Comparison of four different programs for the analysis of hemispherical photographs using parameters of canopy structure and solar radiation transmittance

There have been many studies involving the use of hemispherical photographs to indirectly estimate canopy structures and forest light environments. A variety of commercial and free software packages are available for the analysis of hemispherical photographs. The costs of investment might represent an advantage of the free programmes over the commercial, but as yet little has been documented about the differences in their outputs and in the technical applications from a user (ecologist and forester) perspective. The objective of the study was to compare the canopy structure variables (canopy openness and effective plant area index) and solar radiation transmission estimates (direct, diffuse and global solar radiation transmittances) from digital hemispherical photographs taken under two forest canopy conditions (gap and closed canopy) in three different broadleaf forest regions (Chile, Germany, Venezuela) and calculated using four different programmes. The hemispherical photographs were analysed using one commercial (HemiView) and three free programmes (Gap Light Analyzer, hemIMAGE and Winphot). The results obtained revealed that all of the programmes computed similar estimates of both canopy structures and below-canopy solar radiation. Only the results relating to the effective plant area index with an ellipsoidal leaf angle distribution made with HemiView and Winphot deviated significantly. Other user aspects are also discussed, such as costs, image formats, computer system requirements, etc.In vielen Studien werden Hemisphärenphotos genutzt um indirekt die Kronenstruktur und die Belichtungsverhältnisse zu schätzen. Verschiedene kommerzielle und kostenfreie Softwarepakete sind zu Analyse von Hemisphärenphotos verfügbar. Es gibt bisher keine umfassende Vergleichsstudie zu Ergebnissen oder technischer Handhabung aus Sicht der Nutzer dieser Programme (Ökologen und Forstwissenschaftler). Das Ziel dieser Studie war der Vergleich der Schätzungen von Kronenstrukturvariablen (Kronenöffnung und effektiver Pflanzenflächenindex) Solartransmission (direkte, diffuse und Global-Strahlung) aus digitalen Hemisphärenphotos berechnet mit vier verschiedenen Programmen (kostenpflichtig: Hemi- View und frei: Gap Light Analyzer, hemIMAGE and Winphot). Die verwendeten Photos stammen aus drei verschiedenen Laubwaldregionen (Chile, Deutschland und Venezuela) und repräsentieren jeweils Verhältnisse unter geschlossenem Kronendach und in Lücken. Die ermittelten Schätzungen für die verschiedenen Strukturvariablen und Einstrahlungsverhältnisse zeigten eine sehr hohe Übereinstimmung. Einzig der effektive Pflanzenflächenindex basierend auf ellipsoider Blattwinkelverteilung unterschied sich signifikant zwischen den Programmen. Weitere für Nutzer interessante Aspekte wie Kosten, Bildformate, Systemvoraussetzungen und mehr wurden verglichen und diskutiert

Análisis de los micrositios de regeneración para Nothofagus pumilio en sectores perturbados y no perturbados por el efecto del Castor canadensis en Tierra del Fuego, Chile

Castor canadensis afecta a bosques de Nothofagus en Tierra del Fuego, por construcción de castoreras e inundación de bosques. Luego de la eliminación de castores, el sector inundado cambia a una pradera abierta. El objetivo es analizar el establecimiento de plantas de regeneración de N. pumilio (lenga) respecto a micrositios en pradera de castor y bosque no afectado por castor. La investigación se desarrolló en una castorera abandonada, en el sector de Vicuña, Tierra del Fuego (54º8?S, 68º42?O). En la vecindad de la castorera se encuentra un bosque de lenga coetáneo (390 árboles/ha, 93,5 m2/ha). En la pradera de castor y en el bosque se instalaron sistemáticamente 121 y 88 parcelas para estimación de cobertura de cada uno de los sustratos presentes. En las parcelas se identificaron los micrositios que están siendo utilizados por las plantas de regeneración de lenga. Las plantas fueron caracterizadas y se identificó la presencia de ramoneo por Lama guanicoe (guanaco). Los resultados establecen que los principales sustratos en la pradera corresponden a conjuntos de plantas herbáceas (47,9% de cobertura) y madera en descomposición grado 1 (12,6%). En el bosque el sustrato del suelo está cubierto mayoritariamente por plantas herbáceas (30,7%) y hojarasca (13,7%). En la pradera se encontraron 1,9 plantas de regeneración por m2, estableciéndose mayoritariamente sobre plantas herbáceas (entre 52,2 y 55,6% de las plantas). En el bosque de lenga se encontraron 10,0 plantas de regeneración por m2, las que se encontraban creciendo mayoritariamente sobre madera en descomposición grado 3 (39,7 a 44,6%). El 81,5% de las plantas se encuentran ramoneadas por guanaco en la pradera de castor y solamente el 15,9% en el bosque. Actividades de restauración de castoreras abandonadas deberían considerar el establecimiento de plantas de regeneración en micrositios que son utilizados naturalmente por lenga, además de aislar la presencia de guanaco.Fil: Toro Manríquez, Mónica del Rosario. Universidad de Chile; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Promis Baeza, Alvaro Andres. Universidad de Chile; ChileVI Congreso Chileno de Ciencias ForestalesTemucoChileUniversidad de La FronteraSociedad Chilena de Ciencias Forestale

Descripción de la flora vascular en el sotobosque de un bosque pantanoso y de una pradera antropogénica húmeda de Juncus procerus en el valle del río Cisnes, Región de Aysén, Chile

The richness, abundance and density of vascular flora species were evaluated in the understory of a swamp forest (BP) dominated by Luma apiculata and in an anthropogenic Juncus procerus wet praire (PHJ). The most diverse taxonomical groups were fern in BP and dycotiledon in PHJ. Introduced species were only found in PHJ. Epiphytic hemicryptophytes and climbing phanerophytes are indicator species for BP and hemicryptophyes for PHJ

Rehabilitation of Nothofagus pumilio forests in Chilean Patagonia: can fencing and planting season effectively protect against exotic European hare browsing?

In forests affected by heavy fires and continuous grazing of exotic herbivorous mammal species, Nothofagus pumilio (lenga) cannot recover naturally. The main factors that hinder the natural recovery of these forests and the feasibility of native tree plantations are the exotic herbivorous pressure, like that produced by Lepus europaeus (European hare), and the environment degradation degree by anthropic disturbances. The objective of this study was to evaluate different plantation efforts to recover N. pumilio forests degraded by fires in Chilean Patagonia. The plantation actions also included wire fences for sapling protection in 100 ha, where 60 ha were established during autumn (May 2012), and 40 ha were established during spring (October 2012). In March 2013 we recorded the height annual growth (cm year−1), the section browsed at each sapling, the modification of plant form (number of new branches), and the vigor expression. We evaluated the data using one- and two-way ANOVAs, Cohen's d effect size, and chi-square analyses. We measured a total of 872 plants, where 42% presented damages caused by European hare browsing. These results indicated that the wire fences were not completely useful to stop the damage on saplings (Cohen's d effect size= <0.2). We also found that autumn plantations were more susceptible to damage than those established during spring. European hares predominantly browsed on a particular sapling section: the apical buds. As a consequence, the browsed saplings had lower height growth than undamaged ones. These outputs highlight the need to explore and implement alternative actions for the rehabilitation of these degraded deciduous forests, to achieve the objectives of sustainable management or to recover the natural ecosystem functions.Fil: Huertas Herrera, Alejandro. Ulterarius Consultores Ambientales y Científicos Ltda; Chile. Universidad de Magallanes; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Promis Baeza, Alvaro Andres. Universidad de Chile; ChileFil: Toro Manríquez, Mónica del Rosario. Universidad de Magallanes; Chile. Ulterarius Consultores Ambientales y Científicos Ltda; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Río, Matias. Fundación Reforestemos Patagonia; Chil

Theoretical proposal for the rehabilitation of Nothofagus pumilio forests degraded by fires based on cluster plantings with Embothrium coccineum

La rehabilitación de bosques templados con especies nativas requiere de ensayos y directrices que permitan alcanzar la recuperación de áreas degradadas del sur de Chile y contrarrestar el desequilibrio ambiental producto de los impactos recibidos. Este documento tiene como objetivo presentar una propuesta teórica de rehabilitación basada en plantaciones en núcleo para mejorar las potencialidades de recuperación de bosques de lenga (Nothofagus pumilio) degradados por incendios en la región de Aysén. La estrategia propone núcleos de lenga rodeados de notro (Embothrium coccineum), que actuaría como planta nodriza para acelerar el desarrollo de plántulas de lenga a través de mecanismos de facilitación, como el mejoramiento de las condiciones microclimáticas, y la protección de posibles daños por herbívoros de las plántulas dentro de cada núcleo. Esta propuesta podría ser utilizada en bosques degradados de lenga, tanto en Áreas Silvestres Protegidas como en bosques productivos, así como en paisajes fragmentados por incendios históricos.The rehabilitation of temperate forests with native species requires trial and guidelines to achieve recovery of degraded areas ofsouthern Chile and counteract the environmental imbalance caused by the impacts received. This study aims at presenting a theoreticalproposal of rehabilitation based on cluster plantings to improve the recovery of lenga (Nothofagus pumilio) forests degraded byhistorical fires in Aysén Region. A rehabilitation strategy based on cluster plantings is proposed, in which individuals of lenga areestablished together with notro (Embothrium coccineum), the latter as a nurse plant, to accelerate the development of lenga seedlingsthrough facilitation mechanisms, such as the improvement of microclimatic conditions, and protection from possible damage byseedling herbivores within each cluster. This proposal could be used in degraded lenga forests, both in Protected Wild Areas and inproductive forests, as well as in landscapes fragmented by historical fires.Fil: Huertas Herrera, Alejandro. Universidad de Magallanes; ChileFil: Promis Baeza, Alvaro Andres. Universidad de Chile.; ChileFil: Matías Rio. Universidad de Chile.; ChileFil: Toro Manríquez, Mónica del Rosario. Universidad de Magallanes; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Leaf litter hides post-dispersed seeds from invasive alien removers in a sclerophyll forest in central Chile

Aim of the study: Seed removal may be a determining filter for regeneration. Factors such as leaf litter, tree cover and seed density affect seed removal. This aims to assess three aspects involving on post dispersal seed removal of four woody species (Lithraea caustica, Maytenus boaria, Quillaja saponaria and Retanilla ephedra) of a sclerophyll forest.Study area: Andean Mediterranean sclerophyll forest of Quillaja saponaria and Lithraea caustica located in the Río de Los Cipreses National Reserve, Chile.Materials and methods: Seven experimental plots were set up, in which seeds were offered in an experiment with variations in leaf litter, tree cover and seed density. Generalized Linear Mixed Models (GLMM) were used for the statistical analysis. Camera traps were installed to identify the seed removers.Main results: Q. saponaria seeds were more removed than the seeds of the other species (0.84, observed mean). Whereas that M. boaria and R. ephedra did not show significant differences on the removal of their seeds (0.77 and 0.67 respectively), both were more removed than L. caustica (0.59). The removal of M. boaria, Q. saponaria and R. ephedra seeds was lower in the presence of leaf litter. No factor influenced the removal of L. caustica seeds. Seed removers were identified as invasive alien species such as Rattus sp. and Oryctolagus cuniculus and native species such as Lycalopex culpaeus.Research highlights: Three woody species of this forest suffer severe seed removal by invasive alien fauna with major implications for the resilience of these forests. The coverage of leaf litter is key to hide away the seeds, increasing survival and could promote germination.Keywords: invasive alien fauna; Mediterranean forest; sclerophyll forest; seed removal factors

Tree seedlings respond to both light and soil nutrients in a Patagonian evergreen-deciduous forest.

Seedlings of co-occurring species vary in their response to resource availability and this has implications for the conservation and management of forests. Differential shade-tolerance is thought to influence seedling performance in mixed Nothofagus betuloides-Nothofagus pumilio forests of Patagonia. However, these species also vary in their soil nutrient requirements. To determine the effects of light and soil nutrient resources on small seedlings we examined responses to an experimental reduction in canopy tree root competition through root trenching and restricting soil nutrient depletion through the addition of fertilizer. To understand the effect of light these treatments were undertaken in small canopy gaps and nearby beneath undisturbed canopy with lower light levels. Seedling diameter growth was greater for N. pumilio and height growth was greater for N. betuloides. Overall, diameter and height growth were greater in canopy gaps than beneath undisturbed canopy. Such growths were also greater with fertilizer and root trenching treatments, even beneath undisturbed canopy. Seedling survival was lower under such treatments, potentially reflecting thinning facilitated by resource induced growth. Finally, above-ground biomass did not vary among species although the less shade tolerant N. pumilio had higher below-ground biomass and root to shoot biomass ratio than the more shade tolerant N. betuloides. Above- and below-ground biomass were higher in canopy gaps so that the root to shoot biomass ratio was similar to that beneath undisturbed canopy. Above-ground biomass was also higher with fertilizer and root trenching treatments and that lowered the root to shoot biomass ratio. Restricting soil nutrient depletion allowed seedlings of both species to focus their responses above-ground. Our results support a view that soil nutrient resources, as well as the more commonly studied light resources, are important to seedlings of Nothofagus species occurring on infertile soils

Leaf litter hides post-dispersed seeds from invasive alien removers in a sclerophyll forest in central Chile

Aim of the study: Seed removal may be a determining filter for regeneration. Factors such as leaf litter, tree cover and seed density affect seed removal. This aims to assess three aspects involving on post dispersal seed removal of four woody species (Lithraea caustica, Maytenus boaria, Quillaja saponaria and Retanilla ephedra) of a sclerophyll forest. Study area: Andean Mediterranean sclerophyll forest of Quillaja saponaria and Lithraea caustica located in the Río de Los Cipreses National Reserve, Chile. Materials and methods: Seven experimental plots were set up, in which seeds were offered in an experiment with variations in leaf litter, tree cover and seed density. Generalized Linear Mixed Models (GLMM) were used for the statistical analysis. Camera traps were installed to identify the seed removers. Main results: Q. saponaria seeds were more removed than the seeds of the other species (0.84, observed mean). Whereas that M. boaria and R. ephedra did not show significant differences on the removal of their seeds (0.77 and 0.67 respectively), both were more removed than L. caustica (0.59). The removal of M. boaria, Q. saponaria and R. ephedra seeds was lower in the presence of leaf litter. No factor influenced the removal of L. caustica seeds. Seed removers were identified as invasive alien species such as Rattus sp. and Oryctolagus cuniculus and native species such as Lycalopex culpaeus. Research highlights: Three woody species of this forest suffer severe seed removal by invasive alien fauna with major implications for the resilience of these forests. The coverage of leaf litter is key to hide away the seeds, increasing survival and could promote germination

Three-way ANOVA for mean (± SE) initial density (D), initial root collar diameter (RCD) and initial height (H) of seedlings per plot by species, canopy condition and treatment as main factors.

<p>Three-way ANOVA for mean (± SE) initial density (D), initial root collar diameter (RCD) and initial height (H) of seedlings per plot by species, canopy condition and treatment as main factors.</p