Daddy Longlegs spiders

As far as i am aware these do not afflict trees but i am seeing an awful lot up in my trees as i work on them, ect. What do these things do? Are they a possible indicator of a bigger problem i.e. aphids, ect. I usually dont bother them but i just cant help but wonder why so many immediately around the vicinity of the bonsai garden.

They're cool, they will keep the other insects in check.

It must be a very well protected area. Daddy long legs hate air movement. Maybe some just hatched nearby?

My motto in life , concerning inhabitants of this Planet.... They were here first.