The major biome characterized by the relative absence of trees is the grassland.

Here's why:

* Grasslands are dominated by grasses and other herbaceous plants. While some scattered trees may exist, they are not a defining feature.

* Other biomes have different dominant vegetation:

* Forests are dominated by trees.

* Deserts have sparse vegetation due to low rainfall.

* Tundra has low-lying vegetation due to cold temperatures and permafrost.

Let me know if you'd like more information about any specific biome!