Effects of tree shelters on young olive (Olea europaea) tree growth and physiology

Abstract

A 3-year study was conducted to evaluate the effects of tree shelters on young olive (Olea europaea) tree growth and physiology. The trial was carried out in the Apulia region in southern Italy using 1-year-old plants of the cultivar 'Coratina'. Four different types of polypropylene shelters were tested: 75-cm-high brown; 90-cm-high brown; 75-cm-high green; 120-cm-high light-green vented, with holes in their basal part. Both green shelters significantly increased the vertical growth of the trees, especially the 120-cm light-green vented ones. Shelters did not increase the amount of dry matter produced, but they modified its allocation within the tree, favouring vertical growth and the development of shoots in the apical parts of the trees.

Effects of Tree Shelters on the Survival and Growth ofArgania spinosaSeedlings in Mediterranean Arid Environment

“…In continental climate, the use of shelters allowed a mean survival gain of 17% for cottonwood and Siberian elm [25]. Indeed, the shelters played likely a decisive role around the seedlings by creating a favorable microclimate by reducing light intensity [26,27] and plant transpiration [28] during the summer. According to some studies [29], the soil temperature around unsheltered seedlings may exceed the soil temperature registered in tree shelters by 10 to 20 ∘ C. Moreover, the shelter protected the plants against attack of many mammals in the fenced plot: hares and Barbary ground squirrel (Atlantoxerus getulus) that attacks seedling's shoots and especially its apical part which greatly hinders in growth and causes the death of the plant in case of repeated assaults on young argan trees.…”

Effects of treeshelters and polyethylene mulch sheets on survival and growth of cork oak (Quercus suber L.) seedlings planted in northwestern Tunisia

“…A few seedlings emerged from the top of the non-vented 1.2-m treeshelters during the first season after planting. This shoot elongation of the sheltered plants could be a response to radiation reduction, and, as a result of low ventilation, to increase in temperature, and most likely to increase in relative humidity (Holly et al, 1994;Bergez and Dupraz, 2000;Famiani et al, 2007), especially in non-vented shelters. It could also result from the protection against wind desiccation, from the structural support, and from the reduction of the mechanical stress offered by shelters .…”

“…However, treeshelters often had negative effects on both diameter growth and a seedling's ability to support itself without a stake (Burger et al, 1996;Mayhead and Boothman, 1997). These effects are limited to when seedlings are inside the shelters (Potter, 1991;Burger et al, 1996;Famiani et al, 2007). Moreover, the use of relatively shorter treeshelters (0.6-1.2 m high) is recommended in order to reduce their negative effects on seedling growth (Burger et al, 1996;Dupraz, 1997;Mayhead and Boothman, 1997), since the few studies on the effect of treeshelter height on seedling establishment (Applegate and Bragg, 1989;Mayhead and Boothman, 1997;Hemery and Savill, 2001) showed greater tree heights but lower base stem diameters and a higher proportion of seedlings unable to support themselves unaided after stake removal in taller shelters.…”

Grow Tubes Reduce Root and Crown Growth but Not Early Production during Establishment of Highbush Blueberry

“…Grow tubes (commonly called ''tree shelters'' in forestry) have been used successfully to improve the establishment of grape (Vitis sp. ), walnut (Juglans regia L.), olive (Olea europaea L.), and landscape or forest trees (Burger et al, 1996;Famiani et al, 2007;Hall and Mahaffee, 2001;Kjelgren et al, 1997;Laliberté et al, 2008;Potter, 1988;Tuley, 1983). Grow tubes were originally developed and used in Great Britain to protect young trees from animal browsing; the use of grow tubes in commercial crop plants also offers this advantage in addition to protecting young plants from drift when contact herbicides are used to control weeds.…”