No kicking bamboo trees, lol
jujitsu is self defence art, supposedly developed in japan for samuri warriors. Grapling, throws, trips, holds, locks, chokes, etc. Also involved weapons training. This is the organisation that I train at,
Jikishin Ju Jitsu Association Homepage
TBH like most places, 2/3 of the session we do sparring, ground work, street defense and attack techniques, etc. Stuff that is not on the 'syllbus', pure JJ is about 1/3 of the session.
ground fighting is a combination of brazillian jujitsu and grappling. You spend a lot of time on working position to control and gain a submission holds, so in a street situation for example if a fight goes to the ground (the worst place to IMHO) then you know how to control them and work a submission hold. BTW its probably the most intense workout you can get cardio wise.
In a way bruce was one of the fore runners to MMA, he trained with one of the most renowned wrestlers and strikers of his time. Tooks bits of what worked and what didn't. Somebody who understood that all martial arts (including boxing) have something to offer, no art is perfect in all situations. A fight can go through many stages, striking at range, close quarter fighting, ground fighting. Be adaptable, be ready.