That's because it just completed the city's first ever tree census.
It took a year to count every tree on San Francisco streets as well as note the type and condition.
Trees on private property or within public parks were not included.
Data shows San Francisco has almost 125,000 total trees. A searchable database of the information gathered in the tree count is available here.
The city identified 500 different species.
As well as 40,000 places that it could plant new trees.
Starting in July, proposition e will go into effect, which makes the city - not private property owners - responsible for street trees.
$19 million has been budgeted for tree maintenance as a result.