Hello there Dicko,
Before I go on, I'd like to point you towards a lovely thread that already exists for the sole purpose of Acacia IDs, aptly named "
Acacia and Mimosa Identification Thread". I will also link
this amazing resource which is packed full of acacia content from our resident acacia specialist nen. These are just for future reference! The thread started by Nen also contains the answer you are looking for.
The images you provided look strikingly like an Acacia Mucronata var Longifolia.
Click Here and read post 209. The first page has an index and will tell you what pages have significant mentions of what species. The above page and post is one of many on A.Mucronata within that thread and I highly recommend you challenge my ID by browsing that thread.
Onto whether or not Acacias can yield some dangerous alkaloids. Well, as it stands, Acacias are still very under studied. So, I can't really answer that, although, I will recommend caution if you are at all concerned. Do your research and get your extraction perfected before ingesting anything.
Love the trees and they will love you back! Do not destroy this tree in hopes of alkaloid content! This has already been observed in large scale and it sickens me.
That's about all! Good luck and I hope to hear about future adventures!