Using field and nursery treatments to establish Quercus suber seedlings in Mediterranean degraded shrubland

Abstract

Biogeosciences and Forestry Biogeosciences and Forestry Using field and nursery treatments to establish Quercus suber seedlings in Mediterranean degraded shrubland Julio Muñoz-Rengifo (1-2) , Esteban Chirino (3) , Vicent Cerdán (4) , Jesús Martínez (4) , Osvaldo Fosado (5) , Alberto Vilagrosa (6) Cork oak (Quercus suber L.) is a suitable species for restoring Mediterranean ecosystems due to its capacity to resprout after wildfires and its economic importance for the use of cork. Several studies have focused on improving the seedling quality and abiotic conditions at the outplanting site to favour the field performance of Q. suber, however, most studies have been conducted by independently testing treatments. The aim of this study was to assess the combined effect of three techniques that focused on reforestation success with Q. suber in Mediterranean degraded shrubland: (i) a nursery technique to improve root system development, such as the use of deep containers to develop a longer tap root, combined with two field techniques such as (ii) the use of tree shelters to diminish solar radiation stress, and (iii) shrubland treatments to reduce competition for soil water and nutrients. For this purpose, 1-yearold Q. suber seedlings were grown in two containers types: a shallow container (CCS-18) and a deep container (CCL-30). Seedlings were established in a degraded shrubland at three experimental sites in the Calderona mountain range of Castellón, Spain. A factorial design was combined based on container type (CCS-18 and CCL-30), shrubland management (undisturbed shrubland and cleared shrubland in strips) and tree shelters (vegetable fibre tree shelters and no tree shelters). After 2 years of monitoring, the outplanting results indicated that using: (i) a deep container produced a longer taproot, but did not favour better survival or better field performance of seedlings; (ii) tree shelters improved the microweather conditions around seedlings, particularly by reducing excess incoming solar radiation; (iii) cleared shrubland strips reduced competition for soil water by favouring a higher water potential, better maximum photochemical PSII efficiency and higher survival rates for the seedlings established into cleared sites. The results indicate that the cleared shrubland treatment effects overlap the effects of using deep containers and tree shelters. This, in turn, reveals that shrubland clearing is the most suitable technique for favouring the introduction of a resprouter species like Q. suber into ecosystems characterized by predominantly degraded shrublands.

Influence management and disturbances on the regeneration of forest stands

“…In lowproduction years a larger proportion of seeds is used as a food source, whereas in masting years satiation is reached for a much smaller percentage of the seed yield (Löf et al, 2019). Animal population density control and/or protection of regeneration may potentially increase the success of regeneration (Dey et al, 2019;Oliet et al, 2019;Vaz et al, 2019;Muñoz-Rengifo et al, 2020;Bolibok et al, 2021;Borderieux et al, 2021). For some species (e.g., for most Pinus spp.)…”

“…Animals tend to browse mainly new branches and leaves. This originates in the development of one or several buds and seedlings may develop a shrubby habit (Vaz et al, 2019;Muñoz-Rengifo et al, 2020), especially for the species with weak epinastic control (Oliver and Larson, 1996;Cline, 1997). Site conditions, in particular weather, determine seedling survival, e.g., for Pinus nigra soil mobilization promoted germination and seedling density (Lucas-Borja et al, 2011).…”

Problems and solutions to cork oak (Quercus suber L.) regeneration: a review

“…Controlling competing vegetation until seedling establishment (4 to 5 years) is a requirement to assure homogeneous growth of seedlings (Albouchi & Abassi 2000). When competing vegetation is not managed, it can severely reduce survival and/or plant growth (Munoz-Rengifo et al 2020). Methods commonly used to control competing vegetation are manual, mechanical, and chemical (Mechergui et al 2021b).…”

Mesh-shelters provide more effective long-term protection than tube-shelters or mulching for restoration of Pinus halepensis in a Mediterranean arid ecosystem

“…Limitations imposed by these factors can be alleviated by employing suitable restoration techniques. Most ecotechnological tools commonly used in arid environments have focused on deterring seedling predation or improving microsite conditions and resource availability (Piñeiro et al, 2013;Muñoz-Rengifo et al, 2020). The implementation of these ecotechnologies is particularly important in highly degraded areas with low retention of water and nutrients (Vallejo et al, 2012), which generally experience more extreme and harsh summers (IPCC, 2014) and require continuous improvements in planting techniques (Chirino et al, 2009;Valdecantos et al, 2014;Jacobs et al, 2015).…”