Here's why:

* Abiotic factors are non-living components of an ecosystem. They include things like:

* Sunlight: Provides energy for photosynthesis, the process by which plants make their own food.

* Water: Essential for plant growth and survival.

* Temperature: Affects the rate of plant growth and activity.

* Soil: Provides nutrients and support for plants.

* Air: Provides oxygen for respiration and carbon dioxide for photosynthesis.

* Trees are living organisms, making them biotic factors in an ecosystem. However, sunlight is not alive. It's a form of energy that is essential for plant growth, but it's not a living thing itself.

So, while trees play a crucial role in an ecosystem, sunlight is an abiotic factor that influences their growth and survival.