168
GZ that extends from 41° 30′ to 42° 30′ S in latitude. The South PR fits the South
GZ, excluding the population Leleque (RAPR), and is the less genetically variable
region. Finally, the Eastern PR corresponds to the Glacier Edge GZ and is made up
of some ecotone and marginal forest patches. This is the PR of smaller area and of
more difficult delimitation because of large discontinuities between patches.
Concluding, after having taken into account all the available genetic information
and geographic and operational criteria, a total of 11 OGMUs were proposed. Five
of them are provenance regions, with a clear north-south trend, and the other six,
quite smaller in area and number of tree patches, are Restricted Area Provenance
Regions. Their proposed borders and general delineation are presented in Fig. 6.8.
6.5 Domestication and Breeding Strategy
First attempts to cultivate Patagonian cypress were made in the 1950s, using plants
collected in natural seedling banks. For example, there is a still standing 700-m
2
plantation installed in 1947 in Los Alerces National Park, in which a volumetric
increment of 12.2 m
3
ha
−1
year
−1
was registered at 57 years of age (Loguercio et al.
2005). Since the last two decades, interest in using the Patagonian cypress in afforestation has focused on the ecological restoration of degraded forests (Urretavizcaya
2006). Several small- to medium-scale active restoration projects were carried out
with the species (e.g., Oudkerk et al. 2003, ~7 ha; Perdomo et al. 2009, ~50 ha)
mainly to restore forests devastated by extensive anthropogenic fires. However, its
potential use in plantations for productive purposes is still in force. Although with a
slow initial growth, it is the best adapted native tree for the semiarid ecotone between
the North Patagonian temperate forest and the steppe.
Seed availability is not a limiting factor for cultivating the species due to frequent
good production in the natural forests (approximately every other year) and their
good viability after storage, that is, seeds are expected to conserve ca. 70% germination capacity for some 5 years if dried and stowed at −18 °C (Urretavizcaya et al.
2016). Also, seed viability is commonly high: a mean emergence capacity of 76.2%
was measured in a nursery trial with 177 open-pollinated mother trees from 10
Argentine natural populations (Pastorino et al. 2013). There is a good experience in
the collection of seeds from the natural forest, and practical recommendations have
been given for this task (Pastorino et al. 2001).
The technology of seedling production has been improved in the last years,
including the development of specific ferti-irrigation protocols, successively
adjusted and optimized (Massone et al. 2018; Massone 2020). However, the species
seems to be recalcitrant to fertilizer aggregate since it responds dimly during the
entire first growing season. Only in the second season, with the root system already
well developed and colonizing the whole container, seedlings react vigorously to
the addition of fertilizers. Thus, two growing seasons are necessary to obtain a suitable plant for planting in the field (~25 cm high), and according to quality standards
A. G. Aparicio and M. J. Pastorino
GZ that extends from 41° 30′ to 42° 30′ S in latitude. The South PR fits the South
GZ, excluding the population Leleque (RAPR), and is the less genetically variable
region. Finally, the Eastern PR corresponds to the Glacier Edge GZ and is made up
of some ecotone and marginal forest patches. This is the PR of smaller area and of
more difficult delimitation because of large discontinuities between patches.
Concluding, after having taken into account all the available genetic information
and geographic and operational criteria, a total of 11 OGMUs were proposed. Five
of them are provenance regions, with a clear north-south trend, and the other six,
quite smaller in area and number of tree patches, are Restricted Area Provenance
Regions. Their proposed borders and general delineation are presented in Fig. 6.8.
6.5 Domestication and Breeding Strategy
First attempts to cultivate Patagonian cypress were made in the 1950s, using plants
collected in natural seedling banks. For example, there is a still standing 700-m
2
plantation installed in 1947 in Los Alerces National Park, in which a volumetric
increment of 12.2 m
3
ha
−1
year
−1
was registered at 57 years of age (Loguercio et al.
2005). Since the last two decades, interest in using the Patagonian cypress in afforestation has focused on the ecological restoration of degraded forests (Urretavizcaya
2006). Several small- to medium-scale active restoration projects were carried out
with the species (e.g., Oudkerk et al. 2003, ~7 ha; Perdomo et al. 2009, ~50 ha)
mainly to restore forests devastated by extensive anthropogenic fires. However, its
potential use in plantations for productive purposes is still in force. Although with a
slow initial growth, it is the best adapted native tree for the semiarid ecotone between
the North Patagonian temperate forest and the steppe.
Seed availability is not a limiting factor for cultivating the species due to frequent
good production in the natural forests (approximately every other year) and their
good viability after storage, that is, seeds are expected to conserve ca. 70% germination capacity for some 5 years if dried and stowed at −18 °C (Urretavizcaya et al.
2016). Also, seed viability is commonly high: a mean emergence capacity of 76.2%
was measured in a nursery trial with 177 open-pollinated mother trees from 10
Argentine natural populations (Pastorino et al. 2013). There is a good experience in
the collection of seeds from the natural forest, and practical recommendations have
been given for this task (Pastorino et al. 2001).
The technology of seedling production has been improved in the last years,
including the development of specific ferti-irrigation protocols, successively
adjusted and optimized (Massone et al. 2018; Massone 2020). However, the species
seems to be recalcitrant to fertilizer aggregate since it responds dimly during the
entire first growing season. Only in the second season, with the root system already
well developed and colonizing the whole container, seedlings react vigorously to
the addition of fertilizers. Thus, two growing seasons are necessary to obtain a suitable plant for planting in the field (~25 cm high), and according to quality standards
A. G. Aparicio and M. J. Pastorino