^TEMS 



respect. One can distinguish among 

 lowland tropical or equatorial rain 

 forest, subtropical rain forest, sea- 

 sonal forest, forest savannah, and 

 tropical mountain forest. These for- 

 est types all have some common and 

 some unique features, which do not 

 clearly separate themselves into tropi- 

 cal or temperate; for example, ever- 

 greenness appears in both regions. 

 A selection of compositional, struc- 

 tural, and functional criteria are com- 

 pared in Figure IX— 11. Here, the dis- 

 cussion will center on comparisons 

 between temperate deciduous forests 

 and tropical rain forests. 



Although we know a great deal 

 about the properties of almost all 

 existing vegetation types, we seem 

 hopelessly confused about how much 

 of each vegetation type exists in the 

 world. The terminology for distinct 

 types is weak, and the accounts of 

 different authors conflict. Even in 

 such apparently clear traditional 

 groupings as forest, grassland, desert, 

 and cultivated land there are many 

 discrepancies about areal extent. 

 Total land surface is always the same, 

 of course — 147 million square kil- 

 ometers. But statistics for various 

 vegetation types gathered within the 

 past fifteen years, including the offi- 

 cial calculations of the Food and Agri- 

 culture Organization, vary greatly. 

 Thus, one can find the following 

 estimates: 



Figure IX-11 — COMPARISON OF TEMPERATE AND TROPICAL FOREST 1 



a. 



The table lists several properties of forest types and compares these within the 

 temperate and tropical zones. Note the importance of temperature in the tempera- 

 ture zone and that of rain in the tropics. 



Discrepancies are even greater with 

 respect to subdivisions of the above- 

 mentioned formation classes. 



Such uncertainty offers a weak basis 

 for world management planning. A 

 new plan must incorporate the evalu- 

 ation of a new size inventory for 

 whatever the management units might 

 be. These units are fairly easy to 

 establish along the biome concept, 

 which coincides generally with the 

 "zonal vegetation," "climax vegeta- 

 tion," or "vegetation formation" of 

 the phytogeographers. 



Classical Models — Any manage- 

 ment plan requires a model. The 

 "models" of the ecologically oriented 

 phytogeographers have traditionally 

 included the following categories: (a) 

 altitudinal profile; (b) soil pattern and 

 catena; (c) climatic (microclimatic) 

 pattern; (d) species composition; and 

 (e) successional series. 



The correlation between some of 

 these properties is so significant that 

 predictions can be made in the tem- 



perate zone and, to a lesser extent, 

 in the tropics. The predictions are 

 usually more reliable for plants than 

 for animals; they are usually better 

 for qualitative statements than for 

 quantitative statements; and they are 

 normally better for dominant species 

 or factors than for the less important 

 components. In the deciduous forest, 

 the traditional models are already re- 

 fined and commonly used for manage- 

 ment practices. In the humid tropics, 

 they are generally an order of magni- 

 tude cruder; some are just being elab- 

 orated. A generalized model of a suc- 

 cession, including productivity data, 

 is impossible to draw for the humid 

 tropics with any degree of confidence. 



Knowledge of tropical and tem- 

 perate-zone ecology is about equal 

 almost everywhere. However, knowl- 

 edge in certain geographical regions 

 or with regard to certain factors may 

 be more advanced in the tropics, and 



299 



