1995 Volume 5 Issue 1+2 Pages 1-40
Summer-rain warm-temperate, wet subtropical and tropical zones in East, South and Southeast Asia are widely covered by evergreen broad-leaved forests. These forests are dominated mainly by evergreen tree species of Fagaceae, Lauraceae, Theaceae, Magnoliaceae and Hamamelidaceae. Trees have leathery smooth leaves ready to reflect the sunshine and brighten, and Kira (1977) put forward a proposal of lucidophyll forest as a new nomenclature of this type of evergreen broad-leaved forest. It was fIrst reported as Lorbeerform by Griesebach (1872) in Canarias Islands. The lucidophyll oak-laurel forests are found in ranges among 85 and 180°C month of Kira’s warmth index, which corresponds to warm temperate zone and among 180 and 240°C month to subtropical zones in Japan.
Such lucidophyll oak-laurel forests have a wide range of distribution in Asia, New Guinea, Macaronesia and southeastern United States. The northern limit of its distribution is at about 40°N of the seashore or islets of Northeast District of Japan in the PacifIc and at 39°N in Açres Islands in the Atlantic. The altitudinal limit goes up to about 1,000 m from sea shore in warm-temperate Japan, and upwards to about 3000 m in the wet tropical Asia.
The constituent species of the forests becomes diversifIed as it goes to the tropics. In the area of northern limit the forest is dominated only by a laurel, Persea thunbergii, but forests are diversifIed with many species of a number of genera and families as shown in Appendix. In the tropics they are mixed with some tropical species such as climbing bamboos, screw pines, palms and climbing species of Araceae. On the other hand, some species of Lauraceae and Fagaceae are found in the lowland tropical rain forests, but they are minority of tall lowland rain forests.
In Africa temperate and montane forests (afromontane forests) do not have lauraceous and fagaceous dominants but for Ocotea as a companion, and their species composition is not similar with the Asian lucidophyll oak-laurel forests. Southeastern evergreen hardwood forests of the United States are dominated by Quercus (Quercus) species under summer-rain climate with hot and humid summer and not so severe winter. As their leaves also reflect sunshine and brighten, this type of forest should be included into lucidophyll forest formation as well as Macaronesian laurel forests.
The nomenclature of the lucidophyll oak-laurel forest is diversifIed, and a number of names have been used. They are largely classified into five groups of terms based on vertical zonation, climatic zone, leaf characters, species composition and plant sociology. The author thinks that it is desirable to give a standard name like summer green forest formation to the forest formation widely distributing in the lowland of warm-temperate, and montane areas of subtropical and tropical regions dominated by oaks and lor laurels. Lucidophyll oak-laurel forest formation is a recommendable name of the formation.
Evergreen Nothofagus forests evolved and developed only in the southern hemisphere under similar climate to that of lucidophyll oak-laurel forest formations, could be included into the latter formation, because trees in evergreen southern beech forests are also lucid under humid climate and both forests assembled only in New Guinea and its adjacent islands. Discussion is carried out on other types of vegetation in the Middle and South America.
