If you compare the weather extremes of a rocky desert to the weather extremes of a rain forest, you will see a vast difference. A lot of the difference is caused by the plant mass. It is the plant mass that changes the environment as much, if not more, then the elements allowing the plant life to grow. The animals also help in maintaining the biomass as well of course.
In a desert with rocks and cliffs, there is little to shelter a physical being from the elements. If the sun is shining, it full strength of light, including ultra violet, and all it's other waves (gamma, radiation etc.) hit all things directly. It gets unrespitingly hot. At night, when there is no sun, it gets icy cold, because there is nothing to keep the heat in the land, living biomass like a blanket.
When the wind blows, dry earth and sand is lifted into the unrestricted wind. There is no living plant biomass to buffer the gusts and keep the earth in place. It is basically down to raw element on raw element, breaking the other down, an unfriendly place for any lone life form.
Inside a rain forest though, the air is still (staying more in the tree tops) and often smells very pleasant. It is a lot cleaner, like blood that comes straight from the lungs, rich with oxygen.
The light (and other waves such as U.V.) is filtered through other living things (plant biomass), and is therefore buffered and softened. This probably reduces cancer. Just like it is good to eat plants with antioxidant properties to reduce damage from free radicals, it is good to have the living plant biomass around you to shelter you from the harsher elements of radiation (such as free radicals), by absorbing and filtering them.
Inside the rain forest, the temperature is regulated by the living biomass to be fairly cool and still near the bottom, probably so they get knocked about less. The plants do this by releasing aerobacter, shading etc. The temperature extremes are lessened by the consistency and softening effect of a blanket of plant life.
Environments like cities have quite harsh desert like effect. If a wind blows, it is unfettered by wind breaks in the form of thick foliage, dissipating the wind current. If the sun shines, there is little to buffer one from it's harder waves.
I think it is essential to have a healthy environment with lots of living biomass around you to soften the elements if you want to reach any kind of rest on the body from the insidious hardness of the environmental elements. Cities, and building in general can be vastly improved with chunks of solid living biomass to bring rest from the raw elements to residents and workers.
It improves your health.