I heard someone say earlier in the year to stay close to the large tree on the left.

I used to make it 90% of the time a few years ago and now it is more like 50%. I don't ride Sunder as much now as I used to and I don't know all the new lines but that climb seems to have gotten harder.

I find the sit and spin approach better for technical climbs. When mashing on the pedals the rear tire is more prone to slippage because of the uneven application of torque and higher peak forces throughout the revolution. The tire looses traction mid mash and typically causes a temporary loss of balance which leads to dabbing or corrective steering and wastes any momentum you may have had before. Unweight the front and rear wheels by changing body positions when passing over larger roots and try to be as smooth as possible to maintain traction on the rear wheel. Also, time the pedal stroke to start when the back tire first makes contact with the root/obstacle to help lift the bike over it. When you do it correctly it should feel like the bike is floating over the obstacle instead of crashing into it.