Implications of structural diversity for seasonal and annual carbon dioxide fluxes in two temperate deciduous forests
Implications of structural diversity for seasonal and annual carbon dioxide fluxes in two temperate deciduous forests
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DOI：
10.1016/j.agrformet.2018.08.027
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发表时间：
2018-12
影响因子：
6.2
通讯作者：
Rijan Tamrakar;M. Rayment;F. Moyano;M. Mund;A. Knohl
中科院分区：
文献类型：
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作者：
Rijan Tamrakar;M. Rayment;F. Moyano;M. Mund;A. Knohl
结构多样性对森林二氧化碳交换的影响已成为提高未来二氧化碳预算可预测性的一个重要研究领域。我们报告了一个成对的涡度协方差塔研究的结果与11年的数据在两个森林网站相似的平均林龄，几乎相同的网站条件，并占主导地位的山毛榉树（山毛榉），但有一个非常不同的林分结构（包括。年龄、直径分布、枯木蓄积量和物种组成），因为管理制度不同。在这里，我们解决了管理和相关结构多样性如何影响二氧化碳通量的问题，并测试了结构多样性较高的林分对非生物和生物驱动因素的变化不太敏感的假设。年净生态系统生产力（NEP）在管理，年龄均匀，同质的森林（585 ± 57.8 g C m− 2 yr −1），比在未管理，年龄不等，结构多样的森林（487 ± 144 g C m− 2 yr −1）。两个地点之间的NEP差异中约有三分之二是由同质森林中较高的年总初级生产力（GPP，1627 ± 164 vs 1558 ± 118 g C m− 2 yr −1）和较低的年生态系统呼吸（Reco，1042 ± 60 vs 1071 ± 96 g C m− 2 yr −1）贡献的。春季（4 - 5月）和夏季（6 - 7月）是造成样地间总体年差异的两个主要季节，在这两个季节，同质林的季节NEP和GPP对环境变量的敏感性更强。NEP的年际变化是较高的同质林（变异系数（CV）= 25%）相比，异质林（CV = 12%）。在年度时间尺度上，在同质森林的NEP的较高的变异性是由于生物因素，如水果生产和时间依赖性的增长趋势，超过了环境敏感性的差异。
The effects of structural diversity on the carbon dioxide exchange (CO2) of forests has become an important area of research for improving the predictability of future CO2budgets. We report the results of a paired eddy covariance tower study with 11 years of data on two forest sites of similar mean stand age, near-identical site conditions, and dominated by beech trees (Fagus sylvatica), but with a very different stand structure (incl. age, diameter distribution, stocks of dead wood and species composition) because of different management regimes. Here we address the question of how management and related structural diversity may affect CO2fluxes, and tested the hypothesis that more structurally diverse stands are less sensitive to variations in abiotic and biotic drivers. Higher annual net ecosystem productivity (NEP) was observed in the managed, even-aged, and homogenous forest (585 ± 57.8 g C m−2yr−1), than in the unmanaged, uneven-aged, and structurally diverse forest (487 ± 144 g C m−2yr−1). About two-third of the difference in NEP between the sites was contributed by a higher annual gross primary productivity (GPP, 1627 ± 164 vs 1558 ± 118 g C m−2yr−1) and one-third by a lower annual ecosystem respiration (Reco, 1042 ± 60 vs 1071 ± 96 g C m−2yr−1) in the homogenous forest. Spring (April – May) and summer (June – July) were the two main seasons contributing to the overall annual differences between the sites, also, the sensitivities of seasonal NEP and GPP to environmental variables were stronger in the homogenous forest during those periods. Inter-annual variation of NEP was higher in the homogenous forest (coefficient of variation (CV) = 25%) compared to the heterogeneous forest (CV = 12%). At annual time scale, the higher variability of NEP in the homogenous forest is attributed to biotic factors such as fruit production and a time-dependent growth trend, outweighing differences in environmental sensitivities.