North Branch
The North Branch of the grove is the most traditional, closest to their roots and unchanging in their way of life.
Defences
The Elves rely on their guards and the forest itself to protect them. The animals and the vines, twigs and plants provide warnings and help catch intruders.
Industry & Trade
While they do not much leave the forest, they will trade with outsiders if they need to, unless they trade with the East Branch instead. While they don't have much use for coin, they still have some from the large amounts they were given when the humans first arrived. But they pay with agricultural guidance. If someone wants to trade with the North Branch, they'll usually come because of a bad harvest, help with bad soil, or they take gardening very seriously. The North Branch can fix almost anyway plant related problem.
History
They were the the last to leave when the Celestial Grove toppled, and the first to return home. They spent years trying to regrow the 3 trees, and almost completely ignored the humans when they first came. Only stopping to acknowledge them when their numbers became to large. They kept to the old ways of using non grove trees to build weapons and armor, and began using iron when the humans came. The North Branch felt that even using the wood from dead trees didn't feel appropriate for them. They continued to live in their brush wood bramble.
Tourism
It's rare but people who the North Branch feels respects their home are allowed to visit it freely.
Architecture
Their brushwood bramble is the elven traditional way of living. The great trees dropped plenty of seeds over the years and things constantly grew on or over each other. It became a thick, dense, maze of dead and live trees, growing bushes next to their leaves. Stacked up on each other outward in strange positions, the elves lives in the sometimes giant nooks of the bramble. And when you've reached the top of that, you were in the location where the rest of the elves lived. On branches naturally grown and with guided growth to add living spaces if they needed.