*2.3.1 The general characterization model of LCA*

Different ecological impact factors have different potential for the same type of environmental impact. Based on a certain ecological impact factor, the relative impact potential could be characterization [29]. Characterization is the main step to quantify the environmental impact intensity, which includes resource and energy consumption and waste discharge:

1.Consumption of resources and energy. Heat consumption is usually taken as a characteristic factor, and the material consumed in the system boundary is converted into a unified heat unit according to their energy consumption coefficients accumulated:

$$EC\_t = \sum\_{i}^{n} a\_i \times RC\_i \tag{1}$$

In the formula, *REi* refers to the standardized result of environmental impact factor *i*. *Ei* is the LCA characteristic quantity of environmental impact factor *i*, including both EC and EI. *Si*(2000) refers to the world per capita standardized

Resource and energy consumption MJ 2.59 � <sup>10</sup><sup>6</sup> 1.1 � <sup>10</sup>�<sup>1</sup> Global warming potential (GWP) kg CO2-e 6.87 � 103 1.2 � <sup>10</sup>�<sup>1</sup>

**Unit The reference value of**

**standardization unit/person [32]**

The weighted assessment is based on the actual environmental load of each environmental impact factor to determine the weighted coefficient, which is used to

*i*

In the formula, *WEs* is the weighted value of environmental impact within the boundary of the LCA system. *Wi* is the weighted value of environmental impact

Standardized reference values and weight coefficients of two environmental impact factors, resource and energy consumption and climate warming potential

In the environmental ecology research, LCA has been widely used in plant nursery, forestry management, and agricultural production. *Lazzerini* assessed the carbon emissions of two types of nursery plant cultivation (in-pot and on-field) in Tuscany (Italy). Guided by LCA, this study summarized the carbon emissions of farm structure, aboveground structure, input of cultivation, and packaging in nursery cultivation. He pointed out the GHG emission of in-pot cultivation was 7.4–

on-field cultivation [34]. *Berg* summarized the energy consumption and carbon emissions in Sweden's forestry management process by LCA. The forestry life cycle

includes seedling production, silviculture, logging, and haulage to the wood processing plant. In Sweden forestry, the energy consumption (in m<sup>3</sup> wood unit) is

, which was much higher than that of 0.6–1.0 kg CO2/m<sup>2</sup>

. The energy consumption and carbon emissions in logging and transportation are the most obvious, accounting for more than 60% of the total amount [35]. *Ingram* used LCA method to study the management carbon footprint of red maple forest during planting. The life cycle of the study included 1-year seedling production and 4-year seedling field management. It was found that the carbon emission (CO2-eq) footprints were 2.9 kg/plant for tube feeding materials and the consumption of fuel and energy was 10.3 kg/plant during production, at a distance. In 386 km of transportation, 4.0 kg/plant and 3.3 kg/plant in planting and landscape sites, the most carbon emissions were from production to planting, accounting for 17.7 kg/plant and accounting for 86% of the total greenhouse gas emissions [36]. Haas et al. assessed the environmental impacts of intensive, extensive, and organic forage management in 18 grasslands in Allgau, Bavaria, and southwestern Germany

, and the carbon emissions (CO2-eq) is about 12.5–17.1 kg/

*Wi* � *REi* (3)

**Weight coefficient [33]**

/y�<sup>1</sup> of

*WEs* <sup>¼</sup> <sup>X</sup>*<sup>n</sup>*

*Reference values and weight coefficients of some environmental impact characteristic factors.*

benchmark of environmental impact factor *i* in 2000.

**2.4 The application of LCA on ecological research**

revise the standardized results of LCA system:

factor *i*.

**Table 1.**

26.5 kg CO2/m<sup>2</sup>

m3 /y�<sup>1</sup>

**225**

about 150–200 MJ/m<sup>3</sup>

(GWP), are shown in **Table 1**.

**The characterization factors of environmental impact**

*Sustainable Design in Urban Green Space DOI: http://dx.doi.org/10.5772/intechopen.90026*

/y�<sup>1</sup>

/y�<sup>1</sup>

In the formula, *ECs* is the characteristic quantity of resource and energy consumption; take MJ as a characteristic index. *RCi* is the consumption of material *i* in a certain process of the system. *α<sup>i</sup>* is the equivalent coefficient of material *i*. At present, GB/T 2589-2008 standard offered majority kinds of materials in coal calorific equivalent coefficient.

2.Waste discharge. At present, a unified equivalent model has been established for the environmental impact of the LCA system on climate warming, environmental acidification, eutrophication, and environmental toxicity. The *EIs* of an environmental impact factor in the waste generated within the system boundary can be calculated by the following formula:

$$EI\_s = \sum\_{i}^{n} \beta\_i \times EC\_i \tag{2}$$

In the formula, *ECi* refers to the emission amount of factor *i* in waste discharge characteristic factors. *β<sup>i</sup>* is the equivalent coefficient of factor *i*. The coefficients of factors CO2, CH4, and N2O are 1, 21, and 310, respectively [30].

#### *2.3.2 Standardization and weighted assessment of LCA characteristic result*

Standardization refers to the ratio between the LCA characteristic quantity of an environmental impact factor and the regional total or average quantity of the factor, with the aim of eliminating the difference in dimension and series of each environmental impact factor. At present, data of energy and resources and emissions of environmental waste per capita in the world in 2000 are mostly used as standardized reference in the field of environment [31]. The calculation process is as follows:

$$RE\_i = E\_i / \mathcal{S}\_{i(2000)}$$


**Table 1.**

Currently the word mainstream database includes "ecoinvent" in Europe and

Different ecological impact factors have different potential for the same type of

1.Consumption of resources and energy. Heat consumption is usually taken as a characteristic factor, and the material consumed in the system boundary is converted into a unified heat unit according to their energy consumption

environmental impact. Based on a certain ecological impact factor, the relative impact potential could be characterization [29]. Characterization is the main step to quantify the environmental impact intensity, which includes resource and energy

*ECs* <sup>¼</sup> <sup>X</sup>*<sup>n</sup>*

system boundary can be calculated by the following formula:

factors CO2, CH4, and N2O are 1, 21, and 310, respectively [30].

*2.3.2 Standardization and weighted assessment of LCA characteristic result*

*EIs* <sup>¼</sup> <sup>X</sup>*<sup>n</sup> i*

materials in coal calorific equivalent coefficient.

*i*

In the formula, *ECs* is the characteristic quantity of resource and energy consumption; take MJ as a characteristic index. *RCi* is the consumption of material *i* in a certain process of the system. *α<sup>i</sup>* is the equivalent coefficient of material *i*. At present, GB/T 2589-2008 standard offered majority kinds of

2.Waste discharge. At present, a unified equivalent model has been established for the environmental impact of the LCA system on climate warming, environmental acidification, eutrophication, and environmental toxicity. The *EIs* of an environmental impact factor in the waste generated within the

In the formula, *ECi* refers to the emission amount of factor *i* in waste discharge characteristic factors. *β<sup>i</sup>* is the equivalent coefficient of factor *i*. The coefficients of

Standardization refers to the ratio between the LCA characteristic quantity of an environmental impact factor and the regional total or average quantity of the factor, with the aim of eliminating the difference in dimension and series of each environmental impact factor. At present, data of energy and resources and emissions of environmental waste per capita in the world in 2000 are mostly used as standardized reference in the field of environment [31]. The calculation process is as

*REi* ¼ *Ei=Si*ð Þ <sup>2000</sup>

*α<sup>i</sup>* � *RCi* (1)

*β<sup>i</sup>* � *ECi* (2)

"Chinese life cycle database" (CLCD) in China [26].

**2.3 The quantitative method of LCA**

*Sustainability in Urban Planning and Design*

consumption and waste discharge:

coefficients accumulated:

follows:

**224**

*2.3.1 The general characterization model of LCA*

*Reference values and weight coefficients of some environmental impact characteristic factors.*

In the formula, *REi* refers to the standardized result of environmental impact factor *i*. *Ei* is the LCA characteristic quantity of environmental impact factor *i*, including both EC and EI. *Si*(2000) refers to the world per capita standardized benchmark of environmental impact factor *i* in 2000.

The weighted assessment is based on the actual environmental load of each environmental impact factor to determine the weighted coefficient, which is used to revise the standardized results of LCA system:

$$\text{WE}\_{\text{s}} = \sum\_{i}^{n} \mathbf{W}\_{i} \times \text{RE}\_{i} \tag{3}$$

In the formula, *WEs* is the weighted value of environmental impact within the boundary of the LCA system. *Wi* is the weighted value of environmental impact factor *i*.

Standardized reference values and weight coefficients of two environmental impact factors, resource and energy consumption and climate warming potential (GWP), are shown in **Table 1**.
