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Fire and elevation affect reproduction of woody species and, therefore, their distribution in the landscape; however, the effect of both factors are often confounded. In addition, plant size may also influence reproduction. Our objective was to investigate the combined effects of fire, elevation and pre-fire size on woody species reproductive potential in a seasonally dry mountain ecosystem. We tested the predictions that fire and elevation impair reproductive potential and that the negative effects of fire are enhanced at high elevation. Our study was carried out in the mountains of central Argentina, from 800 to 1700 m a.s.l. We selected individuals of two dominant resprouting woody species (Vachellia caven and Lithraea molleoides) in burned and comparable unburned areas. We estimated pre-fire size and fire damage level in each tree. We monitored parameters related to reproductive potential during four post-fire fruiting seasons in 185 V. caven and 78 L. molleoides trees. Our main results for V. caven show negative fire effects on most reproductive parameters, and on the expected number of germinable seeds per tree, which was estimated as an integrated parameter. The negative fire effects decreased over time until the fourth post-fire fruiting season, when we detected almost no fire effects. Moreover, the negative fire effects were greatly enhanced with elevation, while pre-fire size showed consistently positive effects on most reproductive parameters. For large trees located at low elevation, fire reduced the number of germinable seeds per tree by a factor of nearly six in the third post-fire fruiting season (from 2020 to 358 seeds), while at high elevation fire reduced germinable seeds by a factor of 15 (from 106 to 7 seeds) for similarly large trees. Small trees had a lower reproductive potential than large trees and the negative effects of fire were smaller but noticeable, and were enhanced by elevation, as in the case of large trees. For L. molleoides we found similar patterns to those of V. caven ; however, since few trees produced seeds during the study, we did not compute formal statistics. We conclude that fire reduction should gradually increase reproductive potential, tree density and forest cover at high elevation, even when, according to previous studies, survival is not affected by fire or elevation in the study species. • We evaluated post-fire reproductive potential across elevation in resprouting species. • Reproductive potential decreased with elevation and was higher in larger trees. • Fire reduced reproductive potential up to the third post-fire fruiting season. • The fire effects on reproductive potential were worse at high than at low elevation. • A reduction in fire frequency could promote forest expansion at high elevation. [ABSTRACT FROM AUTHOR]

A comparative study of the effects of woodland degradation on “brea” (Parkinsonia praecox) gum production was conducted in the Arid Chaco, Argentina, over a two-year period. We also analyzed the relationship of brea gum yield per tree with rainfall, tree size, soil water content, and other surrounding tree species. The results showed that the woodland degradation state has a strong effect on brea gum yield per tree, with the secondary woodland specimens being the most gum-productive during the dry seasons (p < 0.0001). However, during wet years, we found that the woodland degradation state did not affect gum yield (p = 0.5615). We found no significant differences in brea gum productivity per hectare between secondary woodland and degraded woodland colonized by Parkinsonia praecox (p > 0.05). In both brea gum production per tree and hectare models, we found a significant covariation with the number of surrounding Prosopis spp. trees (p < 0.0001), an indicator of good state woodland, which can improve soil water content and thereby enhance brea gum production. Moreover, the number of surrounding Prosopis spp. trees was the variable that best predicted brea gum yield in a replicated regression model (R2 = 0.41). The results of this study present the basis for a sustainable brea gum production in the Arid Chaco of Argentina. [ABSTRACT FROM AUTHOR]

In Argentina there is no productive development of the non wood forestry products (NWFP), so it is difficult to include them in the regional economies. As an example, brea gum from Parkinsonia praecox produces an exudate gum as a food additive and safety to use in human consumption. However, it is not known, which is the economical feasibility for the farmers. The aim of this study is to evaluate the socioeconomical aspects of the brea gum production in the Arid Chaco from Córdoba, Argentina. The methodological approach for this study includes socio-economical surveys, gum production and finally, labour costs. Data were analyzed using Benefit/Cost analyses for the different woodland degradation states. The economical feasibility of brea gum production includes Chaco woodland in good state or "monte" and "breal". Additionally, it is possible to include brea gum production within the producer of the social agrarian types with lower incomes, which economies depends mostly on external work. The production of brea gum makes a substantial contribution into farmers' incomes, giving more sustainability to the system. [ABSTRACT FROM AUTHOR]