Forest Inventory: Challenges, Trend, and Relevance on Conservation and Restoration of Tropical Forests

Introduction

Among the terrestrial ecosystems, tropical forest is one of the most species diverse ecosystems. It accommodates a variety of resources that supports the livelihood of local communities (Dash et al., 2009; Gandhi and Sundarapandian, 2014). Murphy and Lugo (1986) stated that about 40% of the earth's subtropical land area is dominated by closed or open forests and, out of which, 42% is covered by tropical dry forest (TDF), 33% is covered by moist forest, and 25% is covered by wet and rain forest. More than half of the TDF (54.2%) is located within South America and 45.8% is distributed among North and Central America, Africa, Eurasia, Australasia and Southeast Asia (Miles et al., 2006). TDF was defined by Baker et al. (2005) as areas within the tropics where there is a drought (<30 mm of rain per month for at least four months) during the low sun period, and a rainy season of several months duration with more than 100 mm of monthly rainfall when the sun is highest in the sky. While other tropical forests tend to have at least one period of lowered water availability in a year, tropical dry forests (TDFs) experience both prolonged and severe dry season. Tropical dry forests present well-defined phenological cycles, which make them potential proxies for the biological response to climate change and specifically to the drought effects. Since TDF are ecologically, socially and economically high valued all over the world (Mooney et al., 1995), therefore, comprehensive research studies are required to understand the ecosystem services provided by TDF (Maass et al., 2005).

In addition to being a major source of wood, tropical forest also acts as a mean of protecting the ecosystems (via regulating stream flow, watershed protection and reducing the rate of soil erosion) for tourism, Non-Timber Forest Products (NTFPs) provision and wildlife protection among many others (Zerihun and Yemir, 2013). However, tropical dry forests are under great anthropogenic pressures and require urgent management intervention to ensure the conservation and restoration of the region for sustainability. Habitat destruction, forest fragmentation, and the adverse physical and biological consequences of edge and buffer effects are some of the effects of deforestation in the tropical dry forests.

The biological diversity of tropical forests has been poorly documented, while the available data is grossly inadequate. Most species (plants, terrestrial and aquatic invertebrate, small mammals, reptiles, amphibians, among others) in the tropical forests remain undocumented (Boboye and Jimoh, 2016). Basic data and information play key role in the conservation and restoration of tropical dry forest. This information is largely obtained through forest inventories. However, inadequate or irregular inventory of tropical dry forest has resulted to paucity of information on which forest management decisions can be based. Forest inventory provides the data on condition of tropical forests for decision-making and management (such as planning, monitoring, evaluation, research, growth and yield), information on site quality and biodiversity, and timber harvest and sale plans. This study aimed at illustrating the need to carryout regular inventories of the tropical dry forests; which will help the forest managers to make informed decisions towards the conservation and restoration of economical tree species and endangered animals in the tropical regions.

The conservation and restoration of tropical dry forest have become an issue in the past decade, out of concerns of both overexploiting the resources (Powers, 2001; Monserud, 2003), and possible climate change effects (Watson et al., 1995; Schwalm and Ek, 2001). Sustainable forestry comprises a host of management regimes to maintain and enhance the long-term health and integrity of forest ecosystems and forest-dependent communities, while providing ecological, economic, social, and cultural opportunities for the benefit of present and future generations (Wilson and Wang, 1999). Therefore, the present chapter aimed at enlightening conservationists, ecologists and forest managers the need to carryout assessment or inventory of resources and flora and fauna biodiversity in the tropical forests; to ensure sustainable yield and prevent the extinction of economic tree and endangered animal species in the tropical forest ecosystems.