Carbon storage estimation in a secondary tropical forest at CIEE Sustainability Center, Monteverde, Costa Rica

Secondary growth tropical rainforests have the potential to sequester large amounts of atmospheric carbon dioxide and as such are an important carbon sink. To evaluate a local forest, a Carbon Neutrality Program was initiated at the Council on International Educational Exchange, San Luis Campus, Monteverde, Costa Rica. The study was conducted on 50 hectares of forest classified as Premontane Wet Forest. The forest, part of the Arenal-Monteverde Protected Zone, is estimated to be aproximately 50 years old and is in the upper regions of the San Luis valley at 1100 m elevation. Assessment of the carbon stock in trees was carried out in two permanent, 1 hectare plots, 100 m by 100 m, Camino Real and Zapote. The plots were divided into 25 subplots, 20 m by 20 m totaling 400 m2 per subplot. Ten subplots in each area were studied which represented 1.6% the total surface area of the forest. All of the trees were measured within the subplots that had a diameter at breast height ≥ 10 cm and the height of 10% of the trees measured. The estimated total CO2 sequestered by the campus forest was 18,210 ton (in 2019).

What Is Secondary about Secondary Tropical Forest? Rethinking Forest Landscapes

Forests have long been locations of contestation between people and state bureaucracies, and among the knowledge frameworks of local users, foresters, ecologists, and conservationists. An essential framing of the debate has been between the categories of primary and secondary forest. In this introduction to a collection of papers that address the questions of what basis, in what sense, and for whom primary forest is ‘primary’ and secondary forest is ‘secondary,’ and whether these are useful distinctions, we outline this debate and propose a new conceptual model that departs from the simple binary of primary and secondary forests. Rather, we propose that attention should be given to the nature of the disturbance that may alter forest ecology, the forms of regeneration that follow, and the governance context within which this takes place.

Rainwater Interception Pattern of a Regenerated Secondary Tropical Forest and Oil Palm (Elaeis guineensis Jacq.) Canopies in Bintulu, Sarawak

Regenerated secondary tropical forest that resulted from logging activity and transforming of forest into oil palm (Elaeis guineesis Jacq.) estate are expected to influence the magnitude of rainfall water fraction under these plant canopies. In depth information and knowledge regarding interception pattern of rainwater are still very much lacking, especially under these canopies in tropical region. Thus, the objective of this study was to evaluate the amount of rainwater passing the regenerated secondary tropical forest and oil palm canopies, which currently cover 14.7% of the total land area in Malaysia. Three sampling sites were established, which consisted of a regenerated secondary tropical forest (RSTF), productive oil palm plantation (POP) and non-productive oil palm area (NPOP). The computed throughfall (Tfd) for RSTF, POP and NPOP were 77.2%, 91.1% and 87.4%, respectively. The stemflow (Sfd) was worked out as 0.5% (RSTF), 0.7% (POP) and 0.4% (NPOP) of gross rainfall during the study period. The findings revealed that 22.3%, 8.2% and 12.2% were intercepted by RSTF, POP and NPOP canopies, respectively and evaporated back to the atmosphere. The measured Tfd, Sfd and evaporation (Ei) were different among the three study sites even within the local environment and thus, suggesting the findings to be influenced by 1) canopy structures and trunk morphology; 2) installation of sampling material; 3) species and age of tree or trunk; and 4) local meteorological condition. The study recommends extra caution should be considered during the installation of sampling material, especially for Sfd measurement to avoid leakage and improve the accuracy of Ei values. This is important because the portion of rainwater intercepted by these canopies is a significant component, which is vital for managing forest resources, oil palm estate, as well as catchment area for sustainable clean water resources.Keywords: Interception loss, oil palm, rainfall, regenerated secondary tropical forest, Sarawak