请详细描述树的结构，并使用JSON格式呈现。
user
```json
{
  "tree": {
    "trunk": {
      "description": "The main central stem of the tree, supporting the branches and leaves."
    },
    "branches": [
      {
        "description": "The woody structures extending from the trunk, providing support for leaves and sometimes fruit."
      }
    ],
    "leaves": [
      {
        "description": "Flattened, often green structures that carry out photosynthesis and respiration."
      }
    ],
    "roots": [
      {
        "description": "Underground structures that absorb water and nutrients, providing stability and support to the tree."
      }
    ]
  }
}
```
assistant