Nodes are essential to production in Black Desert.
Assuming a node is connected to a city, via contribution investment, you will be able to send your workers to gather resources, as well as, allow you access to additional housing for storage, processing and more.
Also, if nodes are connected between the starting point and destination, you will receive a greater yield on trading, and a lower transportation fee, for warehouse items.
Types of Nodes
Throughout the world you will find NPCs called "Node Managers". Discovering these NPCs will uncover a portion of your world map and allow you to invest your contribution into a Node. When investing in a node you will start at a major city, and work your way outwards, to the desired node. If you are unsure of the order in which to link the nodes check with the node manager, and you can see the nearest connected nodes.
Additionally, sometimes the Node Manager will require you explore the area to gain knowledge about the node prior to letting you invest.
Some Nodes are attached to a major city and have their own housing. These are considered production nodes, and investing in their housing will grant their bonuses to the nearest major city.
To recover your investment, open your world map, click the node you invested in and select withdraw. However, nodes must be connected to a capitol, so withdrawing from a node in the middle of connected nodes requires that the furthest nodes be withdrawn from first.