Changes in very fine root respiration and morphology with time since last fire in a boreal forest
Changes in very fine root respiration and morphology with time since last fire in a boreal forest
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DOI：
10.1007/s11104-016-2801-9
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发表时间：
2016-01
期刊：
影响因子：
4.9
通讯作者：
N. Makita;J. Pumpanen;Kajar Köster;F. Berninger
中科院分区：
文献类型：
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作者：
N. Makita;J. Pumpanen;Kajar Köster;F. Berninger
目的研究森林演替过程中不同林龄、不同林龄的细根的生理和形态响应，以确定细根呼吸和形态特征在森林演替过程中的变化。方法对芬兰北方樟子松的细根呼吸进行调查。结果155年生林分0.5 mm根系的比呼吸速率分别比5年生、45年生和63年生林分高74.0%、38.0%和31.3%。不同林分间粗根呼吸速率随时间的变化不显著。同样，火干扰对0.5 mm根的形态特征有很大影响，但对较粗的根影响不大。各林龄的根系呼吸速率与比根长(单位质量根长)呈正相关，与根组织密度(单位体积质量)呈负相关。63年生和155年生的根系呼吸与比根长或根组织密度的线性回归直线截距显著高于5年生林分。结论呼吸共同斜率截距与形态的显著变化反映了不同林龄林龄间生理指标变化的不同。尽管有一个特定的小地理区域，我们认为野火过后北方森林的恢复导致了一种有利于碳投资于养分和水分开发效率的战略，结果是极细根的呼吸、长度和组织密度更高。
AimsWe examined the physiological and morphological responses of individual fine root segments in boreal forests stands with different age since the last fire to determine changes in specific fine root respiration and morphological traits during forest succession.MethodsWe investigated the respiration of fine roots divided into three diameter classes (<0.5, 0.5–1.0, and 1.0–2.0 mm) in a Finnish borealPinus sylvestrisL. in forest stands with 5, 45, 63, and 155 years since the last fire.ResultsSpecific respiration rates of <0.5 mm roots in 155-year-old stands were 74 %, 38 %, and 31 % higher than in 5-, 45-, and 63-year-old stands, respectively. However, the respiration rates of thicker diameter roots did not significantly change among stands with respect to time after fire. Similarly, fire disturbance had a strong impact on morphological traits of <0.5 mm roots, but not on thicker roots. Root respiration rates correlated positively with specific root length (length per unit mass) and negatively with root tissue density (mass per unit volume) in all stand ages. The linear regression lines fitted to the relationships between root respiration and specific root length or root tissue density showed significantly higher intercepts in 63- and 155-year-old than in 5-year-old stands.ConclusionSignificant shifts in the intercept of the common slope of respiration vs. morphology indicate the different magnitude of the changes in physiological performance among the fire age class. Despite a specific small geographic area, we suggest that the recovery of boreal forests following wildfire induces a strategy that favors carbon investment in nutrient and water exploitation efficiency with consequences for higher respiration, length, and lower tissue density of very fine roots.