Gustavo Cruz

Solar radiation transmission in and around canopy gaps in an uneven-aged Nothofagus betuloides forest

The transmission of direct, diffuse and global solar radiation in and around canopy gaps occurring in an uneven-aged, evergreen Nothofagus betuloides forest during the growing season (October 2006–March 2007) was estimated by means of hemispherical photographs. The transmission of solar radiation into the forest was affected not only by a high level of horizontal and vertical heterogeneity of the forest canopy, but also by low angles of the sun’s path. The below-canopy direct solar radiation appeared to be variable in space and time. On average, the highest amount of transmitted direct solar radiation was estimated below the undisturbed canopy at the southeast of the gap centre. The transmitted diffuse and global solar radiation above the forest floor exhibited lower variability and, on average, both were higher at the centre of the canopy gaps. Canopy structure and stand parameters were also measured to explain the variation in the below-canopy solar radiation in the forest. The model that best fit the transmitted below-canopy direct solar radiation was a growth model, using plant area index with an ellipsoidal angle distribution as the independent variable (R2 = 0.263). Both diffuse and global solar radiation were very sensitive to canopy openness, and for both cases a quadratic model provided the best fit for these data (R2 = 0.963 and 0.833, respectively). As much as 75% and 73% of the variation in the diffuse and global solar radiation, respectively, were explained by a combination of stand parameters, namely basal area, crown projection, crown volume, stem volume, and average equivalent crown radius.

BOSQUES DE NOTHOFAGUS BETULOIDES (MIRB.) OERST 1871 (FAGALES: NOTHOFAGACEAE) EN LA PATAGONIA AUSTRAL Y TIERRA DEL FUEGO

1 Institute of Silviculture, Faculty of Forest and Environmental Sciences, University of Freiburg, Tennenbacher Str. 4, D-79085 Freiburg, Germany*.2 Department of Silviculture, Faculty of Forest Sciences, University of Chile, Santa Rosa 11315, La Pintana, Casilla 9206, Santiago, Chile.3 Department of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2H1, Canada.* Corresponding author. Tel.: 0049 761 203 8622; Fax: 0049 761 203 3781. alvaro.promis@waldbau.uni-freiburg.de

Importance of irrigation and plant size in the establishment success of different native species in a degraded ecosystem of central Chile

El riego ha sido frecuentemente considerado un paso necesario en la reforestacion de areas abiertas de ecosistemas semiaridos. Sin embargo, el exito del riego ha sido evaluado principalmente usando plantas jovenes, tipicamente menores de un ano de edad. Muy pocos estudios han explorado si el rol del riego es tambien importante en plantas de mayor edad y tamano y si el uso de plantas mas grandes incrementa el exito de procesos de reforestacion. En este estudio se evalua el efecto del riego y del tamano de las plantas en la sobrevivencia y crecimiento en seis especies arboreas de la region Mediterranea de Chile sobre un area de depositos de cenizas residuales de carbon mineral. Entre 2008 y 2010 se llevo a cabo un experimento en el cual se plantaron y monitorearon 160 plantas de cada especie en un diseno factorial, incluyendo plantas de 1 y 4 anos de edad, con y sin riego. Los resultados indican que el riego mejoro la sobrevivencia independiente de la edad en las especies mas demandantes de agua, y principalmente en las plantas mas jovenes en especies clasificadas como intermedias en un gradiente de requerimiento de agua. En especies mas resistentes a la sequia, el riego no fue importante. El uso de plantas de mayor tamano incremento la probabilidad de sobrevivencia pero no el crecimiento, tambien principalmente en especies mas demandantes de agua. El crecimiento en altura fue en general mayor con riego y en plantas mas grandes en algunas especies.

DESCRIPTION OF THE VASCULAR FLORA IN THE UNDERSTORY OF A SWAMP FOREST AND IN AN ANTHROPOGENIC JUNCUS PROCERUS WET PRAIRIE IN THE VALLE DEL RÍO CISNES, AYSÉN REGION, 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.