Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The young leaves of Astrocaryum chambira are used by the indigenous people in the Amazon as raw material for handicrafts. However, few studies have been made on the natural history of this palm and on the indirect impact caused by the decrease of its dispersal agents. Considering that the loss of animal dispersal vectors due to hunting and landscape modification can affect seed dispersal processes of tropical forest plants, the goal of this study was to compare seed dispersal of A. chambira in three terra firme forests of the Colombian Amazon, with different degrees of human intervention. We censused densities of dispersal agents of A. chambira, and characterized the seed shadow. We also marked seeds to estimate dispersal distances, and established density and distance-dependent experimental stations to assess their relevance on seed dispersal. The results showed that seed removal was proportional to dispersal agent densities and forest intervention levels. Insects were the main seed predators in all sites but their effect was less pronounced in the low intervened forest site. Seed density did not show any effect on removal, while a higher probability of survival at intermediate distances from the parent palm (10 m) was found. Future studies should focus on seedling establishment, recruitment rates and the effects of human intervention on subsequent life stages of the palm.

We determined the effect of efficient microorganisms (em) on the cation exchange capacity for soil recovery in the municipality of Mondoñedo, Cundinamarca. A greenhouse unit was installed in order to maintain stable conditions. After harvesting, sifted and homogenization of the soil sample, initial physical and chemical analyses were made. For the experimental units we used Acacia melanoxylon seedlings from Zabrinsky. A completely randomized design was done with eight treatments and three repetitions. For the maintenance and moni toring of the seedlings behaviour, a frequency of irrigation of three times per week was found. The application of the em was done during three months: in the first month, it was applied four times (once a week); during the second month, it was applied twice (biweekly), and during the third month there was only one application. Additionally, every 15 days morphological analyses were made (number of leaves, branches and stem diameter). In the end, soil samples were taken from each plant pot. In the laboratory we analysed the cation exchange capacity, alkali ion exchange, saturation alkali, relations between elements and plant tissue. These were done using an atomic absorption spectrophotometer. Statistical analyses consisted on multiple comparisons test and variance tests, in order to find whether or not treatments exhibited significant differences.In that way, the best alternative for improving environmental quality of eroded soils as the Zabrinsky desert is the efficient microorganisms in 5% doses in irrigation water. Additionally, the cation exchange capacity must be enhanced using organic fertilizers (compost, mulch and gallinaza) in one pound doses, and chemical fertilizers: electrolytic Mn (0.0002 g), Cu (0.0002 g), Zn (0.0001 g), urfos 44 (166.66 g) and klip-boro (5 g).

Based on floristic and structural characterization, four stages of secondary succession were analyzedwithin a matrix of vegetation that had been disrupted (185 ha) at Cárpatos Forest Reserve. This reserve is located in the foothills of Colombian's Eastern Mountain Range (Cordillera Oriental), among 2600 and 3000 meters above sea level, and it is aimed at making a contribution to prepare a restoration protocol. In flat, wet areas, vegetation represented by grassland whit Rubus floribundum y Pteridium aquilinum, grows up to 0.7 m height on average. It is characterized by Pteridium aquilinum, which holds an average of 1638 individuals per 0.1 ha and a total of four species with the same number of genera and families bushes of Solanum inopinum and Chusquea scandens, less than 3 m height, were dominated by Chusquea scandens, with an estimated average of 638 individuals per 0.1 ha and a total of four species and the same number of genera and families. In areas of steeper slopes and lower humidity more structured vegetation grows. This forests in recovery dominated by Miconia theaezans y Myrsine coriacea, which contains two types of vegetation: Hedyosmum crenatum y Myrsine coriacea, which are dominated by a shrub layer no taller than 5 m, with Myrsine coriacea as its most important species, and an estimated average of 1742 individuals per 0.1 ha and a total of 18 species, 16 genera and 13 families, and Weinmannia pinnata y Miconia theaezans, represented by Myrsine coriacea, Miconia theaezans and Weinmannia pinnata as important species, which held an estimated average of 1833 individuals per 0.1 ha and a total of 14 species, 12 genera and 11 families. Myrsine coriacea, Miconia theaezans, Weinmannia pinnata and Hedyosmun crenatum are regarded as the most suitable to start reproductive, adaptive and developing silvicultural protocols. Management analysis suggests that there is a correlation between higher clay content and the secondary-succession initial-state communities, while in previous stages the values are higher in terms of sand content, cation exchange capacity, organic matter and slope.

The rubber yield of four Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg. clones was evaluated on the Colombian high plains in the Meta department: ian 873 and rrim 600 (third year of tapping being done) and pb 260 and gt 1 (first year of tapping). Six tapping systems were used, including a combination of different tapping frequencies (d/4 and d/5), Ethephon concentrations (0%, 2.5%, 3.3% and 5%) and a number of applications per year (4 to 8) were also used depending on the clone. The production figures for one commercial year were obtained from assays, using a completely randomblock design (having four repetitions) independently defined for each clone: having on average 4446 g rubber/tree of produce per year for the rrim 600 clone within a system ½S, d/4, 6d/7, 10m/12, et 2.5%, Pa 7/y; 2696 g rubber/tree for the pb 260 clone with ½S, d/4, 6d/7, 10m/12, et 2.5%, Pa 5/y; 3822 g rubber/tree for the ian 873 clone, ½S, d/4, 6d/7, 10m/12, et 3.3%, Pa 8/y, and 3472 g rubber/ tree for the gt 1 clone, ½S, d/4, 6d/7, 10m/12, et 2.5%, Pa 5/y. The highest produce was obtained with a four-day tapping frequency.

The floristic composition and the structure of a humid hill forest were determined. The forest is located in the northernmost area of the Colombian Central Mountain Range. The methodology proposed by isa-jaum was employed in this study, from a 0.1 ha sample. Moreover, plant material was collected from clear spots, stubbles and grasslands. A total of 421 vascular plants species were found. Two hundred and thirty eight of these come from the 0.1 ha sample and only 150 had dbh > 2.5 cm, which highlights the benefits of the sample method employed, since it was possible to record a large number of epiphytic and herbaceous elements in the forest. In general, the composition matches what was previously reported in similar areas. The families Melastomataceae (32), Lauraceae (31), Rubiaceae (29) and Araceae (15) were the ones holding the largest number of species. New chorological records for the state of Antioquia were reported in this study; for instance, Colombobalanus excelsa (Fagaceae). High density of individuals (388) was found at structural level. The patterns of height and diametrical classes followed the typical distribution of disetaneous tropical forests, in which the largest amount of individuals occur in the lowest classes and few species with individuals having the greatest diameters and heights account for the major ecological weight in the forest. Despite the great diversity documented, these forests are currently subject to an intensive process of fragmentation and loss of coverage.

We have studied nutrient related variables such as reallocation, nutrient use efficiency (nue) and fine litter fall for three years in an oak forest Quercus humboldtii Bonpl. and also in some other forest plantations like pine, Pinus patula, and cypress, Cupressus lusitanica, in Antioquia, Colombia. Leaf litter quantities returned to the soil followed a falling sequence: oak (5313.3 kg ha-1 year-1) > pine (4866.5 kg ha-1 year-1) > cypress (2460.3 kg ha-1 year-1). The coniferous species showed the highest nue for the majority of elements that were examined, except for P, which reached its absolute maximum in the oak forest ­where a clear reallocation of this nutrient was also recorded­, probably because of its reduced availability in these volcanic ash-derived soils. Nutrient reallocation allows the conservation of the nutrients by reducing its loss from leaching and litter-fall, thereby closing the nutrient cycle in this native forest. In fact, P gains from net deposition were found there ­this includes foliar leaching and atmospheric deposition­, which indicates that the species absorbs the P contained in rainfall from the leaves before it reaches the forest ground. N's low-efficiency use was probably due to its low availability in soil, given its low mineralization rates in these montane forests. K showed the highest reallocation values. Such figures are influenced by its clearly mobile character, according to the highest net deposition levels also verified for this element. With the exception of Mg, there was no clear relationship between the reallocation process and nue.

The "tripeperro" (Philodendron longirrhizum) is a widely distributed hemiepiphyte along the Andean region of Colombia. The aerial roots of this species have been employed as a source of fiber for the production of baskets and other handicrafts in the Eje Cafetero region (Cordillera Central). This activity is concentrated in the town of Filandia, in the Quindío state, where a decrease in the availability of appropriate roots for craftsmanship has been detected over the last years. In order to propose sustainable harvest alternatives, we evaluated the natural stock and product demand of "tripeperro". Root production and life cycle, distribution of the harvested areas, harvest time and costs, and product demand were studied. It was found that "tripeperro" natural stock can only supply the demand for Filandia's traditional artisans, and that many harvesting and commercialization practices in other regions are not sustainable. Additionally, depletion of the "tripeperro" has reduced the income by handicraft activities. Therefore, we propose options for the sustainable management of the "tripeperro" in order to increase its natural offer as well as to improve the economic benefits for artisans.

The Amazon forests are among the most diverse ecosystems in the planet. Although some countries of the Amazon Basin have a fairly complete record of their plants, in Colombia much effort is still needed to have a good idea of the plant diversity patterns and floristic composition. Three one hectare vegetation-land plots (dbh 10 cm) were established in Vaupés, Colombia, regarding three types of forest: Colina, Terraza (Terra Firme forests) and Igapó (periodically flooded). Plant diversity was estimated and floristic composition was described classifying the most important families and species. The highest diversity was found in Colina (Fisher's = 160.3), followed by Terraza ( = 78.4) and Igapó ( = 44.7). Fabaceae s.l. was the most important family of all plots, but in Terraza forest the importance of Arecaceae was similar to that of Fabaceae. Floristic composition was also remarkably different amongst the three forest types, especially Igapó, which was the most dissimilar. However, both Terra Firme forests showed strong floristic differences, which may be caused by differences in abiotic factors (i.e. soils). High plant diversity reported in this study agrees with the hypothesis that central and western Amazon forests are the most diverse of the Amazon Basin.

Xylophagous and xylomicetophagous insects can cause serious deterioration of timber. The insects attacking the thirteen most traded timbers in the Valle de Aburrá were identified and their presence was confirmed. Insects causing most of the damage were determined and the wood tissue most attacked was characterized. Comments on the handling and storage conditions of the wood were recorded in 27 wood industries visited and 426 wood samples were inspected. The most important and most common insects found belong to the Scolytinae and Bostrichidae subfamilies. In addition, the most attacked wood tissue was identified in 41% of the samples. Even though all species studied showed traces of damage caused by insects, insect samples were not recovered from each wood sample. In general, there were deficiencies in wood handling and storage at the visited industries, which may increase the impact of decay agents.

A greenhouse experiment was carried out to determine the mycorrhizal dependency of laurel (Ocotea sp.). In order to do this, a completely randomized experimental design was used, with six treatments in a factorial array of 3x2 and five repetitions. The treatments involved a combination of three Phosphorus (P) levels in soil solution (0.002, 0.02 and 0.2 mg L-1) and two levels of mycorrhizal inoculation, either inoculated or non-inoculated with Glomus aggregatum Schenck Smith. The leaf P content as a function of time was used as an output variable. Shoot dry matter, shoot P content, mycorrhizal colonization of roots, and mycorrhizal dependence were measured at harvest. The results indicated that the leaf P content increased significantly when using the mycorrhizal inoculation in laurel at P level 0.2 mg L-1, but not in the other P levels, on some of the sampling days. Shoot dry weight and total plant P content did not increase at all levels of soil available P. Mycorrhizal dependency of laurel reached 28%, which allows this species to be classified as moderately dependent