Once you have selected a biome, you can start adding trees to it.
You can add trees individually, and select their type manually, or you can also add multiple at once using the multi-import operator.
You can also filter trees by name, species, size and variant, which helps when working with large libraries that contain lots of trees.
Furthermore, you can then also control the size and shape of the trees individually, to better define the look. With this you can make thin trees fat, and bushes into large trees.
Finally, you can control the quality to optimize render times and memory usage even more.
The tree panel in use:
High versus Medium versus Low quality:
Here you can:
See a rendered preview of the tree
Set the visibility of the tree
Add or remove tree slots
Rearrange tree slots
Access extra tree operators (more details below)
Below the tree list, you can choose the type of tree you want by clicking on the large tree preview. By default, this shows the Alpha Trees logo until you change it by clicking on it.
From there, you can see all trees in the currently selected library. This can be annoying to scroll through though if there are a lot of trees, so you can use the search dropdown to filter the results
The search settings are, from top to bottom:
Search term: This could be the name of a species, whether the tree is coniferous or deciduous (whether the tree loses its leaves in the winter), or even the size of the tree (small, medium, big).
Type: By default can be coniferous, deciduous or shrub.
Subtype: The species of tree you want to select.
Tags: Narrow search based on metadata such as size, whether it is flowering or whether it is pruned.
This has various controls for the current tree:
Quality: The resolution of the tree. You can choose from:
High (full res), Medium (1/4 res) and Low (1/8 res).
By default, particle trees are set to medium quality, although if the trees are at a decent distance from the camera, they can be quite easily set to low quality.
Scale: Value to multiply the scale of this tree by.
Width: The Y scale of the tree.
Z offset: How far to raise or lower the tree from the ground.
Multi add allows you to add multiple trees to a biome at once.
To use it, open the extras menu next to the tree list, and choose "Multi add".
This will open the multi add panel.
In the multi add panel, you can select the trees you want to add.
There are a few options that allow you to:
search the trees
set the UI scale
set the quality to import the trees with
toggle or invert the selected trees
Then, simply click "OK" or press the enter key to confirm, and the trees you selected will be added automatically.
This shows all the tree settings being used: