The leaf on the ground is from a Tulip Poplar, yes, but we cannot see the foliage on the trees in the distance well enough to determine if they are the same species. They are a common canopy tree in our woods and have good value to wildlife, including as a host plant to at least one of our swallowtail butterflies.

Are you able to send us photos of the patio in its entirety (so we can see what other plants may be growing around it) as well as a close-up of the black substance you are finding there? We hope to determine if it is indeed sooty mold, which is a fungus that grows on aphid excrement (which is mostly sugar-water). This fungus does not infect plants nor cause much harm, but can be a nuisance, especially in this circumstance.

Many sap-sucking insects, like aphids, can produce honeydew, the excrement in question which sooty mold grows upon. If honeydew is being produced, aphids might not be the culprit. Aphids are rarely a problem beyond just a nuisance on mature plants - particularly a tree of this size - and thus do not warrant treatment in most circumstances. Many beneficial insects prey on aphids, which is another reason to avoid insecticide use. (It would probably also be costly to treat this large of a tree, which will also need multiple injections, the intervals of which will depend on the product used.)

Tree pruning is always risky, although there are certainly times when the benefits of doing so can outweigh that risk. The concern is that the pruning cut, even when professionally made, may become infected with wood-decay organisms or insects which will actively destroy the wood, progressing beyond the cut and into healthy trunk tissue. Trees have a way to seal wounds like these cuts from the inside, so these issues are not guaranteed to happen, but as they are not always successful it creates at least some risk to tree health, and careful consideration should be made prior to pruning. Here, pruning to avoid leaf-drop won't be practical, as leaves will shift direction in the air as they fall and may not be falling directly underneath the branches they originated from. Even once down, they can blow around and onto the patio anyway.

Tulip Poplars predominantly shed leaves early in response to drought, and commonly do so here in the suburban mid-Atlantic, where temperatures are high and rainfall patchy in the summer months. It is a way for the tree to conserve the resources it has, by jettisoning some foliage it cannot keep adequately hydrated. This does not hurt the tree, even though it can be a nuisance to us. The only efforts one can take to avoid this is to irrigate the tree's root zone when rainfall is lacking. In wooded areas, this may not be practical, but in areas where the tree roots share space with lawn or other garden plants, irrigation can be useful for all involved.

Miri

My patio is very small and hard to take a photo of as the area around it is small.  I live in a small condo townhouse.  There is a very small strip of trees behind the row of houses.  I am attaching more photos showing substance (mold) on items.  That tree is the only one hanging over my house.  The flagstones on my patio are covered in black.  They should be light colors of greys and blues. I was not able to show you this as I could only add three images.
Thank you for your assistance.

Thank you for the additional photos. The black growth could be sooty mold or it could be another kind of mold or fungus growing on surfaces that remain damp and shaded due to the overall tree cover. The greener growth on the siding looks like a type of algae which is commonly seen on home siding and structures that are protected from the drying effects of direct sunlight, at least for a measurable portion of the day. While it's possible honeydew is raining down from one or more trees nearby, it's not likely it's causing all of this secondary growth. One of the professional house-cleaning chemicals or pressure-washers should help remove this buildup. Such treatments are outside our realm of expertise, so we do not have any specific recommendations and consulting a company in that industry for an assessment might be best.

You can always try having an arborist inspect the Tulip Poplar for scale (more likely than aphids to be problematic, plus they would be present year-round). You can search for an arborist by using the second and third links on this page: https://extension.umd.edu/hgic/topics/how-do-you-decide-when-remove-tree

Miri