中国16个地点天然次生林细根产量分布格局

Distribution pattern of fine root production from natural secondary forests in 16 sites of China

细根产量(FRP)是森林生态系统地下产量的最大组分,对森林生态系统的碳和养分的分配和循环起着重要作用。细根根序对于FRP有较大的影响。目前较少通过根序分级法、以我国16个地点的天然次生林为整体的大尺度FRP研究。采用根序分级法对我国16个地点的天然次生林进行为期1年的、群落水平的大尺度FRP实验研究,来探索我国16个地点的天然次生林FRP分布格局。结果表明,FRP分布格局总体上由北向南逐渐增加,吸收根(AFR)产量、运输根(TFR)产量以及FRP均为海南尖峰岭最高,分别为(115.42±17.87)g/m^(2)、(298.6±76.82)g/m^(2)和(414.01±84.05)g/m^(2),大兴安岭呼中区最低,分别为(11.25±1.28)g/m^(2)、(12.44±0.97)g/m^(2)和(23.7±1.21)g/m^(2)。山西太岳山、安徽鹞落坪和湖南会同显著低于邻近纬度地区(P<0.05),FRP分别为(50.89±5.58)g/m^(2)、(58.85±17.24)g/m^(2)和(67.26±15.31)g/m^(2)。年均温(MAT)和年均降水量(MAP)与AFR产量、TFR产量和FRP显著正相关,纬度与AFR产量、TFR产量和FRP显著负相关。

The root system is an important organ of the tree and plays two main roles,one of which is to support the tree,which is mainly performed by the coarse roots,and the other is to absorb water and nutrients,which is mainly performed by the fine roots.Fine roots are not only responsible for water and nutrient uptake,but also contribute significantly to carbon sequestration and net primary productivity(NPP)in forest ecosystems.Fine roots are an important component of the root system,an important soil resource in terrestrial ecosystems,and a mediator of soil geochemical cycling,and are the most active component of the root system.Fine root production(FRP)is the largest component of below⁃ground production and plays a critical role in the allocation and cycling of carbon and nutrients in forest ecosystems.Root order has a large effect on the FRP.At present,there is fewer large⁃scale research on FRP based on the method of segment order⁃based classification with the natural secondary forests of 16 sites in China as a whole.In this study,we conducted a 1⁃year experimental study of fine root production at the stand level in natural secondary forests at 16 sites in China using the segment order⁃based classification method to explore the distribution patterns of fine root production in natural secondary forests at 16 sites in China.The results showed that the distribution pattern of fine root production increased gradually from north to south.Absorptive fine root(AFR)production,transport fine root(TFR)production and FRP were the highest in Jianfengling,Hainan,with(115.42±17.87)g/m^(2),(298.6±76.82)g/m^(2) and(414.01±84.05)g/m^(2),respectively,and the lowest in Huzhong District,Daxing′anling,with(11.25±1.28)g/m^(2),(12.44±0.97)g/m^(2) and(23.7±1.21)g/m^(2),respectively.Taiyue Mountain,Shanxi,Yao Luoping,Anhui,and Huitong,Hunan were significantly lower than those in neighboring latitudes(P<0.05).FRP was(50.89±5.58)g/m^(2),(58.85±17.24)g/m^(2) and(67.26±15.31)g/m^(2),respectively.Mean annual temperature(MAT)and mean annual precipitation(MAP)were significantly and positively correlated with AFR production,TFR production and FRP,while latitude was significantly and negatively correlated with AFR production,TFR production and FRP.China′s forest ecosystems are huge and diverse,accounting for a large proportion of the global forest ecosystems and playing a very important role in carbon and nutrient cycling at the global scale,whereas global databases seldom cite data from China′s forest ecosystems.Therefore,it is of great importance to carry out a study on fine root production on a large scale based on the segment order⁃based classification method in natural secondary forests at 16 sites in China.