Optimizing Hardwood Reforestation in Old Fields: The Effects of Treeshelters and Environmental Factors on Tree Seedling Growth and Physiology

Abstract

Strong competition for water is largely recognized as the main factor explaining the resistance of herbaceous old fields to tree invasion. Therefore, site preparation as well as chemical and mechanical vegetation control are recommended when establishing hardwood tree plantations on such sites, but those methods are sometimes socially or ecologically inappropriate. The main objective of this study was to analyze whether treeshelters could improve early tree growth in herbaceous old fields, when mulching alone is used to partially control herbaceous competition.Our results indicate that treeshelters can facilitate tree growth in those conditions but that this was not caused by an improvement of tree water relations. Rather, it appeared to be related to an optimization of light levels inside the shelter, where light intensity was low enough to lead to a photosynthetic system less costly to maintain due to a greater specific leaf area but high enough to have no adverse effects on photosynthetic rates. Although treeshelters increased tree growth when surrounding herbaceous vegetation was low (either height or standing biomass), allowing high light levels, they reduced growth when surrounding vegetation was high and blocked a substantial quantity of light. Therefore, environmental factors such as light availability need to be considered to optimize the success of hardwood plantations when treeshelters are used in recently abandoned agricultural fields.

Is tree shelter protection an effective complement to weed competition management in improving the morpho-physiological response of holm oak planted seedlings?

“…This trend was more evident in shelter protected plants, especially those from the MT treatment, where the tree shelter stimulated plant height growth (Bellot et al 2002, Navarro Cerrillo et al 2005, Oliet & Jacobs 2007, Pemán et al 2010. Stimulation of seedlings' height growth by the shelter may help seedlings to overcome more quickly the dominance exerted by weeds in the early stages of establishment, if light interception by surrounding vegetation is moderate (Laliberté et al 2008).…”

“…Despite the current interest in forestry restoration, few studies have used a morphophysiological approach to describe the combined effect of weed control and tree shelters on tree establishment (Oliet & Jacobs 2007, Laliberté et al 2008, Navarro Cerrillo et al 2009). Weed control and tree shelter effects on seedling response have been widely studied as independent factors in reforestation literature (Oliet & Jacobs 2007, Willoughby et al 2009, Puértolas et al 2010, Ammer et al 2011).…”

Can intensive management accelerate the restoration of Brazil's Atlantic forests?

“…This process, however, is slow (Finegan, 1996;Martins and Engel, 2007). In many places, even where an adequate seed source is present, soil compaction, nutrient depletion, and competition from introduced C 4 grasses prevent seedlings from ever establishing (Engel and Parrotta, 2001;Parrotta and Knowles, 2001;Doust et al, 2008;Laliberté et al, 2008).…”

“…As an alternative to relying on natural processes, some have suggested that intensive site preparation should reduce competition from grasses while increasing survival and growth rates of planted or naturally established tree seedlings (Parrotta et al, 1997;Singh et al, 2000;Florentine and Westbrooke, 2004;Lamb et al, 2005;Laliberté et al, 2008).…”

Avaliação De Métodos De Restauração Florestal De Mata De Tabuleiros-Es

“…Segundo Parrotta et al (1997), a regeneração natural de florestas tropicais é, muitas vezes, lenta e incerta em virtude da combinação de fatores, como a agressividade e dominância de plantas invasoras, a recorrência das queimadas, as condições microclimáticas desfavoráveis, a baixa fertilidade dos solos e a exaustão do banco de sementes. Como alternativa, vários estudos têm sugerido a preparação intensiva do local, reduzindo a concorrência causada por gramíneas, aumentando a sobrevida e taxas de crescimento de mudas plantadas ou naturalmente estabelecidas (PARROTTA et al, 1997;SINGH et al, 2000;FLORENTINE;WESTBROOKE, 2004;LALIBERTE et al, 2008).…”