Annually, the festival attracts about 1.5 million people.

It's estimated from the visitors who attend the National Cherry Blossom Festival that they put in about 150 million dollars worth of economic impact to this area.

This setting is extraordinarily special.

For over a century, Washington DC's flowering cherry trees have heralded the beginning of spring and served as an enduring symbol of International friendship.

This is a time of year when we have people coming focused on a natural resource.

These trees are greatly valued because they're a wonderful symbol of friendship between nations.

The original trees were a gift from Japan in 1912.

Now, cherry tree dates vary from year to year, but the long-term trend shows earlier and earlier blooming.

Here in Washington DC, weather station measurements since 1946 show a statistically significant temperature increase a 1.6 degrees Celsius per century - double the global rate.

In flowering trees, heat breaks winter dormancy, so earlier cherry blooming is consistent with heating caused by climate change.

Man plans and mother nature laughs.

You know, we we can do our best to the plan the festival around the median peak bloom date, we can just base our estimates off history and science.

Phenology is the timing of life events in plants and animals.

A great example is right here: the blooming of cherry blossoms along the tidal basin in National Capital Parks, Washington DC.

Phenology is a potential indicator of climate change.

Published research by the Smithsonian Institution shows a statistically significant advance of spring blooming of cherry trees in Washington DC by seven days from 1970 to 1999.

You know, a potential vulnerability of climate change, is that it could create a mismatch in phenology, that is a mismatch between when flowers bloom and when bees and butterflies and other pollinators mature and are ready to pollinate.

Published scientific research shows that if we don't reduce our emissions from cars, power plants, and deforestation, additional warming could advance spring blooming by another week to month by the end of the 21st century.

With the more than 25 million visitors that we receive on the National Mall each year, the challenges are certainly great in regards to climate change, but the opportunities are great, too.

It's our hope as visitors come and enjoy this wonderful are,a and specifically these trees, that they will have a sense of stewardship and want to help the National Park Service protect our treasures.

When visitors choose to bike, or to walk, or to use our recycling containers, they make a real difference in helping to reduce our greenhouse gas emissions.

When people leave this area they can carry that message with them too, so we can have a wonderful ripple effect of instilling a sense of concern for the environment and stewardship.

This festival is deeply rooted in the mission in the Park Service.

We have culture and history on display before our eyes.

These are relics, these are cultural icons and we have to do our best, as visitors, as Rangers, as Americans, as International guests, to make sure that we take care of our resources, so that future generations can experience the same events as have an opportunity to enjoy today.