Colombia Forestal

7

Authors: Orlando Riaño Melo, Iván Lizarazo

Estimating the volume of wood from trees is an expensive, time-consuming and error-prone task. Traditional methods use mathematical models that need to be matched to existing species and specific areas using a case by case approach. Such methods have high operating and environmental cost, as several trees in the plantation are cut down. This article presents an alternative model to quantify the volume of a tree, which uses a single polynomial, which requires not felling the tree, which is relatively quick and inexpensive with good accuracy, and can be extended to estimate the trade volume of the plantation. To this end, the proposed method is described mathematically and its results compared with those obtained for five ideal methods described by FAO (1980). Results show that the polynomial method has a maximum relative error that does not exceed 1.6% in any case and allows calculating tree’s diameter at a given height and height for a given diameter.

9

Authors: Manuel Eduardo Lequerica Támara, Maurico Bernal, Pablo Roberto Stevenson Díaz

Secondary growth forests have increased their extension in the last decades, and have been suggested as potential conservation reservoirs. The objective of this study was to evaluate diversity and vegetation composition in pastures and forests at (Granada, Cundinamarca, Colombia) to assess if successional processes show evidence of directionality, we placed six plots by 0.1-ha in the forest edges, one towards the forest and other to the abandoned paddocks in three locations. We determined the average vegetation structure, diversity, and floristic composition for each plot. We found that diversity is significantly higher in forest plots than in paddock plots (at early succession stage) in high Andean cloud ecosystems. The successional stage of each one of the study sites was characterized using non-metric multidimensional scaling. This analysis shows that vegetation tends to group in function of age groups more that it does by geographic location of the plots, suggesting succession is a directional process. Seedling recruitment was not significantly different between forest edge and forest interior. An inverse relation was found between floristic and geographic distances, reflecting the fact that matrix discontinuity is a limiting factor for seed dispersal, thus it is a barrier for high Andean cloud forest succession.

13

Authors: Nathalia María Forero-Cabrera, Jesús Hernán Camacho-Tamayo, Leonardo Ramírez-López, Yolanda Rubiano Sanabria

Techniques such as near infrared spectroscopy (NIR) can be used to identify classes and properties of soils with good precision. The aim of this study was to calibrate models to predict the content of clay, silt and sand of a Typic Hapludox by NIR spectroscopy. The study was carried out in the Carimagua Experimental Station located in the municipality of Puerto Gaitán, Meta, Colombia. A grid design was used, 1200 samples were collected in an area of 5100 ha. The development of the models have made by partial least squares regression. A low representatively models were obtained for sand and silt contents, with values of R2 (0.41 and 0.34, respectively).The clay model content showed a high R2 (0.76). For the clay was possible the development of similar digital maps and digital spectrum maps . The results for the clay content indicate that laboratory analysis can be substituted, in large part by spectral models. In the case of sand and silt, in the future, it would be convenient to improve the model for substituting the laboratory analysis for this class of soil.

16

Authors: Laura Isabel Mesa Castellanos, Angélica María Toro Buitrago, Carolina Isaza Aranguren

We present information about the spear leaves harvest, fiber processing and trade of Mauritia flexuosa L.f. for the handicrafts production by the Sikuani people in Wacoyo indigenous Village, in Puerto Gaitán, Meta, Colombia. We made a semi-structured interviews and workshops with harvesters, artisans and traders. During these sessions we inquired about their harvesting techniques, characteristics of harvestable individuals, distribution area of the palms, market aspects and other uses of the species. Mauritia flexuosa, locally known as moriche, is one of the economic livelihoods for the artisans who inhabit the Wacoyo reservation. The harvest of spear leaves is carried out in juvenile and subadult palms. The fibers are extracted from the spear leaves to manufacture handicrafts like bags, baskets, hats and hammocks. Artisans sell the products to tourists visiting the reservation, and intermediary sellers who commercialize them in the municipality center of Puerto Gaitán and Puerto Lopez, Meta. The use of M. flexuosa has the potential to become a sustainable activity, since the leaf harvest does not involve the death of the individuals.