In order to explore the effects of different forest types on active soil carbon pool, the amounts and density of soil organic carbon （SOC） were studied at different soil horizons under typical coniferous and broad-l...In order to explore the effects of different forest types on active soil carbon pool, the amounts and density of soil organic carbon （SOC） were studied at different soil horizons under typical coniferous and broad-leaved forests in the mountainous area of Beijing. The results showed that the amount of total SOC, readily oxidizable carbon and particulate organic carbon decreased with increasing depths of soil horizons and the amounts at depths of 0-10 cm and 10-20 cm in broad-leaved forest was clearly higher than that in coniferous forests. The trend of a decrease in SOC density with increasing depth of the soil horizon was similar to that of the amount of SOC. However, no regular trend was found for SOC density at different depths between coniferous forest and broad-leaved forests. The ratio of readily oxidizable carbon to total amount of SOC ranged from 0.36-0.45 and the ratio of particulate organic carbon to total amount of SOC from 0.28-0.73; the ratios decreased with increasing depths of soil horizons. Active SOC was significantly correlated with total SOC; the relationship between readily oxidizable carbon and particulate organic carbon was significant. A broad-leaved forest may produce more SOC than a coniferous forest.展开更多
This paper presents a general standard for the low-benefit black locust （Robinia pseudoacacia L.） torests m Loess Plateau based on defining the concept of “tri-low forest”, and emphasizes the major factors which r...This paper presents a general standard for the low-benefit black locust （Robinia pseudoacacia L.） torests m Loess Plateau based on defining the concept of “tri-low forest”, and emphasizes the major factors which result in low-benefit black locust, such as, lack of soil moisture of forest and nutrient, breaching the principle of matching tree species to sites, and high density of forests. Based on different characteristics of low-benefit forests, following the principle of “adjusting measures to local conditions, giving priority to ecological benefits, assisting with economic benefits”, the authors put forward some technical ways to reform low-benefit black locust forests, for example, taking measurements of collecting runoff and storing water, lowering the forest density, introducing mixed forests and transforming species, directive breeding and so on.展开更多
冠层气孔导度(g_(s))是衡量冠层-大气水汽交换的重要指标,研究其特征及对环境因子的响应,有助于深入了解冠层水汽交换的过程及环境因子对林木冠层控制的综合机制,目前针对不同退化程度的同一树种冠层气孔导度特征及对环境因子响应的差...冠层气孔导度(g_(s))是衡量冠层-大气水汽交换的重要指标,研究其特征及对环境因子的响应,有助于深入了解冠层水汽交换的过程及环境因子对林木冠层控制的综合机制,目前针对不同退化程度的同一树种冠层气孔导度特征及对环境因子响应的差异性仍不清楚。该研究于2019年生长季(5-9月)以坝上张北县4种退化程度(无退化、轻度退化、中度退化、重度退化)小叶杨(Populus simonii)人工林为研究对象,利用热扩散技术对林中小叶杨树干液流进行连续监测,同步监测气温(T)、光合有效辐射(PAR)、饱和水汽压差(VPD)、空气相对湿度(RH)、土壤含水率(SWC)等环境因子,分析小叶杨的液流速率、g_(s)特征及其对环境因子的响应。结果显示:(1)小叶杨液流速率日变化总体呈单峰曲线,g_(s)呈双峰曲线,月尺度上两者均呈先升高后降低趋势,7月两者值最大,在5月和9月4种退化程度人工林中小叶杨液流速率及g_(s)均差异显著。(2)4种退化程度人工林中小叶杨g_(s)均受T、VPD及SWC的影响,但由于退化有一定的差异性,无退化人工林中小叶杨g_(s)主要受T、VPD和80-160 cm SWC影响,轻度退化人工林中小叶杨g_(s)主要受T、0-80 cm SWC和VPD影响,中度退化人工林中小叶杨g_(s)主要受0-80 cm SWC、T、VPD影响,重度退化人工林中小叶杨g_(s)主要受T、PAR、VPD的影响。(3)对于4种退化程度人工林中小叶杨,T在18℃以上时g_(s)与其呈正相关关系,VPD在0.6-2.2 kPa时g_(s)与其呈正相关关系,g_(s)与SWC呈负相关关系;当PAR小于250μmol·m^(-2)·s^(-1)时,重度退化小叶杨g_(s)与其呈正相关关系。(4)重度退化程度人工林中小叶杨与另3种退化程度人工林中小叶杨相比,对T变化的响应更积极,对其他环境因子响应的敏感性降低,且因形态学上的退化,其对冠层蒸腾的控制会更加严格,以避免进一步退化或死亡。展开更多
基金supported by the Forestry Non-profit Scientific Research Special Funding Project (Tech-nologies for the forest ecology system health mainte-nance and management in typical area) (200804022)the Project of Tree Water Consumption Based on Forest Ecosystem Research Station in Beijing Capital Circle Area
文摘In order to explore the effects of different forest types on active soil carbon pool, the amounts and density of soil organic carbon （SOC） were studied at different soil horizons under typical coniferous and broad-leaved forests in the mountainous area of Beijing. The results showed that the amount of total SOC, readily oxidizable carbon and particulate organic carbon decreased with increasing depths of soil horizons and the amounts at depths of 0-10 cm and 10-20 cm in broad-leaved forest was clearly higher than that in coniferous forests. The trend of a decrease in SOC density with increasing depth of the soil horizon was similar to that of the amount of SOC. However, no regular trend was found for SOC density at different depths between coniferous forest and broad-leaved forests. The ratio of readily oxidizable carbon to total amount of SOC ranged from 0.36-0.45 and the ratio of particulate organic carbon to total amount of SOC from 0.28-0.73; the ratios decreased with increasing depths of soil horizons. Active SOC was significantly correlated with total SOC; the relationship between readily oxidizable carbon and particulate organic carbon was significant. A broad-leaved forest may produce more SOC than a coniferous forest.
文摘This paper presents a general standard for the low-benefit black locust （Robinia pseudoacacia L.） torests m Loess Plateau based on defining the concept of “tri-low forest”, and emphasizes the major factors which result in low-benefit black locust, such as, lack of soil moisture of forest and nutrient, breaching the principle of matching tree species to sites, and high density of forests. Based on different characteristics of low-benefit forests, following the principle of “adjusting measures to local conditions, giving priority to ecological benefits, assisting with economic benefits”, the authors put forward some technical ways to reform low-benefit black locust forests, for example, taking measurements of collecting runoff and storing water, lowering the forest density, introducing mixed forests and transforming species, directive breeding and so on.
文摘冠层气孔导度(g_(s))是衡量冠层-大气水汽交换的重要指标,研究其特征及对环境因子的响应,有助于深入了解冠层水汽交换的过程及环境因子对林木冠层控制的综合机制,目前针对不同退化程度的同一树种冠层气孔导度特征及对环境因子响应的差异性仍不清楚。该研究于2019年生长季(5-9月)以坝上张北县4种退化程度(无退化、轻度退化、中度退化、重度退化)小叶杨(Populus simonii)人工林为研究对象,利用热扩散技术对林中小叶杨树干液流进行连续监测,同步监测气温(T)、光合有效辐射(PAR)、饱和水汽压差(VPD)、空气相对湿度(RH)、土壤含水率(SWC)等环境因子,分析小叶杨的液流速率、g_(s)特征及其对环境因子的响应。结果显示:(1)小叶杨液流速率日变化总体呈单峰曲线,g_(s)呈双峰曲线,月尺度上两者均呈先升高后降低趋势,7月两者值最大,在5月和9月4种退化程度人工林中小叶杨液流速率及g_(s)均差异显著。(2)4种退化程度人工林中小叶杨g_(s)均受T、VPD及SWC的影响,但由于退化有一定的差异性,无退化人工林中小叶杨g_(s)主要受T、VPD和80-160 cm SWC影响,轻度退化人工林中小叶杨g_(s)主要受T、0-80 cm SWC和VPD影响,中度退化人工林中小叶杨g_(s)主要受0-80 cm SWC、T、VPD影响,重度退化人工林中小叶杨g_(s)主要受T、PAR、VPD的影响。(3)对于4种退化程度人工林中小叶杨,T在18℃以上时g_(s)与其呈正相关关系,VPD在0.6-2.2 kPa时g_(s)与其呈正相关关系,g_(s)与SWC呈负相关关系;当PAR小于250μmol·m^(-2)·s^(-1)时,重度退化小叶杨g_(s)与其呈正相关关系。(4)重度退化程度人工林中小叶杨与另3种退化程度人工林中小叶杨相比,对T变化的响应更积极,对其他环境因子响应的敏感性降低,且因形态学上的退化,其对冠层蒸腾的控制会更加严格,以避免进一步退化或死亡。
