In a mangrove forest in southern Thailand, the root biomass was estimated for the Sonneratia zone, the Sonneratia-Bruguiera ecotone, the Bruguiera zone and the Rhizophora zone. A 0.2 m (width) × 15.5 m (length) × 1.0 m (depth) trench was dug between two trees of Rhizophora apiculata and the roots in the trench harvested, rinsed, sorted by diameter and weighed. The dry weight of roots collected from the trench was 135.6 kg, equivalent to a total root biomass of 437.5 t ha−1 including 220.5 t ha−1 of fine roots.

The root density distribution of a single tree was assumed to be predictable exponentially. Two variables of the equation were determined by iteration using the data from a trench excavation and tree distribution study. This equation was applied to 1.3 ha and the root biomass distribution was analysed. The root biomass in each of the above four zones was estimated at 171.8, 84.8, 242.6 and 509.5 t ha−1, respectively. The proportion of fine roots (<2 mm) ranged from 46.4% to 66.4%.

Miombo woodland in Zambia is divided into wetter and drier types by the 1100 mm mean rainfall isohyet. In the present study two wetter (Northern, Northwestern) and three drier (Central, Eastern, Western) miombo subtypes were recognized.

A survey of the woody flora of 94 old-growth and 58 coppice stands in the five miombo subtypes revealed some significant differences in species diversity among them. The floristic differentiantion of miombo subtypes was best achieved by the use of the Shannon species diversity index (H′) and species density (number of species 0.1 ha−1 or 0.4 ha−1). H′ in miombo decreased from 2.247 in Northwestern to 2.136 in Northern, 2.052 in Eastern, 1.918 in Central and 1.824 in Western subtypes. Although species density was not significantly different between wetter miombo subtypes, this decreased in a similar fashion from 18.78 0.1 ha−1 in Northwestern to 18.30 in Northern, 16.65 in Eastern, 14.79 in Central and 12.29 in Western subtypes. The low species diversity in Western drier miombo was attributed to the combined effects of low soil fertility and rainfall.

Although the mean number of species per 0.1 ha plot was higher in coppice samples, species richness (d) and index of diversity (H′) were lower than in old-growth samples. These results indicate lower species diversity in regenerating miombo. The dynamic aspects of species structure should therefore be considered in the future conservation of biological diversity in miombo woodland.

The numbers and biomass of litter and soil invertebrate fauna were investigated in six plots at altitudes of 280 m, 330 m, 480 m, 610 m, 790 m and 870 m on Gunung Silam, Sabah, East Malaysia. There were relatively high numbers and biomass in the lower plots, where the Oligochaeta were a high proportion of the total invertebrate biomass. The biomass of other invertebrate groups was low in the soil. There was a marked effect of altitude, particularly for the Oligochaeta above 610 m. The low biomass of the Oligochaeta in the higher plots suggested that the importance of this group may be diminished at relatively low altitudes on small mountains. However, several other soil faunal groups showed no evidence of an altitudinal effect, and it is suggested that the stunted forests near the summits of small mountains such as Gunung Silam may have a different litter and soil fauna from forests of a similar physiognomy at high elevations on large mountains.

A modified Kempson apparatus is described, the extraction procedure for arthropods in neotropical soils is given, and an example from Central Amazonia is presented.

The germinable seed bank of the colonizing weed Eupatorium odoratum was studied at the University of Ghana's Agricultural Research Station, near Kade. Five sites representing different successional stages were selected: a closed-canopy forest; intermittent-canopy forest; secondary forest; agricultural land; and a burnt forest. Twenty-five soil samples (each 500 cm3; 10×10×5 cm) were taken at random in each site, to be used for germination experiments. The secondary forest site had significantly more seeds of Eupatorium odoratum (8428 seeds per m2) than any of the other four sites. In this site Eupatorium odoratum constituted 81% of the total seed bank and had significantly more rapid germination of seeds than any other species. The results indicate that the existence of a soil seed bank may depend on: (1) time allowed for seed accumulation; (2) habitat accessibility to dispersing seeds; (3) the type of disturbance that occurs in an area; (4) dispersal capabilities of colonizing species; and (5) the history of the species′ distribution in the area.

Long-term growth rates of 32 palms (Prestoea montana) were studied using height and diameter measurements taken four times between 1946 and 1982. All leaf scars were counted to estimate leaf production rate, and the distance between scars was measured to establish relationships between leaf production and height growth. Height and diameter growth and leaf production of these palms were not constant during this 36-year period. A greater distance between leaf scars was indicative of rapid height growth but not of high leaf production rate. Dominant palms always grew fast (> 20 cm/yr) in height when they were small, but height growth slowed down when they reached the canopy. Small palms with slow height growth remained suppressed and lost the capacity to grow rapidly in height as adults. Diameter growth decreased with age from 0.07 cm/yr (SE = 0.02) between 1946–51 to 0.01 cm/yr (SE = 0.003) between 1951–82. Annual leaf production averaged 4 leaves/yr over the 36 years of study, was significantly different (P = 0.001) between 1946–51 (5.6 leaves/yr) and 1951–82 (3.8 leaves/yr), and was 4.6 leaves/yr for palms that grew >5 m since 1946 and 3.7 leaves/yr for those that remained suppressed. The best estimate for the mean age of all palms was 61.1 yr (SE = 2.4), obtained from long-term population leaf production rates.