Oaks are a very important component of the Mediterranean forest landscape and can be seen throughout Israel. Unlike conifers, which are considered "pioneer trees" due to their rapid growth, oaks are slow-growing but long-lived, sometimes surviving for hundreds of years. Cork oaks, which are famous for their thick and knobbly dark grey bark, which is known as "cork", are rare in Israel. In addition to the Gilat Nursery, cork oaks can also be found in KKL-JNF's 32 acre Ilanot National Arboretum, which was originally established in 1950 as a research site to determine which trees from around the world could be successfully acclimated in Israel.
Unlike many other oak trees, cork oak is an evergreen and does not drop its leaves. During cork harvest, the tree remains standing while large sections of its outer bark are cut and peeled from the tree. Cork oak is unique in its ability to regenerate its outer bark. After a tree reaches 25 years of age, it can be stripped of its cork once every 9 to 12 years without causing damage to the tree. A single cork oak, which lives up to 200 years, can be harvested over 16 times. Cork oaks don't like too much moisture, which causes the bark to rot. After they reach a certain height, they grow horizontally rather than vertically.
Cork is primarily used as a stopper for wine bottles, but also functions as a closure for olive oil and other products. In addition, it is used to create flooring, furniture and even footwear. Though it is lightweight and elastic, cork remains impermeable to gases and liquids -- the reason it has remained a popular liquid stopper since the times of ancient Greece.
Cork oak also provides its ecosystem with several benefits. The trees help prevent soil erosion from wind and water, and increase the absorption rate of rainfall. The cork oak forests of the Mediterranean act as a barrier to the advancing process of desertification from North Africa. Furthermore, a harvested cork oak tree stores up to five times more carbon than an unharvested tree, since the tree utilizes additional carbon in the regeneration of its bark. Each year, cork oak forests account for 10 million tons of CO2 absorption.