"关于热带方面" can be translated into English as "regarding/concerning the tropical aspect/region" or more naturally as "in relation to the tropics" or "with regard to tropical areas", depending on the specific context.
For example:
Regarding the tropical aspect, we need to conduct further research. (关于热带方面,我们需要进行进一步的研究。)
In relation to the tropics, climate change poses significant challenges. (就热带地区而言,气候变化带来了重大挑战。)