Making trees for your next diorama need not be intimidating. In fact, here’s how I make trees for my scenes. It is a bit labor intensive, but the results are worth it.
For trees with larger trunks, make a core (balsa wood works well) wide at the bottom and tapered toward the top and wrap it in tissue paper soaked with white glue.

After the tissue and glue have dried, apply AK Interactive Light & Dry Crackle Effects (No. AK8033) with a wide, flat brush. When the acrylic paste dries, it will have a naturally cracked surface, like the bark of a maple, oak, or similar tree.

Use a scribing tool to create realistic contours in the bark running vertically along the length of the trunk. This further simulates a tree trunk’s naturally undulating surface.

If you need trees with thinner trunks, trim lengths of sprue of any unwanted branches.

Glue the lengths of sprue together with liquid plastic cement. Feel free to bend them into natural-looking shapes, or even heat and stretch the ends to get tapers. Be creative!

Wrap with tissue and white glue as before and let dry. However, instead of reaching for the Crackle Effects, add texture with water-based wood putty that you can thin and stipple with a brush.

Joefix Studio Sea Foam (No. 903) works well to model branches. Superglue pieces in place and then apply wood putty to hide the joins. Of course, you’ll want to paint your tree trunks colors appropriate to the species of tree you’re modeling.

In this case, I painted the larger tree trunk AK Real Color Earth Yellow (No. RC064) and then applied lamp black and burnt umber artist-oil washes. The smaller trees were airbrushed Tamiya Flat Earth (No. XF-52) and then treated with a lamp black wash.

Using a leaf punch, like this one from Green Stuff World, make as many leaves as you can — too many is better than not enough. Although, you can always make more if you need them. I punch them out of fallen leaves that aren’t too deteriorated.

Attach the leaves to branches with white glue. Yes, this takes time, patience, and an eye for realism. No matter the color of the leaves when punched, they will fade with time. So, we’re not done quite yet.

Carefully paint the leaves with water-based acrylic colors appropriate to your tree species and season for the model. A fall scene with vibrant summer leaf colors isn’t going to look right! In my case, I applied diluted Vallejo Uniform Green (No. 70.922) and Light Yellow (No. 70.949) in various ratios to obtain a realistic appearance.