377
heights of 19 m were obtained at the age of 31 years.
4
It is important to know at
which age each Cedrela species form the heartwood, since the value of its wood
resides in that portion of the trunk. It has been reported the early formation of heartwood in individuals of C. angustifolia, C. balansae, and C. fissilis in plantations,
with values between 80 and 97% of the trunk at the ages between 12 and 30 years.
An alternative for small- and medium-sized producers is the development of
agroforestry systems, where high-value timber species are combined with consociated crops that allow a profitability anticipated to the cutting cycle of the trees.
Through the combination of agricultural and forestry production, the best functions
of the production of forests and food crops can be achieved. There are environmental as well as socioeconomic advantages of integrated systems over agriculture and/
or tree monocultures (Wiersum 1981). In Alto Paraná Rainforest, native forest species are combined with Ilex paraguariensis, Carica papaya, or Manihot esculenta.
In Yungas, a combination of Cedrela sp. can be carried out with native fruit species
such as Solanum betaceum, Physalis spp., and Eugenia uniflora, among others.
These species also require half shade, especially in the juvenile stages. As they
grow, openings in the canopy should be made, allowing more light to enter.
14.2 A Tiny Enemy Threatens the Cultivation of Cedrela sp.
The moth known as “Meliaceae borer,” Hypsipyla grandella Zeller, (order
Lepidoptera, family Pyralidae) is the main pest affecting cedar species, limiting
their potential in commercial forestations. It is specific of Cedrela and Swietenia
genus in the American continent. In Argentina, it affects all native cedar species.
The incidence of this pest is verified in the native forest, but in plantations (either in
blocks or enrichment strips), it becomes more notorious. It can also affect plants in
nurseries.
The main damage is caused by the larva, which destroys the main and lateral
terminal buds, drilling the apices and making tunnels in the young stems. In the
affected plants, the loss of apical dominance and its subsequent sprouts result in
numerous lateral branches and consequently malformed trees, which lose their
value for the production of wood (Fig. 14.2).
The biology of H. grandella has been well studied in Argentina (Tapia 2012). It
lays the eggs externally both on the leaves and on the stem of the host plant. Between
48 and 72 h later, the larvae are born and penetrate the axillary bud first and move
by boring the terminal non-lignified stem, the axillary bud, or the tip of the branches
(Briceño Vergara 1997). The feeding continues generally in the marrow, consuming
the bark, phloem, and leaf. Inside the plant, the insect meets between 5 and 7 larval
stages and pupa until the adult emerges, which has nocturnal habits and a wingspan
4 Personal Communication: Adrián Trápani and Miguel Gatto, Programa de Domesticación y
Mejoramiento de Especies Forestales Nativas e Introducidas para Usos de Alto Valor (PROMEF)
14 Breeding Strategy for the Cedrela Genus in Argentina
heights of 19 m were obtained at the age of 31 years.
4
It is important to know at
which age each Cedrela species form the heartwood, since the value of its wood
resides in that portion of the trunk. It has been reported the early formation of heartwood in individuals of C. angustifolia, C. balansae, and C. fissilis in plantations,
with values between 80 and 97% of the trunk at the ages between 12 and 30 years.
An alternative for small- and medium-sized producers is the development of
agroforestry systems, where high-value timber species are combined with consociated crops that allow a profitability anticipated to the cutting cycle of the trees.
Through the combination of agricultural and forestry production, the best functions
of the production of forests and food crops can be achieved. There are environmental as well as socioeconomic advantages of integrated systems over agriculture and/
or tree monocultures (Wiersum 1981). In Alto Paraná Rainforest, native forest species are combined with Ilex paraguariensis, Carica papaya, or Manihot esculenta.
In Yungas, a combination of Cedrela sp. can be carried out with native fruit species
such as Solanum betaceum, Physalis spp., and Eugenia uniflora, among others.
These species also require half shade, especially in the juvenile stages. As they
grow, openings in the canopy should be made, allowing more light to enter.
14.2 A Tiny Enemy Threatens the Cultivation of Cedrela sp.
The moth known as “Meliaceae borer,” Hypsipyla grandella Zeller, (order
Lepidoptera, family Pyralidae) is the main pest affecting cedar species, limiting
their potential in commercial forestations. It is specific of Cedrela and Swietenia
genus in the American continent. In Argentina, it affects all native cedar species.
The incidence of this pest is verified in the native forest, but in plantations (either in
blocks or enrichment strips), it becomes more notorious. It can also affect plants in
nurseries.
The main damage is caused by the larva, which destroys the main and lateral
terminal buds, drilling the apices and making tunnels in the young stems. In the
affected plants, the loss of apical dominance and its subsequent sprouts result in
numerous lateral branches and consequently malformed trees, which lose their
value for the production of wood (Fig. 14.2).
The biology of H. grandella has been well studied in Argentina (Tapia 2012). It
lays the eggs externally both on the leaves and on the stem of the host plant. Between
48 and 72 h later, the larvae are born and penetrate the axillary bud first and move
by boring the terminal non-lignified stem, the axillary bud, or the tip of the branches
(Briceño Vergara 1997). The feeding continues generally in the marrow, consuming
the bark, phloem, and leaf. Inside the plant, the insect meets between 5 and 7 larval
stages and pupa until the adult emerges, which has nocturnal habits and a wingspan
4 Personal Communication: Adrián Trápani and Miguel Gatto, Programa de Domesticación y
Mejoramiento de Especies Forestales Nativas e Introducidas para Usos de Alto Valor (PROMEF)
14 Breeding Strategy for the Cedrela Genus in Argentina