Our Psalms today uses a compare and contrast against the righteous versus the wicked:

Psa 1:3  They are like trees planted along the riverbank, bearing fruit each season. Their leaves never wither, and they prosper in all they do.

Psa 1:4  But not the wicked! They are like worthless chaff, scattered by the wind.

Trees that are along the river bank have a strong source of nourishment, they are right next to the water, so they don’t go thirsty and wither away and die.  The metaphor here is that if we are in Christ, we too have a constant source of nourishment, as Jesus says, His bread is eternal life…He never leaves us, when we are with Christ, we don’t need to fear death.  

However, quite the different story for the wicked, the similarity used is chaff.  When farmers were farming their crops, the good wheat was preserved with a winnowing fork, while the worthless chaff was disregarded….or Like the ears of corn, you peel away the worthless stuff and throw it aside before you get to the actual corn to eat.  This chaff or trash is how The Bible today describes the wicked, and it can also be scattered by the wind.  Sadly for the wicked, they are seduced by the empty pursuits of the world, like greed or prominence, and these vices scatter them like wind.   Think how often someone who was once famous fell from their short lived fortune, having their lives cut short by addiction to drugs or some other scandal —  it happens with professional athletes and entertainers all the time.  

So today’s verse…compare and contrast – the righteous have a strong and unshakeable root that is always nourished, while the wicked are like dead weeds that are blown away by the winds of worldly desires.