As cities look to plant more trees, they're trying to diversify the mix, in order to make sure they can withstand extreme temperatures and other climate disasters.
A US Forest Service study indicates that street trees save lives and provide direct health benefits that far outweigh the costs of planting and maintenance.
Around three-quarters of the tree and shrub species currently grown in cities worldwide are predicted to be at risk from hotter and drier conditions by 2050.
Places like Harrisburg are planting more trees to improve the urban canopy. But if roots of trees buckle a sidewalk, for example, a homeowner is on the hook — which leads some to resist.
