Natural and Artificial Regeneration of Boswellia papyrifera in the Blue Nile State – Sudan

Abstract

Boswellia papyrifera is an important resource in the dryland of
the Blue Nile State. However, its population is declining due to many
biological and environmental factors. Moreover, there was hardly any
regeneration of the species in its natural habitat. The objectives of this
study were to count the new regeneration of seedlings, before and after
rainfall, to assess the viability of B. papyrifera seeds in the soil seed bank,
to detect the effect of soil types on seedlings’ growth and to determine the
optimum diameter and time of cutting. Natural regeneration surveys were
carried out in the field by counting the young seedlings at different
elevations before and after the rains. Soil samples from plots 2x2 metres
were randomly collected. B. papyrifera seeds were sown in two types of
soil mixes namely, 1 sand: 2 silt by volume; and in soil collected from the
site where B. papyrifera trees are growing. Branch cuttings of one meter
length and 4-5cm and 6-7cm in diameter, each, were taken at three
different dates, namely first of April, mid of April and first of May and
planted in the nursery. The results showed that B. papyrifera produced
plenty of seeds that were stored in the soil seed bank. However, seedlings
were almost absent after the dry season. A significant (P<0.05) difference
was found between the mean number of seedlings growing at the foot of
the mountain and the slope as compared to those growing on top of the
mountain. A significant (P≤0.05) difference was found between the mean
height of seedlings raised in the two types of soils. There was no
significant difference between the number of survived branch cuttings due
to planting date and/or branch diameter, but large diameter cuttings
showed better results. These results suggest that additional management
interventions, such as artificial regeneration, to support early seedlings