Restoration of Mediterranean ecosystems, particularly on seedling establishment success under dry conditions. Focused on ecophysiology of root growth and survival during first stages after planting and best management to encourage the process: nursery culture to optimize seedling quality and cultural treatments after planting to enhance environmental conditions of planted seedlings.
The effect of shelter tubes on plant performance has been widely studied. Although, the role of s... more The effect of shelter tubes on plant performance has been widely studied. Although, the role of shelter tubes in alleviating the effects of drought and high-irradiance stresses during seedling establishment has been less studied than its effect on survival. The present study compares the effects of shelter tubes with different light transmissivities (Lt) on survival and morpho-physiological responses of two coexisting tree species (drought-tolerant Quillaja saponaria and relatively more drought-sensitive Maytenus boaria ) of the Chilean matorral during an exceptionally dry and warm growing season (2014–2015). Two-year-old seedlings were randomly assigned to shelter tubes differing in Lt (20, 40, 60, 80%) or to a control (no shelter, Lt 100%) at field conditions. Survival was measured monthly, while shoot and root biomass, root length, pre-dawn xylem water potential, and non-structural carbohydrate concentration (NSC) were measured 8 months after transplanting. Shelter tubes increased the seedling survival of Q. saponaria by 80–100% relative to the control conditions, where full mortality was observed by the end of the experiment. By contrast, M. boaria exhibited high mortality regardless of the presence of shelters, suggesting that tubes were ineffective to alleviate the summer-related stresses in this species. Xylem water potential of Q. saponaria seedlings was significantly lower at 80% Lt than at 40% Lt, where maximum values were observed. Also, at 40% Lt, plant height and root length were highest and shoot/root ratio the lowest. By contrast, no differences in NSC, stomatal conductance, and photochemical efficiency were observed among Lt treatments. We conclude that shelter tubes may alleviate summer stresses in drought-tolerant species such as Q. saponaria ; hence, they appear to be effective reforestation ecotechnology under severe water limitations and high-irradiance stress imposed by the current drought and heatwaves conditions in central Chile.
Freezing stress is a critical environmental factor affecting survival, distribution, and evolutio... more Freezing stress is a critical environmental factor affecting survival, distribution, and evolution of plants. Although there is evidence that nitrogen (N) affects frost tolerance of juvenile conifers, the magnitude and direction of such effect can diverge among species. The influence of the N source on frost tolerance has been barely studied. Particularly, how organic N sources could affect the cold acclimation dynamics of seedlings is poorly understood. We studied morpho‐physiological responses to organic N supply (amino acids) in comparison to inorganic N in seedlings of two Mediterranean pine species: Pinus halepensis and P. sylvestris. Fertilization was applied at low and high N doses (30 and 130 mg N seedling−1) in the first growing season. Then, tolerance of seedlings to freezing stress was evaluated through the cold season. This study confirmed that organic N supply promotes growth of both species as effectively as inorganic N sources. At low N availability, seedlings had acute phosphorus deficiencies when grown with inorganic N, but not with organic N. Likewise, high organic‐N availability improved chlorophylls concentration. Both species increased their frost tolerance through time, especially during late autumn. Although organic N supply did not show clear benefits on frost tolerance, it seemed to enhance cold acclimation via increases of compatible solutes, such as soluble sugars and proline, particularly in P. halepensis. Thus, the effects of organic N supply could depend on the extent that such osmolytes contribute to the dormancy strategy of the species. Other species‐specific mechanisms to cope with freezing stress are further discussed.
Nursery cultivation practices can be modified to increase resistance to water stress in forest se... more Nursery cultivation practices can be modified to increase resistance to water stress in forest seedlings following field establishment, which may be increasingly important under climate change. We evaluated the morphological (survival, growth) and physiological (chlorophyll fluorescence, leaf water potential) responses to water stress for three ecologically diverse Quercus species (Q. robur, Q. pubescens, and Q. ilex) with varying traits resulting from the combination of growing media (peat, coir) and fertilization (standard, P-enriched, K-enriched). For all species under water stress, seedlings grown in coir had generally higher growth than those grown in peat. Seedlings fertilized with P performed better, particularly for survival; conversely, K fertilization resulted in inconsistent findings. Such results could be explained by a combination of factors. P fertilization resulted in higher P accumulation in seedlings, while no K accumulation was observed in K fertilized seedlings. A...
Forest restoration is challenging in arid and semiarid lands. Research has identified ecotechnolo... more Forest restoration is challenging in arid and semiarid lands. Research has identified ecotechnologies that may alleviate stressful conditions of planted seedlings, but studies are often limited to the first few years of regeneration establishment. Over 20 years, we tested the effects of tree shelters (mesh- and tube-shelters) and competition suppression (two types of synthetic mulch and manual weeding) on soil water content and development of Pinus halepensis on an arid site in southeastern Spain. Competition suppression increased soil water content at shallow depths only using a polyethylene sheet, with no effect on survival. Tree shelters had a much greater effect than competition suppression on tree responses. Survival was mostly affected by shelter type, with lower survival in tube-shelters compared to mesh-shelters and non-protected seedlings; differences began after the first year, but became more pronounced following an intense drought at 3 years. Survival for pines protected...
Forestry: An International Journal of Forest Research
Mycological resources have attracted considerable interest from the public recently. In this cont... more Mycological resources have attracted considerable interest from the public recently. In this context, forest mycological management of wild mushrooms has emerged a research field and is developing rapidly with the objective to sustainably use and conserve mushrooms in multifunctional forests. Although the term ‘mycosilviculture’ was coined relatively recently, forest management of mycological resources and fungal silviculture began already in the 1980s. This study reviews the literature on the forest management of wild mycological resources with emphasis on studies in Spanish Mediterranean forests. The review covers some of the most important aspects of management, such as the diagnosis of mycological resources through inventory and sampling protocols, predictive models of mushroom yield, stand variables and mycosilvicultural practices that affect mushroom yield and fungal diversity. Finally, the potential of mycorrhizal applications for mycosilviculture is briefly discussed. Most o...
The effect of shelter tubes on plant performance has been widely studied. Although, the role of s... more The effect of shelter tubes on plant performance has been widely studied. Although, the role of shelter tubes in alleviating the effects of drought and high-irradiance stresses during seedling establishment has been less studied than its effect on survival. The present study compares the effects of shelter tubes with different light transmissivities (Lt) on survival and morpho-physiological responses of two coexisting tree species (drought-tolerant Quillaja saponaria and relatively more drought-sensitive Maytenus boaria ) of the Chilean matorral during an exceptionally dry and warm growing season (2014–2015). Two-year-old seedlings were randomly assigned to shelter tubes differing in Lt (20, 40, 60, 80%) or to a control (no shelter, Lt 100%) at field conditions. Survival was measured monthly, while shoot and root biomass, root length, pre-dawn xylem water potential, and non-structural carbohydrate concentration (NSC) were measured 8 months after transplanting. Shelter tubes increased the seedling survival of Q. saponaria by 80–100% relative to the control conditions, where full mortality was observed by the end of the experiment. By contrast, M. boaria exhibited high mortality regardless of the presence of shelters, suggesting that tubes were ineffective to alleviate the summer-related stresses in this species. Xylem water potential of Q. saponaria seedlings was significantly lower at 80% Lt than at 40% Lt, where maximum values were observed. Also, at 40% Lt, plant height and root length were highest and shoot/root ratio the lowest. By contrast, no differences in NSC, stomatal conductance, and photochemical efficiency were observed among Lt treatments. We conclude that shelter tubes may alleviate summer stresses in drought-tolerant species such as Q. saponaria ; hence, they appear to be effective reforestation ecotechnology under severe water limitations and high-irradiance stress imposed by the current drought and heatwaves conditions in central Chile.
Freezing stress is a critical environmental factor affecting survival, distribution, and evolutio... more Freezing stress is a critical environmental factor affecting survival, distribution, and evolution of plants. Although there is evidence that nitrogen (N) affects frost tolerance of juvenile conifers, the magnitude and direction of such effect can diverge among species. The influence of the N source on frost tolerance has been barely studied. Particularly, how organic N sources could affect the cold acclimation dynamics of seedlings is poorly understood. We studied morpho‐physiological responses to organic N supply (amino acids) in comparison to inorganic N in seedlings of two Mediterranean pine species: Pinus halepensis and P. sylvestris. Fertilization was applied at low and high N doses (30 and 130 mg N seedling−1) in the first growing season. Then, tolerance of seedlings to freezing stress was evaluated through the cold season. This study confirmed that organic N supply promotes growth of both species as effectively as inorganic N sources. At low N availability, seedlings had acute phosphorus deficiencies when grown with inorganic N, but not with organic N. Likewise, high organic‐N availability improved chlorophylls concentration. Both species increased their frost tolerance through time, especially during late autumn. Although organic N supply did not show clear benefits on frost tolerance, it seemed to enhance cold acclimation via increases of compatible solutes, such as soluble sugars and proline, particularly in P. halepensis. Thus, the effects of organic N supply could depend on the extent that such osmolytes contribute to the dormancy strategy of the species. Other species‐specific mechanisms to cope with freezing stress are further discussed.
Nursery cultivation practices can be modified to increase resistance to water stress in forest se... more Nursery cultivation practices can be modified to increase resistance to water stress in forest seedlings following field establishment, which may be increasingly important under climate change. We evaluated the morphological (survival, growth) and physiological (chlorophyll fluorescence, leaf water potential) responses to water stress for three ecologically diverse Quercus species (Q. robur, Q. pubescens, and Q. ilex) with varying traits resulting from the combination of growing media (peat, coir) and fertilization (standard, P-enriched, K-enriched). For all species under water stress, seedlings grown in coir had generally higher growth than those grown in peat. Seedlings fertilized with P performed better, particularly for survival; conversely, K fertilization resulted in inconsistent findings. Such results could be explained by a combination of factors. P fertilization resulted in higher P accumulation in seedlings, while no K accumulation was observed in K fertilized seedlings. A...
Forest restoration is challenging in arid and semiarid lands. Research has identified ecotechnolo... more Forest restoration is challenging in arid and semiarid lands. Research has identified ecotechnologies that may alleviate stressful conditions of planted seedlings, but studies are often limited to the first few years of regeneration establishment. Over 20 years, we tested the effects of tree shelters (mesh- and tube-shelters) and competition suppression (two types of synthetic mulch and manual weeding) on soil water content and development of Pinus halepensis on an arid site in southeastern Spain. Competition suppression increased soil water content at shallow depths only using a polyethylene sheet, with no effect on survival. Tree shelters had a much greater effect than competition suppression on tree responses. Survival was mostly affected by shelter type, with lower survival in tube-shelters compared to mesh-shelters and non-protected seedlings; differences began after the first year, but became more pronounced following an intense drought at 3 years. Survival for pines protected...
Forestry: An International Journal of Forest Research
Mycological resources have attracted considerable interest from the public recently. In this cont... more Mycological resources have attracted considerable interest from the public recently. In this context, forest mycological management of wild mushrooms has emerged a research field and is developing rapidly with the objective to sustainably use and conserve mushrooms in multifunctional forests. Although the term ‘mycosilviculture’ was coined relatively recently, forest management of mycological resources and fungal silviculture began already in the 1980s. This study reviews the literature on the forest management of wild mycological resources with emphasis on studies in Spanish Mediterranean forests. The review covers some of the most important aspects of management, such as the diagnosis of mycological resources through inventory and sampling protocols, predictive models of mushroom yield, stand variables and mycosilvicultural practices that affect mushroom yield and fungal diversity. Finally, the potential of mycorrhizal applications for mycosilviculture is briefly discussed. Most o...
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Papers by Juan Oliet