Our town is fortunate to have an interesting variety of oak trees along our streets and in gardens and parks.
There are roughly five hundred oak species in existence worldwide. Although we are inclined to think of oaks as predominantly European in origin, the region with the largest variety of oak species is North America (Mexico and the USA), followed by China.
One characteristic shared by all oaks is the fact that their fruit is an acorn, consisting of a nut held in a cup-like structure. The shape of the nut, and especially the properties of the cup, are important identifying features.
The leaves, bark, wood and acorns of oak trees are rich in tannins which help to make the wood resistant to attack by insects and fungi. This is one of the reasons why oak wood is so sought after for furniture, flooring and timber-framed houses.
The first of the trees on which we focus in this article is the so-called Algerian oak. In Paarl beautiful specimens of this tree can be seen on the pavement in front of the Strooidak Church. It is a sturdy, medium to large tree, semi-deciduous (in Paarl), and able to adapt to a range of growing conditions, with a high tolerance of drought. It is a superb shade tree, long-lived, and less susceptible to the scourge of powdery mildew than the English oak.
It is native to Spain, southern Portugal, Morocco, Algeria and Tunisia. Interestingly enough, it is not native to the Canary Islands, so the species name canariensis was assigned to it erroneously.
As with all oaks, male and female blossoms appear on the same tree, the male blossoms in the form of long, yellow filaments (called catkins) which facilitate dispersal of the pollen by wind. The fruit that develops from pollinated female flowers is an elongated nut in a shallow cup. The leaves of the Algerian oak are probably the easiest way of identifying the tree. Although variable in size, their shape is fairly constant. They are broadly elliptical, and their margins have numerous, regularly-spaced, shallow lobes. Equally-spaced lateral veins arise from the midrib, each ending in a rounded peak on the margin. Taken together, this makes them easily distinguishable from the leaves of the English oak.
The second tree under discussion is the Turkish oak, which hails from South-Eastern Europe and Asia Minor. It also grows to a fairly large tree, though not quite of the stature of the English oak (but then few trees are).
It has been widely planted in Europe as an ornamental and roadside tree. It is deciduous, providing excellent shade in summer and a lovely display of bright, yellow foliage in autumn.
Here in the Western Cape it has the advantage that it seems even more resistant to the troublesome downy mildew than the Algerian oak.
Unlike the Algerian oak, the leaf shape of the Turkish oak varies widely from tree to tree.
The Turkish oak makes up for that by producing acorns with a highly distinctive feature: the cup is densely covered in soft, hairy, curved, mossy bristles, giving it the appearance of a hat made of moss, and earning the tree the common name “mossy-cup oak”. The acorns take 18 months to mature from pollination, and are reputedly extremely bitter, especially during the first year.
In Paarl, mossy-cup oaks can be seen in the lower part of Faure Street, which could well be named “Oak Lane”.
