The effect of incorporating the height of bordering trees on gap size estimations: the case of Argentinean Nothofagus pumilio forest

Bernal, Pablo M. López; Arre, Jessica S.; Schlichter, Tomás M.; Bava, José Omar

Abstract:

For forests of Nothofagus pumilio (Poepp et Endl.) of Chubut province, Argentina, the Forest Office recommends a type of group selection as the system of regeneration. This method involves the creation of gaps in the canopy. Gap size determines seedling recruitment and sapling growth in these forests as a result of dry summers. However, in the context of N. pumilio forest management, there is no consensus on the best methodology for gap size measurement and this leads to an inaccurate link between ecological studies and management guidelines. This study aimed to produce an experimental method for determining gap size which may be suitable for both forest management and ecological analysis. The sizes of fourteen artificially created forest gaps were determined under a range of scenarios involving two definitions of gap limit, six calculation methods and using either the gap surface or the ratio between the gap diameter and canopy height. These scenarios were compared based on their correlation with three ecological variables (incident radiation, soil moisture and sapling growth). No differences between gap limit definitions or between calculation methods were found. The use of the gap diameter/canopy height ratio significantly improved the correlation with ecological variables. Also, the correlation between dominant height and soil moisture was better than average height with soil moisture. Based on these results, we propose the use of polygonal expanded gap diameter/dominant canopy height ratio as a gap size parameter for the measurement of gap size in N. pumilio forests. This parameter will be applicable to both ecological research and forest management.

Áreas de investigación:

• Planificación, Manejo y Uso Múltiple del Bosque

Año:

2010

Tipo de publicación:

Artículo

Palabras clave:

management; radiation; soil; saplings

Journal:

New Zealand Journal of Forestry Science