Why did the new poplar leaves grow bigger after beginning of autumn?

After beginning of autumn, the reason why the new leaves of poplar became larger may be related to the change of climate conditions and light time.

On the one hand, the high temperature weather in beginning of autumn is gradually weakening, the temperature is gradually decreasing, and the air humidity is increasing. This climatic condition is favorable for the growth of poplars. Mild temperature and humid environment contribute to photosynthesis and water absorption of poplar, thus promoting the growth of leaves.

On the other hand, with the gradual shortening of sunshine time, poplars can get more sunshine in autumn, which is helpful to the photosynthesis of leaves and thus promotes their growth.

To sum up, poplar leaves newly grown after beginning of autumn are more likely to be the result of climate change and shortened sunshine time.