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Introduction
Since 2008, more than half of the world’s population has lived in urban area. The urban population is expected to increase up to 5 billion inhabitants by 2030 (Economic and Social Affairs [ESA], 2006). The growth of the population has resulted in a reduction of natural areas (Barsky, 2005; Shi, 2003) and loss of ecosystem services (Franquis & Infante, 2003). The creation of a greenbelt could be the answer to the need for environmental protection, the threat of urban sprawl, and to the loss of open spaces (Chervin, Gibson, & Green, 2009).
A greenbelt is a “green” structure that helps to stop urban sprawl, preserve biodiversity and safeguard the land for recreation, agriculture, and forestry (Amati, 2008). During the twentieth century, a few greenbelts have been established around cities such as London (1938), Copenhagen (1947), and Frankfurt (1991). It is well documented that these green infrastructures have preserved natural zones and have given the surrounding populations access to a better quality of life (Brander & Koetse, 2011). More recently, the Canadian government decided to create an initiative for the Greater Golden Horseshoe (Ministry of Finance, 2012) area covering 728 000 ha. The goal of this initiative was to safeguard environmentally sensitive land, watersheds, and farmlands (Wilson, 2008). These greenbelts were established following an economic valuation confirming their importance in terms of supplying ecosystem services (Herath, Choumert, & Maier, 2015; Wilson, 2008).
Forests, from the perspective of a greenbelt, provide, among other benefits, watershed protection, carbon sequestration, and biodiversity conservation (Wilson, 2008). In terms of watershed protection, forests play an important role in regulating hydrological flows and reducing pollutants and sedimentation (Pagiola, Landell-Mills, & Bishop, 2002). In addition, the wooded area represents the head of the basin of the city´s water sources, both underground and surface (Legay, Cloutier, Chakhar, Joerin, & Rodriguez, 2015). This ecosystem brings at least two benefits: first, the ecosystem absorbs carbon dioxide from the atmosphere and stores it in the form of organic carbon in the plant and root biomass of various species over a period of time (Kulshreshtha, Lac, Johnston, & Kinar, 2000). Second, the biodiversity conservation in the wooded areas represents a significant proportion of the world’s diversity. Every reduction of the whole area implies the loss of habitats and consequently the lost of species (Pagiola et al., 2002).
De Groot, Alkemade, Hein, and Willemen (2010) and Hackbart, de Lima, and dos Santos (2017) emphasized the relevance of estimating the economic value of different ecosystem services because of the need for sustainable natural resource use. It is feasible to evaluate the ecosystem services in terms of market prices (King & Mazzotta, 2000; Mundell, Taff, Kilgore, & Snyder, 2010). As an alternative, some studies apply indirect market valuations associated with methods such as replacement cost (Alam et al., 2014) and avoided cost (Samuelson & William, 2002) due to their efficiency (Aznar-Bellver & Estruch-Guitart, 2015). Schild, Vermaat, and van Bodegom (2017) concluded that monetary valuation is at least a function of the two elements: valuation method and type of ecosystem. In addition, Alam et al. (2014), Pandeya et al. (2016), Schild et al. (2017), and Spangenberg and Settele (2010) have emphasized the importance of having sustainable data available.
Based on the ecosystem, valuation method and context of study (use of real data), the general objective of the present study was to estimate the values of three ecosystem services of the forestland around Quebec City and compare them with previous studies. Based on the literature, this study focus on the most important services provided by the forest, namely water supply and quality, air quality, and habitat (Wilson, 2008).
Materials and methods
Study area
Quebec province is located east of Ontario province and Hudson Bay, south of Nunavut and the Davis Strait, west of the Maritime Provinces and Labrador and north of several states in the United States of America (New York, Vermont, New Hampshire and Maine). More than 90 % of Quebec’s area is part of the Canadian Shield. Quebec City is located in the Saint-Lawrence valley, on the north bank of the Saint Lawrence River near the St. Charles River. The river valley has rich arable land and the region is the most fertile in the province. In addition, the river, Lake St. Charles and the Montmorency River are sources of drinking water for Quebec City and are in the heart of the forest. Quebec City’s forest area, which is contemplated to be part of the greenbelt, covers mainly the northern ring of the city and affects Laurentian, La Haute-Saint-Charles, Charlesbourg, Beauport and a small part of the Rivières. Quebec City covers 45 400 ha and the forest occupies 35 % of the city, representing approximately 15 998.96 ha.
Assessment of ecosystem services
A total cost of three ecosystem services (water supply and quality, air quality and forest habitat) was estimated to represent the value of a green belt around Quebec City. For this, four valuation methods were used: replacement cost for water supply, cost-effectiveness for water quality, avoided cost for air quality and market price for forest habitat.
Total water service value
This value is obtained by adding together the water supply value and water quality value. Different methods were used for estimating each service value.
Based on the replacement cost method (De Groot, Matthew, & Roelof, 2002), the water supply value was obtained using data for potable water services, wastewater treatment costs, amortization, and rented services from the year 2015; data correspond to the Quebec City municipality (Gouvernement du Québec, 2016). The replacement cost method was used because it is the way that the water source is supplied to Quebec City. The municipality of Quebec, through the water provisioning and treatment plant system, has partially replaced the ecosystem service to provide water to the Quebec City population. The annual water supply value was divided into the total hectares of the forestland around Quebec City (Infrastructure de Géomatique Ouverte [IGO], 2017). The total water supply value was reported on a per-hectare basis.
Based on the cost-effectiveness method (Balana, Vinten, & Slee, 2011), the water quality value was obtained using the costs of decontamination and sediment degradation reported by Alam et al. (2014). The data correspond to prices paid to a treatment plant for the nitrogen, phosphorus, and sediments located in Ontario, Canada for the period 2005-2008. The water quality value was obtained using the following formula:
Vwater = LN * CdN + LP * CdP + S * Cdeg
where,
Vwater |
water quality value per hectare |
LN |
reduced nitrogen (N) leaching rate |
CdN |
N decontamination cost |
LP |
phosphorus (P) leaching rate |
CdP |
P decontamination cost |
S |
sedimentation rate |
Cdeg |
degradation cost. |
The nitrogen leaching losses are about 11 kg N·ha-1 (Alam et al., 2014). MacDonald and Bennett (2009) estimated the phosphorus leaching loss in the south of Quebec between 15 and 22 kg·ha-1. If the same percentage of reduction in the nitrogen is considered in the phosphorus, the quantity would be 7.5 kg·ha-1 (Alam et al., 2014).
The cost for removing the excess of nutrients in water treatment plants was reported in USD 6.53·kg-1 N (Olewiler, 2004) and USD 47.05·kg-1 P (Jiang, Beck, Cummings, Rowles, & Russell, 2005). The estimated cost for sediment retention was USD 5.25·ha-1 (Wilson, 2008). Therefore, the water quality cost was obtained by adding the cost for removing the excess of nutrients and the cost of sediment retention. Afterwards, the water quality cost was updated to 2017 using the Industrial Products Price Index (Statistics Canada, 2018) and divided into the total hectares of the forestland around Quebec City.
Air quality (carbon sequestration)
Carbon sequestration valuation was obtained based on the avoided cost method. For this case, the methodology proposed by Wilson (2008) was used in order to estimate the carbon captured by the forest, per hectare, and then multiply it by the market price. According to the same author, the average net carbon sequestration in a forestland area is 2.26 t C·ha-1 representing the immobilization of 8.3 t CO2·ha-1 (1 t of carbon = 3.67 t of carbon dioxide). The 2014 carbon market price data was obtained from the publication Report of the Auditor General of Quebec to the National Assembly for 2016-2017 (Report of the Sustainable Development Commissioner [RSDC], 2016) and were updated to 2017 through the Industrial Gas Price Index (Statistics Canada, 2018).
Habitat
A value of the habitat was estimated based on the market price method (King & Mazzotta, 2000; Pagiola et al., 2002). The source for market price and land typology was the database of the Ministry of Municipal Affairs and Territorial Occupation (MAMOT, 2016). The typology provides data about the real estate category, valued units per the real estate category and the standard value per unit on July 1, 2015 (Québec Federation of Real Estate Boards [QFREB], 2017). According to the typology, there are three land categories: Farmland, Non-residential and Other. This last category involves any type of forest area and it is used to estimate the habitat value per hectare. Thus, the number of valued units is multiplied by the standard value, and the result represents the forestland value for an area of 15 998.96 ha.
Results and discussion
Water supply and water quality
Water Supply
The municipal service value for the supply and treatment of drinking water and wastewater treatment was estimated by adding together operational cost and amortization and then subtracting rented services (Table 1). Based on replacement cost, a water supply value of USD 1 983.99·ha-1 was obtained. Every year, Quebec City provides the financial resources for supplying and treating water and therefore avoids extracting water from the forestland aquifers for residential water needs. Otherwise, the forest in an area of 15 998.96 ha around Quebec City would supply the water requirements.
Table 1 Cost, amortization and rented services related to water supply and wastewater treatment in Quebec City (2017).
| Item | Cost | Amortization | Rented Services | Total Municipal service value | |||
|---|---|---|---|---|---|---|---|
| (Thousand CAD·year-1) | (Thousand CAD·year-1) | (CAD·ha-1 ·year-1) | (Thousand USD·year-1) | (USD·ha-1 ·year-1) | |||
| Supply and treatment | 14 668 | 4 998 | 77 | 19 589 | 1 224.38 | 15090 | 943.17 |
| Wastewater treatment | 12 553 | 9 908 | 844 | 21 617 | 1 351.15 | 16 652 | 1 040.82 |
| Total water supply value | 41 206 | 2 575.53 | 31 742 | 1 983.99 | |||
Since the Quebec government absorbs the financial costs of water supply year after year, Quebec residents have little appreciation of the water supply value; therefore, the contingent approach would not be a correct alternative valuation method (Alam et al., 2014). Based on the replacement cost, Wilson (2008) obtained a value of USD 1 428.90·ha-1. This value is lower than that estimated for water supply in the present study. Thus, although the same valuation method was used in the two studies, different human-made systems were used. Using the CITYGreen software, Wilson (2008) determined a construction cost for water runoff control of USD 53.48·m-3, whereas in the present research, the cost of the water supply through physical infrastructure was USD 75.22·m-3. Dupras et al. (2015) analyzed different studies and obtained a water supply average value of USD 464.36·ha-1 for the Greater Montreal rural areas. The study carried out by Wilson (2008) assumed a potential number for storm water runoff within an area, whereas the present research calculated the value using real data.
Water quality
Based on the cost-effectiveness method, the water quality value considered the following values: USD 96.18·ha-1·year-1 for N, USD 441.37·ha-1·year-1 for P, and USD 4.71·ha-1·year-1 for sediment retention. The total water quality value was USD 542.26·ha-1·year-1 for 2017 (Table 2).
Table 2 Costs of decontamination and sediment degradation required for guaranteeing the water quality in Quebec (2017).
| Item | Quantity (kg·ha-1·year-1) | Price (CAD·kg-1·ha-1) | Water quality Value | |
|---|---|---|---|---|
| (CAD·ha-1·year-1) | (USD·ha-1·year-1) | |||
| N decontamination | 11.0 | 11.35 | 124.86 | 96.18 |
| P Decontamination | 7.5 | 76.40 | 572.97 | 441.37 |
| Sediment degradation | 1.0 | 6.12 | 6.12 | 4.71 |
| Total water quality value | 703.95 | 542.26 | ||
Alternative studies of water quality valuation were reported by Wilson (2008) based on the avoided method, and by Alam et al. (2014) based on the cost-effectiveness method. These authors obtained values of USD 473.98·ha-1 and USD 505.27·ha-1 respectively. Dupras et al. (2015), based on several studies, obtained an average value of USD 107.10·ha-1 for the Greater Montreal rural areas. Therefore, although the same method used in the present study was used by Alam et al. (2014), the difference obtained can be explained by the market prices of the nutrients used. Comparing the lowest values of the avoided cost and cost-effectiveness methods, the difference between the two can be explained by the efficiency of the forest ecosystem. Wilson (2008) reported a 20 % increase in water treatment costs for each 10 % loss in forest cover.
Air quality (carbon sequestration)
Based on the avoided cost method, total carbon value was estimated at USD 1 179 443.33·year-1 (Table 3). The study considered a carbon value of USD 73.72·ha-1 for 15 998.96 ha of forestland area around Quebec City.
Table 3 Income paid to the Green Fund for carbon sequestration auctions in Quebec City (2017).
| Quebec carbon auction | Income paid to Green Fund | CO2 value | Carbon value (factor [t·ha-1] = 8.29) | ||
|---|---|---|---|---|---|
| Date | CO2 sold units (t) | (CAD) | (CAD·t-1) | (CAD·ha-1) | (USD·ha-1) |
| March, 2014 | 1 035 000 | 11 788 650 | 11.39 | 94.42 | 85.64 |
| May, 2014 | 1 049 111 | 11 949 374 | 11.39 | 94.42 | 86.25 |
| August, 2014 | 694 000 | 7 904 660 | 11.39 | 94.42 | 87.21 |
| November, 2014 | 1 049 114 | 14 351 880 | 13.68 | 113.41 | 101.42 |
| Total 2014 | 3 827 225 | 45 994 564 | 12.02 | 99.63 | 90.20 |
| Updated prices to 2017 | 3 827 225 | 44 182 289 | 11.54 | 95.70 | 73.72 |
Kulshreshtha et al. (2000), using the replacement cost method for afforestation and reforestation and obtained values of USD 24.73·ha-1 and USD 26.62·ha-1, respectively. Dupras et al. (2015), based on several studies, obtained an average value and a maximum value of USD 37.52·ha-1 and USD 90.68·ha-1, respectively, for the Greater Montreal rural areas. Wilson (2008), using the avoided cost method in the Southern Ontario Greenbelt, obtained a value of USD 39.11·ha-1. Van Kooten et al. (2000), based on the avoided cost, obtained a carbon cost of USD 81.74·ha-1 for forestland in western Canada. According to different estimations, the estimated carbon value in the present research was higher than the value obtained by Wilson (2008) and Kulshreshtha et al. (2000), but lower than that obtained by van Kooten et al. (2000). The present study used market prices to obtain the values, whereas other authors used indirect market prices. Using market prices indicated how much the economic agent was willing to pay for the air quality service.
Habitat
The market price method was used and it was based on real estate characteristics according to the MAMOT (2016). This method measures the value that an economic agent would pay for the habitat (King & Mazzotta, 2000). The following values were obtained for land categories (Table 4).
Table 4 Market prices of three real estate categories for habitat estimates in Quebec City (2017).
| Real estate category | Standard value (CAD·unit-1) | Valued units | Forestland | ||
|---|---|---|---|---|---|
| Area (ha) | Value (CAD·ha-1) | Value (USD· ha-1) | |||
| Farmland | 29.80 | 111 753 | |||
| Non-residential | 230.80 | 231 944 | |||
| Other | 59.30 | 659 494 | 15 998.96 | 2 517.78 | 1 939.50 |
The total valued forestland area was 15 998.96 ha with 659 494 units valued. Therefore, the value of forestland in the present study was approximately estimated at USD 1 939.50·ha-1. Snyder et al. (2007), based on the hedonic method, obtained an average value for forestland in Northern Minnesota of USD 2 324.00·ha-1. Variables such as the presence of lake frontage or river frontage and purchasing a place in which to enjoy the wildlife explained the forestland value to a significant degree. Dupras et al. (2015) obtained an average value of USD 2 382.80·ha-1 for the Greater Montreal rural areas. Wilson (2008) valued the biodiversity of the Ontario greenbelt considering three ecosystem services, namely pollination, biodiversity, and recreation. The habitat value was USD 1 774.27·ha-1 and two valuation methods were used: replacement cost used for biodiversity and contingent cost for recreation. Thus, the present study estimated a habitat value lower than the values estimated by Snyder et al. (2007) and higher than the value estimated by Wilson (2008). Difference between estimated values in the present study and the Snyder et al. (2007) study can be explained by the valuation method used as well as the market price location. In particular, the market price location is determined by local supply and demand and a property´s conditions (Monson, 2009). Regarding the study carried out by Wilson (2008), in which the habitat value is defined as the cost of restoration, the difference between estimated values can be explained by the valuation method used.
Total Economic Value
In the present research, the economic value corresponding to the three ecosystems (water supply and quality, air quality and habitat) was USD 4 539.48·ha-1. Thus, the total economic value for 15 998.96 ha of forest area around Quebec City was USD 72 627 025.00·year-1 (Table 5).
Table 5 Estimated economic values of three ecosystem services in Quebec City (2017).
| Ecosystem service | Value per hectare | Total value (15 998.96 ha) | ||
|---|---|---|---|---|
| (CAD·ha-1) | (USD·ha-1) | (CAD) | (USD) | |
| Water supply | 2 575.53 | 1 983.99 | 41 205 782 | 31 741 780 |
| Water quality | 703.95 | 542.27 | 11 262 449 | 8 675 729 |
| Air quality (carbon sequestration) | 95.70 | 73.72 | 1 531 124 | 1 179 461 |
| Habitat | 2 517.78 | 1 939 50 | 40 281 852 | 31 030 055 |
| Total ecosystem value | 5 892.96 | 4 539.48 | 94 281 208 | 72 627 025 |
The highest ecosystem values were attributed to the water supply and habitat services. These ecosystem services were based on the replacement and market price methods respectively. The lowest estimated value was attributed to the air quality service based on the avoided cost method.
Authors such as Alam et al. (2014) and Wilson (2008) obtained an estimated value of USD 2 395.08·ha-1 and USD 3 684.68·ha-1 for an intercropping forest in Quebec and for the Southern Ontario Greenbelt, respectively. These estimates were based on, among other factors, air quality, water runoff control, water filtration, and habitat services of the greenbelt. Dupras et al. (2015), considering information from several studies, obtained an average value of USD 3 277.92·ha-1 for the forest and wetlands of the Greater Montreal rural area. Therefore, the total economic value corresponding to the three ecosystems considered in the present study was higher than the total economic value obtained by other authors.
Although several authors considered a similar forest biomass, the estimated economic values showed differences for the water supply and quality (Dupras, Alam, & Revéret, 2015; Wilson, 2008), carbon sequestration (Kulshreshtha et al., 2000; Van Kooten, Krcmar-Nozic, Van Gorkom, & Stennes, 2000; Wilson, 2008), and the forest habitat (Dupras et al., 2015; Snyder, Kilgore, Hudson, & Donnay, 2007; Wilson, 2008).
Conclusions
In the present study, the economic valuations of three of the most important ecosystem services supplied by the forest were estimated and compared in Quebec City. This study confirmed the relevance of considering two criteria for determining the economic ecosystem valuations: the type of forest and the valuation method. In addition, the results underline the importance of using real instead of assumed data. Variation between our estimates and the values reported in other studies resulted from comparison of different valuation methods, efficiency level between forest and human-made systems, and market price sources used for ecosystem valuation.
