Crecimiento diamétrico de Nothofagus pumilio para dos condiciones de copa en un sitio de calidad media en Santa Cruz, Argentina

Nothofagus pumilio is the species of largest geographical distribution and economical importance of Patagonia forests. There are few biometric related to the Patagonia forest management planning. Then, the aim of this work coas to construct individual growth models in diameter for different crown classes of medium quality site (IS60 = 9,8 m) N. pumilio forest in Santa Cruz Province (Argentina). The Chapman-Richards model showed good biological significance and statistics. Diameter growth had different behaviour according to the crown classes. The peak of the growth was at 62 and 52 years for the superior and inferior strata, being the maximal averages growth of 0.305 cm/year for dominant trees and of 0,12 cm/year for intermediate trees. The indirect validation of volumetric growth of the threw an error that varied between the 2.5 p. 100 and 20 p. 100Nothofagus pumilio es la especie de mayor distribución geográfica e importancia económica de los bosques patagónicos. Son pocos los modelos biométricos relacionados con la planificación del manejo forestal en la Patagonia, por lo que se decidió construir un modelo de crecimiento individual en diámetro para N. pumilio bajo dos condiciones de competencia de copa en un bosque de calidad media (IS60 = 9,8 m) de la provincia de Santa Cruz (Argentina). El modelo de Chapman-Richards presentó muy buenos estadísticos y una excelente significación biológica. Al analizar los ritmos de crecimeinto de acuerdo a su clase de copa, estos se comportaron de manera diferencial. La culminación del crecimiento fue a los 62 y 52 años para el estrato superior e inferior, siendo los crecimientos máximos promedios de 0,303 cm/año para árboles dominantes y de 0,192 cm/año para árboles intermedios. Al realizar una validación indirecta a partir del crecimiento volumétrico por hectárea aplicando el modelo construido, se detectaron diferencias que variaron entre el 2,5 p. 100 y el 20 p. 100 respecto del crecimiento real estimado a partir del análisis de tarugos

Site quality influence over understory plant diversity in old-growth and harvested Nothofagus pumilio forests

<p><em>Aim of study:</em> The effects and interactions of shelterwood forest harvesting and site qualities over understory plant species diversity and composition were compared among primary and harvested <em>Nothofagus pumilio</em> forests.</p><p><em>Area of study: </em>Tierra del Fuego (Argentina), on three pure conditions (one and six year-old harvested, and primary without previous harvesting forests) and three site qualities (high, medium and low).</p><p><em>Material and Methods: </em>Understory richness and cover (%) were registered in five replicates of 1 hectare each per treatment. Taxonomic species were classified in categories (groups, origin and life forms). Two-way ANOVAs and multivariate analyses were conducted.</p><p><em>Main results:</em> Shelterwood harvesting and site quality significantly influenced understory cover and richness, which allow the introduction of native and exotic species and increasing of dicot and monocot covers. In dicots, monocots, exotics and total groups, higher richness and covers were related to time. Meanwhile, cover reached similar high values in all site qualities on dicot, native and total groups. On the other hand, monocot and exotic richness and cover remain similar in primary and recently harvested forests, and greatly increased in old harvested forests. Mosses and ferns were among the most sensitive groups.</p><p><em>Research highlights: </em>Impacts of shelterwood cut depend on site quality of the stands and time since harvesting occurs. For this, different site quality stands should received differential attention in the development of conservation strategies, as well as variations in the shelterwood implementation (as irregularity and patchiness) should be considered to better promote understory plant species conservation inside managed areas.</p><p><em>Key words:</em> plant species conservation; years after harvesting; forest management; Tierra del Fuego.</p

Análisis de la ciclófisis y la topófisis en Populus deltoides Bartr desde la formación del estaquero hasta una plantación comercial.

Commercial propagation of Salicaceae, carried out through cuttings, is influenced by ortet-ramet relations. The most frequently cited relations in the literature are topophysis and cyclophysis. The aim of this work was the study of topophysis and cyclophysis affecting growing shoots and rooting of P. deltoides cuttings from cutting-source formation to the first year in the commercial plantation. The results obtained that cyclophysis affected the new plant architecture as much as growing rate. The cuttings made on diagravitrophic ortets generate plants with: more horizontal branches, more meters per branch, more leaves and biomass, according to ortogratrophic ortets. The differences between the measured parameters point out a residual effect in the growing habit of the cutting into the ortet and the relation between explant efficiency and its situation on mother plant. The residual effect was made evident in the new plant formation. The topophysis modify rooting, being apical and basal cuttings bigger than intermediate-position cuttings. The low rooting percentage in intermediate-position cuttings (5 p. 100) could have physiological or genetical origins. These causes could not be clarified in our experiences. The topophysis and cyclophysis effects over cutting rooting and first year growing of plants in the cutting-source, determine the attainment of a highly heterogeneous population. In agreement with these results and in order to improve the commercial plantations in their first stages, the origin of plant material must be chosen considering the topophysis and cyclophysis effectsLa propagación comercial de especies de la familia Salicaceae, muy influenciada por las relaciones ortet-ramet, se realiza por medio de estacas. Las relaciones que se citan con mayor frecuencia dentro de la literatura son la topófisis y la ciclófisis. El objetivo de este trabajo fue estudiar si los fenómenos de ciclófisis y topófisis afectan la capacidad de enraizamiento y la modalidad de crecimiento de los brotes en estacas de P. deltoides en los primeros años de crecimiento en estaquero y el comportamiento posterior de las estacas obtenidas de éste en una plantación comercial al primer año. Los resultados obtenidos muestran que la ciclófisis afectó tanto la arquitectura de la nueva planta como su ritmo de crecimiento. Las estacas provenientes de guías diagravitrópicas, generan plantas con ramas más horizontales, producen más metros de ramas, mayor número de hojas y mayor biomasa, respecto de las ortogravitrópicas. Estas diferencias en los parámetros medidos indican que existe un efecto residual del hábito de crecimiento de la estaca en la guía, que se pone de manifiesto al formar una nueva planta y que además la eficiencia del explanto está condicionada a su ubicación en la planta madre. La topófisis modifica el enraizamiento, siendo éste mayor en las estacas apicales y basales respecto de las del tercio medio. La baja obtención de plantas a partir de estacas del tercio medio de las guías (5 p. 100), puede tener causas fisiológicas o causas genéticas del clon en estudio, que no hemos podido aclarar en este experimento. El efecto de la topófisis y de la ciclófisis sobre el enraizamiento de la estaca y el crecimiento de la planta en su primer año en estaquero, determinan la obtención de una población altamente heterogénea. De acuerdo con estos resultados se deberá tener en cuenta el origen del material a plantar, tanto por su topófisis como por su ciclófisis, con el fin de mejorar las plantaciones en sus primeras etapas de crecimiento

Retention Forestry to Maintain Multifunctional Forests: A World Perspective

The majority of the world's forests are used for multiple purposes, which often include the potentially conflicting goals of timber production and biodiversity conservation. A scientifically validated management approach that can reduce such conflicts i

A major shift to the retention approach for forestry can help resolve some global forest sustainability issues

Approximately 85% of the global forest estate is neither formally protected nor in areas dedicated to intensive wood production (e.g., plantations). Given the spatial extent of unprotected forests, finding management approaches that will sustain their multiple environmental, economic, and cultural values and prevent their conversion to other uses is imperative. The major global challenge of native forest management is further demonstrated by ongoing steep declines in forest biodiversity and carbon stocks. Here, we suggest that an essential part of such management-supplementing the protection of large reserves and sensitive areas within forest landscapes (e.g., aquatic features)-is the adoption of the retention approach in forests where logging occurs. This ecological approach to harvesting provides for permanent retention of important selected structures (e.g., trees and decayed logs) to provide for continuity of ecosystem structure, function, and species composition in the postharvest forest. The retention approach supports the integration of environmental, economic, and cultural values and is broadly applicable to tropical, temperate, and boreal forests, adaptable to different management objectives, and appropriate in different societal settings. The widespread adoption of the retention approach would be one of the most significant changes in management practice since the onset of modern high-yield forestry

Integrating methods for ecosystem service assessment: experiences from real world situations

International audienceThe Ecosystem Services (ES) concept highlights the varied contributions the environment provides to humans and there are a wide range of methods/tools available to assess ES. However, in real-world decision contexts a single tool is rarely sufficient and methods must be combined to meet practitioner needs. Here, results from the OpenNESS project are presented to illustrate the methods selected to meet the needs of 24 real-world case studies and better understand why and how methods are combined to meet practical needs. Results showed that within the cases methods were combined to: i) address a range of ES; ii) assess both supply and demand of ES; iii) assess a range of value types; iv) reach different stakeholder groups v) cover weaknesses in other methods used and vi) to meet specific decision context needs. Methods were linked in a variety of ways: i) as input-output chains of methods; ii) through learning; iii) through method development and iv) through comparison/triangulation of results. The paper synthesises these case study-based experiences to provide insight to others working in practical contexts as to where, and in what contexts, different methods can be combined and how this can add value to case study analyses. Part of Special Issue: Synthetizing OpenNESS