The flag of Lebanon is formed of two horizontal red stripes enveloping a horizontal white stripe. The white stripe is to be two times a red one (ratio 1:2:1) - a Spanish fess. The green cedar in the middle touches each of the red stripes and its width is one third of the width of the flag.
It was designed to be a neutral flag, not allied to any one of Lebanon's religious groups. The red stripes symbolize the pure blood shed in the aim of liberation. The white stripe symbolizes peace, and the white snow covering Lebanon's mountains. The green cedar (Arz) (Species: Cedrus libani or Lebanon Cedar) symbolizes immortality and steadiness.
This cedar is referenced many times in the Bible: "The righteous flourish like the palm tree, and grow like a cedar in Lebanon" (Psalms 92:12). There is also some reference in W. Smith's 1980 book on the colours: "The red and white colours are those associated, respectively, with the Qaysites and Yemenites, opposing clans that divided Lebanese society between 634 and 1711 AD". However, that explanation is poorly known (not to mention quite unheard of) in the Lebanese tradition.
Red is thought to be for the color of the uniforms worn by the Lebanese Legion during World War I. Officially the red is said to represent the people of Lebanon's sacrifice during the struggle for independence, and white represents purity and peace. Although the flag has existed only for half a century, the tree at the center of the flag - the Cedar of Lebanon - has been an emblem of the country since the time of King Solomon, almost 2,000 years ago. Specifically, the cedar is the symbol of the country's Maronite Christian community. It first appeared on a flag in 1861 when Lebanon was part of the Ottoman Empire. Soon after its collapse, the country became mandated to France and its flag was a French Tricolore, with the Cedar of Lebanon in the white band of the flag. The cedar symbolizes happiness and prosperity for the country.
It is a common mistake to draw the branches of the cedar and the tree trunk in brown or black. Nevertheless the mistake could be seen as unconstitutional. The cedar should be fully green regarding the provisions in the Constitution.