| Quercus tomentella | |
|---|---|
| Island Oak grove, Santa Rosa Island | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fagales |
| Family: | Fagaceae |
| Genus: | Quercus |
| Section: | Protobalanus |
| Species: | Q. tomentella |
| Binomial name | |
| Quercus tomentella Engelm. |
|
Quercus tomentella, the Island Oak, also the Island Live Oak or Channel Islands Oak, is an oak in the section Protobalanus.
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The Island Oak, Quercus tomentella, is endemic to six islands off the coast of California and the Baja California Peninsula including:
Island Oak is a tree usually less than 20 metres (66 ft) in height. Its bark is usually gray and becomes furrowed with age. The specific epithet tomentella, Latin for "beset with tomentum (fuzz)", references the dense hairs found on the undersides of its leaves. Leaves, which are evergreen, are usually 5-8 cm in length, oblong to oblong-obvate in shape, with a toothed margin, deeply indented. Acorns take 2 years to mature and are saucer- to bowl-shaped with a rounded tip, and large in size (cup 20-30 mm wide, 6-8 mm deep, nut 20-35 mm).
Island Oak can hybridize with all other members of the section Protobalanus, although its natural range overlaps only with the Canyon Live Oak (Quercus chrysolepis).
Fossils of Island Oak have been found in mainland California; the youngest known fossils are two to ten million years old and were found near St. Mary's College, somewhat near the Oakland hills. The oldest known fossils are 30 to 60 million years old and were found in the Mojave desert. Island Oak is no longer native to mainland California, and is thought to be a relict of a climate that was warmer and wetter than today's. However, it will grow readily in mainland California if planted and regularly watered.
The Island Oak is listed as Vulnerable (VU B1+2ce) by the IUCN. Many populations are in need of immediate restoration due to severe impacts of grazing by non-native herbivores. The National Park Service has classified Island Oak as a species of special environmental concern.
On Guadalupe Island, the local population is threatened as it has declined some 80-90% since the 1950s, and one or two dozen trees are all that remains. These do not seem to be reproducing any more.[1] While the Island Oak was once an important part of the local ecosystem, its decline was caused by tens of thousands of feral goats swarming the island since the mid-19th century. Removal of the goats was finally all but complete in 2005 and fenced enclosures have been built since 2001, permitting recovery of local flora.[2] Even if the local oaks should disappear, the population could be reestablished from Channel Islands stock.