting smaller due to the storage of biomass from the conversion of carbon dioxide (CO2), which is getting smaller in line with the less CO2 absorbed by the mangrove tree”, and indicator X3.7, “Mangrove conservation efforts are not optimal.” These four indicators meet the convergent validity test requirements, which have a factor loading value of more than 0.5.
The convergent validity test on objective 4, namely “Weak carbon sequestration”, identified three valid indicators out of the five initial indicators used. Valid indicators are indicator X4.2, “The conversion of mangrove land functions intensively”, indicator X4.4, “Mangrove deforestation is intensive”, and indicator X4.5, “Many mangrove trees are made into charcoal by residents.” These three indicators meet the convergent validity test requirements, which have a factor loading value of more than 0.5.
The convergent validity test results on goal five, namely “Law enforcement”, obtained three valid indicators from the four initial indicators used. Valid indicators are indicator X5.2 “There are no clear legal sanctions”, indicator X5.3 “Low community involvement”, and indicator X5.4 “Limited number of human resources for law enforcement.” These three indicators meet the convergent validity test requirements, which have a factor loading value of more than 0.5.
Table 3: The result of discriminant validity and constructive reliability
|
Discriminant Validity
|
Constructive Reliability
|
|
AVE roots
|
X1
|
X2
|
X3
|
X4
|
X5
|
Composite Reliability
|
Cronbach’s Alpha
|
X1
|
0.769
|
1.000
|
0.564
|
0.613
|
0.605
|
0.638
|
0.877
|
0.822
|
X2
|
0.778
|
0.563
|
1.000
|
0.686
|
0.659
|
0.667
|
0.817
|
0.652
|
X3
|
0.826
|
0.613
|
0.686
|
1.000
|
0.627
|
0.634
|
0.892
|
0.839
|
X4
|
0.904
|
0.605
|
0.659
|
0.627
|
1.000
|
0.618
|
0.929
|
0.884
|
X5
|
0.777
|
0.638
|
0.667
|
0.634
|
0.618
|
1.000
|
0.817
|
0.652
|
The discriminant validity test results obtained by the root value of AVE from each latent variable or the destination variable are higher than the correlation between latent variables to meet the discriminant validity test requirements. The construct reliability test obtained the Composite Reliability value of each latent variable, which is more than 0.70, and the Cronbach Alpha value of each latent variable is more than 0.60, so it meets the construct reliability requirements.
Testing the inner model was done by testing the influence between latent variables. The results of the inner model and hypothesis testing are presented as follows:
- The influence of variable X1, “Irrational use”, on the X2 variable, “Illegal logging”, obtained a path coefficient of 0.963 with a significance value of 0.000 (p <0.05). So, a significant positive effect was obtained. It means that the higher the respondent’s perception of variable X1, namely “Irrational use” of mangrove forests, will significantly influence the respondent’s perception of variable X2, namely “Illegal logging”.
- The influence of the X2 variable, “Illegal logging”, on the X3 variable, “Effect of forest damage on carbon sequestration”, obtained a path coefficient of 0.986 with a significance value of 0.000 (p <0.05). So, a significant positive effect was obtained. It means that the higher the respondent’s perception of variable X2, namely “Illegal logging”, will significantly influence the respondents’ perceptions of variable X3, namely “effect of forest damage on carbon sequestration”.
- The influence of variable X2, “Illegal logging”, on variable X5, “Law enforcement”, obtained a path coefficient of 0.963 with a significance value of 0.000 (p <0.05). So, a significant positive effect was obtained. It means that the higher the respondent’s perception of the X2 variable, namely “Illegal logging”, will significantly influence the respondent’s perception of the variable X5 “Law enforcement”.
- The influence of the X3 variable, “Effect of forest damage on carbon sequestration”, on X4 variable, “Weak carbon sequestration”, obtained a path coefficient of 0.963 with a significance value of 0.000 (p <0.05). So, a significant positive effect was obtained. It means that the higher the respondent is on the X3 variable, namely “Effect of forest damage on carbon sequestration,” will significantly affect the respondent’s perception of the X4, namely “Weak carbon sequestration”.
Table 5 Inner model results and hypothesis testing
|
Original Sample (O)
|
Standard Error (STERR)
|
T Statistics (O/STERR)
|
P-value
|
Remarks
|
X1 -> X2
|
0.963
|
0.003
|
347.960
|
0.000
|
Significant
|
X2 -> X3
|
0.986
|
0.001
|
1272.164
|
0.000
|
Significant
|
X2 -> X5
|
0.867
|
0.012
|
70.959
|
0.000
|
Significant
|
X3 -> X4
|
0.927
|
0.002
|
424.362
|
0.000
|
Significant
|
The constructed model generating an essential point that irrational use means illegal logging (Fig. 7). The respondents’ perception indicated that illegal logging creates irrational activities with no permission, and sometimes the people can exploit mangroves every time they have an opportunity without government supervision. The respondents also mentioned that illegal logging leads to forest damage, which works against carbon sequestration. Data from mangroves’ carbon sequestration and stock show that people will suffer from global warming, and there will be no protection from tsunamis. The presence of illegal logging suggests that law enforcement is weak, and forest damage will lead to weak carbon sequestration.
Irrational use ‘will significantly affect the higher respondents’ perceptions of the X2 variable “Illegal logging”. Fig. 7 above shows the relationship between the five objectives and the relevance of each variable.