Prediction of Resin Production in Copal Trees (Bursera spp.) Using a Random Forest Model

Abstract

Non-timber forest products (NTFPs) are essential for community development, but their enormous demand has posed a serious threat to trees growing in their natural habitat. Copal resin is one of these products, which has a great deal of religious and ceremonial significance in Mexico and around the world. Resin extraction from a tree depends on its morphological and physiological characteristics, as well as its physical and sanitary condition. In this study, a methodology was proposed for determining the yield and health status of Copal trees, and a random forest (RF) model was developed to explain their resin production based on their morphological and condition characteristics. The experiment was conducted in the Agua Escondida watershed in Puebla, Mexico. With the training data, the average accuracy of the model was 99%, with a Kappa index of 98%, which is considered an excellent level of agreement beyond chance, and with the validation data, the average accuracy was 71% and 47%, which is considered a good level of agreement beyond chance. Tree condition was the most important factor affecting resin production in Copal trees, followed by stem diameter (33 and 38 cm), height (2 and 2.5 m), and diameter of secondary branches (from 8 to 15, 22 and 32 cm).

Effects of copal resin extraction on the diversity and composition of species in tropical deciduous forests

“…There are two main climates within the watershed: warm sub-humid with summer rains and semi-warm sub-humid with summer rains. Primary land use is agriculture, and the predominant vegetation type is tropical deciduous forest [17][18][19][20] . The experimental site was in the Ejido de San Juan Raboso, municipality of Izúcar de Matamoros, located in the region of the Cerro de la Virgen, within the watershed (Fig.…”

“…1), with an elevation 1 282 m and an area of 30.8 ha. Tropical deciduous forest is predominant in this area, typical of an area with two distinct seasons of moisture availability, rainy and dry 7 , as well as species that shed their leaves during the dry season and a variety of species with scaly bark that is similar to papyrus, or with thorny or corky protuberances, with sparse crowns 20,21 . The experimental site is for communal use.…”

“…Other factors impact the natural area such as overgrazing, scarce natural regeneration of copal, and the lack of an adequate resin extraction method among others. 20 .…”