Search

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seasonal xylem water potentials (Ψ, MPa) and their relationship to soil water content and evaporative demand components were studied in the shrub speciesAcacia amentacea, Celtis ehrenbergiana, Forestiera angustifolia, andParkinsonia texanavar.macra. Predawn (Ψpd) and midday (Ψmd) water potentials were estimated at 15 days intervals, between January 15 and October 30, 2009 using a Scholander pressure bomb at 06:00 h (predawn) and 14:00 h (midday), respectively. During the humid period, Ψpd ranged from −0.30 MPa (C. ehrenbergiana), to −0.90 MPa (P. texana). In contrast, over the driest period, Ψpd varied between −2.18 (P. texana) and −3.94 MPa (F. angustifolia). At midday,P. texanaandF. angustifoliashowed the highest (−1.14 MPa) and lowest (−3.38 MPa) Ψ values, respectively. Average soil water content accounted for 35 to 70% of the variation in predawn Ψ. Furthermore, both Ψ reflected the environmental conditions, as indicated by typical correlations observed. The studied shrub species exhibited what seem to be different strategies to avoid damage caused by drought. Thus,P. texanabehaved rather as an isohydric plant able to deal well with severe, but short periods of drought. Under exceptionally dry environmental conditions, Ψpd undercut Ψmd values. Similar observations have been made by researchers studying plants in dry ecosystems. All studied native species are recommended for reforestation of the Tamaulipan shrublands, althoughC. ehrenbergianaandF. angustifoliaseem to have limited tolerances for extreme water stress. [ABSTRACT FROM AUTHOR]

The use and consumption of wood has always captured the attention of forest researchers, mainly from the point of view of forest management and the sustainable processing of raw materials. For this reason, the wood industry has not only been concerned with the maintenance of forests, but also with efficient processing. The objective was to identify, analyse and discuss the main elements that influence the efficient use of natural timber resources at a global, regional and local level, providing a historical and current perspective of the industrial forestry sector in Mexico. Historically, the wood industries worldwide have been concerned with applying intensive silvicultural treatments in native and artificial forest stands, in search of satisfying the demand of a growing market. In this context, industries evolved as processes needed to be more efficient. Therefore, efforts were made to reduce and take advantage of forest residues, at the same time various historical events generated additional needs. At present, the integration of silviculture and forest transformation allow to increase and improve the quality of the products generated. Through the application of intensive silvicultural treatments, products of a single species are obtained. However, it is possible to direct production to a specific market as the forest mass develops. For its part, selective treatments in uneven-aged forests maintain a constant production of diverse products for different specialized markets. In Mexico, it is imperative to analyse and generate innovative or competitive products derived from wood to improve the efficiency of forest harvesting. [ABSTRACT FROM AUTHOR]

Mexican forest ecosystems are exposed to a great variety of natural disturbances such as fire, which is a key disturbance process influencing tree survival and regeneration. Nevertheless, forest fires are one of the primary causes for which a large portion of the forest in Mexico is lost. Thus, the objectives of this research were to determine (1) the pattern of occurrence of forest fires, and (2) their relationship with precipitation and atmospheric circulation patterns. We reconstructed the historical forest fire regime from fire scars of 22 sample trees in a coniferous forest stand on the mountain Cerro El Potosí in southern Nuevo León, Mexico. Frequent surface fires characterized the site. The mean fire return interval for all fires was 11 years and for the more-widespread fires (those that scarred ≥25% of all samples) was longer (15.7 years). The Superposed Epoch Analysis indicated as not statistically significant the role of dry years as well for the subsequent wet conditions for the period from 1881 to 2004. [ABSTRACT FROM AUTHOR]

Forest fires have had a remarkable relevance since the extraordinary fire season in 1998, due to their direct contribution to deforestation, changes in forest structure, species composition, and recently to their impact on the increment of carbon dioxide in the atmosphere. Nevertheless, there is a lack of detailed information about fire impact on forest structure, species composition, and forest dynamics in the Sierra Madre Oriental (SMO). In order to explain possible changes in those factors, this study has examined a chronosequence (134 years), which was determined by analysing tree ring samples in post-fire cohorts of different ages. The objectives of this study were to: (1) determine forest fire historical range of occurrence, (2) quantify present forest structure and tree species composition along a fire chronosequence in order to determinate reference areas to assist restoration programs, and (3) increase the understanding of disturbance patterns in mixed pine-oak forest in this region. The study revealed significant differences between post-fire cohorts in terms of woody species richness, stand composition, and structure. High tree diversity was generally found in young stands, while the intermediate and major ones showed the lowest diversity. In old stands, tree diversity was increased again. [ABSTRACT FROM AUTHOR]