Evaluation model and promotion based on the ecological characteristics of Saihanba

. Saihanba Mechanical Forest Farm is an important sand source control project area in China.In order to promote the excellent case of Saihanba to other regions of the country and even the Asia-Pacific region, we have established a Saihanba ecological environmental impact model and ecological engineering construction assessment model, to provide suggestions for the establishment of ecological protection areas in China and even countries in the Asia-Pacific region. This paper determined the index of Saihanba ecological influence evaluation system using frequency analysis method and theoretical research method, determined the TOPSIS weight based on entropy weight method, to establish a complete ecological and environmental influence evaluation system. Subsequently, the paper introduced the data of relevant indicators around 1962 into the evaluation system, which got good scores, indicating that Saihanba has a great positive impact on the ecological environment. On the basis of problem 1, this paper had redefined the index and weight, established the index system based on the sandstorm background in Beijing, and brought the relevant data of Beijing in recent years into the model, and the establishment of Saihanba had played a relatively significant optimization effect on all the indicators of the sandstorm in Beijing. In view of problem 3, this article was first divided into 9 different ecological system service functional zones according to the National ecological function zoning (revised version) proposed by the Ministry of Environmental Protection and the Chinese Academy of Sciences. Meanwhile, based on the TOPSIS model, proposed a modified model based on DPSIR. The model fully omitted the impact of ecological, economic, policy and other factors on the construction of ecological protection areas .Meanwhile, multi-objective planning method based on genetic algorithm was used to solve the above problems to determine the best number and scale of ecological reserves in the region.


Restatement of the problem
China has always maintained that clear waters and green mountains are the ecological development force of gold and silver mountains.In China's state-owned forest farm, Saihanba Forest Farm, as an environmental model, has an extremely high ecological civilization value.According to the relevant situation of Saihanba, a mathematical model analysis was established to study the following problems: 1. According to the natural environmental conditions of Saihanba and relevant data and information, establish the Saihanba ecological environmental impact assessment model, analyze the impact of Saihanba on the local ecological environment, and quantify and compare the results before and after the recovery of Saihanba. 2. According to the model established in Question 1, study the wind and sand fixation in Beijing.According to the existing data and established indicators, the impact of Saihanba on Beijing against sandstorm capacity is evaluated, and the role of Saihanba in Beijing against sandstorms is evaluated. 3. Promote the ecological model of Saihanba, and multiple social and economic factors should be considered.By establishing which geographical locations are in China, ecological areas, ecological reserves are needed to be established, and the quantity and scale that need to be established.
semi-humid zone. It belongs to the transition zone of the Inner Mongolia Plateau and the Greater Hinggan Mountains, and the terrain is relatively complex.Saihanba machinery forest farm in the national Beijing-Tianjin sand source management engineering area, after more than 50 years of continuous cultivation and protection, part of the forest has been included in the national and provincial scope of forest ecological benefits compensation (Saihanba machinery forest farm forest resources quality analysis and evaluation), it has high ecological benefits, in wind resistance, environmental protection, maintaining ecological balance and stability have played an important role.

Construction of an ecological function evaluation system in Saihanba
3.1.2.1 Design and analysis of Saihanba ecological function evaluation system In order to evaluate the impact of Saihanba on the local environment before and after its construction is a relatively complex process, which involves many kinds of influencing factors. Therefore, we especially combine the function of the ecosystem and mainly consider the following aspects in the process of designing the Saihanba ecological function evaluation system: 2. water conservation.Water conservation is particularly important for the treatment of Saihanba wasteland, which refers to the ecosystem interception, penetration and accumulation of precipitation through its unique structure and water interaction, and realizes the regulation of water flow and water cycle through evaporation.
3. Soil conservation.The benefits of conservation soil in the recovery of Saihanba are obvious. 4. carbon fixation and oxygen release.Absorbing carbon dioxide and releasing oxygen is the most basic biological function of plants and an important ecological function of forest plants. 5. wind prevention and sand fixation.Wind protection and sand fixation is a kind of ecological construction activity carried out in arid and semi-arid in areas to maintain soil and water and prevent dust-arid storms. 6. Biodiversity maintenance.Biodiversity is the sum of the ecological complexes formed by organisms and the environment and the various ecological processes associated with this, including three levels: ecosystem, species, and genes.

Selection method of indicators
The establishment of the function index of the forest ecosystem system is the key to affect the ecological environment evaluation system. The relevant literature and data foundation of Saihanba in the forest evaluation system are relatively weak, so the determination of the evaluation index is particularly important.In this paper, theoretical analysis and frequency statistics are used to determine the ecological function evaluation indicators.

Saihanba ecological function evaluation indicators are determined
For the selection of evaluation indicators, we fully consider the impact of the system on the system, taking into account the data that we can find, and the indicators that we choose are as follows:

Computational steps of the TOPSIS model based on the entropy weights method
The TOPSIS method is a common comprehensive evaluation method that can make full use of the raw data information, and its results can accurately reflect the gap between the evaluation schemes.The entropy method is an objective empowerment method, which determines the weight of the index by calculating the index according to the influence of the relative degree of change on the system overall. The index with a large degree of relative change has a large weight.Organic combination of the two contributes to the more scientific determination of the weight.

Assessment level and classification of Saihanba ecological function level
According to the range of ecosystem functional level numerical scores derived from the TOPSIS model, the functional level evaluation level can be divided into 6 levels (A is the best, F is the worst), and the classification is divided in the The index of Saihanba to Beijing Problem 2 is an example analysis of problem 1, and in combining the indicators in the problem 1 windproof and sand fixation function, we expand the index of problem 1 through the theoretical analysis method and the frequency statistical method. The specific analysis is as follows: First of all, according to the sandstorm cause, we choose temperature, wind speed, annual sandstorm frequency and vegetation coverage, in order to improve the representative of sandstorm, meteorological and vegetation elements, we according to the seasonal distribution of sandstorm (Beijing and Tianjin sandstorm source management engineering area sandstorm spatial and temporal change and its vegetation recovery relationship), the occurrence of Beijing sandstorm has obvious seasonal, namely spring sandstorm frequency.In spring, the surface is bare and the vegetation is sparse, which provides sand source material for the sandstorm. At the same time, the air is dry and windy in spring, which provides conditions for the occurrence of dust storms, so we have narrowed the scope of meteorological indicators to spring.

Relevant judgment of annual dust storm frequency and vegetation coverage rate in Saihanba
According to the established fitting equation, the annual dust frequency is negatively associated with the Saihanba vegetation coverage rate, that is, the increased vegetation coverage rate in Saihanba contributes to the decrease of the annual dust frequency.

Relevant judgment of spring average temperature and vegetation coverage rate in Saihanba
According to the established fitting equation, the annual temperature is positively associated with the Saihanba vegetation coverage rate, that is, the increased vegetation coverage rate in Saihanba contributes to the annual temperature increase.

Relevant judgment of spring monthly wind speed and Saihanba vegetation coverage rate
According to the established fitting equation, the monthly wind speed in spring is negatively associated with Saihanba vegetation coverage, that is, the increased vegetation coverage in Saihanba contributes to the decrease of wind speed. According to the comprehensive evaluation of the above data, Saihanba is of great help to the wind and sand resistance capacity in Beijing.

Horizontal impact assessment of Saihanba on the sandstorm resistance capacity in Beijing
Subsequently, we plan to evaluate the evaluation of the dam on the sandstorm resistance ability of Beijing in the form of a pie chart. The predicted data results are as follows： Figure 6 Preast of sand resistance of three lines of defense Although Saihanba is of great help to Beijing against wind and sand, it is still relatively weaker than other lines of defense.

National ecological function division
The content studied in this section, to explore which areas of the country need to establish nature reserves, in order to simplify the model and let the model has wider applicability, we according to the national ecological function division (modified), the national divided into    The data before the construction of the ecological reserve were brought into the model to get the corresponding scores.

TOPSIS ecological environment evaluation system with carbon neutralization index
From the above data, we obtain that the region should establish nature reserves, and that the establishment of ecological reserves has had a good impact on carbon neutrality. 3.3.3.2 A multi-objective planning model based on the genetic algorithm solves the number and model of ecological reserves Taking into account the economic, political and ecological elements, we use the multi-objective planning method based on genetic algorithms to achieve the solution.We propose to establish [3], an evaluation system based on the DPSIR model.DPSIR, that is, driving force (D), pressure (P), state (S), impact index (I), response (R), which covers social, economic, environmental, human beings and many other factors, and more fully reflects the interaction relationship between human activities and the natural ecological environment. The construction of the ecological protection area has its particularity relative to the construction of other projects. We obtain authoritative and specific calculation formulas by consulting the relevant information, [4], and supplement the calculation formulas of several other dimensions: net present value (NPV) Internal rate of return (IRR)

Dynamic investment payback period
Profit cost ratio This model comprehensively considers the three ecological, economic and social benefits of ecological protection area construction, reflects the unique attributes of ecological engineering construction, and is of good help to the solution of this problem.Based on this, we solve the multi-objective planning problem described above using a genetic algorithm.