title: Soil temperature triggers the onset of photosynthesis in Korean pine.
abstract: In forest ecosystems, the onset of spring photosynthesis may have an important influence on the annual carbon balance. However, triggers for the onset of photosynthesis have yet to be clearly identified, especially for temperate evergreen conifers. The effects of climatic factors on recovery of photosynthetic capacity in a Korean pine forest were investigated in the field. No photosynthesis was detectable when the soil temperature was below 0 °C even if the air temperature was far beyond 15 °C. The onset of photosynthesis and sap flow was coincident with the time of soil thawing. The rates of recovery of photosynthetic capacity highly fluctuated with air temperature after onset of photosynthesis, and intermittent frost events remarkably inhibited the photosynthetic capacity of the needles. The results suggest that earlier soil thawing is more important than air temperature increases in triggering the onset of photosynthesis in Korean pine in temperate zones under global warming scenarios.
authors.affiliation: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China.
authors.forename: Jiabing
authors.initials: J
authors.lastname: Wu
authors.forename: Dexin
authors.initials: D
authors.lastname: Guan
authors.forename: Fenhui
authors.initials: F
authors.lastname: Yuan
authors.forename: Anzhi
authors.initials: A
authors.lastname: Wang
authors.forename: Changjie
authors.initials: C
authors.lastname: Jin
mesh_terms: D057486:Carbon Cycle; D002681:China; D003247:Conservation of Natural Resources; D005544:Forecasting; D065928:Forests; D057232:Global Warming; D010788:Photosynthesis / Q000502:physiology*; D028223:Pinus / Q000502:physiology*; D012621:Seasons; D012987:Soil; D013696:Temperature
chemical_list: D012987:Soil