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On a hike near Viento State Park in the Columbia Gorge, I found this forest of twisted Oregon White Oak (Quercus garryana) trees in the fall of 2000. The delicate colors and bent trunks made a captivating scene. In this area of the gorge, a variety of tree species mix in unusual ways. In the distance is a slope of Douglas fir and cedar, typically found in a wetter climate, while the oaks prefer drier conditions and more sunshine. The red and yellow shrubs in the foreground are Creambush Oceanspray (Holodiscus discolor), a common understory plant in low-elevation forests of the area. Although I have returned to the area several times since I took this photograph, I have yet to find the colors as beautiful as they were in 2000. An important effect of healthy forests such as the one above is removal of moisture from the air and incorporation into the water table. The most telling example of this effect was the deforestation of Easter Island by its native peoples. When the trees were cut down, the rains stopped and the island became a desert. So deforestation can create drought in the immediate area of the logging as well as downwind or regionwide. The drought increases fire danger and can result in further loss of tree cover from fire. Trees seem to play an important hydrologic buffering role in that when cool, moist air comes in over a forest the trees extract moisture and dry the air, preventing flooding and adding water to the soil. On other days when the air is warmer and drier and the soil is wet (from storms or snowmelt), the trees transfer moisture to the air and help to reduce drought as well as keep the soil moisture levels at optimum. This phenomenon is well known in the Pacific Northwest where I live, where on a stormy day clouds are clearly visible on forested slopes and less prevalent on rocky or logged ones. The balance between trees removing moisture from air vs. adding it to the air via transpiration is undoubtedly complex, but within all that are likely some important effects that have huge implications for the environmental movement and for the people dependent on water. Farmers, for instance, may find that their ability to obtain water for crops depends on how much forest has been cleared from areas where prevailing weather passes before arriving at their farms. Called "land-use forcing," this is a relatively new area of study for climatology, driven in part by understanding the relative contributions to climate change from greenhouse gas production and land-use decisions. There is mounting evidence that reducing carbon emissions alone (1) may not be enough to stop human-caused climate change; we may also need to be more responsible about preserving forests. Forests tend to be a difficult subject for color photography as they usually have a lot of shadows along with small areas of highlights that make correct exposure challenging. Large numbers of trees can make camera placement a problem, and the tree canopy often blocks light that would open up the scene. The best light for forest photos tends to be from the side because it lights up tree trunks and accentuates bark patterns. Side light is rare in a deep forest. It's often found near a clearing, river, lake, or hillside. Due to the wide contrast range it took a lot of work to bring out the shadow detail of the tree trunks so that the impression matched what I saw at the time. I came back to the image several times over the last few years, refining it again and again until I got a pleasing result. This photograph is best appreciated in larger sizes as there is a lot of detail in the tree branches and moss-covered trunks. If you like this picture, you might also like Oak Canyon.
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