Control the flow of sugars and hormones to control how fast each branch grows. Favor the extension of old branches by suppressing the growth of new side branches. Favor branches that grow upward over ones that dangle down. And control the sharing of energy through the whole tree to favor bright branches over dark. Favor Bright is one of the strongest parameters in The Grove the heavily controls the shape of your tree.
Control the flow
Trees regulate growth with hormones, which are molecules that flow through the branches and have an effect on the cells they reach. They are a means of communication, giving the sensory parts of the tree a way to tell the other parts what to do.
Branch ends are the senses and the brains of the tree, and they use a hormone called auxin to tell the rest of their branch what to do. Auxin travels down the branch and slows the development of side buds, while the end itself grows full power. Creating smaller side branches and directing most energy to upward growth helps the tree grow taller and win the race for light. If you cut off the end of a branch, the hormone is gone and side buds will grow freely. When pruning a hedge for example, this cuts off all the branch ends and enables the many side buds to grow, resulting in dense foliage.
The scientific name for this effect is Apical Dominance. Simulate this effect with Favor End. The hormones travel down the branch, but at some point the concentration will be too low to stop side branches from growing, the Favor End Reach.
Each branch itself competes for light with all other branches through Escape Shade. This value is added to Favor End according to how much a branch is shaded. So a shaded branch will shoot out, further suppressing its child branches in order to find light and escape the shade. Tree species all have their own strategies for finding light, and avoiding shade can work with that. Beech trees for example do the opposite with a negative shade avoidance. A brightly lit beech twig will have a high favor end, and a shaded twig will allow its sides to grow much quicker. They stay low and harvest as much light as possible without investing in thick, long main branches. Once it gets more light, for example when a neighboring tree dies, it shoots up with a high Favor End.
Favor End helps the tree get a good start in growing towards light. But when the tree grows older, a different effect shows up. The hormone that suppresses side branches only travels a limited distance from the branch tip that created it. After this, side branches can freely grow, and the tree now needs to favor the best performing branches, those with most leaves and those harvesting most light. These are the branches that will keep the tree healthy.
With favor bright, the power of the branch is entirely up to the light it receives. Without getting any backup from the rest of the tree, the branch can quickly dwindle when the growing tree overshadows itself. The loss of energy adds up, because a low power branch will also create less leaves with less capacity for photosynthesis.
Turn it down to more freely share energy through the tree. Bright branches on top will support the lower branches and keep them healthy for longer.
With favor ends, the tree favors the extension of existing branches. This reduces the initial power of new branches along the sides. This is a good starting point to make a tree fight for light. Without it, trees grow more bushy. But Favor Ends also strengthens the effect of favor bright, because the side branches will get less power to start with, which is hard to overcome when the tree doesn’t support weaker branches.