baumzaehlen - Primeval Forests & Their Trees

©2017copyright christoph hase

Garajonay National Park, Canary Islands, Spain

 

Garajonay National Park on the island of La Gomera is the largest (40 km2) and the best preserved example of “laurisilva” on the Canary Islands1, though the same type exists even better preserved on Opens internal link in current windowMadeira. The park is also a World Heritage Site.

 

As the volcanic Canary Islands have never been connected to any continent2, their tree species diversity is low. Indeed, the Garajonay laurisilva is formed by only about 20 tree species1. The forest formations range from stunted thickets of Opens internal link in current windowErica arborea (tree heath), Opens internal link in current windowMorella faya and Opens internal link in current windowIlex canariensis (small-leaved holly) in the exposed sites and the drier highest elevations to tall subtropical forest with little undergrowth in protected valleys where the tallest tree species, more demanding3 Opens internal link in current windowPersea indica and Opens internal link in current windowOcotea foetens grow. The most abundant tree is Opens internal link in current windowLaurus novocanariensis, which is adapted to various habitats. E. arboreaM. faya scrub also occurs as a pioneer community after past felling4. Almost all the species are evergreen. Differences between many species are small but learning to identify the main species is relatively easy.

 

Mean annual temperature is approx. 13–14°C and annual precipitation approx. 600 to 800 mm 4. Additionally, the park is in the cloud zone of the northeastern trade winds; water condensing from fog compensates the lack of summer rains and increases the annual precipitation remarkably5. Elevations range from about 700 m to 1484 m. Many slopes are steep.

 

Particularly in German literature Garajonay is often considered to be primeval forest (Urwald) but true primary forest can only be expected on steep slopes and in ravines3. Old cut stumps can be seen in places near the park boundaries. Grazing continued until the 1940s and its impact on the understory was significant; particularly the southern part of the park (incl. the highest mountain tops) is seriously degraded1. However, for several decades there has been very little human intervention1. Introduced rats, mice, rabbits and cats are abundant6.

 

Most trails are located close to the park boundaries and roads. The park can be reached by bus. Camping is not allowed.

 

References:

 

1       http://www.parquesnacionalesdecanarias.com

2       Wildpret, W. & Martín, V. E. (1997): Opens external link in new windowLaurel forest in the Canary Island: biodiversity, historical use and conservation. Tropics 6(4): 371–381.

3       Kunkel, G. (1993): Die Kanarischen Inseln und ihre Pflanzenwelt, 3. ed. Gustav Fischer Verlag.

4       Del-Arco, M. J. et al. (2009): Bioclimatology and climatophilous vegetation of Gomera. Ann. Bot. Fennici 46: 161–191.

5       Izquierdo, T., de las Heras, P. & Márquez, A. (2011): Opens external link in new windowVegetation indices changes in the cloud forest of La Gomera Island (Canary Islands) and their hydrological implications. Hydrol. Process. 25, 1531–1541.

6       Führer des Nationalparks Garajonay und der Insel La Gomera. CNIG.

 

Official site:

 

http://www.parquesnacionalesdecanarias.com/en/Garajonay/

 

Three over 30-metre Persea indica trees (left), the tallest (central) one being 31.7 m. Other trees are mainly Laurus novocanariensis.
The same Persea indica group as in image 1 (right centre). The tallest is the second tree (with slight bend in stem) from the right of the picture. The other two are to its immediate left. Other trees are mainly Laurus novocanariensis.
Unusually tall and large Erica arborea (tree heath). Height 22.2 m, girth 139 cm. Other trees: Laurus novocanariensis (dark bark) and Persea indica (pale bark).
Unusually tall Ilex canariensis (small-leaved holly, centre). Height 21 m.
Canopy of Garajonay laurisilva. Branches of Erica arborea (tree heath), foreground.
Some trees of the park.