Some macro-pores result from structural pores and cracks in the soil. The volume of these pores and their
continuity determines the flow of water into the soil. Soil organic matter and soil texture are two important factors
that determine soil IR. Organic matter helps to improve soil aggregation, which allows rapid water movement into
the soil. The ages of trees are correlated with litter production. Forest litter layers physically protect the soil surface
from extreme temperature and moisture, and the impacts of raindrops and erosion forces are improving IRs. Older
trees tend to produce more litter, which contributes to the build-up of organic matter. Through the decomposition
process, both litter quality and quantity influence the build-up of organic matter in the soil. Soil with a higher
organic matter content will have a higher IR [34]. In this study, the organic matter content in the site dating to 1999
was the highest and was close to that of the virgin forest because of the higher canopy density and decomposition
rate of the litter.