Google has unveiled a new tool that can help cities keep their populations cool by identifying the places where trees are most needed.

And cities tend to be much warmer than their surroundings.

Because buildings and asphalt trap the heat.

An easy way to cool down urban areas is to plant more trees in neighborhoods where the trees are scattered.

The hope is that planting new trees in these areas can help cities adapt to the heat.

The new tool from Google, dubbed the Tree Canopy Lab, uses aerial photos and Google's artificial intelligence to find the location of every tree in the city.

Tree Canopy Lab puts that information on an interactive map with additional data on the most densely populated neighborhoods that are more vulnerable to warmer temperatures.

Google has tested the "Tree Canopy Lab" in Los Angeles, and the company says data about hundreds of other cities are on the way.

City regulators interested in using the tool in the future can contact Google through a form published online.

"We will really be able to identify the best strategic investment in terms of addressing this heat in urban areas," says Los Angeles City Forestry Officer Rachel Mallarish.

Google claims its new tool can provide information to cities just as it has done Los Angeles when it comes to inventing their trees.

It often does this by sending people to scan each block.

Cities tend to be warmer than their surroundings because buildings and asphalt trap the heat (Reuters)

Los Angeles has also used LIDAR technology to map its urban forests in the past, which uses a laser sensor to detect trees, but this process has been expensive and slow, according to Mallarish.

Google's new service is free to use, and will be updated regularly using Google Maps already captured by the company.

The new tool found that more than half of Los Angeles residents live in places where less than 10% of their area is shaded by trees (the city average is over 20%), according to Malaresh.

It also found that 44% of Los Angeles residents live in places with extreme heat hazards.

Heatwaves in Los Angeles County have become longer, more frequent and intense over the past 50 years, according to a study published this year by researchers at NASA's Jet Propulsion Laboratory.

And trees can cool down a hot neighborhood in two ways;

By blocking people and buildings from the sun, releasing moisture when temperatures rise through evaporation, a process similar to the way our bodies cool down through perspiration.

These two mechanisms can lower extreme summer temperatures by as much as 9 degrees Fahrenheit, according to the Environmental Protection Agency.

Los Angeles is working to green some of these neighborhoods, preparing the city for a warmer world by 2028. The city wants to increase tree canopy cover by 50% in "low-income, heat-affected" neighborhoods.

It has also set a goal of planting 90,000 trees across the city by 2021;

This would bring an additional 61 million square feet of shade to the city.