The answer to 'why is my lawn dead trees' is that there are several common causes for a dead lawn with dead trees, including disease, pests, drought, or improper care. The symptoms may include brown or yellow patches, wilting, and dead or dying trees. Solutions can include proper watering, fertilization, aerating the soil, and treating for diseases or pests. In some cases, the entire lawn may need to be re-sodded or re-seeded.
If the issue is widespread or you're unsure of the cause, it's best to call a professional landscaper or arborist to diagnose and treat the problem. They can provide tailored recommendations based on the specific conditions of your lawn and trees.