All of us look forward to the beautiful fall display as deciduous trees, such as aspen and cottonwoods, change color before losing their leaves. What many of us don’t realize is that evergreen trees also lose their needles in the fall, and that this is a perfectly natural phenomenon. Needle drop occurs on all evergreens in the late summer or early fall and can be alarming to those of us who are concerned about the spread of mountain pine beetle and Ips beetle. The tell tale sign of normal needle drop: interior needles turning brown while the outer needles stay green. If this is the case, you should have nothing to worry about. If you see any yellowing or dieback on the tips of your needles, your tree could have a more serious issue.