Carbon stock and sequestration potential of Ibodi monkey forest in Atakumosa, Osun state, Nigeria

Abstract

Ibodi Monkey Forest (IMF) is one of the least studied forest reserves in Nigeria. This forest is being increasingly subjected to anthropic actions. There is dearth of information on the Carbon sequestration potential of this forest. We investigated the distribution patterns of Carbon pools and overall sequestration potentials in different physiognomies in Ibodi Monkey Forest. We identified three physiognomies in IMF based on levels of anthropogenic interferences as follows: Regrowth Forest (RF), Cocoa Plantation (CP), and Tree Fallow (TF). Four plots (25 × 25 m2) were randomly selected within each physiognomy. Soil Organic Carbon (SOC) was estimated from a total of 48 soil samples collected across the three physiognomies at four depths (0–15, 15–30, 30–45, and 45–60 cm). Carbon stock in Understory Pool (UP) and Standing Litter Pool (SLP) were estimated from samples clipped at 2 cm, and standing litter which were randomly taken at 5 location within 0.5 m x 0.5 m quadrat. Diameter at Breast Height and tree height of all trees within each plot were measured. Basic wood density was determined from wood cores collected at heights 1 m and 1.4 m aboveground level from each species. Aboveground Carbon (AGC), Below Ground Carbon (BGC) were estimated using pantropical allometric equation incorporating wood density, DBH and H. Carbon Sequestration Potential (CSP) was estimated from SOC, UP, SLP, AGC and BGC, and compared across physiognomies. Total SOC up to 60 cm was 332.60 tha−1, with RF (144.34 tha−1), CP (94.37 tha−1) and TF (94.40 tha−1). Total UP was 0.02 tCha−1, in the order TF>CP>RF (0.008 tCha−1>0.007 tCha−1>0.004 tCha−1, respectively).Total SLP was 0.13 tCha−1. The trend followed RF>CP>TF (0.08 tCha−1>0.04 tCha−1>0.01 tCha−1, respectively).Total AGC stock was 57.52tCha−1. The trend followed RF>CP>TF (37.35 tCha−1>19.53 tCha−1>0.64 tCha−1 respectively). Total BGC was 13.80 tCha−1, in the order RF>CP>TF (8.96 tCha−1>4.69 tCha−1>0.15 tCha−1 respectively). The total CSP in IMF was 1481.59 tCO2eha−1. The AGC and BGC pool had CSP of 162.00 tCO2eha−1 and 50.61 tCO2eha−1 respectively and SOC pool had1219.53 tCO2eha−1 SLP had 0.48 tCO2eha−1with UP with the least figure of 0.07 tCO2eha−1. These results suggests IMF has an appreciable Carbon sequestration potential. However, the potential is being threatened by increased anthropogenic effect at the fringes of the forest.