This is to prevent water loss by the trees. Under drought or dry conditions, plants may close their stomata to limit the amount of water that evaporates from their leaves a process called transpiration. In this process water diffuses through the stomata into the atmosphere, in a bid to preserve water plants may close their stomata, especially during very dry climates.
Essential amino acids are amino acids that must be supplied to one's body by their diet because they cannot be synthesized from scratch.
