Soil Respiration In Different Successional Stages Of A Subtropical Forest, China

Soil respiration in different forest successional stages has been treated as an important aspectto study the change of natural forest and also the relationship between soil and plant. Consideringthe particularity of subtropical forest comparing with the temperate forest and boreal forest wheremost experiments have been conducted, we carried out this study about the change of soilrespiration and its three components (root respiration, heterotrophic respiration and litterrespiration) along different successional stagesin a subtropical forest in East China, in order tounderstand the change regulation of soil respiration in a chronological forest ecosystem. FromApril2009to March2012, total soil respiration together with heterotrophic respiration and litterrespiration measurements were made each two-month combining with continuous soil temperatureand soil volumetric water content (SVWC) measurements in three different forest successionalstages. Soil respiration and heterotrophic respiration were modeled based on Lloyd-Taylorequation and annual carbon emissions were estimated. The results of continuously climatemeasurements showed that SVWC in advanced-successional-stage forest was the highest with anannual mean value of approximately25%. Total respiration and heterotrophic respiration wereboth the highest in early-successional-stage forest while lowest in middle-successional-stage forest.Litter respiration was the highest in advanced-successional-stage forest. The ratio of heterotrophicrespiration and total respiration (HR ratio) in different successional stages showed differentchange regulation during one year. HR ratios of all the three successional stages in summer werethe same, however in winter the ratio of middle-successional-stage forest went significantly higher, comparing with a slightly higher HR ratio of advanced-successional-stage forest and a constantHR ratio of early-successional-stage forest. This may indicate that life history strategies ofdifferent forest successional stages exert profound influence on the change regulation of rootrespiration and heterotrophic respiration.