冀北山地4种典型林分固碳释氧效益估算

为探究冀北山地4种典型林分固碳释氧效益，以落叶松纯林、白桦林、山杨林与云杉林作为研究对象，通过将4种林分的蓄积量、生物量、C密度、O₂释放量4个指标为基础对4种林分固碳释氧的效益进行了评价分析，结果表明:（1）云杉林的生物量除了中龄林其生物量都要高于其他3种林分，阔叶林生物量在中幼龄期增长速度比较快，近熟期与成熟期增长速度较慢，而针叶林则相反。（2）4种林分C密度由大到小排序，幼龄林:云杉林 > 白桦林 > 山杨林 > 落叶松纯林，中龄林:白桦林 > 山杨林 > 云杉林 > 落叶松纯林，近熟林:云杉林 > 白桦林 > 落叶松纯林 > 山杨林，成熟林:云杉林 > 山杨林 > 落叶松纯林 > 白桦林，云杉林除了中龄期其C密度都是最大的；4种林分O₂释放量由大到小排序，幼龄林:云杉林 > 白桦林 > 山杨林 > 落叶松纯林，中龄林:白桦林 > 山杨林 > 云杉林 > 落叶松纯林，近熟林:云杉林 > 落叶松纯林 > 山杨林 > 白桦林，成熟林:云杉林 > 山杨林 > 落叶松纯林 > 白桦林。（3）4种林分中固碳释氧总价值随龄林的增加呈单峰曲线，针叶林在近熟林时达到最大价值量，而阔叶林在中龄林时达到最大价值量；不同林分整个生命周期平均固碳释氧总价值排序为:云杉林[9 696元/（hm²·a）] > 山杨林[8 654元/（hm²·a）] > 落叶松纯林[7 704元/（hm²·a）] > 白桦林[7 555元/（hm²·a）]，说明云杉林固碳释氧的总价值是最高的，而白桦林的固碳释氧总价值最低。

Estimating the Benefits of Carbon Sequestration and Oxygen Release from Four Typical Stands in the Mountainous Region of North Hebei Province

In order to explore the efficiency of carbon fixation and release of oxygen in 4 typical forests in the northern Hebei Province, the evaluation and analysis of the efficiency of carbon release and release of oxygen in the 4 stands were performed based on the volume of the four species, biomass, C density, and the amount of O₂ release. The results showed that:(1) except biomass of middle age spruce stand the biomass of spruce was higher than that of the other three species; the growth rates of the biomass in the medium and young ages was faster, the growth rate was slower in the near ripening period and the mature period, while the coniferous forest was the opposite; (2) the C density of 4 species decreased in the oder, young forest, spruce forest > birch forest > Yang Lin > Larix pure forest; middle age forest:white birch forest > poplar > spruce > pure forest, near ripening forest:the spruce forest > birch forest Larix pure forest > poplar, mature forest:spruce forest > poplar forest > pure forest > birch forest > spruce forest; in the middle age forest; the C density was the largest; the 4 kinds of forest O₂ release decreased in the order, young forest:spruce forest > birch forest > poplar > Larix pure forest, middle age forest:white birch forest > poplar > spruce > pure forest, Larix pure forest, spruce forest > Larix pure forest > poplar > white birch forest, mature forest:spruce forest > poplar > Songchunlin > birch forest; (3) the total value of carbon fixation and oxygen release in the 4 stands showed a single peak curve with the increase of the age forest, and the coniferous forest reached the maximum value in the near mature forest, while the broad-leaved forest reached the maximum value in the middle age forest; the average value of oxygen release and the carbon sequestration in the whole life cycle of the different stands decreased in the order:spruce forest[9 696 yuan/(hm²·a)] > poplar[8 654 yuan/(hm²·a)] > Larix gmelinii pure forest[7 704 yuan/(hm²·a)] > Betula platyphylla[7 555 yuan/(hm²·a)], indicating that the total value of carbon fixation and release of oxygen in spruce forest was the highest, while the total value of carbon sequestration in white birch forest was the lowest.