Short-Term Effects of Thinning Intensities on Ecosystem Carbon Stocks and Soil Properties in Black Pine Plantations in Türkiye

Abstract

Black pine plantations play a vital role in forest productivity, carbon sequestration, and ecological restoration in T & uuml;rkiye, particularly across the Central Anatolia region. This study was conducted in Akda & gbreve; National Park, a protected area in Western-Central Anatolia. Thinning treatments with four intensities - unthinned (control), light (15% basal area reduction), moderate (25%), and heavy (35%) - were applied with three replications. Tree measurements (height and DBH) as well as soil and forest floor samples were collected after thinning in 2018 and again in 2023. Tree carbon stocks were estimated using biomass equations. Forest floor characteristics (mass, C, N, P, K) and soil properties (bulk density, pH, organic matter, nutrients) were analyzed. Forest floor mass was significantly higher in light thinning (3.34 kg ha-1), while nutrient contents did not differ significantly. Thinning intensity significantly affected ecosystem carbon stocks, which were highest in the control (285.8 t ha-1), followed by light (264.3 t ha-1), moderate (218.0 t ha-1), and heavy thinning (199.8 t ha-1). Increased thinning intensity reduces carbon storage. Light and moderate thinning more effectively maintain ecosystem carbon stocks than heavy thinning, indicating their suitability for carbon-focused forest management.