**Nature Nugget**

For any of you who have moved to the Half Moon Bay coast from another region, you have surely noticed the presence of the evergreen trees that inhabit our coastside. Among them is the impressive native California Redwood. But you will also notice the many pines and oaks, and the Douglas fir and Sargent cypress.

Evergreen trees have year-round foliage that remains green throughout the seasons. The leaves of evergreens are generally thicker and more leathery than those of deciduous trees and often are needlelike or scalelike in cone-bearing trees. Although they do lose their leaves, evergreens lose them gradually and throughout the many months of the year. In fact, a leaf may remain on an evergreen tree for two years or longer.

There are a combination of factors that support the dominance of evergreen trees within the local landscape. One key element relates to rain and temperature. Here in Half Moon Bay, the rain generally comes during the winter and into the early spring, when it is colder and there is less sun. For this reason photosynthesis becomes more limited. In the early spring, when temperatures start to warm but it is still wet, it takes a lot of energy to grow new leaves. Evergreens have a head start here, as they use their existing leaves for photosynthesis, as they rush to grow new leaves before the dry months of the summer.

Evergreens can also reinforce their own dominance, as their needles and leaf litter have a high carbon-nitrogen ratio that contributes to a high soil acidity and lower soil nitrogen content. These conditions favor the growth of more evergreens and make it more difficult for deciduous plants to persist. Additionally, the shelter provided by existing evergreens can make it easier for younger evergreens to survive a drought.