Factors influencing spatial pattern in tropical forest clearance and stand age: Implications for carbon storage and species diversity

Abstract

[1] Little is known about the tropical forests that undergo clearing as urban/built-up and other developed lands spread. This study uses remote sensing-based maps of Puerto Rico, multinomial logit models and forest inventory data to explain patterns of forest age and the age of forests cleared for land development and assess their implications for forest carbon storage and tree species richness. Accessibility, arability and spatial contagion emerge strongly as overriding spatial controls on tropical forest age, determining (1) the pattern of agricultural abandonment that permits forest regrowth, and (2) where humans leave old-growth forest remnants. Covariation between the factors patterning forest age and land development explains why most forest cleared for land development is younger. Forests are increasingly younger in more accessible and fertile areas where agriculture has lasted longer and land development is most common. All else equal, more species-rich older forest on less arable lands are somewhat less likely to undergo development, but they are still vulnerable to clearing for land development if close to urban centers and unprotected. Accounting for forest age leads to a 19% lower estimate of forest biomass cleared for land development than if forest age is not accounted for.Citation: Helmer, E. H., T. J. Brandeis, A. E. Lugo, and T. Kennaway (2008), Factors influencing spatial pattern in tropical forest clearance and stand age: Implications for carbon storage and species diversity,

Potential for forest vegetation carbon storage in Fujian Province, China, determined from forest inventories

“…Current rapid economic development and major land use and land cover changes are leading to increased conflict between population growth and demand on natural resources, and impose significant challenges in managing carbon storage through increasing forest area. Increasing carbon density through application of different tree species and age structures can be a realistic and effective strategy (Helmer et al 2008;Miguel et al 2006;Ren et al 2010). The results of this study show significantly greater effects of mature, broadleaved and state-owned forests on carbon storage than young and middle-aged, coniferous and community-owned forests.…”

Woody species diversity and forest structure from lowland to montane forest in Hyrcanian forest ecoregion

“…Forest accessibility can affect species diversity along with pattern, frequency and intensity of anthropogenic disturbances such as fuel harvesting, cutting and land-use change (Helmer et al 2008). The observed reverse hump shaped pattern of disturbance in this study ( Figure 3A) coincides with pattern of road density, both hiking and skidding roads, in the area.…”

Forest recovery in a tropical landscape: what is the relative importance of biophysical, socioeconomic, and landscape variables?

“…Previous studies have focused on identifying island-wide drivers of deforestation, through urbanization (Lopez et al 2001;Helmer 2004) and land development (Helmer et al 2008). Other studies have examined forest recovery and associated drivers at relatively small scales (e.g., single municipality, Thomlinson et al 1996;Thomlinson and Rivera 2000).…”

“…Socioeconomic changes in the island during the past 50 years have resulted in dramatic and dynamic landscape transformations (Birdsey and Weaver 1982;Rivera and Aide 1998;Pascarella et al 2000;Lopez et al 2001;Chinea 2002;Helmer et al 2002Helmer et al , 2008Grau et al 2003;Helmer 2004;Lugo and Helmer 2004;Martinuzzi et al 2007). Widespread abandonment of agriculture has led to expansion of secondary forest from less than 10% of the island area in the 1930s to about 42% in 1991.…”