Araucaria angustifolia (Pinheiro do Paraná) is a species of pine that has lived on Earth for 200 millions years (we are talking Jurassic period). Each individual can live up to 450 years and reach up to 45 meters in height. It can be found in South America, mainly in the southern region of Brazil. They are currently at risk of extinction.
This project was made for SpeedTree
The tree models were made in SpeedTree Modeler and the renders in Unreal Engine
Bark materials were generated from photogrammetry scans of real Araucarias.
Leaves materials came from a simple photo and help of Photoshop and B2M. They were used on high-detailed branch models and those were used to generate branch atlases.
There are three tiers of models: 
VFX (up to 1.2 million tris), Game Hero (up to 45k tris) and Game Desktop (up to 15k tris). Each tier has at least 3 LODs.
My references were a mix of photos I've found on internet and some pictures I've taken myself. Living near real Araucarias helped me a lot with rare references like seedlings and leaf variations.