Canopy structure analysis for estimating forest regeneration dynamics and growth in Nothofagus pumilio forests.

Abstract

Introduction Silviculture systems applied in Nothofaguspumilio forests are based on opening the canopy tostimulate natural regeneration by modifying light and soilmoisture. The objective is to evaluate regeneration dynamicsof N. pumilio along different forest canopy and solarradiation gradients.& Materials and methods Regeneration data and seedproduction were obtained in 98 permanent plots establishedin old-growth and harvested stands along a crown covergradient (19?93%). Volumetric soil water content and basalarea were also measured, while crown cover and solarradiation transmission were estimated using hemisphericalphotographs. Sapling height was modeled using plant age,crown cover, and solar radiation transmission of the standsas explanatory variables.& Results Natural regeneration dynamics were closelyrelated to crown cover values, which determined seedproduction and the successful establishment and subsequentregeneration growth. Height growth was found to be relatedto crown cover and solar radiation transmission, where N.pumilio regeneration is optimized at intermediate crowncover levels (45% crown cover, 0.5 effective leaf areaindex, 26 W m2 global radiation, and 65% percentage ofglobal radiation).& Conclusion These findings can be used to develop newsilvicultural methods or to adjust the current practices toensure regeneration establishment and maximize heightgrowth at the stand level.