Saturday at camp

I spend Saturdays at our local Scout Camp and had some quiet time so I decided to paint.  Everything around me was green except the almost white trunks of these very tall poplars.  Maybe by the summer I will learn how to put some colour into green paintings.  I tried to scratch out the light trunks too early and ended with dark trunks so when I put darker layers on I painted around them.  I tried, rather unsuccessfully to mask the dark lines.  I am not unhappy with this painting.