Maple trees in Korea were studied to see how their chlorophyll levels and photosynthesis change throughout the year. Different species had varying levels of chlorophyll, with some reaching their peak in June, July, or September. Chlorophyll content increased with leaf age, but then decreased. Photosynthesis rates were highest in August, and respiratory rates stayed consistent across species. The amount of chlorophyll in the leaves followed a similar pattern to the air temperature, increasing until July.