Also

I understood the chief can do something to increase fruit on the trees, but so far I have not come across any information on this ability, or if they can do it, how to get them to!

Any help would be much appreciated

The chief can direct the farmers harvesting food so that they are more productive, but he can't increase the amount of fruit on the trees.

Your Chief can also:
collect firewood & dry grass, heal people, and put water on the firepit. Probably s/he can also collect flowers for potions, but I haven't actually tried that.

As far as the Chief directing work, I've had limited success with that. Since my villagers never seem to want to build that third hut (!!), I usually have my Chief directing their efforts. Sometimes it even helps, but I've come back to the game on occasion to find that the Chief is the only one still there!! Everyone else has run off to go fishing, or swimming, or "enjoying the bath", or whatever.

The chief can collect herbs. It's very handy, actually. It's so much easier to have him go around picking the herbs you need than to take someone off a job.

He can also make potions, so if you're worried about weakening one of your villagers, use the chief and if the potion blows up and weakens him, well, you don't need to worry about making him rest as he doesn't work anyway. Obviously, let him recover before trying again

The more villagers you have, the more influence your chief will be when he/she directs work.

So if you have only a handful of villagers, they may wander off (maybe because their preference was checked for something else). But, as you increase the number of villagers that you have, the chief seems to get more influential. I've even simply put my chief on directing a task (mid and late game) and watched my villagers wander over to where he was to get to work.

Thanks HappyPlayer - I was also wondering about the chief directing work. My tribe is still small and so I hadn't been seeing any real benefits.

if it is a woman she may still have kids (If she is old enough)