Arbutus menziesii berries

Is there a reason for the quantity of berries on the Arbutus trees this year on Vancouver Island?

Why do some of the trees not produce any berries at all?

---------------

Ron here...

Many reasons for different berries:

1. Rain... more rain in early spring makes more blossoms = more berries in fall.

2. Drought in prior summer can push trees to make more berries in spring.

3. cycles... whether caused by the above or more seem to about every 7 years produce a huge abundance of Arbutus menziesii berries.

4. Trees are not all equal... depending on sun exposure, internal health, age, etc each tree responds differently.

And I am sure a botanist can come up with more reasons!