Dear student
Yes there is negative effect of global warming on forest.
1. Global warming leads to increased temperature. High temperature may not favour growth of many tree species.
2. High temperature is also not favoured by insects and birds who make forest as their home. Due to this pollination process of many trees species which are carried out by insects and birds will get hampered.
3. As carbon dioxide levels increases in the atmosphere due to global warming , chances for forest fires are expected to increase by 40%.
Regards