You will see that it is connected to the Transparency channel of the Material node.

你将看到它是连接到材质节点的透明通道上的。

youdao

If you will add new material using new button in Materials properties panel you will see node tree in the node editor window.

如果你通过材质属性面板新按钮添加新的材质，将会在节点编辑窗口中看到节点树。

youdao

The material is further developed in UE4 adding translucency to leaves and grapes and a node that gives a color variation to the leaves.

材质在UE4中进一步改进，除了给树叶和葡萄增加了半透明度外，树叶还添加了颜色变化。

youdao