海河流域森林生态系统服务功能评估

森林生态系统在流域中发挥着极其重要的生态作用，为流域发展提供着巨大的服务功能。本研究根据生态系统服务功能的内涵，建立了流域森林生态系统服务功能评价指标体系，利用市场价值法、影子工程法和生产成本法等，定量评价了海河流域森林生态系统服务功能的经济价值。结果表明：海河流域森林生态系统总价值2349.4亿元，其中直接价值358.7亿元，间接价值1990.7亿元。从不同的服务功能类型来看，其价值量大小依次为：涵养水源>固碳释氧>环境净化>提供产品>土壤保持>营养元素循环；从不同的森林类型来看，其价值量大小依次为：松柏类>灌丛>栎类>桦木类>混交林>杨树类>松杉类。但是从各种森林类型单位面积价值量来看，大小依次是：松杉类>松柏类>桦木类>混交林>栎类>杨树类>灌丛。从研究结果来看，海河流域森林生态系统服务功能价值巨大，该结果有利于加强人们对森林生态系统的认识，可以为流域生态系统管理、生态保护和生态补偿提供依据。

Evaluation of the forest ecosystem services in Haihe River Basin, China

Rapid human population growth and urbanization have led to the loss of many ecosystem services. However to effectively manage ecosystems so they can provide enough food, fiber, fuel and other services for humanity is a great challenge. One of the most important terrestrial ecosystems is forest, which plays an important role in watershed management. Forests provide important services such as timber, nutrient cycling and soil conservation. To increase our understanding of how to balance economic development with environmental conservation, we used Haihe river basin as a case study to evaluate forest ecosystem services. The Haihe river basin, located in Northern China, covers an area of 3.2×10⁵ km². Haihe river basin is currently confronting many environmental problems making the protection of ecosystem services a high priority for sustainable development across the region. Haihe river basin possesses many environmental challenges such as water scarcity, water pollution and desertification that are exacerbated by rapid economic development and urbanization. The majority of primary forests and secondary forests have been destroyed for timber production despite reforestation effects resulting in the reduction of forest ecosystem services. An index system for forest ecosystem evaluation was established and the economic value of the forest ecosystem services were evaluated using a methodology that included market valuation, shadow price and opportunity cost. The results showed that the total value of Haihe river basin's forest ecosystems were 234.9 billion RMB, of which the direct value accounted for 35.9 billion RMB and the indirect value was 199.1 billion RMB. Water conservation, carbon sequestration and oxygen release, environmental purification account for 37.63%, 21.88% and 19.57% of the total value. These three services were the main ecosystem services in the watershed. Based on our results, the services could be arranged from the maximum to the minimum value as: water conservation (88.4 billion RMB), carbon sequestration and oxygen release (51.41 billion RMB), environmental purification (45.98 billion RMB), product offers (35.87 billion RMB), soil conservation (8.21 billion RMB) and nutrient cycling (5.08 billion RMB). Based on forest types, the value could be arranged from the maximum to the minimum as: conifer, shrub, robur, birch, mixed forest, polar and larch. Shrub, conifer and robur are the main forest types in the watershed, accounting for 47.60%, 26.00% and 15.29% of the total area. Shrub provided services that value to 67.32 billion, conifer to 90.59 billion and robur to 42.08 billion RMB, which account for 28.65%, 38.56%, and 17.91% of the total value. Shrub occupied the greatest area but did not provide the most services. However, larch had a small area (4.31%), yet had the greatest value per unit area (53.9 thousand RMB per hectare). When considering value per unit area, coniferous forest provided more services than broad-leaved forest. The research results show that the forest ecosystem provide an immense value to the Haihe river basin. This study highlights the importance of forest ecosystems and could help facilitate the protection as well as the management of forest ecosystems in Haihe river basin.