Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 13, issue 12
Biogeosciences, 13, 3819–3831, 2016
https://doi.org/10.5194/bg-13-3819-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 13, 3819–3831, 2016
https://doi.org/10.5194/bg-13-3819-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 01 Jul 2016

Research article | 01 Jul 2016

Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters

Wenjuan Zhu1,2, Wenhua Xiang1,2,3, Qiong Pan4,1, Yelin Zeng1, Shuai Ouyang1,2,3, Pifeng Lei1,2,3, Xiangwen Deng1,2,3, Xi Fang1,2,3, and Changhui Peng5,1 Wenjuan Zhu et al.
  • 1Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, Hunan Province, China
  • 2Huitong National Field Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystem in Hunan Province, Huitong 438107, China
  • 3National Engineering Laboratory of Applied Technology for Forestry & Ecology in Southern China, Changsha 410004, China
  • 4Changsha Environmental Protection College, Changsha 410004, China
  • 5Institute of Environment Sciences, Department of Biological Sciences, University of Quebec at Montreal, Montreal, QCH3C 3P8, Canada

Abstract. Leaf area index (LAI) is an important parameter related to carbon, water, and energy exchange between canopy and atmosphere and is widely applied in process models that simulate production and hydrological cycles in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have yet to be fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (Pinus massonianaLithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaberCyclobalanopsis glauca evergreen broadleaved forests) from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs) respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for the three forests measured in January and for the L. glaberC. glauca forest in April, July, and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stem number, crown coverage, proportion of evergreen conifer species on basal area basis, proportion of deciduous species on basal area basis, and forest types affected the spatial variations in LAI values in January, while stem number and proportion of deciduous species on basal area basis affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity, and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.

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We used hemispherical photography to measure LAI values in three subtropical forests from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs), respectively. Our results showed that LAI values differed greatly in three forests and their seasonal variations were consistent with plant phenology. Stand characters significantly affected the spatial variations in LAI values.
We used hemispherical photography to measure LAI values in three subtropical forests from April...
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