Status of Native Woody Species Diversity and Soil Characteristics in an Exclosure and in Plantations ofEucalyptus globulusandCupressus lusitanicain Northern Ethiopia

Abstract

Exclusion of grazing animals and tree plantations are 2 methods that have been used for restoration of degraded lands in tropical semiarid areas. These 2 options can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents, and modifying microclimate for understory growth. We compared native woody plant diversity and soil chemical and physical attributes under exclosure and on Eucalyptus globulus (EGP) and Cupressus lusitanica (CLP) plantations. Vegetation data were collected by an inventory of stands with circular plots of 5.64 m radius, and soil samples were collected from the 4 corners and center of 20 3 20 m plots. As a result, 15 native woody plant species belonging to 13 families were recorded. Importance value index (IVI), Shannon-Wiener, Simpson's diversity, and species richness were higher in the exclosure, followed by EGP and CLP. Contents of soil organic carbon and total nitrogen showed significance difference and were highest in the exclosure, followed by CLP, EGP, and grazing land. Although the difference was not significant, an increasing trend was observed for cation exchange capacity and K + . Bulk density was highest on the grazing land, followed by EGP, CLP, and exclosure. Our results suggest that degraded land reclamation can be achieved with plantation of rapidly growing tree species as well as exclosure. However, native woody species diversity and improved soil attributes are better achieved with exclosure. Exclosures can be established interspersed strategically with single-or mixed-species plantations to facilitate restoration of native vegetation. However, it is important to conduct further research on the comparative advantage of enrichment planting of exclosures with preferred tree species or exclosures interspersed within blocks of plantation.

The potential of smallEucalyptusplantations in farmscapes to foster native woody plant diversity: local and landscape constraints

“…However, sometimes there is still poor regeneration even after excluding grazing even in forests with access to seed sources, indicating that many factors are interacting for a successful regeneration to take place (Ayenekulu et al ; Wassie et al ). Anyhow, excluding livestock is one of the main strategies in many types of restorations (Abiyu et al ; Waswa et al ). For example, in Northern Ethiopia it has become widespread with exclosures to restore native vegetation (Abiyu et al ).…”

“…Anyhow, excluding livestock is one of the main strategies in many types of restorations (Abiyu et al ; Waswa et al ). For example, in Northern Ethiopia it has become widespread with exclosures to restore native vegetation (Abiyu et al ). However, an important question is if perhaps excluding livestock from tree plantations may be a more efficient method than exclosures of open areas, as many native tree species have poor growth under sunny conditions (Wassie et al ; Teketay ).…”

The Effect of Age of Exclosures and Aspect on Aboveground Carbon of Boswellia papyrifera Dominated Woodland of Kafta Humera, Western Tigray, Northern Ethiopia

“…Vegetation sampling: Vegetation sampling for Boswellia papyrifera dominated exclosure was done on transect lines perpendicular to the contours [16]. The first sample plot was placed randomly, following systematic sampling procedure with 100 m interval between plots of the same transect [14,17].…”

Seed production, seed dispersal and seedling establishment of two afromontane tree species in and around a church forest: implications for forest restoration

“…Restoration can be achieved using tree species (active restoration), relying on natural re-colonization, or through assisted natural regeneration (passive restoration). Both approaches have been discussed as restoration options to re-vegetate the highlands of Ethiopia (Abiyu et al 2011). In the past, reforestation programs with plantation species were successful due to the fast growth of such species and their well-known management practices (Zanne and Chapman 2001;Lemenih and Teketay 2006).…”

“…In the past, reforestation programs with plantation species were successful due to the fast growth of such species and their well-known management practices (Zanne and Chapman 2001;Lemenih and Teketay 2006). While these plantations improve soil fertility (Lemma et al 2006;Abiyu et al 2011), they do not have any positive effect on biodiversity (Chazdon 2008) and therefore represent an incomplete first step of a restoration process (Stanturf et al 2001). Assisted natural regeneration and natural regeneration rank highest on the restoration ladder (sensu Chazdon 2008) with the highest ranks in biodiversity and ecosystem services at the lowest associated cost.…”