1. Introduction
The cornerstone of achieving global sustainable development is effectively harmonizing economic growth with environmental conservation [
1,
2]. The United Nations’ SDGs also include the goal of harmonizing the global economy with the environment [
3]. In recent years, countries have gradually accepted and thoughtfully implemented the concept of sustainable development. Countries are keenly aware of forestry’s prominent role in sustainable development. All countries try to maximize the dual function of economic production and environmental protection that forestry possesses [
4]. For example, the United States enacted the Multiple-Use Forest Management Policy, emphasizing sustainable yields, community participation and ecosystem health [
5]. The EU proposes a forest strategy to enhance sustainable forest management, improve biodiversity and support the rural economy [
5]. Finland employs an integrated approach with strict regulations, forest certification and financial incentives to promote sustainable forest management [
6]. Indonesia has adopted the landscape approach, which integrates forestry, agriculture and environmental protection to reduce deforestation and combat climate change [
7]. In 2020, forests covered 5% of the global land area in China [
8]. This substantial coverage underscores China’s forestry industry’s critical role in the global quest for economic and environmental balance. Eco-efficiency measures the synergistic relationship between environmental impact and economic performance [
9]. Measuring forestry eco-efficiency becomes a fundamental basis for exploring how to optimally utilize the dual functions of forestry. However, in agroforestry economics, the study of agroecological benefits is richer in breadth [
10]. Scholars need to emphasize the importance of research in the forestry eco-efficiency field.
The concept of eco-efficiency was originally introduced by Schaltegger and Sturm [
11]. Since then, it has become a tool many scholars use to measure the degree of harmonization between ecological environment and economic development [
12,
13,
14]. Generally speaking, eco-efficiency optimizes economic production while minimizing resource use and pollutant emissions [
15]. Based on the definition, initially, some scholars used the single-indicator ratio approach to measure eco-efficiency [
16]. The establishment of a system of indicators soon replaced this single measure. In addition to focusing on economic and environmental output, resource inputs and pollutant discharges are also considered in the indicator system [
17]. Eco-efficiency is the efficiency of inputs and outputs derived by considering resource and environmental constraints [
18]. Such a measure is more comprehensive and rigorous than its predecessor.
The DEA models have been extensively applied in research exploring eco-efficiency metrics [
19]. Charnes et al. introduced the DEA model, which has gained extensive utilization [
20]. However, some things could be improved in the traditional DEA model. First, traditional DEA models do not emphasize negative environmental output indicators but only consider economic output indicators, which is an inaccurate way of measurement [
21]. Second, classical models of economic efficiency analysis are essentially radial models that expect inputs or outputs to change proportionally. This model could make the calculated efficiency values higher than the actual values [
22]. Finally, traditional DEA models are unable to estimate the resource allocation efficiency of decision-making units (DMUs) exceeding 1, leading to a situation where DMUs with an efficiency score of 1 cannot be differentiated. The literature review reveals that the SBM model, which considers unwanted outcomes, is highly effective and addresses many of the limitations of the standard DEA model [
23]. This model can calculate eco-efficiency more scientifically and reasonably [
24]. Studies on topics such as renewable energy efficiency [
25,
26], urban water resources’ greening rate [
27], industrial green development efficiency [
28] and water utilization [
29] frequently employ the super-efficient SBM model. This model’s widespread application across various research areas is well documented. In addition, using the method at a constant scale, the combined efficiency is calculated. Aggregate efficiency considers the scale factor and the technical progress factor, which better reflects the comprehensive nature of efficiency. In the existing literature, most of the measures of forestry eco-efficiency are based on the DEA models [
23], which will lead to a relatively homogeneous choice of measurement methods. Therefore, this paper lays the foundation for the study by using a super-efficient SBM model. The model integrates undesirable outputs of constant size to effectively measure explanatory variables.
Is government environmental policy formulation a powerful tool for addressing environmental challenges and influencing economic growth? There has yet to be a consensus in the academic community on this question. On the one hand, many scholars have supported the view that environmental regulation can effectively harmonize economic production and environmental protection through many empirical studies [
24,
30,
31]. This view supports Porter’s hypothesis [
32]. On the other hand, some scholars are opposed to this view [
33,
34]. This view supports the neoclassical school of economic theory [
35]. Based on this, this paper will explore this topic of debate.
In coordinating economic production and environmental protection, China has explored institutional models for sustainable development by promulgating environmental policies relating to pilot ecological civilization zones. China issued the “Opinions on Establishing Unified and Standardized National Ecological Civilization Pilot Zones” (later referred to as the “Opinions”) in 2016 [
36]. The pilot area includes Fujian, Jiangxi and Guizhou (three provinces). The measures proposed in the “Opinions” and their effectiveness are specifically six points [
36,
37]. First, quantitative red lines were set according to the characteristics of forests and other ecosystems, and a red line control system was established. As of 2020, approximately 311,500 square kilometers, or 31% of China’s national territory, has been designated for ecological protection. Second, market-based mechanisms were explored to promote ecological environmental protection, implementing opinions to foster market players in environmental governance and ecological protection. By 2020, the national eco-environmental protection industry had already boasted an output value of CNY 8 trillion. Third, improvements were made to the compensation mechanism for ecological public welfare forests, implementing a forest ecological benefits compensation mechanism that links provincial and national levels and combines categorized compensation with graded subsidies. By 2020, the total amount of compensation reached CNY 10 billion. Fourth, a mechanism was established to seamlessly integrate administrative enforcement and criminal justice for severe environmental protection and natural resource use law violations. In 2020, the number of cases referred to the judiciary for environmental violations increased by 30% year on year. Fifth, a property rights system for natural resources has been established. According to statistics, by the end of 2020, the area of China’s natural resource rights registration had exceeded 500,000 square kilometers. Sixth, the green development indicator system will be incorporated into the performance appraisal of regional leading cadres. By 2020, the weight of green development indicators in government appraisals increased to over 20%.
Since the release of the 2016 “Opinions”, numerous scholars have evaluated the policy’s effectiveness using it as a quasi-natural experiment. These studies have demonstrated that the policy can positively impact ecological, social and economic development [
24,
38,
39]. However, fewer scholars have explored the multiplier effects of this policy by establishing a comprehensive system of evaluation indicators. Therefore, this paper examines this by creating a comprehensive measurement system. In addition, we analyze heterogeneity and spatial spillover effects, thus contributing to research in this area.
3. Model and Data
To measure the ecological benefits of forestry, this paper employs a super-efficiency SBM model with undesirable outputs, as detailed in
Section 3.1, and utilizes the forestry eco-efficiency indicators described in
Section 3.4.1. Provincial panel data from 2011 to 2022 were analyzed, with data processing conducted using Matlab version 2022. Additionally, this study uses the ChiPlot academic website for hotspot mapping to present the data. The hierarchical clustering method employed is complete-linkage clustering, with Euclidean distance as the metric.
3.1. Super-Efficiency SBM Model
Referring to the related literature [
49,
50], the formulation of this model is shown in Equation (1).
In Equation (1), is the inputs; is the undesired outputs; and is the desired outputs. is a weight vector indicating the weight of each DUM. is an indicator of the inputs; is an indicator of the undesired outputs; is an indicator of the desired outputs. is the slack variable for the inputs; is the slack variable for the undesired outputs; is the slack variable for the desired outputs. Forestry eco-efficiency is defined in the article as . The slack variables , , in the objective function are strictly decreasing. In the SBM model with undesired outputs , when DUM is in effect, . The in Equation (1) is the value of efficiency with calculations.
3.2. DID Model
Referring to related research [
51], the model equation is as follows.
In the model, the dependent variable denotes forestry eco-efficiency in province i, year t. “treat” is a dummy variable for experimental and control groups, while “post” signifies policy implementation. is the coefficient of “treat_post”. The name “Controls” refers to the collection of control variables. The remaining symbols represent province fixed effects, time fixed effects and random error terms in the order in which they appear in Equation (2).
3.3. Spatial Model
Referring to related research [
51,
52], the neighboring matrix is expressed as Equation (3).
Referring to related research [
53], the spatial Durbin model is expressed as Equation (4).
In Equation (4), W is the constructed adjacency space matrix; is the spatially lagged term of the explanatory variables; is the spatially lagged variable of the average observations in neighboring provinces.
3.4. Data Sources and Variable Measurement
3.4.1. Dependent Variable: Forestry Eco-Efficiency
The sustainable development theory emphasizes the compatibility of economic growth and environmental sustainability [
54]. Thus, it is essential to consider both economic and environmental outputs and energy consumption.
Figure 2 illustrates the logical framework for establishing specific forestry eco-efficiency indicators. Based on relevant theories, the selected indicators are grounded in the literature [
55,
56].
The input variables comprise land, human capital and energy. The measurement of land input is determined by the extent of land dedicated to forestry. The quantification of human contribution is determined by the total workforce working in the forestry sector at the end of the year [
57]. Capital input is quantified by the perpetual inventory approach, which measures completed investment in fixed assets associated with forestry. The value of σ is 9.6% based on relevant studies [
58]. The energy input is determined by considering the overall energy consumption associated with forestry output. This was calculated by multiplying the total consumption in each district by the overall forestry output and dividing it by the GDP of each district.
The desired outputs include economic and ecological benefits. For the economic output, gross forestry product is chosen, with 2011 as the base year for constant price calculations [
56]. For the ecological output, afforestation area is selected, as it directly correlates with the ecological benefits of forestry [
56].
The undesired outputs are exhaust emissions, solid waste emissions and wastewater emissions, based on references [
50,
55]. These are calculated using secondary industry output values and relevant industrial waste indicators. For example, forestry SO
2 emissions are calculated as industrial SO
2 emissions × forestry secondary production value/total industrial production value. Similar formulae are used for solid waste and wastewater outputs. Secondary forestry industry output is used as the primary source for these calculations, as most forestry waste emissions originate from this sector.
Table 1 lists the specific indicators.
The “China Forestry Statistical Yearbook”, “China Statistical Yearbook”, “China Environmental Statistical Yearbook”, “China Energy Statistical Yearbook” and the official websites of provincial and local governments are the sources of all the data in
Section 3.
3.4.2. Independent Variable: Interaction Term “treat_post”
The article identifies three provinces in the pilot region of eco-civilization as the treatment group. The remaining provinces are the control group. Due to the limited data for Tibet, the province is not included. The year 2016 is the time point of policy implementation, with the pre-implementation group before 2016 and the post-implementation group after 2016 [
59].
3.4.3. Control Variables
Based on relevant literature [
51,
52], the following control variables are selected: Industrial Scale (
IS), Forestry Pests Area
(lnFPA), Urbanization Level (
UL), Government Support (
lnGS) and Environmental Governance Level (
EGL).
3.4.4. Descriptive Statistics
Table 2 shows the descriptive statistics of this paper.
Table 2 shows the article’s data, which contains 300 observations from 30 provinces from 2011 to 2020. Among the variables, the most central variables are “treat_post” and FEE. The former represents the implementation status of the policy pilot, with a mean of 0.0500, a standard deviation of 0.218, a minimum value of 0 and a maximum value of 1. The latter represents the efficiency level of forestry ecology, with a mean of 0.631, a standard deviation of 0.399, a minimum value of 0.0901 and a maximum value of 2.105. This suggests excellent variations in the ecological efficiency among the observations.
5. Discussion
This paper may present the following contributions. First, in this paper, NECP is chosen as the research object to study its impact on forestry eco-efficiency. The impact of environmental policies on the synergy between conservation and economic development is explored. This differs from current studies examining this multiplier effect [
63,
64]. Second, compared with the traditional DEA model used by other scholars [
23,
65], this paper adopts a more scientific and rigorous calculation method, making forestry ecological benefits more accurate. Finally, this paper provides further research on NECP, thus enhancing the depth of research in this area.
Table 9 provides a complete overview of the assumptions and results of this paper. The section that follows is based on the research findings.
First, it is clear from evaluating China’s forestry eco-efficiency that the country’s average eco-efficiency has not yet achieved a practical level and urgently needs to be improved. This is consistent with Hanting Chen et al.’s findings [
50], indicating that resource allocation in China’s forestry sector needs to be more rational.
Second, given the above problems, exploring the ways to promote a rational allocation of resources is essential, so that the forestry economy can better utilize the multiplier effect. Our analysis validates that NECP policies positively influence forestry eco-efficiency, supporting Hypothesis H1. This suggests that government environmental policies can foster synergies between the forestry economy and the environment. This aligns with findings by Aziz Noshab et al. and Muhammad Salman et al., who, through different perspectives, showed that such policies reduce carbon footprints while promoting economic gains [
66,
67]. Therefore, governments around the world should emphasize forestry development as a sector that combines the dual functions of production and environmental protection and could become an essential component of integrated economic and environmental development.
Third, there is heterogeneity in the harmonizing effects of NECP policies. This finding highlights that while synergizing the economy and the environment is a common global goal, a single environmental policy cannot be universally applied. Different regions must develop policies tailored to their specific contexts. Policies from various regions can inspire countries around the world but should not be directly replicated.
Lastly, the spatial benefits of NECP policies support Hypothesis H2. This suggests that countries around the globe that want to achieve better multiplier effects can prioritize implementing environmental policies in specific regions and achieve this through spatial spillover effects. This is similar to the findings of Liu et al., who concluded that government environmental policies can curb carbon emissions in the manufacturing sector and that these effects have spatial spillovers [
68]. The same conclusion can be drawn from different research perspectives: government environmental policies exhibit spatial spillover effects.
6. Conclusions
Harmonizing economic development with ecological and environmental protection is essential in the global quest for sustainable development [
1,
2]. This issue has garnered significant global attention, and the international community is eager to incorporate more policies and experiences that contribute to sustainable development [
69,
70]. As a crucial sector for global sustainable development, forestry requires a careful balance between economic progress and protection of the environment [
4]. By 2022, China’s forest area had reached 2.2 million square kilometers, accounting for 5% of the global land area. In terms of economic output, China’s forestry output value exceeded CNY 590 billion in 2020, a 1.37-fold increase from 2015 [
8]. It follows that China’s advantage in forestry development and its experience in harmonizing economic and environmental objectives position it uniquely. In recent years, China has emphasized forestry development through various policies, including the NECP. This paper examined the NECP from the perspective of forestry eco-efficiency research, aiming to offer new insights for global sustainability. On the basis of the above research significance, we used provincial data from 2011 to 2020 to conduct an empirical analysis using the DID model and the spatial Durbin model and drew the following conclusions.
First, in this paper, through hotspot clustering analysis, forestry eco-efficiency in each province is categorized into three categories: effective, semi-effective and ineffective. Our findings suggest that China’s average forestry eco-efficiency falls into the ineffective category, highlighting the need to optimize resource allocation within the sector.
Second, NECP significantly enhances forestry eco-efficiency, with robust findings across various stability tests. Thus, implementing government environmental policies can have a multiplier effect on forestry, i.e., it can synergize its economic development with environmental protection.
Third, in provinces with a strong ecological foundation, the NECP significantly enhances forestry eco-efficiency. However, in other provinces, the improvement is only moderate. Furthermore, while the NECP has a substantial positive impact in the eastern region, it has yet to show a discernible effect in other regions.
Lastly, the positive impacts of NECP implementation on forestry eco-efficiency have spatial spillover effects due to demonstration effects and comparative advantages.
The limitations of this paper and the future outlook are described first because forestry eco-efficiency may be characterized by a long period of effectiveness. This paper chose 10 years as the research period after referring to related research. However, our future direction is to adopt a more extended research period for related research. Second, in the construction of the indicators of forestry eco-efficiency, the non-expected output indicators applied in this paper were selected concerning relevant studies and data availability. However, when selecting such indicators, the limitation of data availability leads to a lack of comprehensiveness. This point will be the direction of our future research.