The effects of heartwood and sapwood on kraft pulp properties of Pinus nigra . and Abies bornmuelleriana Mattf. were investigated. The differences in terms of chemical composition and fiber properties between the heartwood and sapwood of these species were also examined. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2013) 37: 243-248 © TÜBİTAK doi: The effects of heartwood and sapwood on kraft pulp properties of Pinus nigra and Abies bornmuelleriana Mattf. 1, 1 Received: 2 Yasin ATAÇ *, Hüdaverdi EROĞLU Police Academy, Forensic Sciences Institute, Ankara, Turkey 2 Emeritus Professor, Ankara, Turkey Accepted: Published Online: Printed: Abstract: The effects of heartwood and sapwood on kraft pulp properties of Pinus nigra . and Abies bornmuelleriana Mattf. were investigated. The differences in terms of chemical composition and fiber properties between the heartwood and sapwood of these species were also examined. Heartwood had more holocellulose and extractive compared to sapwood. Moreover, heartwood fiber length was shorter than that of sapwood. Kraft cookings of heartwood and sapwood each species were separately done under fixed cooking conditions. The results indicated that heartwood pulp had lower pulp viscosity and total pulp yield than sapwood did. The tear index of sapwood unbeaten and beaten kraft pulp was higher than that of heartwood. However, the burst and tensile indices of heartwood unbeaten and beaten kraft pulp were higher than those of sapwood. Key words: Heartwood, kraft method, sapwood, softwood 1. Introduction When a tree stem is cut transversely, a surface appears, composed of various annual growth rings present in concentric bands. The tree consists of 6 layers from outside to inside: outer bark, inner bark, vascular cambium, sapwood, heartwood, and pith. The outer bark layer protects the softer inner bark from mechanical impact and helps to restrict water loss via evaporation. In the inner bark (phloem) layer, sugars produced by photosynthesis are translocated from the leaves to the roots or growing portions of the tree. The vascular cambium .
