Drought decreases carbon flux but not transport speed of newly fixed carbon from leaves to sinks in a giant bamboo forest

Carbon (C) allocation among different plant tissues is crucial for maintaining the C balance in forest ecosystems, especially under changing climate conditions. The partitioning of newly assimilated C among plant tissues, interconnected ramets, and soil in forests dominated by giant clonal plants, such as moso bamboo (Phyllostachys edulis), and the influence of drought on this partitioning remains poorly understood. In August 2019, we performed in situ labeling of the entire crown of R0 (ramets that emerged in 2019) of moso bamboo with 13CO2 in plots subjected to a 5–year drought or left untreated (ambient control) in subtropical China. We then traced the 13C signatures in the leaves, twigs, and fine roots of R0, R1 (ramets that emerged in 2018 and are connected with R0), and R2 (ramets that emerged in 2017 and are connected with R1), as well as in soil organic C (SOC) and soil respiration over the course of one year post–labeling. Drought reduced leaf 13C assimilati..., Experimental design and sampling
In July 2014, three bamboo forests with similar slopes and altitudes were selected (Table S1). In each forest, two 12 m × 12 m plots were established, separated by a 10–m–wide buffer zone (Fig. S2). One plot out of them was randomly selected to be subjected to drought (i.e., throughfall exclusion), while the other served as a control (natural rainfall) (hereafter referred to as ‘drought’ and ‘control’, respectively). For the drought treatment, we set up transparent PVC waterproof boards suspended at about 1.5 m above the ground surface to exclude 70–80% of precipitation. A trench measuring 12 m in length, 40 cm in width, and 60 cm in depth (with roots concentrated in the 20–40 cm soil depth) was dug to prevent water from flowing into the drought treatment area from the surrounding soil and to restrict root access to areas outside the throughfall exclusion treatment area. PVC waterproof boards were inserted into the trench before the soil was refilled. Th..., # Drought decreases carbon flux but not transport speed of newly fixed carbon from leaves to sinks in a giant bamboo forest

Dataset DOI: [10.5061/dryad.5tb2rbpfh](10.5061/dryad.5tb2rbpfh)

## Description of the data and file structure

In 2019, we conducted an experiment in China using stable carbon isotopes to track their movement in young bamboo plants and among their older, interconnected neighbors. The experiment was carried out under long-term dry conditions (a five-year drought) and normal conditions. We monitored the labeled carbon signals for a year, examining leaves, branches, roots, soil, and the carbon released from the soil.

### Files and variables

File: Data_Dryad_Drought_Decreases_Carbon_Flux_but_Not_Transport_Speed_of_Newly_Fixed_Carbon_from_Leaves_to_Sinks_in_a_Giant_Bamboo_Forest.xlsx

#### Sheet \"Leaves to Soil\" variables

* Ramets:
* R0 (ramets that emerged in 2019)
* R1 (ramets that emerged in 2018 and are connected with R0)
* R2 (ramets that emerged in 2017...,

碳（Carbon, C）分配（Carbon allocation）在不同植物组织（plant tissues）间的模式对维持森林生态系统（forest ecosystems）的碳平衡至关重要，在气候变化背景下尤为关键。针对以毛竹（Phyllostachys edulis）这类大型克隆植物（giant clonal plants）为主的森林，新同化碳（newly assimilated C）在植物组织、相互连接的分株（interconnected ramets）以及土壤之间的分配格局，以及干旱对该分配格局的影响仍有待深入阐明。

2019年8月，我们在中国亚热带地区的样地中，对经过5年干旱处理或未处理（自然对照）的毛竹R0分株（2019年萌发的分株）的整个冠层进行了¹³CO₂原位标记（in situ labeling）。随后在标记后的1年时间内，我们追踪了R0、R1（2018年萌发且与R0相连的分株）、R2（2017年萌发且与R1相连的分株）的叶片、枝条和细根（fine roots），以及土壤有机碳（soil organic C, SOC）和土壤呼吸（soil respiration）中的¹³C信号（¹³C signatures）。干旱降低了叶片的¹³C同化量……

# 实验设计与采样

2014年7月，我们选取了3块坡度与海拔相近的毛竹林（详见表S1）。在每片竹林中设置2个12 m × 12 m的样方，样方之间以10 m宽的缓冲带分隔（详见图S2）。随机选取其中一个样方进行干旱处理（即穿透雨排除法（throughfall exclusion）），另一个作为对照（自然降雨），下文分别称为“干旱组”与“对照组”。干旱处理通过悬挂于地表约1.5 m处的透明PVC防水板实现，可排除70%~80%的降水（precipitation）。我们挖掘了一条长12 m、宽40 cm、深60 cm的壕沟（trench）（根系主要集中在20~40 cm土层），以阻止水分从周边土壤流入干旱处理区域，并限制根系侵入（root access）穿透雨排除处理区外的区域。在回填土壤前，将PVC防水板嵌入壕沟中……

# 大型毛竹林中干旱降低碳通量但不改变叶片新固定碳向汇的运输速率

数据集DOI：[10.5061/dryad.5tb2rbpfh](10.5061/dryad.5tb2rbpfh)

## 数据与文件结构说明

2019年，我们在中国开展了一项实验，利用稳定碳同位素追踪其在幼年竹株以及老龄且相互连接的相邻竹株间的迁移过程。实验设置了长期干旱（5年干旱）与正常环境两组处理，我们对标记碳信号进行了为期1年的监测，检测对象包括叶片、枝条、根系、土壤以及土壤释放的碳。

### 文件与变量

文件：Data_Dryad_Drought_Decreases_Carbon_Flux_but_Not_Transport_Speed_of_Newly_Fixed_Carbon_from_Leaves_to_Sinks_in_a_Giant_Bamboo_Forest.xlsx

#### 工作表"Leaves to Soil"变量

* 分株（Ramets）：
* R0（2019年萌发的分株）
* R1（2018年萌发且与R0相连的分株）
* R2（2017年萌发且与R1相连的分株）……