Simulated forests for the Changbaishan ForestGEO site

This dataset contains tree records generated with the forest model Formind fitted to the forest at the Changbaishan ForestGEO site.

The data correspond to one hectare of forest, which was recorded in time intervals of five years. The considered forest is in equilibrium state: prior to the first records being taken, the forest was simulatd for 2000 years. Then, every five years, key properties (position, dimension etc.) of all individual trees in the forest were recorded and their productivity in the succeeding productive period determined.

The data set contains 1000 forest states and can be used to analyze how the structure of a forest is related to its productivity. An example script for the data analysis is provided along with the data.

The data set comes with the following assets:

A markdown readme file README.md with the contents of this description.

The data file TreeLists.csv, which is a comma-separated text file with one header line.

A data anaylsis example script data_analysis_example.py, showing how the data can be analyzed.

The data set contains the following fields:

Field
Descritpion

State index
Index of the forest state. There are five years difference between forest state i and state i+1. Each forest state includes the trees of one hectare of forest. 

X [m]
x coordinate of the tree in metres.

Y [m]
y coordinate of the tree in metres.

PFT
Plant functional type of the tree. 0: small light demanding, 1: large light demanding I, 2: large light demanding II (Q. mongolica), 3: large mid-tolerant, 4: small shade-tolerant, 5: large shade-tolerant. 

DBH [m]
iameter at breast height of the tree in metres.

Height [m]
Height of the tree in metres.

Biomass [t ODM]
Biomass of the tree in tons organic dry matter.

LAI [m² / m²]
Leaf area index of the tree.

LAI above [m² / m²]
Leaf area index above the tree's canopy.

Mature
Indicates whether the tree is in the mature (fullgrown) state (True / False). 

GPP [t ODM / yr]
Gross primary production of the tree in the upcoming year, provided in tons organic dry matter per year. The value is undefined for trees that died in the upcoming year.

NPP [t ODM / yr]
Net primary production (of above-ground biomass) of the tree in the upcoming year, provided in tons organic dry matter per year. The value is undefined for trees that died in the upcoming year.

Respiration [t ODM / yr]
Total respiration (and other carbon losses) of the tree in the upcoming year, provided in tons organic dry matter per year. The value is undefined for trees that died in the upcoming year. 

Respiration without size limit [t ODM / yr]
Total respiration (and other carbon losses) of the tree in the upcoming year, provided in tons organic dry matter per year if the carbon usage of mature trees was not decreased to 0. The value is undefined for trees that died in the upcoming year. 

Stayed alive
Indicates whether the tree stayed alive in the upcoming year (True / False).

Data analysis example

An example for the data analysis is provided in the file `data_analysis.py`. To run the script, Python needs to be installed along with the packages pandas, numpy, and matplotlib.

本数据集包含基于适配于长白山ForestGEO样地的森林模型Formind生成的林木记录。

该数据集对应一公顷林分，以五年为时间间隔进行观测记录。所研究的林分处于平衡状态：在首次观测前，该林分已被模拟运行2000年。随后每五年记录一次林内所有单木的关键属性（位置、尺寸等），并测定其在后续生产周期中的生产力。

本数据集包含1000个森林状态样本，可用于分析林分结构与其生产力之间的关联。随数据集一同提供了数据分析示例脚本。

本数据集附带以下资源：
- 一份Markdown格式的README.md说明文件，包含本数据集的详细描述。
- 数据文件TreeLists.csv：该文件为逗号分隔文本格式，包含一行表头。
- 数据分析示例脚本data_analysis_example.py，演示如何对该数据集进行分析处理。

本数据集包含以下字段：

### 状态索引（State index）
森林状态的唯一标识。相邻森林状态i与i+1的时间间隔为五年。每个森林状态对应一公顷林分的林木组成。

### X坐标 [m]
林木的x轴空间坐标，单位为米。

### Y坐标 [m]
林木的y轴空间坐标，单位为米。

### 植物功能型（Plant Functional Type，PFT）
林木所属的植物功能类型，编码规则如下：0代表小型喜光树种，1代表大型喜光树种I，2代表大型喜光树种II（蒙古栎），3代表大型耐荫中间型树种，4代表小型耐荫树种，5代表大型耐荫树种。

### 胸径（Diameter at Breast Height，DBH） [m]
林木的胸径，单位为米。

### 树高 [m]
林木的株高，单位为米。

### 生物量（Biomass） [t ODM]
林木的生物量，单位为吨有机干物质。

### 叶面积指数（Leaf Area Index，LAI） [m²/m²]
单木的叶面积指数。

### 冠层上方叶面积指数（LAI above） [m²/m²]
林木冠层上方的叶面积指数。

### 成熟状态（Mature）
标识林木是否达到成熟（完全生长）阶段，取值为True/False。

### 总初级生产力（Gross Primary Production，GPP） [t ODM/yr]
林木在下一年度的总初级生产力，单位为吨有机干物质每年。对于在下一年度死亡的林木，该值无定义。

### 净初级生产力（Net Primary Production，NPP） [t ODM/yr]
林木在下一年度的地上生物量净初级生产力，单位为吨有机干物质每年。对于在下一年度死亡的林木，该值无定义。

### 呼吸作用（Respiration） [t ODM/yr]
林木在下一年度的总呼吸作用（及其他碳损失），单位为吨有机干物质每年。对于在下一年度死亡的林木，该值无定义。

### 无尺寸限制呼吸作用（Respiration without size limit） [t ODM/yr]
若未将成熟林木的碳使用量降至0，则林木在下一年度的总呼吸作用（及其他碳损失），单位为吨有机干物质每年。对于在下一年度死亡的林木，该值无定义。

### 存活状态（Stayed alive）
标识林木在下一年度是否保持存活，取值为True/False。

数据分析示例
本数据集附带数据分析示例脚本data_analysis.py。运行该脚本需安装Python环境，并依赖pandas、numpy及matplotlib数据包。