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在浙江古田山常绿阔叶林区域选择了4个具代表性的不同干扰强度森林类型:常绿阔叶老龄林(OF)、一次皆伐后自然恢复的天然次生林Ⅰ(SFⅠ)、皆伐后自然恢复过程中经历一次重度择伐的天然次生林Ⅱ(SFⅡ)、人工杉木林(AF)为研究对象,进行了为期1年的土壤呼吸动态监测,定量分析了不同林型土壤呼吸的昼夜和季节变化,同时结合相关环境和生物因子的监测,从日尺度和季节尺度上探讨了影响我国亚热带常绿阔叶林区不同森林土壤呼吸的主要驱动因子,并就不同的森林管理方式对亚热带森林土壤碳释放的可能影响做出了初步评估.研究发现4种林型土壤碳日累积释放量呈现显著的季节变化,从5月份开始各林型土壤碳日累积释放量以较快速率升高,老龄林8月中旬达到最大,次生林Ⅰ在7月中旬达最大,次生林Ⅱ和人工林在6月中旬达最大,之后各林型持续下降到翌年1月份,而后开始缓慢回升.4种林型年平均土壤碳日累积释放量分别为1.48,1.48,1.51,0.87 g C m 2d 1,人工林的土壤碳日累积释放量显著低于其他3种林型.各林型的土壤呼吸速率的日变化幅度均不显著.土壤表层温度是影响该地区土壤呼吸季节动态的主要因素,二者呈显著的指数相关关系,相关系数R2为0.88~0.94;土壤表层含水量与土壤呼吸之间没有显著的相关关系.老龄林土壤温度敏感性(Q10值)显著高于其他林型.上述结果表明,受干扰强度最大的人工林的土壤呼吸速率显著降低,对温度变化的敏感性显著降低;受干扰强度相对较小的次生林其土壤呼吸速率和温度敏感性基本上和老龄林保持一致.古田山不同林型土壤呼吸季节变化的主要驱动因子均为土壤温度.这些结论说明不同干扰强度对亚热带森林土壤碳释放的影响不同,这为精确估算该地区不同植被类型碳收支提供了重要依据,此外土壤呼吸无显著昼夜变化的结论将对该区域后续的动态监测工作起到积极的指导作用.
Four representative types of forest with different disturbance intensity were selected in the evergreen broad-leaved forest in Gutian Mountain of Zhejiang Province: OF evergreen broad-leaved forest (OF), natural secondary forest Ⅰ (SFⅠ) The natural secondary forest Ⅱ (SFⅡ) and artificial fir forest (AF) undergoing a severe selective cutting process after natural recovery were studied for one year. Soil respiration dynamics was monitored for one year. Quantitative analysis of diurnal Seasonal changes and the monitoring of relevant environmental and biological factors, the main driving forces affecting soil respiration in different forest soils of subtropical evergreen broad-leaved forest in China were discussed from the daily and seasonal scales. The effects of different forest management methods on subtropical forests Soil carbon release was evaluated.The results showed that the daily carbon emission of four types of forest showed a significant seasonal variation, and from May onwards, the daily carbon emission of each forest type increased at a faster rate, The number of old forest reached the maximum in mid-August. The number of secondary forest I reached the maximum in mid-July, and the number of secondary forest II and plantation reached the maximum in mid-June. Afterwards, the forest types continued to decline to the following January, And then began to slowly rise.The total annual carbon emission from the four forest types was 1.48, 1.48, 1.51 and 0.87 g C m 2d 1, respectively, and the soil carbon emission of plantation was significantly lower than that of the other three forest types. The diurnal variation of soil respiration rate was not significant in all forest types.The soil surface temperature was the main factor affecting the soil respiration season in this area, and the correlation coefficient R2 was 0.88-0.94. There was no significant correlation between soil water content and soil respiration.The soil temperature sensitivity (Q10) of aged forest was significantly higher than that of other forest types.The above results showed that the soil respiration rate of the plantation with the highest disturbance intensity decreased significantly, The sensitivity of the secondary forest was relatively low and the soil respiration rate and temperature sensitivity of the secondary forest were basically the same as that of the old forest.The main driving factors of the seasonal variation of soil respiration in different types of forest were the soil temperature.These conclusions It shows that the effect of different disturbance intensity on soil carbon emission in subtropical forest is different, which provides an important basis for accurately estimating the carbon budget of different vegetation types in this area. The conclusion that there is no significant diurnal variation of soil respiration outside the soil will play a positive guiding role in the follow-up dynamic monitoring in this area.