Hi Timothy. Thanks for taking time to respond. I didn't include a
description of the fungus I guess because I thought only one type of
fungus was likely to grow on a forsythia. I didn't realize there could
be many different types of fungus. If you email me
) I could reply with a photo. Otherwise, the
fungus looks pretty much like brown/grey "spikey" balls. These grow on
the stems, not the trunk or leaves. It did not affect flowering last
year as the bushes looked just fine from a relative distance, but it
does appear to have killed some of the branches, though not all. These
bushes are very large and dense, so perhaps it was lacking proper
airflow as you mentioned. Do you think I need to cut these down to a
few inches or is there something I could treat the fungus with? I
realize you don't know the exact problem here, but in general with
things like this - what would one do?

Thanks again.
Amber