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View of Stream CrossingCross the stream using the new bridge which leads to the north-facing slope.   This part of the trail receives considerably less direct sunlight than the more southerly exposed sections on which we have been hiking. The effects of this reduced incoming light differ from season to season and also from year to year. In the winter, snow melts more slowly on this slope and often persists on into the early spring. In the spring, soil temperatures rise more slowly and fern fiddleheads emerge and wildflowers bloom often weeks later than on the warmer, sunnier parts of the trail. In the summer, the impact of this shading depends upon the season's rainfall. In years in which rainfall is average or above average you will see less dense vegetation on these shady slopes because of the reduced incoming sunlight. In years of below average rainfall, we are likely to see denser vegetation on this slope due to the water conserving influence of the shade. These observations are consistent with the ecological "law" called the Law of Limiting Factors. When rainfall is limiting anything that slows evaporative water loss from the soil (like shading) will favor overall plant growth. When rainfall is not limiting, soil moisture will remain high even on the sunnier slopes so the stimulatory effect of sunlight on photosynthesis will be the driving "limiting" factor.

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