SEEDLING QUALITY AND SURVIVAL OF A TRUE FIR [Abies religiosa (Kunth) Schltdl. et Cham.] FOREST PLANTATION FROM TWO PROVENANCES IN CENTRAL MEXICO.

Abstract

In Mexico, research about the seedling quality of tree species has only increased as of 1999; despite its importance for successful plantations, there are still few species with validated data in plantation sites. In order to compare the seedling quality attributes of Abies religiosa (Kunth) Schltdl. et Cham. plants from La Soledad, Tlaxcala and Santa Ana Tlacotenco, Mexico City, in nursery conditions and further evaluations of increments in the field site, we cultivated the trees from both provenances in containers in the nursery of San Luis Tlaxialtemalco, Xochimilco, Mexico City. The studied variables were height, diameter at root collar, shoot and root dry weights, total dry weight, shoot to root ratio, slenderness coefficient, and Dickson quality index, along with the root growth potential. We established the experimental plantation in Santa Ana Tlacotenco. Six and 12 months after planting, we evaluated the survival of the trees; and 12 months after planting, we measured height, diameter at root collar, and shoot, root, and total dry weights. In both, the nursery and the plantation, we used a randomized block design with four repetitions. We analyzed the data with ANOVA; we used a Tukey test (p?0.05) to compare the data and Pearson correlations between all the variables during the plantation and one year after the plantation. The provenance did not affect the indicators of seedling quality nor the survival one year after the plantation. The mean values of the seedlings in the nursery were: 4.5 mm (diameter at root collar), 29.2 cm (height), 6.0 g (total dry weight), 6.6 (slenderness coefficient), 1.4 (shoot to root ratio), and 0.8 (Dickson quality index). The test of root growth potential produced 22 new roots. In the trees from Mexico City, we observed a significant correlation between the shoot to root ratio and the root dry weight one year after the plantation. In the trees from Tlaxcala, the initial Dickson quality index correlated significantly with the increase in the root dry weight one year after planting. These values represent the seedling quality and allow us to predict a high survival in plantations of A. religiosa in the area of study