There are ways of modifying the light of the direct sun when photographing smaller subjects, such as wildflowers, and we use diffusing disks quite a lot during our wildflower tours. Forests are a different story, though! You just can't hold up a large enough diffuser to soften the light in a forest scene! Therefore, I always check the weather forecast for cloudy or overcast conditions and plan my shooting schedule accordingly. Clouds make a great diffuser!
As Sheila and I were photographing the various redwood forests in Northern California, the light conditions changed from day to day. Some days were cloudless and some were a perfect overcast. It seems I always need to prove to myself that - by golly - you just can't capture a decent forest scenic in sunny weather (as below), so most of the shots taken this day were discarded. This first shot was photographed with full sun and I tried my best to shoot only in the shade most of the time, but this is often what I'm presented with for review by novice shooters.
Redwood forest scene shot in full sun.
This first shot had a lot more contrast prior to adjusting in Lightroom. I toned down the Exposure and brought up Fill Light, which evened things out quite a bit. But there are still bright highlights, which tend to pull the eye away from the central subject matter. It's OK, but not great.
Redwood forest scene shot in overcast skies.
While it's difficult to find a comparable scene when we're traveling from park to park, this one is fairly typical. There are no bright highlights and the tonal value of the scene as a whole is a lot more consistent. Much easier on the eyes!