塞罕坝北曼甸林场森林生态功能等级评价

Grade evaluation of forest ecological function forBeimandian Forest Farm of Saihanba, Hebei Province of northern China

【目的】塞罕坝机械林场是全球最大的人工林场,2017年被联合国授予“地球卫士奖”,如何科学评价造林对塞罕坝森林生态功能恢复的贡献显得尤为重要,本研究旨在从不同角度分析塞罕坝森林生态功能现状,为未来森林经营提供理论依据。【方法】基于GB/T 26424−2010《森林资源规划设计调查技术规程》,采用森林蓄积量、森林自然度、森林群落结构、物种结构、植被总覆盖度、郁闭度、平均树高和枯枝落叶厚度8个评价因子对塞罕坝北曼甸林场各类森林进行生态功能等级评价。【结果】北曼甸林场有林地的森林生态功能指数平均为0.488,其中生态功能等级达到较好水平的林分占总林分的3.8%;生态功能等级达到中等水平的占总林分的52.7%;生态功能等级为较差的林分占42.4%;生态功能等级为差的林分占1.1%。不同森林起源的生态功能指数表现为:天然林(0.545)>人工林(0.474)。不同森林类型的生态功能指数排序为:针阔混交林(0.710)>阔叶混交林(0.617)>白桦天然次生林(0.535)>针叶混交林(0.487)>落叶松人工林(0.478)>云杉人工林(0.443)>樟子松人工林(0.429)。不同龄组的森林生态功能指数排序为:过熟林(0.588)>中龄林(0.512)>近熟林(0.509)>成熟林(0.504)>幼龄林(0.434)。【结论】经过近60年的造林工程,北曼甸林场各类森林生态功能相较于沙荒地有了显著提升,但人工林生态功能仍具有较大的提升空间,结合近自然经营理念需要对人工林进行必要的近自然改造。

[Objective]Saihanba Mechanical Forest Farm,Hebei Province of northern China,is the largest plantation forest farm in the world,it has been awarded the“Earth Guardian Award”by the United Nations in 2017.Thus,it is particularly important to scientifically evaluate the contribution of afforestation to the restoration of Saihanba forest ecological function.This study aimed to analyze the current situation of Saihanba forest ecological function from different aspects and provide a theoretical basis for future forest management.[Method]The ecological function grade of various forests in Beimandian Forest Farm in Saihanba had been evaluated based on Technical Regulations for Inventory for Forest Management Planning and Design(GB/T 26424−2010)with 8 evaluation factors of forest volume,forest naturalness,forest community structure,species structure,total vegetation coverage,canopy density,mean tree height and litter thickness.[Result]The forest ecological function index of Beimandian Forest Farm of Saihanba was 0.488,in which the stand with good ecological function grade accounted for 3.8%,the stand with medium ecological function grade accounted for 52.7%,the stand with bad ecological function grade accounted for 42.4%and the stand with worse ecological function accounted for 1.1%.The ecological function index of different stand origins was as follows:natural forest(0.545)>planted forest(0.474).The ecological function index of different forest types was as follows:mixed forest of needleleaf and broadleaf species(0.710)>mixed forest of broadleaf species(0.617)>Betula platyphylla natural secondary forest(0.535)>mixed forest of needleleaf species(0.487)>Larix principis-rupprechtii plantation(0.478)>Picea asperata plantation(0.443)>Pinus sylvestris var.mongolica plantation(0.429).The ecological function index of different age groups was as follows:over-mature forest(0.588)>middling forest(0.512)>near-mature forest(0.509)>mature forest(0.504)>young forest(0.434).[Conclusion]The forest ecological function of Beimandian Forest Farm has significantly improved after nearly 60 years of afforestation projects compared with sandy wasteland.However,the ecological function of artificial forests still has great space for improvement.The artificial forests should be subject to necessary management combined with the concept of near natural management.