Load sense hydraulic pump alignment

A hydraulic system for a tree harvester having a chassis and a harvester head configured to cut trees, the hydraulic system comprising:

• a plurality of hydraulic units including a main hydraulic unit associated with the chassis and a head hydraulic unit associated with the harvester head;
• a valve unit having a plurality of valve sections for controlling the plurality of hydraulic units;
• a head pump providing pressurized hydraulic fluid exclusively to the head hydraulic unit via a head valve section of the valve unit;
• a main pump providing pressurized hydraulic fluid to the main hydraulic unit via a main valve section of the valve unit and providing supplemental pressurized hydraulic fluid to the head hydraulic unit via the head valve section only when load requirements of the head hydraulic unit exceed a power provided by the head pump;
• a load sense system that detects the load requirements of the plurality of hydraulic units and provides a load sense signal via a load sense line for the main pump to produce pressure sufficient to satisfy the requirements of a highest of the load requirements of the plurality of hydraulic units;
• and
• a pressure control device that is disposed between the valve unit and a tank;
• wherein, when the load requirements of the head hydraulic unit exceed the pressurized hydraulic fluid provided by the head pump, the main pump provides the supplemental pressurized hydraulic fluid to the head value section to increase pressurized hydraulic fluid supply at a pressure sufficient to meet the load requirements of the head hydraulic unit;
• and
• wherein an output pressure of the head valve section is limited to the pressure sufficient to meet the load requirements of the head hydraulic unit by the pressure control device discharging pressurized hydraulic fluid from the load sense line to the tank to modify the load sense signal such that, when supplementing the head pump, the main pump operates below maximum pressure unless required to meet the load requirements of the head hydraulic unit.