|Willow leaf sheath|
|Opening Willow catkin|
I'd expect to see that happening around the end of February, but something has completely confused this particular tree because many of the catkins were in the same condition. This early opening will have a short-term adverse effect on the tree because these flowers will be destroyed by the frost, requiring the tree to make a second set of flowers later in the spring.
This, of course, will impact our willow-dependent moths and other insects. Bees such as Andrena clarkella are only seen during the normal flowering season for willows, and this tree might flower too late to support them. On the other hand, it might just be possible that some of the other dependent species could extend their season a little due to the later availability of some pollen and nectar.
In our natural environment nothing ever happens in isolation.