Did some experiments with various configurations for the leaves and twigs. I decided to take out some details which may not be necessarily important like those curving leaf surfaces, leaf stems and some fancy twigs. The result was a smaller file size less than 110kb with much of the detail you had come to expect from a detailed model still intact.
Renderings of the model using Indigo Renderer are shown below. I already uploaded the model in the 3D warehouse and is now included in the 3d tree collection under the name 'tall tree'.