Climate Influences
Compared to Western Europe, North America provides many more arbor species (more than 800 species and about 70 oaks, compared to 51 and three respectively in Western Europe) which adds many more different colors to the spectacle. The main reason was the different effect of the ice ages—while in North America, species were protected in more southern regions along north–south ranging mountains, which was not the case in Europe.
Global warming and rising carbon dioxide levels in the atmosphere delay the usual autumn spectacle of changing colors and falling leaves in northern hardwood forests, and increase forest productivity. Experiments with poplar trees showed that they stayed greener longer with higher CO2 levels, independent of temperature changes. However, the experiments over two years were too brief to indicate how mature forests may be impacted over time. Also, other factors, such as increasing ozone levels close to the ground (tropospheric ozone pollution), can negate the beneficial effects of elevated carbon dioxide.
Read more about this topic: Autumn Leaf Color
Famous quotes related to climate influences:
“A tree is beautiful, but what’s more, it has a right to life; like water, the sun and the stars, it is essential. Life on earth is inconceivable without trees. Forests create climate, climate influences peoples’ character, and so on and so forth. There can be neither civilization nor happiness if forests crash down under the axe, if the climate is harsh and severe, if people are also harsh and severe.... What a terrible future!”
—Anton Pavlovich Chekhov (1860–1904)