Water‐saving techniques for restoring desertified lands: Some lessons from the field

Abstract

Nature-based solutions can significantly contribute restoration projects in areas affected by desertification processes, where they are necessary for reverting land degradation. Currently, one innovative solution is The Cocoon™, which has been designed as a new ecotechnology for improving seedling establishment. The Cocoon consists of a donut-shaped container made of recycled cardboard that provides water and shelter at least during the first year of a seedling, which is the most critical for plant establishment. To determine the effectiveness of this ecotechnology under different conditions, the Cocoon was tested on a variety of soils, climates, vegetation and land uses. Six planting trials were performed in Spain and Greece, which covered a range from humid to arid climates. With the objective of studying its functionality, the survival of the seedlings, their vigor and growth were monitored for two years. Compared to conventional planting systems, the Cocoon has effectively increased seedling survival especially under dry growing conditions (low rainfall, soils with low water holding capacity). The Cocoon also allowed for higher growth of some species (olive trees, holm oaks and Aleppo pines). Moreover, a positive correlation between the rainfall on the site and the biodegradation degree of the Cocoon device was observed. Overall, the Cocoon becomes more efficient in arid climates or adverse growing conditions.
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RESEARCH ARTICLE
Water-saving techniques for restoring desertified lands: Some
lessons from the field
Vicenç Carabassa
1,2
| Daniela Alba-Patiño
3
| Sergio García
1
| Julián Campo
4
|
Harrie Lovenstein
5
| Gertruud Van Leijen
6
| Antonio J. Castro
3,7
|
Francisco González
8
| Gustavo Viera
9
| Dimitrios-Sotirios Kourkoumpas
10
|
Argyro Aliki Zioga
10
| Christos Emmanouel Papadelis
10
| Vicente Andreu
4
|
Eugènia Gimeno
4
| Sven Kallen
11
| Josep Maria Alcañiz
1,2
1
CREAF, Univ Autònoma de Barcelona,
Cerdanyola del Vallès, Spain
2
Universitat Autònoma de Barcelona,
Cerdanyola del Vallès, Spain
3
Department of Biology and Geology,
Andalusian Center for the Assessment and
Monitoring of Global Change (CAESCG),
Universidad de Almería, Almería, Spain
4
Centro de Investigaciones sobre
Desertificaci
on (CIDE-CSIC), Valencia, Spain
5
Land Life Company, Amsterdam, The
Netherlands
6
Van Leijen Srl, Rome, Italy
7
Department of Biological Sciences, Idaho
State University, Pocatello, Idaho, USA
8
Consejería de Medio Ambiente, Cabildo de
Gran Canaria, Las Palmas de Gran Canaria,
Spain
9
Gesti
on y Planeamiento Territorial y
Medioambiental, Gobierno de Canarias, Las
Palmas de Gran Canaria, Spain
10
Centre for Research and Technology Hellas/
Chemical Process and Energy Resources
Institute (CERTH/CPERI), 4th km Ptolemaida
Mpodosakio Hospital, Athens, Greece
11
VOLTERRA ECOSYSTEMS, Bellaterra, Spain
Correspondence
Vicenç Carabassa CREAF, Soil Protection and
Restoration Group, Edifici C, Universitat
Autònoma de Barcelona, E08193 Bellaterra
(Cerdanyola del Vallès), Catalonia, Spain.
Email: v.carabassa@creaf.uab.cat
Funding information
EU Life Program, Grant/Award Numbers:
LIFE15 CCA/ES/000125, LIFE19
CCM/ES/001199
Abstract
Nature-based solutions can significantly contribute to restoration projects in areas
affected by desertification processes, where they are necessary for reversing land
degradation. Currently, one innovative solution is The Cocoon™, which has been
designed as a new ecotechnology for improving seedling establishment. The Cocoon
consists of a doughnut-shaped container made of recycled cardboard that provides
water and shelter at least during the first year of a seedling, which is the most critical
for plant establishment. To determine the effectiveness of this ecotechnology under
different conditions, the Cocoon was tested on a variety of soils, climates, vegetation,
and land uses. Six planting trials were performed in Spain and Greece, which covered
a range from humid to arid climates. With the objective of studying its functionality,
the survival of the seedlings, their vigor, and growth were monitored for 2 years.
Compared with conventional planting systems, the Cocoon has effectively increased
seedling survival, especially under dry growing conditions (low rainfall, soils with low
water holding capacity). The Cocoon also allowed for higher growth of some species
(olive trees, holm oaks, and Aleppo pines). Moreover, a positive correlation between
the rainfall on the site and the biodegradation degree of the Cocoon device was
observed. Overall, the Cocoon becomes more efficient in arid climates or adverse
growing conditions.
KEYWORDS
climate change adaptation, Cocoon, drylands, irrigation, planting
Received: 26 March 2021 Revised: 14 October 2021 Accepted: 16 October 2021
DOI: 10.1002/ldr.4134
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.
© 2021 The Authors. Land Degradation & Development published by John Wiley & Sons Ltd
Land Degrad Dev. 2021;1–12. wileyonlinelibrary.com/journal/ldr 1

1|INTRODUCTION
One of the most current ecological concerns is the increasing deserti-
fication rate as a direct impact of the climate crisis. According to the
United Nations Convention to Combat Desertification, areas with the
highest susceptibility to desertification are dry, arid, semiarid and sub-
humid areas (MAP, 2019), such as large parts of the Mediterranean
region. These 'drylands' occupy 41% of the Planet's land surface and
are inhabited by ca 2 billion people (MEA, 2005). A common trait of
these areas is that the aridity index ranges between 0.05 and 0.65
(MAPA, 2019).
Desertification, particularly its consequent reduction of ecosys-
tem services, can threaten future improvements in human wellbeing
and impede progressive efforts in dryland areas affected by climatic
impacts, such as control measures for dust storms or floods. Desertifi-
cation reduces primary production and microbial activity, modifies the
nutrient cycles, and increases soil degradation, which altogether result
in the inability to capture carbon and the loss of biodiversity of
affected ecosystems (MEA, 2005). The consequences of desertifica-
tion can also be their causes, thus embodying a detrimental cycle.
Therefore, combating desertification becomes one of the great global
environmental challenges, and its effects must also be considered
globally.
However, at the local level, desertification may depend on the
combination of multiple factors and site-specific processes that may
aggravate the problem. These include indirect factors, such as popula-
tion size pressure, political and socioeconomic scenarios, on the one
hand, and direct factors, such as land use and management as well as
climate-related processes, on the other. The main aggravating factors
at the local level include seasonal droughts with extreme rainfall vari-
ability and/or heavy rains, poor soils prone to erosion, steeped slopes
that increase the energy of runoff, recurrent forest fires causing loss
of vegetation cover and changes in the physical, chemical, and biologi-
cal soil properties (Campo et al., 2006, 2008), crisis of traditional agri-
culture resulting in land abandonment, unsustainable exploitation and
salinization of aquifers, bad agricultural and livestock practices, and
overpopulation in some areas (MAP, 2019).
All these factors cause direct impact and stress on vegetation and
its growth. Most of these conditions occur or have occurred through-
out the Mediterranean basin. Specifically, more than two-thirds of the
Spanish territories are classified as arid, semiarid, and dry subhumid
areas, and more than two-thirds of these territories present a risk of
desertification to a greater or lesser degree (MAP, 2019;
WWF, 2016). The capacity of ecosystems to regenerate is limited in
those areas, and therefore restoring degraded land is becoming essen-
tial for restoring the integrity of impacted forests, rangelands, mine-
affected areas, and numerous habitats that host valuable biodiversity
(Muñoz-Rojas et al., 2021).
At present, despite the efforts made, reforestation in the Mediter-
ranean region cannot be considered satisfactory in many cases due to
the slow growth of planted seedlings and extremely high mortality
rates (Valdecantos et al., 2014). Planting sites suffer water stress due
to droughts that last between 3 and 5 months. They can also
experience nutrient limitations when the seedlings are transferred to
the soil, which is typically poor in the Mediterranean region (Díaz-
Hernández et al., 2003). Water stress increases in mine soils because
of their shallow depth and lack of soil structure. Thus, they have very
low water holding capacity (L
opez-Marcos et al., 2020), which limit
plant establishment even in Mediterranean subhumid climate (Alday
et al., 2016). Even if reforestation is carried out with regular irrigation,
the survival rate is at most 50% for many species, but in many cases
even less, since root systems with inadequate irrigation do not pene-
trate deep enough into the soil and remain in the surface layers
(Salem, 1989).
In this context, nature-based solutions could help solve environ-
mental problems and improve reforestation projects by increasing
seedling establishment. Nature-based solutions are defined as actions
that protect, sustainably manage, and restore natural or modified eco-
systems addressing societal challenges effectively and adaptively,
while simultaneously providing human well-being and biodiversity
benefits. Nature-based solutions are usually regarded as an umbrella
concept that covers a range of different approaches (Cohen-Shacham
et al., 2016). Therefore, ecotechnologies designed for supporting res-
toration projects and plantings could also be included in this group of
solutions.
The Cocoon™, a new water-saving ecotechnology for supporting
plantings in drylands, is currently used abroad (Land Life
Company, 2021). The Cocoon resembles the buried clay pot used in
ancient times, in which water slowly seeps into the subsurface to sup-
port plant growth and restricts evaporation losses, as would be
expected during conventional watering of the soil surface. Instead of
fragile and bulky pots, a paper pulp-based alternative was devised to
support early tree establishment in reforestation schemes under dry-
land conditions. With preliminary tests of an early version of the
Cocoon as proof of principle, larger field tests have been laid out since
2016 in the Mediterranean basin and Canary Islands (VOLTERRA,
2021) and in the Lower Rio Grande Valley of South Texas (Mohsin
et al., 2021), among others.
The objective of this work is to analyze the results of the large-
scale implementation of the Cocoon solution by means of the data
collected in different field trials carried out in restoration projects. The
main parameters evaluated have been seedling survival, vigour, and
growth to verify the effectiveness of this technology in the wide
range of land uses and environmental conditions present in six study
areas located in the Mediterranean region and the Canary Islands.
2|MATERIAL AND METHODS
2.1 |The Cocoon device
The Cocoon™consists of a doughnut-shaped container (like a torus
geometrical figure) made of recycled cardboard. This device has a
capacity for 25 litres of water and a central space to install the seed-
ling. It is designed to provide water and shelter to the seedling, at least
during its first year, which is usually its most critical survival stage. A
2CARABASSA ET AL.

lid reduces evaporation losses from the bowl and a shelter protects
the seedling against small herbivores and reduces evapotranspiration.
For the Cocoon installation, the soil must be prepared beforehand by
first digging a hole of 20 cm depth and 50 cm diameter, where this
device can be introduced (Figure 1). Over time it biodegrades and
integrates itself into the ground.
2.2 |Study areas
The Cocoon system was used in six restoration areas located in Spain
and Greece (see Table S1). In Spain, five large demonstration areas were
located in El Bruc (Catalonia), Jijona and Tous (Valencia), Sierra de María
(Almería), and Tifaracás (Canary Islands); and in Greece, one area in
Ptolemais (Western Macedonia). These areas cover a variety of soils,
Mediterranean mesoclimates (from humid to arid), vegetation and land
use, where the effectiveness of the Cocoon device can be tested in dif-
ferent conditions on several desertification scenarios, and in combina-
tion with different nature-based solutions for forest fire vulnerability
reduction, endangered/endemic species protection, open-pit mines res-
toration or recuperation of agricultural land (CREAF, 2017a).
For our case-studies, we focused on burned forest soils with rela-
tively high organic matter content in El Bruc and Tous and poor soils
with low organic matter content in Jijona (abandoned cropland) and
Tifaracás (volcanic parent material). In Ptolemais, the soil derives from
the mining debris of a former coal mine, where the planting was car-
ried out. The soil in this particular location presents very high contents
of carbonates and coal particles. Table 1 presents the main character-
istics of the studied areas, and Table 2 presents the respective soils.
2.3 |Planting
The planting scheme was based on the combination of one set of
seedlings planted directly in the soil (controls), which represent the
traditional way, and another set planted with the Cocoon. Each con-
trol was surrounded by several associated Cocoons, depending on the
planting possibilities of the site. As a rule, a 1:3 control:Cocoon ratio
was used. Thus, each control provides paired measures with its associ-
ated Cocoon, whereby an encoding system was set that allowed data
coupling.
In total, 22,301 seedlings of 31 different species or varieties were
planted on an entire surface of 73 ha (see Table S1), according to res-
toration objectives, environmental conditions and climate change sce-
narios. Planting was carried out in two phases: the first phase in
Autumn 2016, and the second in Spring–Summer 2017. Cocoon
installation was carried out using a 50 cm diameter drill installed in a
tractor or a backhoe whenever topographic and soil conditions made
it possible. In steeped slopes and extremely stony soils, holes were
made manually (see Table S1). Once planted, the Cocoons were filled
with 25 L of spring water, in addition to natural rain, while the con-
trols were watered with a similar amount of water, but no refilling/
irrigation was performed thereafter, with the exception of third and
fourth plantings in Tifaracás, where the Cocoons were refilled.
2.4 |Monitoring parameters
Monitoring parameters were divided into two groups: (i) one for eval-
uating the Cocoon effects on plant vigour and growth, vegetation
exclusion, and Cocoon biodegradation; and ii) the other for evaluating
the recovery by means of passive restoration of the plantation areas.
Plant vigor was evaluated according to the following semiquanti-
tative scores during their normal growing period:
3: Healthy seedling, with more than 75% of green, no wilted
leaves, with active growing points (apices) visible
2: Affected seedling, with 25%–75% of the leaves being wilted,
yellow, or brown
1: Severely affected seedling with less than 25% of the leaves
being green (i.e. the majority wilted, yellow or brown)
0: Presumably dead seedling with no leaves or only wilted leaves;
however, seedlings may still recover by resprouting after rain
occurs
R: Resprouted seedling
With the use of a caliper, plant growth was assessed by measuring
maximum plant height, from the root crown to the shoot apex, and the
FIGURE 1 Cocoon scheme and
functioning [Colour figure can be viewed
at wileyonlinelibrary.com]
CARABASSA ET AL.3

stem diameter at the tree base (at the level of the Cocoon's lid, at
10 cm of soil). Vegetation exclusion was evaluated in 1 m diameter cir-
cle around the seedling, measuring vegetation cover in two perpendic-
ular transects. Additionally, biomass was evaluated by harvesting and
weighing all the vegetation inside the circle (wet weight: weight at
field; dry weight: weight after drying at 60C for 4 days). Cocoon bio-
degradation was evaluated by ranging each Cocoon from States 1 to
4, 1 being the intact device, and 2, 3, and 4 being increased biodegra-
dation until complete incorporation into the soil. State 2 corresponded
to a Cocoon without lid or a partially collapsed one.
Passive restoration was measured by means of vegetation struc-
ture measures and floristic inventories. Structure was evaluated by
quantifying cover types and height, each having 20 cm in 25 m tran-
sects, a minimum of 3 transects per ha, which are parallel and perpen-
dicular to the slopes (see the area of each study site in Table S1).
Transect vertex was fixed with metal bars in order to repeat measure-
ment at the same place. For this, each vertex was identified with UTM
coordinates or a specific code (Carabassa et al, 2019).
Floristic inventories were made identifying all plant species in
each area, which distinguished each site or subsite (according to site-
specific variability). Additionally, an abundance estimation per species
was performed using these pattern rankings:
1: 0%–5% soil cover
2: low frequency (<25% soil cover)
3: high frequency (25%–75% soil cover)4: dominant (>75% soil cover)
A protocol for measuring all these parameters was specifically
defined (CREAF, 2017b). Data were obtained in two field campaigns
carried out in all plantations: one before Summer 2017 and another
one after 2 years, in late Spring 2019. For the third and fourth plant-
ings in Tifaracás, further monitoring was carried-out in 2020, whereby
only seedlings survival was measured (Table S1).
2.5 |Statistical analysis
Seedling survival and physiological state, Cocoon degradation, plant
height, stem diameter, root development, and microsite biomass and
cover (vegetation exclusion) were analyzed using R Studio. The normal
probability test and the Breusch–Pagan test were used to check nor-
mality and homoscedasticity. Analyses of the differences between
treatments (control and Cocoon) were performed using the Mann–
Whitney test, since only two treatments were tested. Analyses on the
study sites were performed using the Kruskal–Wallis test, since more
than two treatments were tested. To determine significant differ-
ences, a value of α=0.05 was applied.
3|RESULTS
3.1 |Seedling survival and physiological state
Analyzing the survival values together for all the study areas, plant
species and contrasted differences could be observed. Seedlings that
TABLE 1 Study areas identification and location, climatic parameters, geologic substrates, and nature-based solutions applied
Site Region
UTM
coordinates
(ETRS89)
Mean annual
precipitation (mm)
Averages monthly
max and min T (C)
Potential
evapotranspiration
(mm yr
1
)
Aridity
index
Mediterranean
climate type
Geological
substrate
Nature-based solution
scenario
Tifaracás Canary
Islands
28N 427779,
3095798
177 14.3–28.6 1100 0.16 Arid Volcanic Endangered/endemic
species restoration
Jijona Alicante 30N 721173,
4267646
445 8.9–24.7 1388 0.32 Semiarid Early
Cretaceous
marls
Cropland restoration
Tous Valencia 30N 700667,
4343691
424 10.6–25.5 1143 0.37 Semiarid Cretaceous
dolomites
Passive restoration
acceleration
Sierra
María
Almería 30N 571368,
4164540
350 0.8–30.3 678 0.52 Dry subhumid Alluvial Cropland restoration +
rambla* restoration
El Bruc Barcelona 31N 394519,
4609198
666 6.7–22.1 982 0.68 Dry subhumid Conglomerates Forest fire vulnerability
reduction
Ptolemais Western
Macedonia
34N 565459,
4482995
570 1.8–22.5 737 0.77 Humid Marls-lignite Mine restoration
Note: * Temporary river bed.
4CARABASSA ET AL.

planted with the Cocoon methodology showed greater survival, with
a rate close to 60%, while the control ones showed lower rates of up
to 40% (p< 0.0001). Regarding the vigor of the survivors, the seed-
lings with good health predominated in both cases (control and
Cocoon treatments), but with a higher percentage in the Cocoon
treatment, in which only few plants were severely affected or res-
prouted. However, some particular tendencies can be observed when
data are analyzed for each planting area (Figure 2).
In the El Bruc, Jijona, and Tous planting sites, differences
between controls and Cocoons were observed in terms of mortal-
ity and the number of healthy plants (see Figures S2–S5). In con-
trast, in Sierra María, there were no differences in seedling
mortality between the control and Cocoon treatments, which both
yielded 37% survival rates. In addition, control seedlings showed
greater vigor, with a greater number of healthy seedlings (36%),
compared with those with Cocoon (26%). Survival in Ptolemais'
planting sites was high on both treatments. The percentage of
affected seedlings was very low, and only appeared in the Cocoon
treatment. In contrast, survival in Tifaracás was low in both treat-
ments, even though the seedlings planted with Cocoon presented
a higher percentage of healthy seedlings (21%), compared with
controls (12%).
However, vigor results are not only dependent on location but
also on plant species, for example, Rosmarinus officinalis L. (rosemary)
and Prunus dulcis (Mill.). D. A. Webb (almond tree) in Sierra María
showed high survival ratios in Cocoons like respective controls, while
Tamarix gallica L. (French tamarisk) presented high mortality ratios in
both treatments, with mortality being much higher in the controls,
which reached a 100% mortality ratio (see Figure S1). In Ptolemais,
the highest mortality basically affected Cupressus sempervirens
L. (cypress) specimens (see Figure S2).
The overall results in Tifaracás were largely determined by local
harsh conditions, especially the drought in Summer 2017, which
occurred just after planting. Despite this, seedlings planted in the
Cocoon had better physiological state than controls. Pistacia atlantica
Desf. (mastic tree) had high mortality rates in both treatments, but
survival was higher in Cocoons, albeit with a high percentage of
severely affected seedlings. Mortality was also high in Juniperus
turbinata ssp. canariensis Guyot (Canarian juniper), being 100% in con-
trols and close to 80% in Cocoons. The best survival results were
obtained with Olea europaea L. ssp. guanchica (Canarian wild olive),
having a mortality rate that did not reach 25% of the specimens and a
relatively high percentage of healthy seedlings, which was close to
50%. In respective controls, mortality and affected seedling rates were
higher (32% and 38%, respectively).
All the species planted in El Bruc and Jijona showed a similar
trend, whereby a better physiological state in the Cocoon treatment
could be observed. However, for some of them, such as Ceratonia
siliqua L. (carob tree), Olea europaea L. var. europaea (vera olive tree),
Prunus avium L. (cherry tree), and Prunus spinosa L. (blackthorn), the
mortality of controls exceeded 80%. In El Bruc, the best results
were obtained for the two subspecies of Quercus ilex L. (subsp. ilex
and subsp. ballota [Desf.] Samp.), Quercus faginea Lam. (Portuguese
oak), Olea europaea L. var. europaea (cornicabra olive tree), and
Juglans regia L. (walnut tree), where Cocoons had survival rates well
above their respective controls (see Figure S3). In Jijona, also Que-
rcus ilex and Olea europaea exhibited good results with the Cocoon,
exhibiting survival rates close to 100% in some cases (see
Figure S4), but Tetraclinis articulata (Vahl) Masters (Cartagena's
cypress) also exhibited good results using both treatments, in which
controls reached 86% survival rates.
3.2 |Seedling growth
Seedling growth depended not only on local environmental conditions
but also on the species. At the same time, a similar trend toward sur-
vival was observed (see Figures S7–S13, Annex 3). A clear tendency
toward a better growth of seedlings planted with Cocoon was noted
in diameter and height when survival is higher, such as in Quercus ilex
and Olea europaea (Figure 3). However, for some species, like
Rosmarinus officinalis, there were no significant differences between
treatments, and for other species, controls presented higher growth
than Cocoons, such as almond trees in Sierra María (Figure 3). Regard-
ing root development, differences were only observed in the
cornicabra olive tree (Figure S13, Annex 3).
TABLE 2 Main soil characteristics of the study areas
Site Texture CaCO
3
(%)
CEC
(cmol kg
1
)
pH water
(1:2,5 w/v) EC (dS m
1
) SOM (%)
SOC stock
(T ha
1
) Comments
Tifaracás Clay 6.5 ± 3.0
a
43.7 ± 3.4
c
7.70 ± 0.23
a
0.95 ± 0.13
ab
1.62 ± 0.35
a
12.99 ± 3.81
a
Steep slope, stony
Jijona Loam 77.9 ± 6.8
d
11.5 ± 4.9
a
7.82 ± 0.20
a
0.75 ± 0.30
ab
1.79 ± 1.18
a
27.67 ± 6.21
ab
Abandoned terraces
Tous Clay 9.4 ± 13.9
a
28.1 ± 5.4
b
7.49 ± 0.28
a
0.46 ± 0.11
a
3.39 ± 1.30
a
26.69 ± 9.59
ab
Shallow and stony
Sierra
María
Clay loam 58.1 ± 5.7
c
20.8 ± 4.5
ab
7.72 ± 0.04
a
0.78 ± 0.27
ab
3.18 ± 1.30
a
38.09 ± 7.23
b
Tilled, petrocalcic
horizon
El Bruc Sandy clay 28.7 ± 3.3
b
14.1 ± 2.2
a
7.72 ± 0.12
a
0.71 ± 0.26
ab
3.28 ± 1.28
a
58.03 ± 3.97
c
Shallow and stony
Ptolemais Sandy 67.2 ± 14.6
cd
24.4 ± 13.6
ab
7.66 ± 0.20
a
1.51 ± 1.08
b
7.47 ± 14.39
a
29.19 ± 14.02
b
Mining debris, stony
Note: Values represent mean ± standard deviation. Different letters indicate significant differences at p< 0.05 between study areas for each variable.
Abbreviations: CaCO
3
, Calcium carbonate content; CEC, cation exchange capacity; EC, electric conductivity; SOC stock, Soil organic carbon stock; SOM,
Soil organic matter
CARABASSA ET AL.5

3.3 |Cocoon biodegradation
Cocoon biodegradation is an important aspect to evaluate, since its
design, which foresees using biodegradable material, aims at incorpo-
ration into the soil once its watering function is completed. At a gen-
eral level (Figure 4), the vast majority of Cocoons presented the bowl
in functional condition, but with the lid of the device sunk, damaged,
or not present (State 1). In a quarter of the installed devices, the
Cocoon began showing signs of biodegradation, such as cracks or
holes in its bowl (State 2). There were a lower percentage of
completely biodegraded Cocoons (State 4). As observed, some
Cocoons in State 1 could retain runoff and rainwater, thereby increas-
ing the water availability for the respective seedlings. In fact, this
water retention capacity 2 years after implantation, which is longer
than the expected useful life, had been utilized in the new Tifaracás
plantings (third and fourth plantings, see Table S1) for refilling the
FIGURE 2 Physiological state of all seedlings (without discriminating by plant species) after 2 years of planting with cocoon technology and
without (control) in each experimental site. Different letters show statistically significant differences (α=0.05%) [Colour figure can be viewed at
wileyonlinelibrary.com]
6CARABASSA ET AL.

FIGURE 3 Height and diameter growth between 2017 and 2019 of Quercus ilex ssp ilex and Olea europaea var. cornicabra (El Bruc),
Rosmarinus officinalis and Prunus dulcis (Sierra María). Different letters show statistically significant differences (α=0.05%). C, control; CO,
Cocoon [Colour figure can be viewed at wileyonlinelibrary.com]
CARABASSA ET AL.7

bowls during the summer, in which the retained water greatly
improved the survival ratios.
These results differed according to the study area (Figure 4).
Although State 2 occurred most frequently (except in Calabria), the
differences could still be observed locally. The presence of Cocoon
residues incorporated into the soil was very scarce or not observed in
most areas, except in El Bruc, Calabria, and Jijona. These three zones,
together with Sierra María (a large proportion of Cocoons in State 3),
were the ones with the greatest global Cocoon biodegradation. The
area with the least biodegradation was Tifaracás, with States 1 and
2 occupying 96% of the Cocoons studied, followed by Tous and
Ptolemais (Figure 4).
3.4 |Vegetation structure and diversity
The structure and floristic biodiversity data are presented in Tables S2
and S3 of Annex 4, respectively. All uncropped areas in the Iberian
Peninsula showed a positive trend in view of herbaceous and/or
woody vegetation cover and/or floristic composition. However, in
Ptolemais and Tifaracás, we could not identify differences in the
structure or composition of the vegetation with the 2017 sampling.
The characterization of the natural vegetation in Sierra María was
carried out in the temporary dry riverbank (rambla), since the almond
plantations are subjected to tillage. Table S2 shows a reduction in the
cover and height of woody plants, which were accompanied by an
increase in the cover of herbaceous plants. Regarding plant diversity,
there was a net change in 12 species (14 new species appeared and
26 were not found). Among these, we noted, on the one hand, the dis-
appearance of abundant species in 2017 such as Hordeum murinum or
Tamarix gallica, and on the other, a high frequency in the appearance
of Avena fatua and Euphorbia sp. In 2019, the vegetation cover of the
dry temporary riverbank upper zone suffered the effects of sporadic
torrential rains common in this area, which generated a flood that
washed away the vegetation.
In the El Bruc area, there was an increase (2019 vs. 2017 sam-
pling) in both herbaceous and woody covers for the three subzones of
sampling, which was accompanied by an increased average height of
both types of vegetation (Table S2). This increased plant cover was
also accompanied by increased species richness. With respect to the
inventories of 2017, in stony and shallow soils, some Asteraceae
appeared abundant (Centaurea scabiosa ssp. scabiosa,Helichrysum
stoechas, and Scorzonera angustifolia) and grasses, such as Brachy-
podium phoenicoides, increased in abundance, which eventually
became the dominant species in this area. In general, Rosaceae plants
(Amelanchier ovalis,Rosa canina, etc.) and Fabaceae also increased. In
agricultural soils that are deeper and finer textured, the trend was
very similar, but with some differences. In these soils, Asteraceae
FIGURE 4 Cocoon's degradation State after 2–2.5 years installed at field. Stage 1: Cocoon OK: With or without shelter, but with lid; Stage 2:
Lid collapsed but bowl apparently in good state (without cracks, holes); Stage 3: Bowl with signs of degradation (cracks, holes); Stage 4: Highly
degraded bowl (almost incorporated into soil) [Colour figure can be viewed at wileyonlinelibrary.com]
8CARABASSA ET AL.

showed a reduced abundance, which became testimonial species,
while the Rubiaceae like Galium lucidum and Rubia peregrina appeared.
As in the previous area, the Fabaceae, in particular Dorycnium pen-
thaphyllum, presented great abundance, and several species of grasses
appeared albeit with low abundance. In addition, Helianthemum
syriacum and Rosmarinus officinalis, abundant plants in neighbouring
areas, which were absent in 2017, appeared with high frequency
in 2019.
In the Jijona and Tous areas, there was also a tendency of increas-
ing vegetation cover of both woody and herbaceous species. More-
over, in Jijona, for woody species, the trend of cover increment was
accompanied by an increase in the average height of the plants. How-
ever, for the herbaceous species, the average height scarcely
increased when compared with 2017. In Tous, there is an increase in
both the cover of woody and herbaceous species. However, this gain
was not accompanied by an increase in average height, which
remained stable. Regarding floristic diversity, both areas remained
quite stable between 2017 and 2019.
3.5 |Plant competition evaluation
With respect to the data collected from the vegetation surrounding
the seedlings in the different study sites (Table 3), we could observe
two different tendencies. In some areas of El Bruc and Jijona, we see
a pattern of higher biomass weight with greater cover in controls. In
the driest areas, such as Tifaracás, or even in areas experiencing simi-
lar annual rainfall like Tous, we could see a greater development of
vegetation around Cocoons.
4|DISCUSSION
Overall, significant differences were found between seedlings planted
with Cocoons and controls. Seedling mortality in Cocoons was close to
40%, while in the control group reached 60%. In addition to this moder-
ate improvement in survival, surviving plants had a better physiological
state when Cocoon was used. These differences could be attributed to
nutrient uptake being highly dependent on water availability in arid and
semiarid environments (Maestre et al., 2005; Powers & Reynolds, 1999).
By providing water to the planting sites using the Cocoon device, the
plants would be able to overcome or reduce this limitation and make
better use of available nutrients, thereby increasing their survival and
growth. In fact, the Cocoon not only provides water to the plant during
the first months, but it also creates a micro catchment that allows for
greater infiltration of rainwater and accumulation of runoff around the
plant. Moreover, it not only increases the water supply, but also reduces
water losses. The plant protector reduces evapotranspiration, and the
lid and the bowl itself reduce competition with herbs, especially during
the first year. In addition, the seedlings planted with the Cocoon had a
tendency toward a more developed root system than controls did,
which resulted in a greater development of the aerial biomass for some
species.
Within the wide range of climates tested, the driest one
(Tifaracás) was also the most challenging for the Cocoon (unless
rewatered), which has a survival rate of below 30%. However, in pre-
vious restoration projects carried out in nearby areas with conven-
tional planting systems, the mortality rates were close to 100%
(CREAF, 2017a, 2017b), for which the Cocoon could be considered an
interesting alternative for planting in these arid climates. It is espe-
cially interesting, in this case, to analyze the balance between the
increase in survival due to rewatering and the consequent increase in
maintenance costs. Although implementation costs of the Cocoon
technology are initially higher than conventional methods, it is never-
theless regarded as a viable option for reducing seedling mortality
without increasing maintenance costs in the long run. In the plantings
carried out in 2018 and 2019 (see Table S1), the Cocoons were
refilled twice during the summer, which improved the survival rate
(see Annex 5). Given the results, the option of refilling the Cocoon
bowl, despite involving higher initial cost, could be an optimal solution
for planting in the drylands of the Canary Islands.
In subhumid regions, like Ptolemais, seedlings planted with
Cocoon present similar survival rates as those planted with common
techniques. Regarding Cupressus sempervirens, differences in mortality
ratios were observed among seedlings having different heights (ages)
planted with the Cocoon: 46% in 50-cm high specimens versus 24%
in 30-cm high specimens. This outcome supports the recommendation
that seedlings planted with the Cocoon should preferably be 1 year
old, as reported previously (Land Life Company, 2016). Cupressus
seedlings are sensitive to extreme weather conditions and adapt bet-
ter when they are small in size (low height) because they are able to
develop stronger root systems quickly. At this site, spring plantings
recorded higher survival rates than autumn ones due to better
weather conditions for Cupressus implantation.
In contrast, in areas with drier rainfall regimes like Jijona or El
Bruc, the differences between control and Cocoon are significant, as
the efficacy of this device is demonstrated in adverse conditions, such
as the prolonged drought and high temperatures of Summer 2017.
This is especially true in the case of El Bruc, where a 30% reduction of
annual rainfall occurred (449 mm throughout 2017), especially in the
summer (70% reduction, 58 mm for the whole season).
Regarding soil conditions, the Cocoons could not be properly
installed in shallow and stony soils, like in some parts of the Tous site.
Additionally, the strong winds at this site blew out the Cocoon shel-
ters, particularly those that were not properly installed. As a result,
the affected seedlings were exposed prematurely to high irradiation
and desiccating winds. Therefore, the Cocoon is not recommended
for Leptosols or those having a petrocalcic horizon near the surface
(IUSS Working Group WRB, 2015), such as those existing in the Sierra
María almond fields. Planting under these conditions means that the
Cocoons could not perform to their full potential, which renders this
technology less competitive compared with usual methods.
Regarding the different plant species, the high mortality in
arbequin olive tree plantings in El Bruc (both in control and Cocoons)
should be attributed to the bad quality of the seedlings, with rotting
roots, stem scars, leaf loss, and chlorosis (CREAF, 2017a, 2017b). In
CARABASSA ET AL.9

contrast, arbequin olive trees planted in Jijona had a very high survival
rate (almost 90%), with approximately 75% of seedlings planted with
Cocoon healthy and growing, probably aided by runoff collection in
the Cocoons. In general, the Cocoon yielded very good results in the
plantings in Jijona, a site with a semiarid climate (<450 mm per year)
and very poor soil with an extremely high carbonate content (77%).
The response of the holm oak (Quercus ilex) subspecies is espe-
cially remarkable. Ballota subspecies performed very well in El Bruc,
with a survival rate greater than 60% and a statistically significant
higher growth with the Cocoon. This holm oak subspecies planting
could be considered as an example of assisted migration strategy for
adapting to climate change (IPCC, 2007; Pramova et al., 2019). This
indigenous subspecies of southern Spain and northwestern Africa was
planted at higher latitude, which simulates the displacement of the
distribution area that this tree could suffer from amidst climate
change by applying the assisted migration mechanism (Sansilvestri
et al., 2016; Schwartz et al., 2012). Another plant species that
responds well to assisted migration is Tetraclinis articulata. This small
tree, which is originally an Ibero-African endemism mostly located in
northwestern Africa and has only two small natural populations in
Europe, namely in Malta and Sierra de Cartagena (SE Spain) (TGM,
2020), was planted in Jijona (outside its distribution area) with very
good results.
These assisted migration tests were also performed with typical
agricultural tree species. The cornicabra olive tree variety was planted
in El Bruc and in Jijona. This variety is typical of central and southern
Spain. They are vigorous, erect bearing, and with thick canopy density.
It adapts better to continental climates than the arbequin olive trees
or the vera variety, the latter being the variety historically used in the
area of El Bruc, which we also found in different places in the prov-
ince of Barcelona and Valencia (G
omez-Escalonilla & Vidal, 2006).
Both in El Bruc and in Jijona, the cornicabra variety responded better
than the arbequin variety. The cornicabra variety also adapted better
than Vera in El Bruc, with cornicabra seedlings showing higher survival
rates and vigor. Since water deficit (moisture stress) is the most persis-
tent environmental stress on fruit crops (Petros et al., 2020), the
Cocoon could help in installing crops in arid and semiarid lands.
Based on the data available, there is still insufficient evidence
demonstrating that the Cocoon improves the growth of seedlings in
comparison to the traditional techniques. Regarding growth in length
and weight of the roots, significant differences were found only for
cornicabra olive trees in El Bruc, which were higher in the plants with
Cocoon. However, as the available data only reflect plant growth in
2 years (2017–2019) in view of the slow evolution of vegetation in
drylands (Yu & Wang, 2018), it is possible to state that the positive
trends observed in many cases suggest that if the growth monitoring
were repeated after some years, these differences could increase
(Shackelford et al., 2018).
The structure and biodiversity of the accompanying vegetation
showed different trends for the studied areas, in terms of climatic and
biotic factors, including anthropogenic ones. Generally, in the non-
extreme Mediterranean climate sites tested, an increase in vegetation
growth and/or plant diversity had been observed. According to the
intermediate disturbance hypothesis (Connell, 1978), the increase in
biodiversity of these communities is an indicator that they are grow-
ing in complexity and maturity, as they have not reached the
TABLE 3 Herbaceous cover and plant biomass in 1 m diameter circles around control (C) and Cocoon (CO) seedlings, after 2–2.5 years of
planting in four areas
Site Subsite Treatment Herbaceous cover (%) Plant biomass (g m
2
, wet weight) Plant biomass (g m
2
, dry weight)
Tifaracás TI1 C 70 ± 35
a
77 ± 41
a
71 ± 36
a
Tifaracás TI1 CO 95 ± 5
a
95 ± 15
a
89 ± 14
a
Jijona JI1 C 19 ± 3
a
258 ± 38
a
128 ± 20
a
Jijona JI1 CO 12 ± 2
a
333 ± 141
a
134 ± 49
a
Jijona JI2 C 52 ± 11
a
596 ± 217
a
342 ± 55
a
Jijona JI2 CO 22 ± 9
b
337 ± 31
b
183 ± 23
b
Tous TO1 C 0 ± 0
a
0±0
a
0±0
a
Tous TO1 CO 8 ± 2
b
98 ± 24
b
48 ± 12
b
Tous TO2 C 3 ± 1
a
57 ± 14
a
23 ± 12
a
Tous TO2 CO 9 ± 1
b
189 ± 26
b
98 ± 12
b
El Bruc EB1 C 47 ± 3
a
178 ± 85
a
76 ± 36
a
El Bruc EB1 CO 33 ± 18
a
271 ± 111
a
132 ± 51
a
El Bruc EB2 C 93 ± 5
a
850 ± 217
a
227 ± 104
a
El Bruc EB2 CO 60 ± 8
b
612 ± 195
a
204 ± 25
a
El Bruc EB3 C 53 ± 22
a
273 ± 207
a
149 ± 93
a
El Bruc EB3 CO 31 ± 7
a
258 ± 118
a
133 ± 62
a
Ptolemais PT3 C 47 ± 7
a
773 ± 8
a
702 ± 5
a
Ptolemais PT3 CO 49 ± 10
a
912 ± 10
a
833 ± 6
a
Note: Values represent mean ± standard error. Different letters indicate significant differences at p< 0.05 between C and CO per subsite and parameter
10 CARABASSA ET AL.

intermediate degree of disturbance (or recovery), where maximum flo-
ristic richness would be produced. However, the elapsed time can be
considered rather short for proper assessment of improvements in
biodiversity.
The Tifaracás and Sierra María sites remained stable without
appreciable changes in plant biodiversity. This slow evolution could be
due to the hard environmental conditions in these areas. The restora-
tion of degraded drylands has several limitations: (1) resource (water,
nutrients, soil organic matter, propagules) levels are uniformly low;
(2) harsh microenvironmental conditions limit seedling recruitment;
and (3) animals have a greater potential for disrupting restoration
efforts in arid systems (Roundy et al., 1995). The effect of animals
impeding restoration dynamics could be clearly observed in Tifaracás,
where there is a large population of wild goats. Moreover, extreme
events are also a limitation in arid land restoration (Olsson
et al., 2019). The slight changes observed in Sierra María, with a
reduction of woody plants, are probably due to the 2018 flood that
affected the restored area.
Cocoon biodegradation is also affected by rainfall regime, increas-
ing in areas with higher rainfall values. As the lid is usually the most
exposed part of this device, it is easily susceptible to damages. Since
Cocoon biodegradation is slower in dry conditions, trees growing
under such conditions can also benefit longer from extended, and still
needed Cocoon support: more water available by Cocoon refilling
after rain events, reduced evaporation losses, and were resilient to
competing for adjacent weeds. As mentioned above, this fact became
advantageous for the planting carried out in Tifaracás in 2018, where
Cocoons were refilled to increase their survival, being an experience
with very good results. Moreover, partially biodegraded Cocoons may
still provide rainwater and be a shield against evaporation, implying an
extended water availability to support tree growth.
As a conclusion, the Cocoon technology proved useful for refor-
estation in drylands. In general, conventional plantations showed
higher mortalities and relatively lower vigour rates than planting sites
using this ecotechnology. The direct and indirect water supply, the
mitigation of plant competition around the seedling, the reduction of
evapotranspiration, and the microcatchment effect, create a suitable
set of conditions for improving the physiological state of plants, which
increases their survival. However, a case-per-case evaluation is
needed before deciding on this technology. Cocoons have an added
advantage when planting site conditions impose more drought stress
(lower rainfall, sandy textured soils with poor water retention), and/or
when tree species used are less adapted to drought stress in the early
stages of development. However, Cocoons are less competitive than
common techniques for planting in soils with high water retention
capacity, or in Mediterranean humid climates, or for planting drought-
tolerant species. Small differences in survival and growth, combined
with higher costs of planting with Cocoons, make this ecotechnology
less interesting in these situations.
ACKNOWLEDGMENTS
This study has been funded by the projects LIFE The Green Link
(Restore desertified areas with an innovative tree growing method
across the Mediterranean border to increase resilience; LIFE15
CCA/ES/000125) and LIFE Nieblas (Reforestation & Climate Change
Mitigation: tests, evaluation and transfer of innovative methods based
on fog collection; LIFE19 CCM/ES/001199), co-funded by the EU
LIFE program. The authors would like to express their gratitude to the
reviewers for their efforts in strengthening the quality of this paper.
DATA AVAILABILITY STATEMENT
The data that supports the findings of this study are available in the
supplementary material of this article.
ORCID
Vicenç Carabassa https://orcid.org/0000-0002-8728-2818
Julián Campo https://orcid.org/0000-0003-0009-138X
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SUPPORTING INFORMATION
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How to cite this article: Carabassa, V., Alba-Patiño, D., García,
S., Campo, J., Lovenstein, H., Van Leijen, G., Castro, A. J.,
González, F., Viera, G., Kourkoumpas, D.-S., Zioga, A. A.,
Papadelis, C. E., Andreu, V., Gimeno, E., Kallen, S., & Alcañiz, J.
M. (2021). Water-saving techniques for restoring desertified
lands: Some lessons from the field. Land Degradation &
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12 CARABASSA ET AL.