Comparative Ecological Study on Subtropical Forest in Canary

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Anaga cloud forests are the subtropical evergreen broad-leaved forests (so-called laurisilva) developed in the cloud zone of Tenerife, the Canary Islands. The forest-interior was humid conditions of Ca. 90 % RH throughout the year, though the humidity fluctuated depending on the wind direction and the height of trade-wind inversion layer. Soil moisture and nutrient conditions were changed gradually along the topographical habitat (ridge, slope, and valley) ; ridge habitat had high C/N ratio, lower NO_3 concentration, and high pF value comparing to those in valley. Depending on the soil and atmospheric conditions (strong wind, etc.), tree height and leaf-size were small at ridge habitat compared to those in valley. Statistics for all the evergreen broad-leaved tree species found in Anaga forest, most abundant tree traits were hypsophyllary-bud type (82.3 %) and notopyll-class leaf (47 %). These features support the notion that the evergreen cloud forest trees in the Canaries are the relic of the Tertiary tropical/subtropical humid forests once spreading much wider areas surrounding Thethys.