Re: why isn't my lilac bush producing any blooms?

Who can say?  It has nothing to do with science, but I'll offer my 
horticultural opinions, many of which are based on good plant science.  1. 
Perhaps the plant is still too small.  I'd give it another year before 
thinking of replacement. Reproduction is a costly investment for plants, 
so a certain minimum size must be reached. Many times especially with 
shrubs you get exactly what you pay for. If you want flowers, don't cheap 
out.  Buy a nice big vigorous bush that's ready to go.  2. I doubt the 
pine trees are adversely affecting the lilac.  If the lilac were 
suffering, the foliage would be sparse or chlorotic. In Ohio the increased 
organic material from pine needles probably will help your soil.  3. 
Incorrect pruning.  Although you did not mentioned any pruning, you must 
prune spring flowering shrubs prior to winter bud formation or you'll 
prune off all the flower buds. 4. Too much nitrogen fertilizer.  Many 
plants respond to ample supplies of nitrogen by vigorous vegetative growth 
and little reproduction, which is OK if you want green leaves.