Effects of Thinning Intensity on Litterfall Production, Soil Chemical Properties, and Fine Root Distribution in Pinus koraiensis Plantation in Republic of Korea

Abstract

It is crucial to evaluate the effects of thinning on litterfall production, soil chemical properties, and fine root dynamics when implementing thinning as a silvilcultural technique to enhance tree growth and timber yield in Pinus koraiensis plantations. Thus, we determined the 10-year effects (2007–2017) of different thinning intensities on litterfall production, soil chemical properties, and fine root biomass and necromass within a P. koraiensis plantation in South Korea. The soil chemical parameters and fine root biomass and necromass were also compared across three soil depths (0–10, 10–20, and 20–30 cm). Three thinning treatments were employed: no thinning (CON), light thinning (32% removed, LT), and heavy thinning (64% removed, HT). Results revealed that litterfall was consistent across all thinning treatments, but broadleaf species had considerably higher litterfall production at HT stands than at CON/LT stands. Soil chemical properties, except exchangeable K+, were generally lower at LT stands, particularly at a depth of 20–30 cm soil. After ten years, there was a decrease in fine root biomass and necromass with increasing soil depth. Over 80% of fine roots were found in the upper layer (0–20 cm), while very fine roots (0–1 mm) consisted mainly of 47% pine and 53% other species and were concentrated in the 0–10 cm soil depth in HT. In conclusion, different thinning intensities had diverse effects on the parameters measured within the plantation. Future studies can explore how the effects of thinning intensities on litterfall production, soil chemistry, and fine root dynamics affect species diversity, carbon storage, and understory vegetation in P. koraiensis plantations.

The Short-Term Effects of Heavy Thinning on Selected Soil Carbon Pools and Microbial Activity in a Young Aleppo Pine Forest

“…No significant differences between treatment and control were observed for WSOC ff . However, different studies report that heavy thinning, especially in the short term (i.e., the first 5 years), reduces litterfall and consequently the different organic carbon fractions [66,67]. The reduction in litterfall may be compensated by the organic debris left with the thinning treatment.…”

The Seasonal Impact of Thinning Intensities on Soil Carbon Cycling in the Lesser Xing’an Range, Northeast China

“…Reduced canopy cover increases sunlight exposure, elevates surface temperature, and potentially alters soil moisture, collectively enhancing litter decomposition [50]. Thinning alters litter's chemical composition and quantity, further affecting its decomposition [51]. Fine root decomposition is vital for soil nutrient cycling and the forest ecosystems' carbon balance.…”